Timing Chains

[shoon]

When the car is idling at low RPM's it sounds like the timing chain is slapping against the valve cover... used a stethoscope and that's exactly where the noise is coming from. It's not a constant noise more or less just an intermittent tapping sound, and it is inaudible if I rev the engine. It made the noise when I first got the car, and I have since put over 10,000km on it, and the noise remains the same. It's got fresh rod bearings that I put in shortly after buying it so I doubt the noise is coming up from the bottom end.

When I had the valve covers off last, the plastic ends on the end of the tensioners were in good shape, and there was absolutely no oil gumming / sludging... everything was immaculate; so I doubt the tensioners are sticking... but I guess its possible. Also, there were NO marks on the timing covers to indicate the chain was slapping against them.


So, timing chains will eventually stretch over time right? with over 130,000 miles on the engine, should I replace my timing chains? and also... chains and sprockets are "supposed" to be replaced as pairs because the chains wear into the sprockets... if I were to replace them, would it be bad to reuse the original sprockets with new chains?

I had measured my valve lash but was unable to get my hands on shims in time when I had it apart, so it went back together. Everything was still within spec, so I wasn't too concerned at the time, but would like to do it properly this time.

So I'm thinking if I do my valve lash, rebuild the chain tensioners and slap some new chains on I should be good?

 

[Mr Anonymous]

The timing chains will almost never actually hit the front valve cover or rear head, instead they hit the composite-lined metal brackets that are opposite the tensioners.

Unless you remove the chains it's hard to get a good look at the surface of the tensioners to verify that they are in good condition. The way the chains sit in the grooves can make it difficult to see the faces of the tensioners.

Because of the roll pins that hold the tensioners together, there is a certain point beyond which the composite tensioner faces will wear where the tensioners can no longer take up enough slack in the chain.

Ultimately it's one of those things that you really have to take apart to get a good look at, and if you're going to go that far it's just as easy to have two good tensioners and chains on hand to replace them with.

 

[Joe_SHO]

does any place sell new chains and tensioners?

 

[rudedog]

Chains are usually fairly easy to come by, the tensioners however, we found a set....new..... they were $190 each.