I just finished rebuilding my d16z6. It has about 50 miles on it. It has a brand new ACL race oil pump. Main bearing clearances are .0018-.002 and rods are about .0024-.0025. I'm running 10w-40 and my oil pressure is a little lower than I would like it. Its about 90 psi on cold idle, but after it gets hot, it hovers around 9-15 psi. 3k rpm is about 65-75. It's not turbo yet, but I plan to turbo it in the near future. I'm worried that I'm gonna have issues down the when the oil gets extra hot from the turbo. My machinist said to run either 10w-40 or 20w-50, but how much of a difference will the thicker oil make? Any ideas for what the problem could be? Should I be worried?

 

I've got a turbo D16Z6 and in the hot months my warmed up idling oil pressure can be down around 8 psi (currently running 10W-30). I'd have to go back and look to see what my bearing clearances are, but I purchased some 20W-50 that I'm going to try running in the hot months, starting with my next oil change. So far though, I haven't had any issues. I'm past a year of having the engine together and almost at a year of being boosted.

 

My B16 that I built a few years back had a similar issue. I ran 10w-30 in it and had 8-9 psi at idle and 60ish at 3k rpm. When I switch to 20w-50 it when up a few psi when hot, but at 8500rpm it buried a 100psi oil pressure gauge. When I tore the engine apart to use some parts for another build everything looked good inside. I ran a high zinc racing oil because it was turboed and I beat on it alot.

 

That's good info - thanks for sharing! Makes me feel a little better about planning my switch to 20W-50

 

Thicker oil is not a fix for low oil pressure.

 

You are correct sir, the minimum specification for engine oil pressure is 10psi on that engine, so with the information provided it should be fine. But since the bearing clearances are greater than the factory specification a thicker oil will provide a better oil film on the journal and help to protect the surfaces from scuffing.