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l28 smokes, thought headgasket, but it tooks fine.


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Ok, my l28et 240z smokes when accelerating, especially in 1st and 2nd gear, at worst at low rpms. White Smoke.

I did a compression test and got about 90 on cylinder 5. everything else was around 138. then a month later another test showed everything at 120, and cylinder 5 still 90. I thought the lost in compression might just be bc its a different day doing it, didn't matter too much since they were all close.

 

Anyways, i figured it was a headgasket problem, especially since there was oil in the radiator. However when I took off the head, there were no signs of a broken headgasket. It looked fine, no cracks or breaks between holes. I already ordered a OEM headgasket from nissan, but the headgasket on the car seems like a custom one, that's better fitted and has more length on the edges. should i replace it anyways? or just return the part or sell it.

What can be the problem now? piston rings? but that seems weird that 1 ring will be soo off, i thought they wear out pretty similarly.

I am about the check the valve guides, but i thought they are damaged only when theres blue smoke.

 

I'm not sure how to tell if the piston/rings/cylinder is bad. Since the block is still in the car, do i have to get the pistons out ( via taking off the oil pan and using a hammer to push the pistons up) to really get a good idea?

thanks

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i'de have the head pressure tested. I had the exact same thing, oil in the radiator, white smoke and head gasket looked good. Took it to a machine shop and he told me it was a casting flaw. It was letting oil flow down into

a coolant jacket. He had to grind out alot of material before he hit good aluminum. Then welded it up.

Been fine ever since.

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