Hello everyone, so I recently just replaced my engine on my 300zx TT. Ive been getting valve noise on and off from time to time since day 1, but its progressively gotten a little worse. If I were to drive the car for 20 minutes around my city and come home and have it idle in about 5 minutes the car starts smoking from the passenger side (no H or X pipe on the car). It smells like burning oil. I check the turbos and charge pipes everything is completely dry no oil in sight. I did an oil change about 50 miles into the new motor and the oil was completely thinned out like water. I just lifted my car and took out a little oil and its getting thin like it was before. It does not smell like gas, like if the injectors were leaking fuel into the engine. I also hear rattling like its valves when i have the accelerator to about 3k rpms sometimes 2k. The car pulls very hard runs really smooth. I just cannot figure out this problem. And the smoke is very noticeable. I had a shop just glance at it and all they said was it smells like oil . So please anyone input on this. thank you-Ricky

You said you replaced the engine, was the engine rebuilt? If so to what extent?

It was rebuilt by courtesy Nissan but that was a few years back. The motor was sitting in the garage for 6 months and has 20K miles on it.

okay... well it sounds like it could be a valve seat it it wasnt replaced gas would be able to get into your oil or oil into the cylinder making it smoke ummm it has to be a head or valve issue, I just hope those nissan guys re-did the heads ohh also maybe a bad hydrolic lifter. does any of that help?

Thats what im aiming at as well. No they only serviced the lover end. But as I driving today the car started heating up. Im going to be pulling the motor out and im trying to think as to what I should do. I have an extra engine with turbos but a cylinder has low compresson which was the reason why I did the engine in the first place. Im thinking of either giving the engine to my machine shop or buying a JDM long block. Im just scared of getting a bad one.

head gasket. if your oil is thinned out then perhaps they never installed it right or it already blew somewhere.. this would make sense why your oil seems thinned and and your burning oil at the same time. And why your heating up. Check your coolant level.