DS timing chain tensioner wear clues

Don B. Cilly

Don B. Cilly

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Hey everyone. Long time no read. Well... life is... life :·/ Congrats on the move to Xenforo. I really like it.
Anyway... long story "short", I told a friend who just got a 21 engine to refurbish, hey, you know, the wear on the timing chain tensioner will give you a good clue as to how many km. the car actually has. He said, yeah? How's that? So I went looking around for the old article that explained it really well... I can't find it.

It might have been on dssmpassion.fr (which has been down a while) - I hope not - but, I can't find it.
I asked on the Italian forum, got a few answers to the tune of, don't fit newly made ones, they're crap, they wear out in no time. But no one knows where the piece explaining the ratio mm.-left/km.-run is.

Anyone has a clue?
 
I think there are too many variables in the equation to simplify it that much.

For example:
Oil change frequency.
Driving habits.... rpm range.
Accessories driven of the camshaft, ie BVH or BVM, aircon etc.
Unknown previous new chains.

There might be a good reason why you can't find such information.
 
Timing Chain wear. Take off distributor cap, turn the crankshaft, clockwise. When rotor starts moving, stop and mark. Turn the crankshaft, counterclockwise, until the rotor moves. Mark again, and see how many degrees the crankshaft moved. If more than 10 degrees you have worn components, tensioner, gears. Timing chains also wear at pins and rollers and get longer. Compare new with old.
Old V12 Jags suffered from this really badly
 
On long stroke Dees you can hear the chain hit the cover during acceleration when it needs replacing.
Short stroke with a tensioner......
You can assume it needs replacing within 200k km of the last new one.
It's not a huge job.
If you are familiar with the process, you can remove engine/ trans unit in about 4 hours, replace chain/tensioner in 30mins, refit the lump in another 4 hours.
Total 1 day......
However while you are in there you will find 17 other things to fix or replace, and allowing 1 month to get the bits......
It'll be a 5 week job.
 
Buttercup said:
On long stroke Dees you can hear the chain hit the cover during acceleration when it needs replacing.
Short stroke with a tensioner......
You can assume it needs replacing within 200k km of the last new one.
It's not a huge job.
If you are familiar with the process, you can remove engine/ trans unit in about 4 hours, replace chain/tensioner in 30mins, refit the lump in another 4 hours.
Total 1 day......
However while you are in there you will find 17 other things to fix or replace, and allowing 1 month to get the bits......
It'll be a 5 week job.
Click to expand...
There is considerable wisdom/experience in THAT statement
 
Er, well. I'm not talking about the chain itself, but the tensioner. How much it is worn.
Obviously, it would indicate how long it ran on that particular chain - on that tensioner actually, and it would not be a precise indication, just an educated guess.

I was just wondering whether anyone here had come across the article.
 
I just found it, actually :deal:
So it's roughly one mm. for 10K clicks.
And the measure is not of the wear itself, but of how much the spring pushes it out.
Obviously a vague indication, but one nonetheless. :approve:

km6__550px.JPG
 
I don't believe it!
1mm per 10k
= 20mm per 200k.
It's just not possible.
I would have approximated maybe one third of that..... 7mm per 200k........ ish.

But it raises the question......

Why bother?
 
Yeah, well, very roughly :)
He says, an engine with 165K had 10 mm. +... and it would hardly start at zero... . so, maybe, between half and one mm. :cool:
 
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