Recently had a Mercury Mountaineer come in the other day with a loud knocking / ticking at RPM's above 2500.
A quick check on the internet has everyone claiming this engine needed a timing chain and or tensioner, but after removing the intake manifold and valve covers I found something totally different.
Never seen a broken camshaft oiler tube break like this! Looks almost like it was cut, but I can assure you the valve cover had not been off this engine in at least a few years given the amount of rust and grime. I also don't know if this is a regular problem with these engines, but I did a search for "4.0 SOHC Ford knock over 2500 RPM's" only to find countless threads about how others had this problem and was told it was the timing chains.
Interesting enough it would seem this design is a lot like how Mercedes Benz oiled their camshafts on their OHC engines of the 80's-90's! Not only that it would appear this Ford 4.0 SOHC engine also has similar timing chain guides, in that a nylon guide snaps over an aluminum tensioner arm.
But still, the Ford SOHC 4.0 liter engine has 4 (yes thats FOUR!) chains in this engine, plus it would seem the passengers side head drives the chain in the back of the engine! LOL! So needless to say changing out the chains on this engine will require engine removal. While there is a little slack in the front timing chain on this engine, it would appear the guides arent too bad looking. I think in this case I may just replace the oil feed tube and see if that makes the knock go away, which I am pretty sure it will. It would also save this customer 1000's in labor and parts cost.
Just wondering if anyone else has ever seen anything like this. After seeing the broken tube I am shocked it did not wipe out the camshafts, but Ford did good by using roller followers as I think that's the only thing that saved the cam from wearing the lobe down.
-- Edited by SELLC on Friday 12th of July 2013 03:50:02 AM
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What is to give light must endure burning -- Viktor Frankl
Really good pics & cool fault-finding. Fingers crossed the "knock" goes away for your customer, but you never know...The oil-pipe does differ from a MB in that ( from looking at your pics) it's not a straight piece of pipe. The "bend" in the pipe would actually act as a "stress-raiser" due to expansion & contraction from hot to cold + vibrations etc. This would also mean that the new pipe will eventually split again...Not much you can do about that ! Quite unusual for Ford to miss this during development...I did here though that now-days companies will spend $1,000,000:00 designing something, & then spend $2,000,000:00 de-designing it so it breaks LOL ! All for the modern "throw-away" market !
The MB pipes by contrast are straight, & are fixed by plastic retainers all along their length, & not bent to locate into the oil-feed holes, so they're under no stress or tension. That being said though, the plastic retainers will need to be replaced on a MB engine as soon as there's any movement at its location, as if there's movement, oil will be by-passing.( I know you already know this SELLC, but some folks might'n.)
Good luck with the chains & guides when the time comes 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.
The oil-pipe does differ from a MB in that ( from looking at your pics) it's not a straight piece of pipe. The "bend" in the pipe would actually act as a "stress-raiser" due to expansion & contraction from hot to cold + vibrations etc. This would also mean that the new pipe will eventually split again...Not much you can do about that ! Quite unusual for Ford to miss this during development...I did here though that now-days companies will spend $1,000,000:00 designing something, & then spend $2,000,000:00 de-designing it so it breaks LOL ! All for the modern "throw-away" market !
The MB pipes by contrast are straight, & are fixed by plastic retainers all along their length, & not bent to locate into the oil-feed holes, so they're under no stress or tension. That being said though, the plastic retainers will need to be replaced on a MB engine as soon as there's any movement at its location, as if there's movement, oil will be by-passing.( I know you already know this SELLC, but some folks might'n.)
Yes, as you mention Rastus, the design of the pipe is a bit different on Mercedes than the Ford 4.0 SOHC however the "Idea" where a rod that spans the camshaft with oil holes is the same.
I got a new tube from Fords, but here is the funny part/irony-
MADE IN GERMANY! LOL! No doubt PowerStroker will be in here to say that was the problem! LOL
Anyway, I installed the new oil tube and it's still thwapping away! I also found flat silver like shavings in the heads which means for all practical purposes this engine should be replaced with a used engine or rebuilt. I am thinking this oil tube broke in half and internally bled itself of pressure. If you look at the tube the end of it is sealed, so when it cracked in half I am betting that the serious oil pressure loss was enough to wipe out the engine.
It sucks, esp. since I had to half the original cost of the job because I felt bad. I had to start somewhere and this was the least expensive. I told the customer should he elect to have me pull the engine I'd apply the money thus far to future repairs on this vehicle.
-- Edited by SELLC on Wednesday 17th of July 2013 03:20:06 PM
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What is to give light must endure burning -- Viktor Frankl
Too bad about the noises not going away, & the rest of the new issues yourself & the customer now face...Looking at the new-part though, it would "seem" that the weld that secures the mounting bracket is / will be the cause of the issues now, & to come... Maybe an inspection at each service-interval is needed. Good luck & fingers crossed for a happy-ending...
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.
Interesting failure, I haven't seen a 4.0 with that specific failure, but I don't work on many of those anyway. A few years back it was common to see timing chain guides fail... And further back on the old body style (pre 02 my) there was a recall for the tensioners, but that was a long long tme ago, and I don't miss doing them.
I had one where the engine got backed up a few degrees and the timing chain tensioner twixt crank and jackshaft fell apart. Mine started out with a failed rear (right side) casette. I did it with the engine in place (trans had to come out). I should add that the original complaint had nothing to do with noise and everything to do with ran poorly. After reassembly and hearing this new noise, I assumed it was something I did or missed. Out came the trans again and NPF. Finally bit the bullet and llet it run ling enough to localize the noise.
