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Nissan Z18ET compression/oiling issue


BlownCorona

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If you want to confirm bad rings without pulling down the engine.

Do a wet test.

Same procedure as a normal compression test but you put a couple of caps of engine oil into the cylinder before you test.

If the rings are buggered this should tell you, all your results will appear normal, ie all around 115psi.

 

May want to consider a cylinder wall crack as well.

 

 

I literlly just came in here to suggest this

 

Was driving round in a mini thinking about your issue and was like, oh, he should do a wet test, why did I not suggest that sooner lol

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Was also having another think

 

Another test you can do with your pressure tester, is take cap off, fit tester and put on like 18psi

Start vehicle and reset pressure to 18, then give a few blips on the revs.

What you should see if everything is good, is that the pressure should raise then drop back down to 18 psi

If it keeps building more and more pressure and not dropping back, then your cooling system is pressurizing from combustion somewhere

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results of the wet comp test are 

1 - 110

2 - 90

3 - 90

4 - 110

 

the test was done is much cooler conditions so i think that would explain the slight drop in one and four. (and the previous readings were after the engine ran a bit)

 

but yes a decent increase on 2 and 3 seems to indicate rings/lands 

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Not cleaning out thread before winding in head bolt is a possibility. If there is oil slash shit in there you can end up putting alot of force on the threads trying to compresse whats in there

Not saying that is what has happened. But it is one possibility

Also sorry to hear you're block is fucked. Atleast it answered a few questions

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dad spoke with the engine shop that did the headwork, and they rekond that cracking between water jackets and bolt holes is fairly common and that he wouldn't be that worried about it and that the head gasket will seal it. 

 

its two water jackets and a bolt hole involved so naturally i think there is another issue somewhere involving the oil side of things and currently the block is out of the car ready to be torn down, but naturally im rather hesitant to agree with the shop saying the crack in the block is okay. thoughts??

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