Timing chain and/or tensioner.

[tom7035]

Expert help required please. Now that I've got everything working which didn't before, I'm now thinking of some preventative maintenance.
I notice a regular 'clacking' noise, only at low idle revs, which seems to emanate from the area right at the front/top of the engine. Not the heavy 'clicking' of a faulty hydraulic tappet, but a 'clacking' (best way I can think to describe it - it's exactly like the noise knackered centrifugal weights made in a old worn dizzy). It disappears on the slightest touch of throttle. I suspect a timing chain or tensioner issue but I'm open to suggestions.
If it is a timing chain fault, is it an endless chain or is there a removeable link? If the latter, can the chain therefore be replaced without removal of the front timing cover, by threading it down over the sprockets from the top, or is this wishful thinking!?
On the tensioner issue, is this accessed from outside the engine block or is it internal? For some strange reason my book does not make this clear, nor does it make any reference to chain renewal.
Your thoughts and advice would be greatly appreciated.
Cheers, Tom.

 

[tom7035]

Found the tensioner, external. Decided to remove and replace it & see whether it makes a difference. Would still appreciate advice regarding the chain though, just in case.
Thanks, Tom.

 

[TimN]

It's easy enough to see if the car has been fitted with a split link chain. Just rotate the crank twice through 360 degrees. If not then you will have to split the chain with a chain spliter. Feed the new chain around the sprockets by temporarily.

Not sure what engine your fitted with but some of them have a cover which extends over the camchain. It isn't that greater job to take it off and fit a chain.

 

[tom7035]

It's easy enough to see if the car has been fitted with a split link chain. Just rotate the crank twice through 360 degrees. If not then you will have to split the chain with a chain spliter. Feed the new chain around the sprockets by temporarily.

Not sure what engine your fitted with but some of them have a cover which extends over the camchain. It isn't that greater job to take it off and fit a chain.

Hi Tim. Thanks for your input, but there seem to be a bit missing from your instructions.
My engine is the 1998cc 111 16V job.
Cheers, Tom.

 

[tom7035]

Solved.

Would you believe it! 'Clacking' sound was nothing more than a loose air duct into the air filter! (The short fishtail bit which clips into another plastic panel at side of the rad.)
It was so 'regular' at low idle speed I was convinced it was an engine thing.
Why do I always look for the complicated and expensive explanations first?!

 

[shirubaby]

Is a split link chain a good option when replacing the timing chain. My mechanic seems to think it might be a bad idea to use the 'new chain on old chain feed through mechanism' that is commonly described in forums. For example:
http://www.mercedesshop.com/Wikka/M117TimingChain

He thinks a split link might be a big weak point.
Not that i dont trust him (he's an honest chap), but...

Any opinions?

Shiru

 

[television]

Is a split link chain a good option when replacing the timing chain. My mechanic seems to think it might be a bad idea to use the 'new chain on old chain feed through mechanism' that is commonly described in forums. For example:
http://www.mercedesshop.com/Wikka/M117TimingChain

He thinks a split link might be a big weak point.
Not that i dont trust him (he's an honest chap), but...

Any opinions?

Shiru

I think that all timing chains in the world are still made by reynolds, they have only made metric chains from 1905. many years ago rebuilding a Masserati Ghibli I could have bought an Masserati chain for £380 or 125 links of reynolds for £27 + joiner, have done the same with Hi spec Alfa's and many XJ6's.

Re threading the chain through, Bad idea, what do you do about setting up the guides.

Malcolm

 

[shirubaby]

Re threading the chain through, Bad idea, what do you do about setting up the guides.

Malcolm

You mean guide rails? I thought there is no adjustment on them. Unless of course they are worn, then the whole lot has to come off...so bang goes the method of threading through the chain.

But I guess It's likely that the guide rails will be worn before the chain.:-(

P.S. this is not an issue for me just yet, as having had a look at my rails and chain, they seem to be in good order.

 

[tom7035]

Shiru, don't become paranoid about your chain. Unless it's clattering like a tin of nails, forget it - it will very problably outlive the engine!
I once had a crankshaft shear at the front pulley but I don't worry about that happening again every day!
I'm of the opinion people have only started worrying about timing chains since the introduction of these stupid (IMO) toothed belt systems!