The car: 98 Sentra SE w/stock 9.5:1 bottom end,DET head/turbo etc..
Symptoms: Smoke from exhaust while engine braking and idle. Blueish grey and smells like oil and burning plastic!

I did a compression test: 1=180 2=130 3=125 4=185

What do you guys think? bad rings??

TIA,
Mike
Will be ordering a new DET soon. :-(

check the exaust oil level with an exhaust oil meter. you should be able to get one from the local parts place. check the muffler bearings too. sounds like the rings though.

I say the compression braking smoking is from the rings or scarred cylinder walls which I have.

The smoking at idle is probably the turbo in need of a rebuild.

The low compression test numbers are a result of bad rings. Oil is probably blowing by the rings and causing the smoke. A turbo that needs to be rebuilt will burn oil, but it won't cause low compression test reults. Do another compresion test. Make sure the car is at normal operating temperature and make sure you do the compression test @ WOT. If #2 & #3 are still low try pulling a little oil in those 2 cylinders, if the number goes up then you know it is the rings.

I was just thinking and remembered reading somewhere that if you have low compression in two adjacent cylinders, it is most likely a blown head gasket...again just something I remember reading.

-saaby

I'll try the oil in the cylinder thing and see what happens. I'm probably just going to end up replacing the motor with another DET sometime soon.

Thanks,
Mike

"check the exaust oil level with an exhaust oil meter. you should be able to get one from the local parts place. check the muffler bearings too"

Heh..Nice! I checked the muffler bearings too... Full of oil. The ic piping is also full of oil 8-(

Originally posted by Saaby
I was just thinking and remembered reading somewhere that if you have low compression in two adjacent cylinders, it is most likely a blown head gasket...again just something I remember reading.

-saaby

Correct, if the other things fail, then I think you have a blown head gasket. It is a pain to change the head gasket compared to the other things that might be wrong so do that last.

BTW Plastic is made from oil, so if you smell burning plastic then you're smelling burning oil.