Sr20det white smoke/low compression

[Sr20_44]

New to the 240sx sr20det. The car runs great but smokes like cheech n chong out the exhaust (white smoke). I did a compression test last night and got pretty low numbers. Doing another today with throttle open. It has an aftermarket cosworth head gasket. Don't know the thickness. The motor was also rebuilt from previous owner. Makes no noises, no visual leaks. I'm thinking turbo? Any suggestions would be appreciated, thanks.

[JustinRB25s13'92]

white smoke is usually coolant/headgasket friend..

[Sr20_44]

But wouldn't I lose power from loss of compression? It still pulls
Also doesn't leak and fluid from exhaust.. Just smoke

[JustinRB25s13'92]

You correct, it also depends on how bad the leak...think about this, you may still be able to have power and it may still "pull" pretty hard, but in reality you are turbocharged, so no matter what is happening the other cylinders may still be okay it just depends on how badly the gasket was destroyed and the location....or it could be even dumping a minor amount of coolant in X number of cylinders, but its not enough to be a noticeable loss of power...but another possibility is the turbo its self...theres a myth that shaft seals can allow coolant out, but it would be kinda far fetched....how much boost are you running?

[Sr20_44]

Stock 7psi. I just did a leak down test and came to conclusion of turbo. After I jacked it up and looked I also saw oil around turbo. The motor was rebuilt and only has about 1500 (says the guy I got it from). I'm thinking the rings haven't set yet, causing the low compression. Thoughts?

[JustinRB25s13'92]

hmm, i'd try and run it through cycles to set the rings, and is it a stock turbo???

[Sr20_44]

Yup just a t25. What do you mean run it through cycles?

[peacetoyou5]

could be that the studs were not replaced during the rebuild. the metric head studs only torque to spec ONCE. they need to be replaced with new ones after you pull the head no matter what.