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Automatic cam chain tensioner help

Posted: Fri May 09, 2025 10:01 pm
by Leo44
Hi everyone, first time posting here, happy to be part of this.

I recently got my hands on a 1986 1VJ, she has a bit of mileage but nothing crazy, around 80k km (50k miles or so), starts and rides fine but she is a bit rattly, most noticeably at idle of course because the exhaust is quieter.

I read a bit in the forums and I came to the conclusion that it's either the crankshaft/countershaft nut that came loose or the timing chain that doesn't have much life left in term of stretching and the tensioner is almost fully extended.

Since I just did an oil change and I (stupidly) didn't check the crank/countershaft nuts tightness, I'd like to extend the tensionser a couple of clicks (the last 5/6 clicks don't engage by themselves as far as I've read) before taking off the clutch cover to inspect said nuts.

Is there something I need to know that might make the engine stop engining after re-assembling the tensioner or do I just have to remove the big bolt, take off the spring, remove the two smaller allen bolts, extend the tensioner and put everything back together without much worry?

Thanks in advance of any help!
Leo

Re: Automatic cam chain tensioner help

Posted: Sat May 10, 2025 8:35 am
by donnybach
Just a quick easy one, check the auto decompression isn’t too tight and keeping a valve open slightly. Can make quite a racket.

Re: Automatic cam chain tensioner help

Posted: Sat May 10, 2025 11:30 am
by Leo44
donnybach wrote: Sat May 10, 2025 8:35 am Just a quick easy one, check the auto decompression isn’t too tight and keeping a valve open slightly. Can make quite a racket.
Yeah I was also thinking about it, how would I go about checking its play and how can I adjust it?
Right now the auto decompression cable is out, would that be enough to eliminate the possibility of the decompressor sticking open?

Re: Automatic cam chain tensioner help

Posted: Sat May 10, 2025 12:49 pm
by donnybach
Yeah, the lever would be kept forward by the spring.when it’s running, you could move it backwards under finger pressure and see the difference (and feel it).

Re: Automatic cam chain tensioner help

Posted: Sun May 11, 2025 4:21 pm
by dzl
The cam chain tensioner automatically extends as your cam chain stretches. There is no manual adjustment. Remove large bolt and then remove tensioner assembly to see how far out it is. Install new cam chain on these engines if it has extended more than 3/4 of full extension.