camshaft bearing clearance or wear ?

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carl - 10 Jul 2005 22:14 GMT

Hi all,

Thanks to all who replied to my other post. I fear I have another question.

When checking valve clearances, I noticed that the valves farthest from the
distribution belt are influencing one another. That is, the inlet valve
clearance becomes higher when the outlet valve is open. This is about
2/1000th of an inch. The problem is also present on the third cylinder,
albeit much less so. And even slighter on cylinder 2.

Is this just bearing clearance dissappearing under the valve spring load ?
It seems a lot of interaction to me, given that it is about half the
difference between hot and cold valve clearance. If so, the valves near the
distribution belt will always be given fewer clearance, because it is always
under load when adjusting.

Or can this be something else troubling me ? Could it be wear ?

Thanks in advance,

Carl

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twillmon@cybermesa.net - 11 Jul 2005 01:43 GMT

>Newsgroups: rec.autos.tech
>When checking valve clearances, I noticed that the valves farthest
>from the distribution belt are influencing one another. That is,
>the inlet valve clearance becomes higher when the outlet valve is
>open. This is about 2/1000th of an inch. The problem is also
>present on the third cylinder, albeit much less so. And even
>slighter on cylinder 2.
Ages ago (1963 VW) I noticed a similar inconsistency in my valve
settings - adjust, then check and they would be different. My
solution was to disconnect power to the ignition and crank the engine
with the starter for a few seconds before doing the adjustment. My
theory was that the cranking built up oil pressure and centered the
cam in its bearings. Worked.

(Adjusted cold, after sitting over night.)

You appear to have an overhead cam with belt drive; I expect the belt
tension is pulling that end of the cam down into its bearing, making
its position more stable. Not a problem I've noticed on my old
Hondas.

Tom Willmon
near Mountainair, (mid) New Mexico, USA

Why do we park on driveways and drive on Parkways?

Net-Tamer V 1.12.0 - Registered

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carl - 11 Jul 2005 10:11 GMT

Hello,

Thanks, and I'm happy for you it worked. But I did crank the engine around
without ignition, some 6 seconds, and still the same problem occurred.

I adjusted the valves now in a position when all load is away from the
cylinder I'm busy with ( rockers on adjacent cylinders as well ) but I
suspect the problem is still there. I wonder whether it is wear or something
else. As the engine has had some problems, I don't exclude anything.

Thanks again,

Carl

> >Newsgroups: rec.autos.tech
> >When checking valve clearances, I noticed that the valves farthest
[quoted text clipped - 23 lines]
>
> Net-Tamer V 1.12.0 - Registered

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