To my best knowelege the later ZX turbos use the P90 head and F54 Block...

So my question is what is the differnce between the turbo f54 short block and non turbo short block ?

just the compression ? or does the turbo have forged internals ?

because i know the heads are the same

dish top for the turbo and better rings, flat top for the na

Also the non-turbos did not have the P90 head, they had the P79 head (I have one of these engines in my garage now).

I have a 1981 280zx that has a P90 with a F54 BLock (my best guess)

So the internalls like rods and crank are the same from turbo to non turbo ? its just the pistons ?

just another small note the turbo L28 uses a higher capacity oil pump on the block than the std L28

Originally posted by 280zx Fever

I have a 1981 280zx that has a P90 with a F54 BLock (my best guess)

why is it your best guess? why cant you view the castings?

Because i cannot find the castings...

Where do i look for them ?

I know for sure the head is a P90

I think all the differences have been pointed out. The block casting number is on "drivers left" side of engine near the bottom just behind the motor mount. If your engine has a P90 head than most likely it is a F54 block. I say this because using a N42 cast L28 block with a P90 head would require a piston change to produce enough compression for even a turbo motor.

Have fun!

Originally posted by 280zx Fever

Because i cannot find the castings...

Where do i look for them ?

I know for sure the head is a P90

Its a bitch on the L28E becuase of the EFI gear but if you hunt around with a torch you will find the casting in big letters on the manifold side down low

Ok i checked it... i got a F54 block...

So if i use differnt rings with the flat top pistons i could run a half decent turbo setup ? stock l28et turbo and boost ? Or would i need the dished to make it safe ?

I think all 280ZXs after 1980 used an F54 block. The NA 280ZXs had flat top pistons, and either a P90 or a P79 head. The turbo engines had special dished pistons (not the garden variety), and only the P90 or P90A head. The F54 block has extra reinforment between cylinder bores for better rigidity.

Does you F54 have dished on flat tops? If it has dished, it is a turbo motor. If the cylinders have little wear (any ridge at the top of the cylinder?), and you are going to turbo charge it, then you should just re-ring and intstall fresh bearings. Your compression ratio will be around 7.5:1. Good for a turbo. With flat tops the CR would be close to 8.8:1, which is too high for forced induction.

If you are building an NA motor, pick up some flat top pistons, and either an N42 (square port) or an n47 (round port) head. You'll get close to 10:1 compression ratio with a slight overbore. You'll need to run super, but you'll have a spunky little motor in your Z!

Pete

Yes those are my plans... just finding out how easy it is too boost the F54 with the P90

I also have a N42 Engine aswell thats in good condition.. so what i do is sorta uncertain....

Thanks for the response.