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no compression

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Old May 17, 2010 | 08:26 PM
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Default no compression

I bought this 93 xj 2 wheel drive for parts. I thought I would tinker with it and see what was wrong. It has no compression in all 4 cylinders, I didn't check the other two it started raining. I verified that it is in time so timing chain has not jumped or broken. There is no water in the oil.

I don't think head gasket would blow that bad. Anybody got any clues?
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Old May 17, 2010 | 09:17 PM
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How are you checking compression? With an accurate gauge/tester?
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Old May 17, 2010 | 09:33 PM
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Originally Posted by djb383
How are you checking compression? With an accurate gauge/tester?
yes, it also spins over like it has no plugs in it.
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Old May 18, 2010 | 07:26 AM
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what do you know about this engine? check the head bolts mabye someone started to change head gasket and said screw it, also take the tstat out and crank it see if it bubbles out the radiator.
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Old May 18, 2010 | 09:07 AM
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Originally Posted by 1fast68
yes, it also spins over like it has no plugs in it.
It's not supposed to have the plugs in it when doing a compression check......only the cylinder being tested is plugged. When cranking the engine over it should be "hissing" like a steam engine if it has really bad cylinder/compression leaks, above the rings anyhow. Does it have pistons in it???????
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Old May 18, 2010 | 09:11 AM
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Originally Posted by djb383
It's not supposed to have the plugs in it when doing a compression check......only the cylinder being tested is plugged. When cranking the engine over it should be "hissing" like a steam engine if it has really bad cylinder/compression leaks, above the rings anyhow. Does it have pistons in it???????
Lol, yes it has the pistons in it. I know how to do the compression test, I just don't understand why it is dead on all the cylinders
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Old May 18, 2010 | 09:15 AM
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Bent valves, blown gasket between cylinders, etc..
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Old May 18, 2010 | 10:31 AM
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Did you actually pull the timing cover off of it to verify the crank to cam timing? It would be very difficult to lose all compression on all cylinders. Very unlikely that you could have bent all of the valves, and very unlikely to have a headgasket go bad on all cylinders at once. Equally unlikely to have put a hole in all 6 pistons. The most likely reason for zero compression on all 6 cylinders is for the timing to have slipped or jumped. Not an uncommon thing to happen on a high milage or worn out engine.

Corey
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Old May 18, 2010 | 10:33 AM
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edit: I was reading back over your post, and realized you said 4 cylinders, but what I said still stands even if it is a 4cyl.
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Old May 18, 2010 | 11:16 AM
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I bought an engine to do my stroker with the guy said it overheated and cracked the head so he bought a another used engine for it I turned it over and no compression on any cylinders come to find out he had removed the head and headgasket, thats why I asked if you knew the story of this engine
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Old May 18, 2010 | 12:05 PM
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No insult intended but is your gauge good? Some the older gauges had to have some pressure to get past the valve.
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Old May 18, 2010 | 01:33 PM
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The gauge is good. I checked timing by getting no1 to top dead center and pulling dist cap off and verifing rotor was pointing to no1.

And yes it has a head and head gasket on it.

I just didn't check the other 2 cause it started raining and didn't see the point anyway.
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