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Re: Why is compression so low?

The thing is... I said all cylinders have compression, but I never

> asked my buddy what the compression was. So, today I checked for > myself, and saw that the cylinders only had 90ish compression, and I'm > reasonably sure that's the reason the car won't start. The rings and > valves were all replaced, everything was torqued back to factory specs > with new gaskets blah blah... any ideas on why the compression is so > low?

Didn't read the old post, but if everything is new and good, then the timing of the valves may not be 'in phase' with the crank. As if the timing chain or belt skipped a tooth or three.

Reply to
Brent P
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Also if the engine has NEVER fired, the rings may not have seated yet. try a compression test "wet" if it is still low I'd suspect that Brent is on the right track.

nate

(alt.autos.honda deleted because teranews doesn't carry it apparently)

Reply to
Nate Nagel

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I'm with Brent - recheck the valve timing (the timing marks on the cam pulleys compared with TDC). I bet you will find it at least one tooth off.

90ish compression won't prevent an engine from starting but valve mistiming - which usually shows up as gross ignition mistiming - sure will. Be sure to pull the engine through by the crank turning only CCW or the belt will jump more.

In the original thread I saw you set the ignition timing by eyeball on the distributor, but you will need a timing light to get it close enough to run right... maybe even to run at all. First check the valve timing by the marks. When the valve timing is right the distributor should go right back where it was originally and it should be good.

Mike

Reply to
Michael Pardee

That can happen when the timing belt or chain is installed. If the timing isn't right the valves don't close at the right times to get full compression.

If the rings are no good or won't seat, that can blow the compression out too. You can try a spoonful of oil into the plug hole just before testing the compression again. If the compression comes up, you have faulty rings, if not, look to the valve timing.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

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Reply to
Mike Romain

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