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One Cylinder Low Compression-Post Valve Adjustment
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Author:  Mitch [ Tue Apr 16, 2002 7:27 pm ]
Post subject:  One Cylinder Low Compression-Post Valve Adjustment

I went through the valve adjustment not expecting things to be any better for my effort. Here's what I found:

All the intake adjustments were virtuually dead-on. All were between .010 and .011. The exhausts, however, were tight. The lash on the problem #5 cylinder was .014. All others were about .018. I last adjusted the valves about 50K ago. I now have about 110K. I made my current adjustments after about one hour of running time with temps stabilized. I set the lash a bit on the loose side at .011 and .021.

The result? The engine now runs smooth. No miss. The idle vacuum went up from 19 to just over 20. I did not redo the compression check, but cranking the engine with the ignition disabled does not indicate an 'easy' cylinder as it had before.

Conclusion? I believe the exhaust valves receeded. More so on #5. How long will the engine hold up? I'll stretch it for as long as I can. I went back to adding Marvel Oil to my gas. I stopped doing this after my second converter plugged up. I'd rather replace a converter than a head though. I also backed off on the spark timing a bit.

Who would have thought a valve adjustment would have been so critical?

Your thoughts?

Thanks

Mitch

m5black@aol.com

Author:  Doctor Dodge (Doug Dutra) [ Tue Apr 16, 2002 7:45 pm ]
Post subject:  Re: One Cylinder Low Compression-Post Valve Adjust

Valve adjustment is important, always something to be checked.
Use the gas additive and drive the car easy, it should last a while.
DD
Quote:
:
: I went through the valve adjustment not
: expecting things to be any better for my
: effort. Here's what I found: All the intake
: adjustments were virtually dead-on. All
: were between .010 and .011. The exhausts,
: however, were tight. The lash on the problem
: #5 cylinder was .014. All others were about
: .018. I last adjusted the valves about 50K
: ago. I now have about 110K. I made my
: current adjustments after about one hour of
: running time with temps stabilized. I set
: the lash a bit on the loose side at .011 and
: .021.
:
: The result? The engine now runs smooth. No
: miss. The idle vacuum went up from 19 to
: just over 20. I did not redo the compression
: check, but cranking the engine with the
: ignition disabled does not indicate an
: 'easy' cylinder as it had before.
:
: Conclusion? I believe the exhaust valves
: receeded. More so on #5. How long will the
: engine hold up? I'll stretch it for as long
: as I can. I went back to adding Marvel Oil
: to my gas. I stopped doing this after my
: second converter plugged up. I'd rather
: replace a converter than a head though. I
: also backed off on the spark timing a bit.
:
: Who would have thought a valve adjustment would
: have been so critical?
:
: Your thoughts?
:
: Thanks
:
: Mitch

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