LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

No compression...what to do?

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Old Jul 27, 2004 | 03:13 PM
  #1  
Valkyn71's Avatar
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From: Cortland NY
No compression...what to do?

After doing a compression test i found that one cylinder had no compression, and another had 1/3 of what it should.

I pulled the head on the side that had no compression, and cant really tell anything. The valve looks good and the piston looks like the others.

Im almost positive i did the test right, i even tightened down the fittings with a wrench and tried 3 times, getting like 3 pounds each time.

So if my rings were bad would i beable to tell it by looking? Cylinder wall looks alright, you can see scratches where it has been bored maybe? But it feels smooth.

Im not sure what to do?
Old Jul 27, 2004 | 04:14 PM
  #2  
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Re: No compression...what to do?

Check your valves too, then try the head gasket just in case
Old Jul 27, 2004 | 04:24 PM
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Re: No compression...what to do?

The valves are a strange white color, i think i may have found why i have no compression, the starting half threads of the sparkplug bung are stripped, so i probebly couldnt get a good enough seal.
Old Jul 27, 2004 | 04:26 PM
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Re: No compression...what to do?

Do a wet compression test. that will tell you if it's the rings. The only difference is that you squirt some oil in the spark plug hole. This will temporarily seal the rings and if you have a higher # than the dry test, it's your rings. If it's the same it's your valves, or valve seats or something else.
Old Jul 27, 2004 | 08:06 PM
  #5  
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Re: No compression...what to do?

Before you put that head back on,fill the ports with solvent and see if any major fluid leaks out of the valves.Block head up streight and fill the intakes,then turn it over and do exhaust.If no major leaks you are ready to put it back on.(A little seapage does not warrant a valve job).If major leak occures get a valve job.




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