good compression numbers for i head swap

[e30trooper]

so just wondering whats the avg comp numbers for a eta with i head swap.


ive been having a issue with burning oil above 5k rpms so i did a test. came out to 150 on all cyl's.Thats a huge drop compared to my last 325i vert w/ a rebuilt engine i had 180 across the board.

ill do a leak down next week, since i did find oil on the spark plugs

[nny403]

8.5 compression on the high side. Unless you get the head shaved and run it with a different computer you won't see much benefit.

Edit: If you have leaks on the spark plugs and are swapping the head I recommend changing the valve seals they were $15 at Car Quest. You'll need to get valve lapping compound and make sure you have a valve spring compressor tool. This is ideal.

[e30trooper]

The head was sent to a machine shop before i installed it. From what the machinist told me.
It was hot tanked , bead blasted , decked 10/1000th of a inch. valve re-gring new valve seals , valve adjustment, pressure tested and crack test. The head should be fine. I just want to know whats the avg comp psi ppl are getting after a head swap.

Im only burning oil ( blue smoke ) past 5,000 rpms but the car pulls just fine. When I pulled the plugs sat.There was oil in each spark plug seat. I do however have a pretty bad leaky cam shaft seal that I never replaced. Someone said its possible that oil from the leak is getting into the plug seats but im not 100% sure on that.

[e30trooper]

from what im reading 150psi is pretty good for a m20b25 so i guess those would be good numbers for a low comp eta block with a decked i head.