So my car has been burning oil for the past 30k miles, i put in 1.5qts every 2 weeks. Had a compression leakdown test done yesterday and compression was 150 across all 6 cylinders. There is no visible oil leak. Car has a slightly rough idle, was worse before the spark plugs were changed. Car blows out light gray smoke during city driving. Im wondering what else could be causing the OC and smoking? Valve covers/gasket were replaced by Infiniti about 25k miles ago, did not help the OC problem.

Mods are: ztube/popcharger, 5/16 spacer, aam hfc, FI cat back exhaust, Osirus Tune.

BTW car was denied a longblock by Infiniti due to pop charger and cat back exhaust, 2 yrs ago

 

Let me see if I have the numbers right. You are adding 39 quarts/year? I don't know where the oil is going but performance must be adversely effected. This motor is gone. Say bye-bye.

 

Either rebuild the motor you've got or buy a new short block, one with higher compression pistons would be better.

 

^ Compression ratio on pistons has nothing to do with oil consumption or making this engine run better. Stock piston ratio would be fine.

You need a leak down test. That will tell you how much is getting past the rings.

 

"Better for performance" is where I was going.

 

Wait a minute.....you have been having oil issues since 2009? Looks like you have already had tons of info thrown at you. You just have to get it taken care of.

https://my350z.com/forum/na-builds/4...ing-motor.html

 

Leakdown test was done and it was normal, which doesnt make sense to me. I thought the main problem was the piston rings which causes OC.

That sounds about right + or -.

 

What else could be causing the OC, since the compression/leakdown test were normal?

 

I would have thought 150 was a bit low.

 

Comp test and leak-down test are different. Were both done?

 

yup

 

It's probably too late now, but Infiniti had no legal grounds to deny you a long block in 2009. Research the Magnusson-Moss Act.

 

Been there done that, no solution. Infiniti consumer affairs people are ruthless.

 

What were the leak down results (meaning number)?

 

Mileage??? Ive burnt my fair share of quarts...Dodge, Northstar ETC, need more info

 

wasnt given a specific number, just told that it was normal.

84k. Been burning since about 50k though

 

Do another compression test. Put a capful of oil in each cylinder right before each test. If it raises its rings. If it doesn't its probably in the valves. 150 sounds low though.

 

Is a dry test just a standard compression test and a wet test when oil is poured into the cylinder? Is the wet test a leak down test? Should these tests be done with a warm engine?