Thread: Cam Chains
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DonE DonE is offline
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Join Date: Mar 2004
Location: Brooks, GA
Posts: 1,211
Cam Chains

Has anyone experienced their cam chains stretching to the point that their tensioners are ineffective?

I decided to replace my carrera type tensioners with mechanical tensioners when I found that when the idle arm (or each pulley arm) was fully extended to take out all slack, there was 1.5mm of space between the top of the hydraulic tensioner and the idle arm. Consequently, there was a lot of slack in the chain which gave me all the noise, especially on start up.

When I install the mechanical tensioners, and adjusted the tensioner in order to take out all the slack, both idle pulleys max'ed out and came in contact with the housings.

I've spoken to two professional engine builders and they are at a loss for an explanation except that the chain was an after-market model and stretched too far. I built the engine and installed the chain - and set the tensioners. This means that when I installed the tensioners, I had to compress the pistons and use pins just to get them to fit. When I pulled the pins, they snapped into place and provided tension.

So, I am looking at a complete engine tear-down to replace the chains. Why would the chains stretch so much?

My cams are GTII EVO's, competition valve springs, and everything else in the valve train is stock.
Old 07-27-2008, 07:12 AM
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