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Having been tormented all winter by machine gun rattle every cold start, I finally got a chance today to pull the valve cover and nose around.
Some history: 1990 SPG w/ 155K miles. The chain and top guide pad was supposedly replaced when I first got the car (30K ago, 2 1/2 yrs), but I've never trusted the shop that did the work. Last winter, by coincidence I ran Saab 10w30 dino oil and the engine amazingly quiet. This winter I started with synth 10w30, but the lifters would tap for a long time. Dino 10w30 silenced the lifters but I swear the chain rattle has increased and can now hear a slight rattle/knock (lower than lifter tap) when warm too.
Anyway, v.c. off and rotated engine to tdc to check cam marks. They are equal to each other but are ever so slightly off to the intake side of the notch. Maybe 1mm from the center of the notch, but close enough that they are probably fine - especially given the less than scientific tdc mark on the clutch cover.
The question I have is regarding free play in the chain. When I rotate the engine, the chain tightens stiff but when I stop it slackens between the cam sprokets. I don't remember this slack on my previous NA 900's. I can push/pull the chain about 1/2" up and down in the span between sprokets. Wondering if this seems normal. I can imagine that's why it's slamming the guide pad so much. I put in a new pad as well, but the old one (30K old) wasn't too hard, but certainly not as plush as the new one. I couldn't inspect the guides very well, but the cam sprokets looked fine and the chain showed just contact wear but no deformation.
Also, what is the socket size for the later style tensioners? I wanted to pull that to check extension, but don't have the size deep socket. Maybe it's stuck or at full extension. Am I correct in thinking that one removes the tensioner while keeping the small bolt still on it, then removing the small bolt, resetting its extension (in), reinstalling tensioner, then installing sm. bolt and spring to tension the chain?
Sorry for the ramblings. Any insight is greatly appreciated.
burlyb
posted by 165.247.252...
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