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Post Info TOPIC: What does a stock 560 SEL do in the 1/4 mile?


FAR BEYOND DRIVEN

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RE: What does a stock 560 SEL do in the 1/4 mile?


Yo folks,

I was reading through all of the blurb that's been posted here ( yeah, mainly by me LOL !), and realized that SELLC has always reaffirmed or "set it straight" when needed, plus placed things into like a current-stand perspective. I know forsure that qt. " Technology, through evolution, is the mother of all horse-power...", especially now-days where often (believe it or not ), the quest for horsepower still exists, but sadly, has moved from the top priority of a car manufacturers list, so that all af todays "legislative" requirements are adheard to first off.
There are always going to be sneaky-peaks at prototype cars and what-not, but I thought it even more sad when I realized that the "hey-day" for cars ( and motorcycles ) actually happened way back in the 1920's &1930's...

I'm not sure if they'd used (or discovered) nitous back then, but man they were doing things that we still try to replicate to this day ! Probably the best way for me to explain what I'm trying to say is to get you guys to check out the specs of the Mercedes Benz W125 from 1938....A 12 cylinder, 5.5ltr Supercharged engine, producing 736HP, and capable of over 268mph...This is a car that would give the W16 Bugatti run for its money ! LOL !

Cheers,

Rastus

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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



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Hey Rastaman,

 

here's a good article for you to read. It's from issue #1 of the brand new English magazine called "Classic Mercedes."

 Most amusing thing about the article is at the end, where Wax talks about the time I hosted him at the 2001 M-100 Group gathering in Portland, OR (the article mis-quotes it as "Parkland, Oregon) where I used to live. We rented out the entire Portland International Raceway track for an entire day (total cost was like $9,000), so we had a full day of both quarter-mile running and hot laps. All to ourselves. It was awesome.

The story that Wax describes about the track manager (a guy by the name of Mark Wigginton, who now writes for Sports Car Market magazine) being all freaked out and upset about Waxenberger's track antics (much of it in MY 6.3, I might add, with me hanging on for dear life in the passenger seat), is all 100% true. I was the person (as the overall event host) who Mark was complaining TO. And he indeed gave Wax a checkered flag at the end of the day to sign. I witnessed all of it first-hand 

Enjoy the article. If it weren't for Waxenberger creating the 6.3, none of us would be enjoying our V-8 Benzes, particularly the sleeper sedans like the 500E, AMG E55 etc.....

let me know what you think. I cut my Benz teeth on the big-block M100 engine, of 6.3 liters, which was MB's first-ever V-8 and was produced from 1963-1981. It was only ever used in 3 cars.

 



-- Edited by gerryvz on Friday 7th of September 2012 12:06:11 AM

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FAR BEYOND DRIVEN

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Hello gerryvz,

Thanks heaps for the chance to read the article ! I reckon you'd be still laughing at what was said about sliding at high speed around the circuit....In your car !!! It must be a highlight in your life to have had your car driven around a race-track, by the man who ultimately made it !!! - Very lucky indeed !!! Do you still have the car ? These 6.3's just ooze class all over the place I think, still appeal in a BIG - WAY !

It's also really good that you went all out to not only hire the race-track for the day, but to send the invitation to Mr.Waxenberger for a fun day out with the chance to drive the cars that he created, in the good company of people who very-much appreciated his efforts. I'm sure that everyone involved would have shat-themselves when the news arrived of Wax's comming over ! I'm still laughing knowing that he must have been around 70 years young going sideways around Portland International Raceway...Then being told to slow down...Only to pick the pace back up again after a few more laps !!! This was a really cool thing to post up here mate, can't thank you enough ! I have a funny feeling that a few people on this site will more than likely be doing similar things at the same age !

Cheers,

Rastus

__________________

"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



FAR BEYOND DRIVEN

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Yo folks,

As a point of further interest...Whilst visiting my folks a little while ago, my dad brought out another one of his rare Mercedes Books, with this ones subject being the C111 prototype cars built between 1069 and 1979. Ultimately I found it fascinating to read through, and how the on-going development of this vehicle has filtered in a lot of ways to the new cars we can by today from Mercedes.
Anyhow, there were 4 different marks of this prototype vehicle that started with a 3-rotor Wankel Rotary engine, then a 4-rotor Wankel engine, followed by turbo-charged Diesel engines, with the final version being a twin-turbocharged M117 V-8 ( 4.5ltr bored out to 4.8ltr ) and producing well over the 500 hp mark...Aero-dynamics and other fascets were all incorporated into this prototype for analysis etc, and you wouldn't believe me if I told you about the fuel economy figures they were getting with the diesels, so better you investigate the C111 for yourselves. The use of plastics etc were also being considered for future applications, but the main goal as it would appear were to beat speed records etc. I'll try to "borrow" the book and post some facts up if anyone wants some "official figures", but I thought I'd see if you folks were interested first.

Cheers,

Rastus

__________________

"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



FAR BEYOND DRIVEN

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Hello Folks


In the interests of hopefully enhancing this already cool web-sites credo, especially with regards to our V-8 powered Mercedes', I figured that it was warranted, even expected, to find out about the how's and why's of Mercedes deciding to make a V-8 engine for their passenger cars, ( the M100 V-8 of 6.3ltrs was already in production exclusively for their limousine range only ). I've found bits and pieces of information that are period specific and should inform us all about the many number of considerations that had taken place, to design and develop our sublime M116 & M117 V-8's.

A number of factors influenced the choice of vee-8 configuration when design was started in 1963. A primary requirement was to provide a larger capacity power-plant for the important USA market. Also, although West German & European fiscal laws penalized heavily any size engine greater than 2.7ltrs, imported cars such as the 3.4 & 3.8ltr Jaguars were selling well to enthusiasts. Late in the development phase of the M116 it became known that German motor tax laws were likely to be changed to allow for larger capacity engines. A 3.5ltr capacity was a sure bet for the home market, without having to pay the much inflated road tax for owning it.

Having gotten around deciding the engine displacement, a V-8 design was chosen as it was felt that a 3.5ltr 6-cyl engine, with modern over-square cylinder dimensions would prove unexceptably too-long. Also the company was very much becomming even more safety conscious & realized the need to build in a crush-area ahead of the the engine which was either empty or full of "soft" components. A long engine also requires a long bonnet !

A "vee"-engine was the obvious choice. Its shape is much easier to fit in-between front suspensions than a flat-engine, & does not compromise steering-lock. Also, there is room between the cylinders and under them for exhaust system and ancillaries. 6-cylinder & "flat-crank" V-8's were studied on paper & on computer, but were discarded. The former because of its whirl-shake, & the latter because of its own variety of 2ndry cross-shake. A main consideration was that the engine should run for 50,000miles without major attention. Sections of the USA clean-air require an engine to maintain its emission characteristics for this milage. At the same time, the unit had to be economical to produce, ( for Mercedes sell for half the price in Germany when compared to elsewhere ), had to develop 200hp, & should be capable of running at full-power indefinitely.

Constant high-speed running called for low-mean-piston-speeds to minimise wear. The 65.8mm(2.59") stroke chosen resulted in a mean-maximum-piston-speed of 2,800 feet-per-minute, which was well within the capabilities of the then modern piston ring materials. For a point of comparison, a Mercedes 2.5ltr 6-cylinder engine will operate at a mean-piston-speed of 3,100 feet-per-minute, at near maximum RPM, with a road-speed of 105 mph. The 3.5ltr V-8 is geared for 126.2 mph at near maximum engine-RPM, but with the lower mean piston speed.

If cast-iron seemed like an old-fashioned material for the cylinder-block, it should be remembered that the engine was designed at a time when "maximum disillusionment" with light-alloy engines was apparent in the USA ,- ( possibly due to failures experienced at the time by Buick, Oldsmobile & other would-be manufacturers of aluminium V-8's ), where the Mercedes V-8 was also intended to be sold. Mecedes also had a number of good reasons for the choice. Cast-iron is economical to buy and manufacture, predictable and has good-wearing & sound-dampening properties. The weight penalty was 30kg when compared with aluminium, however it was thought that at least the same amount of sound-dampening material would have been required to reduce the increased noise transmission from a light-alloy block. West German noise regulations at the time required noise-measurement from the side of the car aswell as ather places, hence it was uneconomical to introduce extra sound-dampening for this purpose alone.

Regarding rigidity, cast-iron is also better in this respect than aluminium. The short-stroke also made for a compact & therefore stiff cylinder-block & crankcase unit. Every effort was made to keep size down, & therefore weight. The result was a casting that measuered only 10.5" high, & 16" wide in its machined state. These dimensions also include the crankcase wall which extends 2.6" below the crank-shaft centre-line, almost to the bottom of the crank-swing. This was to increase the beam-stiffness of the unit when a gear-box was attached. To further increase stiffness, the 5, malleable-iron main-bearing caps are eached retained by 4-bolts in-line ( *6-bolts with the later aluminium-engines ). They do a double-duty as fasteners of the bearing caps, & as ties between the crankcase walls. The caps fit into "mortise recesses" in the crankcase partition for accurate side location. The recesses also supplement the 4-fixing bolts in preventing cap-shuffle when under high-loads.

Ample water-jackets are provided right around the bores & the full depth of the cylinders. This was essential so as to get as much rejected heat as possible away from the engine when working at full-power inside a hot engine-bay, during a very hot day.

Five 64mm main-bearings support the forged & nitrided two-plane, four-throw crankshaft. With the 90-degree cylinder angle, this arrangement is free from primary & 2ndry out-of-balance forces, and provides equal firing intervals. Irrespactive of firing-order though, the exhaust pulses on each bank are irregular, & a cross-over pipe in the exhaust system was incorporated to reduce the familiar V-8 throb, & enhance exhaust flow at lower RPM's, by trying to equalize exhaust pulses through the system sequentially from each bank of cylinders. Large balance weights on the crankshaft formed on the end-webs, are drilled for final balance. Thrust is taken at the centre main-bearing, and the high-speed garter-spring lip-seal, working on the flywheel boss, retains the lube-oil at the fly-wheel end. A very-nice point is that the boss is ground with a spiral-pattern to work as a micro-groove "Archimedian" pump, that will push any stray oil back into the sump. Also, very much worth noting, is that so the main-bearing-cap-recesses and faces can be machined in 1-pass of a milling-cutter, the rear main seal is carried in a bolt-on diaphragm assy.

These compact dimensions of the engine were not achieved at the expense of an un-favourable "con-rod to stoke" ratio. On the contrary, the 135mm rods ( between centres ) provides a ratio of better than 2 to 1. Apart from reducing piston side-thrust, there is room to use a larger stroke crankshaft in conjunction with a taller cylinder-block, using the same con-rods...( This would lead to the birth of the M117 engine family ! ). The rods themselves are steel-forgings, carefully proportioned to to avoid stress-raisers, with balancing-pads at both ends. The cap dowell-bolts have knurled heads which are an interferance fit in circular recesses in the shoulders of the rods. This avoids the stress-raising notch that is usually milled across the skoulder to go with a "D" head-bolt.

Big & small-end sizes ( of the con-rod ) were 52mm & 26mm respectively. Lubrication to the fully-floating gudgeon-pins is via a drilling through the con-rods, & from oil-traps in the faces of the pistons. The Pistons are 92mm in diameter, hypereutectic, light alloy-forgings with cast-in steel anti-expansion rings. Knowing that customers were likely to drive the car flat-out from the word go, all the rings had molybdenum-sulphide inserts. 2 compression & 1 oil-scraper-ring ( 3-piece ) were fitted. The 2nd compression ring was interesting in having a recessed nose ground in the lower face, & a backing spring...

Going against the trend towards bowl-in-head pistons, the M116 was given cross-flow wedge-heads, with large squish-areas. Mercedes found that large quench areas remained hotter than smaller ones, thus reducing hydrocarbon emission out-put. The size of the vestigial combustion-chamber was virtually defined by the size of the 44mm intake valves which are inclined at a 20-degree angle from the verticle position, and work on hardened cast-iron inserts in the light-alloy cylinder-head. Inlet-throat diameter is 40mm with 38mm inlet tracts. This diameter would provide a mean air-speed of 280-feet-per-second at full-speed, which is relatively slow, & is the probable reason for the high-speed 4000 RPM at which Max. Torque is produced. However, carefull camshaft design and analysis provided a relatively flat, yet productive & strong Torque-curve, giving as much as 170ft/lb at 100RPM, and a Max. of 211 ft/lb at 4.000 RPM. ( 286Nm @ 4,000 RPM for those of us who are metricized...). Camshafts had an installed "Scleroscope Hardness" of 70-82 when new, with a wear limit ( or critical limit ) being 62. Exhaust-valves were Sodium-cooled with special attention being paid to water-cooling / flow around the valve-guides.

Mercedes preferred the valves of their over-head cam engines to be rocker operated. The trend to go shim-under-bucket would have meant costly & specialized service requirements when the service adjustment was required. The 50,000 mile minimum maintenance interval ( for emission output ) would have probably not been possible as required by the then USA clean-Air regulations. Using adjustable rockers meant that most work-shops could perform the task successfully throughout the world without the need of specialized tools / equipment. The Rocker layout has the rockers pivoting on spherical-headed adjustable posts, with the valve actuating end securely located via slotted buckets resting on top of the valve. Adjustment was carried out with the use of a feeler gauge in-between the rocker and camshaft base-circle. This layout ensured that line-contact with the cam is maintained & left the opportunity to simply convert to "Hydraulic compensating elements" at a later stage. This move would eliminate the need to adjust valve clearances due to the automatic hydraulic compensation. Each rocker weighs 80 grams, of which 28 grams is reciprocating weight.

Mercedes chose to use a single Duplex ( double-row ) timing chain rather than a belt to drive the camshafts and distributer drive gear, mainly because of the known long life of a chain. The single run duplex chain is driven by an 18-tooth sprocket on the crankshaft, & passes around 36-tooth sprockets on the camshafts, & under a 36-tooth distributor-drive-sprocket located in the vee at the front of the engine. Long rubber-coated ( back then ) steel-spring guides check lash on the drive-side of the chain, & a hydraulically-backed spring-tensioner controls / maintains the slack-side. This whole assembly is contained by a simple, die-cast alloy cover in which are formed the water-pump & distributor-drive housings.

Lubrication is provided by a gear-pump slung beneath the front main-bearing-cap & driven by a chain-reduction-gear from the front of the crankshaft. Mercedes preferred chain-drive for this application due to the high-loadings produced when using scew-gears. They only tolerated them for the distributer-drive because of its light-load. Oil is picked up from the wall of the stepped sump by a collector fitted with a specially shaped diaphragm-pick-up. It will maintain suction even when the oil is surging under 1-G cornering forces. The shallow sump design was dictated by the need to keep engine height to a minimum, that would allow the engines fitting into many-number of potentially new body / chassis designs, then, and into the future. This fact also allowed their stylists to work with a low-bonnet-line, aiding in new body design asthetics / styles.

Oil, once picked-up, is pumped to a cooler (via a damper), before being filtered & passed to the crankshaft. Separate drillings from the main-gallery, located in the angle of the vee, are taken to copper-pipes running the length of the cam-boxes, whilst feeding the camshaft bearings. The camshaft-lobes are then fed via an oil-tube secured in place to the cam-bearing-towers by clip-in plastic retainers. The camshaft-drive-chain is lubricated by oil-mist.

Cooling was straight-forward with the use of an involute-pump that was bolted to the front timing-cover. It was driven, along with the steering-pump assy via 2-drive-belts from a multi-groove pulley on the crankshaft. The viscous-fan, with a thermal-clutch, was mounted to the outer-end of the water-pump-pulley. Water was pumped first through the cylinder water-jackets, then reversed through the cylinder-heads (& intake-manifold) and on to the radiator via a temperature regulating (wax-bellowed) thermostat-valve, located in the water-pump housing. Suction was obtained from the lower-radiator hose inlet, with quick-engine-warm-up times achieved via a by-pass water-re-circulation system,when the thermostat valve was in the cosed position. This restricted water flow of the cooled / cold radiator water.

Having Bosch practically only around the corner, it was only natural for Mercedes to go to them for their electrical and petrol-injection equipment & services. The Bosch Transistorized Ignition & Electronic Fuel Injection ( "D" Jetronic ) was triggered by 2 independent sets of trigger-points located within a Bosch Distributor. - ( 1-set was used for the dwell-time of the low-current flowing in the primary-side of the ignition-coil, - ( to provide the spark-plugs with the required current to generate sparks in the old "traditional" way), & the other "bi-set " to provide a signal to the computer to initiate the fuel injection pulse-sequence...).

Induction air is drawn through a "pan-cake" style air-cleaner assy into a hollw cast-alloy vertical trunk, where the throttle-valve / butterfly is located. This inturn feeds a horizontal manifold / plenum-chamber located in the vee of the engine, from where 4 - "swan-neck" pipes each feed a pair of inlet ports. Fuel is injected through vertically mounted solenoid-controlled fuel-injectors, just upstream of the engines intake-valves. As with the earlier mechanical-fuel-injection-pumps manufactured by Bosch, ( aka M100 6.3ltr ) the injection-pulses are not exactly timed with the engines valve-timing...There are 4 - pulses to 2 - turns of the crankshaft, & each pulse injects fuel into 2 - intake tracts, that are paired or "grouped" in the order 1 & 5, 4 & 8, 6 & 3, 7 & 2. - ( this is obviousely phased the same as the ignition-system firing-sequence, though naturally timed at different crank-shaft positions ). For example, "group - 1" injection takes place for 2 - cylinders, ( 1 & 5 ) after the intake valve of No.1 cylinder has been open for 30-degrees of crankshaft rotation, with fuel being injected simultaniousely in No.5's intake-port, even though the valve is due to open after another 60-degrees of crankshaft rotation. The Injection-Systems Computer will take into account throttle-position, intake-manifold-pressure & barometric pressure, cooling water temperature and air temperature to help it determine the correct "open-time" of the fuel-injectors solenoid-valve. The temperature sensor ( since it's constantly variable ) is also utilized to activate and control the operation of what's now known as the auxillary air-valve, which provides an air-bleed in the manifold to maintain good idle-speed at the lower engine temperatures.

The virtue of this injection system is that it provdes the same job that can be had of an ideal 8-carburetor induction set-up...eg., one carburetor feeding one cylinder. Power and especially Torque outputs are very-much enhaced ( Torque potential is up to 30% better when compared to an American single- 4-barrell carburetor design feeding all 8-cylinders ) whilst emission outputs are significantly reduced.

I've tried my best to provide as much usefull information with regards to the little 3.5ltr V-8, (as it was the genesis engine of the M116 & M117 engine families), with the intention of informing everyone of how their Mercedes V-8's, (regardless of the capacity ), all started from this tiny motors humble & complicated beginnings ! This little motor ended up producing 200hp ( 147kw ) @ 5,800 RPM with a red-line at 6,300 RPM, and as already mentioned, 211ft/lb's ( 286Nm ) of Torque @ 4,000 RPM, with the capability to propell a vehicle to a top-speed of 126.2 Mph ( or if you rather about 205km/hr ). I reckon that's not too bad an effort for the mid-1960's & with a further 25 years of the engine families production life-span, & countless millions of miles now traveled by happy owners world-wide, It's gotta be worth writing about ! Long live the Benz V-8's !!!



Cheers,



Rastus









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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



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Rastus wrote:

The rods themselves are steel-forgings, carefully proportioned to to avoid stress-raisers, with balancing-pads at both ends. The cap dowell-bolts have knurled heads which are an interferance fit in circular recesses in the shoulders of the rods. This avoids the stress-raising notch that is usually milled across the skoulder to go with a "D" head-bolt.


Interesting read! But don't you think some people *cough* BW members *cough* would be confused with the statement above? Most people would think you are talking about a "Cylinder" head-bolt, when really what you are saying is the "D" shaped head of the connecting rod "Stud" (and after all isnt that what it would be called considering that it does not spin and stays fixed?). And arent these "D" studs pressed in?

But outside of that... Not a bad read... Athough I must mention that now days the old "D" studs are old school tech. Now days they use Dowel pins to center the cap with traditional hardened "Bolts" to hold the con-rod caps to the rods.

 



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FAR BEYOND DRIVEN

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Thanks SELLC,

I'm glad you liked the post, though I've got to admit, it was a l o n g one, with too much typing ! I tried to keep things to the point, but with so many bits of info here & there that I was drawing from, I guess I missed the point on one or two things ( plus typos ), so I'm glad you cleared a few things up for everyone. Thanks heaps, and I'll be trying to sort-out a proper layout for the Bosch Fuel Injection systems that we all use everyday, but it's not easy, & will take a little time. I really liked your rocker-removal thread, keep it going !

Cheers,

Rastus

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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



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Rastus wrote:

I guess I missed the point on one or two things ( plus typos ), so I'm glad you cleared a few things up for everyone.

Cheers,

Rastus


 

I was just giving you shit... It was a long post, but I had to find something to bitch about so you knew I read it all.



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A middle-aged loner on a crusade to champion the cause of the innocent, the helpless, the powerless - in a world of criminals who operate above the law.

LET'S GO BRANDON!

 



FAR BEYOND DRIVEN

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Thanks SELLC,

I'm still laughing to myself ! Your points were very valid though, & needed to be said to make life easier for everyone ! I was going to post up some photos of my little 350 motor, but wasn't sure how to attach them with this thread...I remember somewhere else on this sight that you asked for some pics from another user, but didn't get them. How do I attach some pics ?

Cheers,

Rastus

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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



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Hello folks,

Some of you people may well be really keen to freshen-up your engines, but maybe put-off by the expenses involved, plus your not knowing about other possibilities of how to go about a "quick inspection" with a "mild-freshen-up", so as to buy some time ( years ) before you have to outlay the big-bucks for an OEM re-build...This next post will be written for both this reasoning in mind, plus a few pointers about building a "good-goer" for the daily-driver, or whatever...

PREPARATION OF THE BLOCK ASSEMBLY

The efficiency with which the high pressure gases in the cylinders are turned into usefull mechanical energy depends mainly on the pistons, con-rods and and crankshaft. To be absolutely sure that no power is being wasted, we must pay careful attention to these points. A poorly prepared bottm-end can cost anywhere from 20 - 70 HP on engines as large as as those that we will be dealing with. If we were to realize the full-power potential of any particular engine, then even the "as-new" state of the engine is not up to what is required...

BORE PREPARATION

99 times out of 100 the standard piston to bore clearance is too little as far as Max HP is concerned. A great deal of power can be lost by the extra bore-friction and oil-drag. The power lost in this quater can be severly reduced if the piston-to-bore clearance is increased...But there are limits as to how much this can be increased before we start losing power due to other factors, namely piston rings not being able to function properly due to too-much clearance...Fortunately, there are "guides" that will help you in determining what clearances can be safely used, especially when PERFORMANCE demands out-weigh ENGINE LIFE. This does NOT mean that we are discussing a piston / bore life of a few thousand miles. When we apply the up-comming mathematical formulas, we can expect a bore-life of up to 25,000 miles ( this will vary of course depending on the condition of things when you start ) under normal conditions. It should also be pointed out that for a TRUE RACE ENGINE, the pistons, rings and bores a well-below-par after roughly 10,000 miles...And for a really high revving unit, this figure can be much lower.
As a first step in determining our allowable clearances, we must work out the Diameter to Length Ratio of the piston(s) being used. ie, piston length / piston diameter. Having done this, compare your result with the following table...

Length / Diameter ratio                           Clearance-per-inch

0.9/1 - 1/1                                               1.4 thou.
1.1/1 - 1.3/1                                            1.5 thou.
1.3/1 - 1.5/1                                            1.6 thou.
1.5/1 & over                                            1.7 thou.

From the above, we can establish the "clearance-per-inch" of piston diameter. When we multiply the "clearance-per-inch" by the piston diameter, we will arrive at the figure to use. To make things clear, let's use an example...Let's say we have a piston of 4.2"diameter, with a length of 4.8". The diameter to length ratio will be :

piston length/piston diameter = 4.8/4.2 = 1.143

Looking back to the table above, we find that this is mid-way between 1.1/1 & 1.3/1, so indicating that we should use a clearance of 1.5 thou. per inch of piston diameter. To arrive at the final clearance figure, we now multiply the piston diameter by the "clearance-per-inch"...So,

4.2 x 1.5 thou. = 6.3

There are always "reservations" when using formulas like this one posted - ( I mean, who the heck am I, and why should you believe me ?), however, when applied to when you have to determine if you can use your old/used road-pistons ( ring-grooves etc have checked & OK'd ) all will be fine !

Should you be using new OEM or racing / aftermarket pistons, always follow the rcommended clearances as specified by the manufacturer !

In finishing todays post, it might be worth-while to note how to go about measuring your pistons. If you have "flat-top" pistons, then the length measured will be the over-all length. Should the pistons have a raised crown, then the length is to me measured from the top-edge or deck-face of the piston, & not from the crown. When establishing the diameter of the piston, certain things must also be taken into account. Nearly all pistons are oval-ground and a great many are tapered. To establish the basic size of the piston, you must measure it at 90-degrees from the gudgeon-pin, and should it be tapered ( more than likely ), it needs to be measured at the top, middle & bottom of the thrust-face...The thrust-face starts just beneath the ring-belt.

Cheers,

Rastus



-- Edited by Rastus on Saturday 25th of May 2013 11:46:13 PM

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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together".    Dwight D.Eisenhower.



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Hello folks,

Here's the next installment for your considerations ! Remember that these next few posts are good-"guides" only, in the sence that you're not sure about how to go about things or what you're even looking for...

HONING

Having measured the piston & established it's basic size, this figure must be added to the clearance figure to arrive at the finished bore size. Once you know what size the bores should be, you can go ahead & have the block machined - ( bored or honed as required. All bores need to be honed after boring to a new size ). The honing part of the bore preparation is essential. A plain bored finish in any engine will cost you power and durability / reliability. Should the OEM specs remain unknown, have the block honed to a 15 micro-inch finish with a cross-hatch pattern of 45 degrees. This honing is very important to ensure proper function, bedding-in, & long-term dependability of your new piston rings. The consequences if not done, could also amount to the loss of 20 or more brake-horse-power, & considerably shorter piston-ring life !

There are instances when an engine need not be re-bored. Should the bores be only slightly worn, then you may find that the required bore-size as determined earlier by the formula, is such that it will "clean-up" ( via honing ) to the new size. For instance, should the formula indicate that we need a bore size 0.002" larger than standard, and the bores themselves have only worn 0.001", then honing out to the new size will be fine. Ensure that your "old-pistons" are in good-re-usable specification, especially the ring-lands. It's also very important to ensure that the Gudgeon-pins are a good fit in the piston-bosses.The normal maximum clearance will vary from engine to engine, but generally, we can say that 0.0003" ( 3-tenths of a thou.) is permissable.

RINGS

New Piston Rings should be fitted as a matter of course to each of the pistons. Follow the fitting steps as will be provided by the information-sheet that will be supplied. Note the position of each ring as required. Typically 120-degrees separation of the ring-gap from ring to ring is normal practice. A good standard ring-gap to achieve for a high-performance engine is 0.005" per inch of piston diameter. For instance, a 3.5" diameter piston should have the rings gapped at 3.5 x 0.005" = 0.017". Having gapped all the rings correctly, you can add the finishing touches by by adding a radius of say 0.005" - 0.01" to the corners of the rings gap. This will reduce the possibility of scratching / scoring the bores, as the ends of the rings are the points of highest-pressure. This will also even the tension through the ring.

Another factor to watch is the ring to piston-groove clearance. If the clearance is excessive, we get an increased amount of bore-wear & less effective sealing than desirable. The obvious effects of this show up as a reduction of power, high oil consumption and possibly even fouled spark-plugs. The last 2-points are especially relevant if the oil-control-rings are at fault.

Should the rings be too-tight in the grooves, then ring-sticking can be experienced. This can give similar results to having rings that are too-loose. The idea is that you should check the ring-to-groove clearance to determine the pistons servicability. For a compression-ring, an ideal clearance figure is between 0.002" - 0.004". This can be easily checked with the use of a feeler-gauge. 0.004" should be regarded as the upper limit for the ring-groove clearance.

In many, if not all cases, the oil-contol-ring is not-so-critical, simply because of its 3-piece design & function. The typical oil-control-ring found on most V-8, if not all high rpm / performance engines is the segmented-expander-type. With this ring assembly, little or no ring clearance will be accurately measurable since the outward pressure of the expander section holds the other 2-rings appart, & presses them against the ring-groove. This does not mean however that the oil- ring-assy should be tight in its groove. As a test, you should find that the assy moves freely in its groove. If it's too-tight, sticking will occur, hence defeating the purpose of having the ring there in the first place !

In finishing this post, always follow the OEM instructions & recommendations, but use these above guides as an insight of at least what to look-out for, & use if there's no information to follow. Also, all this measuring / adjusting /work takes a very-long time to do. However, the results of doing a job well-done are price-less !

Cheers,

Rastus



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Juicy...

smile



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Hello people,

I'll continue on with the "juice" to help keep everyone well-watered ! - LOL ...


CON-RODS

So now at this stage, we should go about checking the crank & rods for flaws & cracks...This is a job that can be tackled by your reputable Machine-Shop, & is not as expensive as you may think. If you do not have highly-stressed-parts flaw detected, & it turns out that a flaw does exist in one or more of the components, then the resultant mishap is usually "very"expensive to remedy. You could think of this flaw-detection as nearly like taking out an insurance policy.

We have to check our con-rods for truth...Bent or twisted con-rods can also be a great source of power-loss, so no gross inaccuracies can be tolerated. Firstly, the centreline of the little-end & big-end must be parallel. Any error when checked over the length of the gudgeon-pin should not be greater than 0.001". We need to be just as fussy about the amount of twist in a con-rod, even though any adverse effects are less marked than those caused by bent rods. Even so, the Maximum allowable twist should be kept below 0.0015"-0.002". Just in-case you're worrying as to how to check your rods, don't...Most motor machine shops can accurately check, & straighten your rods quite easily & inexpensively ! Should the rods be found to be badly bent or twisted, then they need to be replaced. You can assume that any rod that's out by 0.010" falls into the badly bent or twisted category. Make sure that the little-end bushes are not worn out. If they are & need replacing, this should be done before checking the alignment of the rods. The clearance for little-ends is usually around the 0.0005" mark. so if you go for this figure, you won't be far out.

CRANKSHAFT & FITTING

We're now left with the crankshaft to come under close inspection as far as the bottom-end assembly goes. Using an accurate micrometer, check the the sizes of the big-end & main bearing journals. If these prove to be worn by more than say 0.007", then a crank re-grind is called for. Whether the crank has been reground or not, new bearing shells are mandatory. Often the sizes of the bearings are stamped on the outside of the shell, so this will aid you in determining the correct size, or new required sizes if needed, should the crank be found to need grinding. ( Crankshafts are usually ground down to the next corresponding under-size bearing shell size ). A good clearance figure for the main bearing assy would be 0.002". Any more is too much and "sustained high rpm operation" could see bearing failure. However, as always, use OEM figures for accuracy of clearances, and the use of "Plastigauge" for measuring makes life that much easier.

Once you have everything sorted out, it will be time to start checking that everything is in order...Fit the main bearing-shells into the block & lightly oil the bearing face of each one. Place the crank in position, then fit & torque down No 1 main journal cap, together with its bearing. At this point, check that the crank spins freely. If does, then everything is fine. If it doesn't spin freely, then a tight bearing is indicated. Sometimes swapping bearing shells will cure any bearing tightness, but if this is not the case, then either the bearing shells, bearing housing-( block ) or crankshaft journals are incorrectly sized. In the case of miss-sized bearings or journals, the fix is easy. On the other hand, if its the block that's at fault, then this would have most likely existed since new, & the only remedy is to have the block in-line-bored.

Assuming that the crank spun freely when No 1 cap & bearings were fitted & torqued down, No 2 cap & bearing should now be fitted & torqued. Again we need to determine that the crank rotates freely, repeating this same procedure with each of the main-caps until they are all fitted. If the crank rotation gradually gets stiffer with each subsequent cap fitted, a distorted block or crank is indicated...The easiest way to determine whether or not this is the case, is to fit one cap at a time to see if the crank spins without undue resistance. If we find that each journal is free on its own, yet the crank is stiff when all the mains are torqued down, then definately something is wrong. Go back & check it all again until you find & fix the fault. Then start again...

Some of you may be wondering what should be regarded as "tight or loose" as far as crank rotation is concerned...You should be able to rotate a crank, even on the largest of engines, when a torque not exceeding 1 ft/lb is applied. Since most torque wrenches don't read down that low, another method can be used...The crank should spin freely with just you using 1-finger and a small amount of force...In fact it should almost run-away from you once it has started to spin...Alternatively, you could use your crankshaft pulley, a piece of rope, & a weight. The mass of the weight required to give us the required torque depends on the diameter of the pulley. Torque is a measure of turning force & is obtained by multiplying the applied force by the radius at which the applied force is turning about. eg, an 8" diameter pulley with a 1 lb weight attached to a piece of string that's then wound around the pulley will exert a torque of 1/3 lb/ft . ie.,4" (radius) x 1 lb = 4 lbs in = 1/3 lb. ft. From this example you can see that to exert 1 lb/ft torque, we need to attach a 3lb weight to the string.

Assuming that we're now at the point where the crank is is a satisfactory running-fit in the block, we need to carry out a similar check on the con-rod big-end journal fit. A good clearance to aim for is once again 0.002". When such a clearance exists, the rod will fall unaided by anything other than gravity from the near-vertical position to horizontal. We should now be in a good position to assemble the rods & pistons together ( probably best done for you at the machine-shop ) & then start re-assembling our "short-motor". Always remember to lube your pistons, bores and rings before assembly. Don't use too much oil on the piston rings as you may cause a hydraulic lock when trying to install them with the ring-compressor. They should slide in reasonably easily. Any resistance does indicate the possibility of too much oil or the ring compressor is not square to the block etc. If you keep tapping away in this situation, you could easily brake your new rings or crack pistons. Take your time and use plenty of patience...CRC make White Lithium Grease in a spray can that will all but eleminate this issue, and provide heaps of lubrication. (In fact, you can spray this stuff on all your internal components knowing that it will stick & stay there & not drain away into your sump ! - ( Especially if start-up day is still a while away !)

With all the bearings lubricated with light engine oil,re-torque down the main bearings & check the big-end bearings etc etc. It's a wise move also to use new big-end nuts & bolts where possible. We're now up to the Free Running Check, but we'll discuss that in the next post.


Cheers,

Rastus



-- Edited by Rastus on Tuesday 28th of May 2013 06:12:09 AM



-- Edited by Rastus on Tuesday 28th of May 2013 10:41:11 AM

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FAR BEYOND DRIVEN

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Hello people,

Let's move on to the next part of our engine assembly checking...

FREE RUNNING CHECK

Once the assembly of pistons, rods & crank into the block is completed, a "free running test" should be carried out. This is best accomplished with the front crank-bolt fitted and checking the torque needed to turn the engine over with a torque-wrench. The average torque required to turn the bottom-end-assy over should definitely not exceed 8 lb/ft per litre of engine capacity. If you've been on-the-ball & done the job very carefully, the whole assembly should turn when 4 lb/ft per litre is applied...

eg, a 560 MB V-8 displaces 5.6 litres, so let's calculate the maximun turning torque required of our bottom-end assy...

5.6 x 4 lb/ft = 22.4 lb/ft...This figure would be a very good result, & guarantees that we've done a spot-on job of assemly. ( * approx 61 cubes is = 1.0 litre )

What do you do if the turning torque for the engine is too high ? ie, in excess of 10 lb/ft per litre ? Very simple...Strip everything back down & start checking it all out again until you've determined exactly what's at fault ! This may seem a little "over-kill" but there's much more to enhancing your engine than fitting a performance cam(s), tuned exhaust, modified cyl-heads etc etc...

Suppose we have an engine of 7.0 ltrs capacity, & it has an internal friction level of 10 lb/ft per litre, which isn't an unreasonable figure for an engine in "as-new" state from the factory. The power absorbed by the friction of the crank, rods & pistons on such an engine running at 7,000 rpm would be 93.8 B.H.P. Now compare this with an otherwise identical engine which requires only 4 lb/ft per litre to rotate the crank assy...This second engine would only absorb 34.72 B.H.P.. This means that we would have nearly 60 B.H.P. extra at the fly-wheel to perform useful work on propelling the vehicle that would otherwise be lost as friction within the engine.

By using lots of patience & being very thorough, it's very likely that you can turn even your otherwise stock-engine into a very surprising performer. I would think that with the numbers posted above, & with a little thought, you can relatively easily calculate your expected targets with the engine that you actually have.

Cheers,

Rastus



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stoma wrote:

BUUUUUUUUUUUAHAAHHAHAHAHAHAHAHAHHAHAHAHAHAHA!!!!!!!!!!!!!!!!!!!!!!!! HEY GAYRRY........ HE'S TALKIN ABOUT A 560 AND NOT A 500E!!!!!!!!!!!!! LOOK AT YOU WITH YOUR CASCADE MOMENT..................... WAITING FOR THE OPPORTUNITY TO POST A VID OR PIC OF THE 500E WHEN NO ONE HERE ASKED FOR!!!!!!!!!!!!!!!!!!!! AHAHHAHAHAHAHAHAHAHAHHAHAHA!!!!!!!!!!!!!!!!!!

THOSE VIDEOS SHOW JACK SHIT.................... CAN'T SEE TIMES AND EVEN BETTER................ CAN'T TELL WHO WON!!!!!!!!!!!!!!!! WHAT A FUCKIN LOSER!!!!!!!!!!!!!! AHHAHAHAHAHHHAHAHAHAHA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! NICE TRY FAGGOT!!!!!!!!!!!!!!!!!!


 LOL

I didn't even see this post ^^^^



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Hello people,

There can be at times a lot of confusion with people about modifying cylinder-heads, and the benefits of such mods for the out-lay of dollars involved. So what's the best way do deal with these items ?...Do you recondition them yourself ? - ( you can buy all the equipment for grinding valves, fitting seats, grinding ports and installing new valve-guides etc etc) Or do you send them away for a shop to re-condition ? Or do you just buy new / reconditioned ones off-the-shelf that have been set-up ( or manufactured new ) to suit your budget or Horse-power expectations ? There's actually quite a lot more to think about even, as everyones needs will be different from one person to the next, but what still remains, is a decision about what to do with your heads ! In this next post, I'll try to put some facts up about results that have been proven on the flow-bench etc, and you might just be able to save a few bucks if you were thinking of putting something on that you don't actually need. You can do it all yourself, but probably things are best left to the pro's.

HEAD PREPARATION

Modifying cylinder-heads for high performance can be a long and tedious job, but nevertheless, one that can improve power out-put right across the rev-range of your engine. When we go looking for more power, our objective is to get the heads to "breathe" as well as possible. The more fuel and air that can be passed into the cylinders in a given time, the more resultant power will be. Unfortunately, the gas-flow characteristics of an engine are not easy to understand, and often the obvious is far from right. You would expect for instance, that the bigger the valves, the better the breathing. However, this is not always the case. In many instances, the fitting of valves which are too big does nothing but lose power. The same goes for ports, they can also be made too-big. It's always better to replace your valve guides with new ones, and new valves are always a good thing. Replace your seats as needed, though like your valves, they are made to be re-serviced where possible...

There is a definite relationship ( in the form of a ratio ) between inlet-port-area & valve-area, & for a typical 2-valve per chamber cylinder-head, that "Ratio" is normally between 0.75 - 0.85 to 1, where 1 = the size of the valve-head / seat etc. The more efficient the valve & its seat are in passing air, the greater the port size required for the best results. For instance, a typical 45-degree seat, and rough-cast ports may dictate that the ratio of the port-size here is as low as 0.7 - 1 of the valve-area. If the efficiency in the region of the valve is vastly improved by subtle reshaping of the chamber in the region around the valve-head, and by ensuring a slightly contoured venturi plus, a mandatory 3-angle valve & seat cut, then the optimum port-size ratio can go up from the previous 0.7, to near 0.85 -1 of the valve area.  Everything is "proportional" and we can only do so much with what we've got ! But a 15% improvement (on average) on air-flow just by "cleaning-up" the port & providing a 3-angle valve-job is something to open your eyes too ! Enhancing the port-area in effect means that we make the greatest use of the "momentum" of the incomming gases. If its too-small, it becomes a restriction, & if it's too large, the gas-speed is slower, thus losing any advantage to be gained by the use of its momentum. We have to remember here that once an engine is running, - even at idle, there is a "momentum" of air movement flowing into all of your cylinders, that grows as rpm increases...Your vacuum gauge indicates this... The most important part governing the breathing ability of a cylinder-head is is the area approx. 1/2" before the valve-seat, & about 1/2" after the valve-seat...It must be your objective to make it as efficient as possible within the inherant limitations of what your stuck with. Follow OEM specs with regards to the width of the valve-to-seat contact area, but 1mm is a not-un-common optimum width, with the valve normally having a 45 degree cut & the seat having a 46 degree cut.

A different set of conditions present themselves on the exhaust side. We would hope to find that the port-area on the exhaust side is larger than the valve area. Usually port areas are in the range of 0.9-1.05 of the valve area. The valve seat requirements are not nearly so critical, as the seat ( & guide ) are needed to transfer the heat away to the cooling water, so once again, OEM specs are the best to follow here. At least make sure that the width of the contact area of the valve-to-seat is 1/16" wide. ( Don't forget that it's easier for an engine to exhaust waste gasses under pressure than it is to fill with a fresh intake charge ). Any work in this area should be limited to removing any casting-dags &/ or sharp edges, though polishing can prolong the time it takes for carbon deposits to start building up again.

PORT SHAPE

There's not a lot that should be done here ( without going radical or on some experiment ), as we're pretty much stuck with what we've got. Look for consistancy of a smooth surface, gently grind / buff away any casting residuals, but do not alter the port size ! This should be done by the Pro's at the Machine shop, and usually it's done to correct intake manifold alignment and maybe to optimize gasket fit etc etc etc. However, it might be worth knowing that a round port flows around 10% better than an oval one, and up to 15% or more better than a rectangular one. Should you be lucky enough to be running a Mercedes engine, you will note that all their engines have round ports !

COMBUSTION CHAMBERS

It's not advised to go modifying anything here, except to say that you need to remove all sharp edges, points & dags to prevent the possibility of hot-spots & detonation, & that all your chambers need to be equal in volume...Better to let the specialists tackle this ! Any other mods are usually associated with the removal of metal from the chamber when over-sized valves have been fitted ( if found necessary to have ) so as to reduce the negative attributes of what's called valve-shrouding. Valve shrouding is where the positves of fitting over-sized valves are turned negative by the valve being too close to the combustion chamber wall when opened, thereby reducing the flow of intake charge, and taking away any hopes of power improvement. Once again, leave it to the pro's.

 

Cheers,

 

Rastus



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FAR BEYOND DRIVEN

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Hello people,

At this stage of the "posting", it 's probably a good time to simplify the things that we should be looking out for, and explain why all this is possible for you to do yourself, especially if you actually own a Mercedes.

* By determining the current state of your bores & pistons, you can re-fresh ( & improve ) the performance & extend the operating life of your engine at a very much reduced cost.

* Ensuring that all the measurements of your crankshaft & bearings are correct is an insurance policy to the long-term continued performance & reliability of your bottom end.

* The free running check of your bottom-end tells you the potential of how much "hidden"extra power you've released to be transfered to your fly-wheel by identifying, rectifying, & then improving on the assemly. Don't have your oil-seals in place when doing these checks !

* Your engine's bottom end is now possibly & quite likely more reliable than the day it first left the factory.

* Reduced friction = more power + more reliability + longer component life.

* Your Mercedes Benz cylinder heads are already pretty much optimized from the factory and are in great shape ! In reality there's very little to do except replace the normal wearing parts if needed, and machine the valves and seats back up to the standard 3-angles as from the factory. When this work has been carried out by a work-shop, pull the valves back out of the head & make sure they've done what you've asked for ! You'll find that the cost of reconditioning your heads will be by far the most expensive part of this freshen up, so it's worth knowing that you got what you paid for !

* Mercedes engines are made already to a very very high standard, which does make life for us heaps better, since we don't have to pay for the extra special things to get modified because they don't need to be ! However, it is a production assembly line, & this means that the clock is the real boss ! You yourself can take as much time as you like, & can possibly improve on something already very excellent.

* Remember to blow out every hole in the block with compressed-air to remove any stray pieces of metal that may be in there after any machining has been carried out.

* When you finally get around for that final re-assembly of the bottom-end, apply as much oil as possible into every hole you find in your crank, block & rods, to ensure that your new parts are not waiting for oil when you go to first start-up. Expect to be able to put well over a litre just into these holes etc to fill them up. Also, disconnect your ignition on first start-up until you have oil-pressure reading on your gauge whilst you crank. Once your oil-pressure is established, then you can start your engine !

* Your oil-pump is probably the most important component in your engine assemly. Do I need to explain what's needed here ? Make sure that it's well primed on assembly. A light smear of vaseline or light moly-grease or engine honey (STP) on the gear-teeth and housing will guarantee suction & pressure when you first go to crank.


All the best and enjoy yourselves !

Rastus



-- Edited by Rastus on Thursday 30th of May 2013 11:23:29 PM



-- Edited by Rastus on Thursday 30th of May 2013 11:24:38 PM

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FAR BEYOND DRIVEN

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Yo people,

We always hear things about cranks needing machining, rods needing aligning etc etc. But how & why do things wear, & what is actually done to repair them ? If I have your interest, read on....

CRANKSHAFT WEAR

It should be understood that there are forces applied to your crankshaft-journals ( big-end & mains ) that are much "heavier" at some points of rotation than others. To elaborate, the force produced during combustion is several-times as strong as when compared to the compression-stroke. Also, the power-stroke applies the force pretty-much always at the same spot of the journal. There is also the action of centrifugal force resulting from the rotation of the crankshaft with its con-rods & pistons. The result is an out-of-round condition forms on the crankshaft journals & crank-pins.

If a con-rod is bent, or is out of alignment, it will tend to wear the crank-journal in a tapered fashion, - that is, more at one-end of the bearing surface-face than the other end. Also, any twisting of the engine crank-case or any excessive vibration of the crankshaft will tend to cause the main-journals to wear in a tapered form.

Should abrasive material get into the oil, the wear may be unequal, more at one-bearing or more at one-spot of the bearing depending on which bearing, & where on the bearing the abrasive enters in greatest quantities. Bearings seldom wear equally for these & other reasons. One bearing may operate with a smaller volume of oil than another-one. Likewise, due to its location in the engine, may operate at a higher temperature than the others. All of these things contribute to unequal wear on your crankshaft journals.

If a con-rod journal has even the least taper, or signs of a flat-spot, it simply cannot be used. Typically, such a condition would actually cause an increase in oil-consumption, audible knocking, excess damage etc, so hence, machining of the journal(s) would need to be completed. Due to close tolerances in the bearings, a "sprung" crankshaft simply cannot be used. The main-bearings must fit the crankshaft journals all around the circumference with only the correct amount of clearance for a film of lubricating oil. If the bearing journal is scored or other than completely round, it cannot be used until its machined or replaced.

As further food-for thought, you may ask why typically the upper bearing in your con-rod tends to wear a little more than the lower half, it's because it's subjected to more continual forces than the lower half...In fact the lower half only sees greater loading during the intake stroke...This may also explain to some of you why often you see an oil-groove for the upper con-rod bearing shell, & not the lower.

More next time...

Cheers,

Rastus

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FAR BEYOND DRIVEN

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Hello folks,

So since we now know a little more about our crankshafts & its bearings, what do the machine-shop specialists actually do to find other defects, & how do they go about repairing the shaft back into a service-able state ?

CRANKSHAFT INSPECTION & REPAIR

As engine crankshafts are usually large & expensive parts, it's often a better option to have them repaired where possible than replaced. Before any extensive work is carried out however, it is well to have the shaft inspected / checked by a specialist with proper magnetic, or chemical equipment to ensure that there are no invisible cracks in it.

Magnetic indicators = Where the use of a fine metal powder is applied to the shaft / journals, then when magnetized, the powder localizes within the cracks to reveal the damage.

Chemical indicators = Where the application of a special chemical to the shaft / journals will reveal the invisible cracks when viewed with special glasses & UV light.

Our crankshafts are exposed / subjected to terrific vibration & stress, & may develop tiny cracks, particularly at or near the ends of the con-rod throws, or at the ends of the main bearing journals. Occasionally, an invisible crack may develop near the oil-feed holes in the shaft.

If the crankshaft is sound, & the journals are worn slightly tapered or out-of-round, the shaft journals can be re-ground & under-size bearings fitted. Should the shaft be badly damaged, it is possible ( though NOT recommended for high-performance use ) to restore the journal by using a special technique where-by metal can actually be "sprayed" onto the shaft until it's over-size, & then reground back to specification.

Cheers,

Rastus

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FUCK MAN!!!!!!!!!!! ALL THAT BULLSHIT WRITTEN BY THAT PUNK ASS BITCH RASTUS PUT ME TO SLEEP!!!!!!!!!!! FUCKIN CANT MAKE IT PAST 3 LINES BEFORE MY EYES GET ALL HEAVY!!!!!!!!!!

QUIT POSTIN SHIT RASTUS BETTER YET.GET THE FUCK OUT OF THIS FORUM CAWKSUCKKAAAAA!!!!!!!!!!!!!!!!!!!!!!!!!

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FAR BEYOND DRIVEN

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LOL,

Oh well RSJ, sometimes it's better to sleep things off so they make a little more sense in the morning ! I'm only trying to get across to folks that there's more to your car & it's engine than turning the key & driving away. And some people actually do like to know more about what goes on inside their engine, so why not open the door to more information ? The www is full of sites that read like sales-type brochures, that really offer no answers to questions people might have about things relating to their cars, only false numbers & comparisons against the competition etc etc. At least what I post tries to validate the need for & skills required to be a Tradesman, so that's why you have to pay when things break, as all things eventually do.

Cheers,

Rastus

PS Happy Christmas & new year !

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