Ok i have an 04 350z track with 78k on it.. I boutght the car with 61k on it with no issues ran great!! I started noticing the oil getting low didnt pay much attention. FOund the car with 1 quart left and was shocked !! My bumper in covered in oil after a day or 2 of driving tips all black. I put about a quart or 2 a week and thats 1-250 miles. The car runs great! i still drive it hard and beat alot of cars it just feels strong!

I always assumed rings, i bought a brand new compression tester kit today got it warm took it apart, ran it.. all cylinders are around 200psi.. SOme a little less some 210psi.. Is that normal?? If so Could it just be the valve seals?

I have oil all over my spark plugs and the ones that dont have it look like they just got back from hell. They are 1000miles old. last set was the same.
Car has megan test pipes, and nismo cat back.

any thoughts? please feel free

 

Did you use the oil on the compression check. That will help determine if the rings are a problem. If the oil in the cylinder raises the numbers its a good indication that the rings are worn. The basis of this test is to see if the oil can help seal the chamber better. I'm not so sure this test works for bad oil control rings however.

Good news though... It pretty much has to be one or the other (Valve seals or rings) bad news... both are a PITA (financially or time consuming if you do it yourself).

 

BTW, 14 psi differential is ok on a dry test.

 

thanks, i hope its valve seals cause there are a newer set of heads loacal to buy. but What is the normal comp. psi?

I didnt add oil because non were low so i figured its valve seals?

 

wouldnt i see a lack in performance if it was rings?

 

I recently had a problem with mine and its been diagnosed as a bad or damaged oil control ring. I don't notice any lack of power, in fact if anything its stronger than before due to other changes. But I know something is off because of the amount of oil it goes through. As for normal figures, the service manual references 150'ish as minimal and 185'ish as normal. Mine are in the 210 range. Personally I'm planning to address both causes (seals and rings) to confirm that I don't have to do it again. This was the first time I pulled the engine apart in this car and I learned quite a bit about the inner-workings.

Also with that many miles on the engine/rings I would go ahead and try the oil test just for the peace of mind, although the rings can easily exceed that mileage number.

 

cool man i will check it out. And then maybe it will be worth waiting and finding a good long block. Gives me a reason to build this one ) thanks for the help!

 

You are burning a quart of oil every 250 miles? Difficult to believe the car still runs.

 

Lmao Trust me I see what ur saying. But I really am putting a quart in every 3-5 days. I drive it hard so Im sure it's nt helping. But it is always low. I filled it up yesterday and a few days of going to work and the. A night of hard driving it will need 1 or 2 more. And at times it feels like a power loss. Then out of no where it starts screaming and kicks ***.

 

How badly is it smoking?

 

My back bumper is covered in black oil by second day of driving. Sometimes it smokes everytime I accelerate, some times clears up.. I put a stop smoke in it and actually it didn't smoke today on the way to work. So Kaye it helped a little. But even tho it's not dumping smoke today I still smell it having no cats makes it worrse

 

Yeah that sounds like it may be either of the two or a little of both.

 

yeah.. well I think ill just keep it running and do a rebuild once my project car is done. Thats the only the z is not fixed and stock. Soon tho.