How to: Tell what head an M20 has, the 2 second way.

[Camper Van Someren]

Sorry I’m reviving some old threads trying to figure out what engine was swapped into my car. If this information here is reliable then it seems I have an 885 head with an eta intake manifold. The head definitely has the 2.5/2.7 circle casting, but the valve cover has the roundel instead of saying BMW (I read somewhere that 885s didn’t have the roundel). The manifold definitely appears to be eta. Weird. Thoughts?

[Camper Van Someren]

Sorry I’m reviving some old threads trying to figure out what engine was swapped into my car. If this information here is reliable then it seems I have an 885 head with an eta intake manifold. The head definitely has the 2.5/2.7 circle casting, but the valve cover has the roundel instead of saying BMW (I read somewhere that 885s didn’t have the roundel). The manifold definitely appears to be eta. Weird. Thoughts?

Never mind the more I look, that is a 325i intake manifold. I also confirmed by putting my phone under the intake manifold and getting a picture of those all-important numbers

[ForcedFirebird]

So many threads.

It appears you have a "cheater" motor. It's common for crap-can racing for people who "think" they are gaining by using a stock eta and adding an 885 head. Sorry to say, but a 318iS will out-rn it....

You need to decide if you are going to run the car as an eta, or 325iS, and stick with your plan. The 325iS trim will produce about 150whp/50wtq on a good JY motor.. The eta will produce about 120whp and 165wtq, also in stock "racing" form. Nearly equal on the racing circuit. That being said, the "2.7i" combo puts about 135whp and 150wtq. If you go to user settings and turn on "signatures" you will fond links to dyno trials we have done on m20's at work. https://www.r3vlimited.com/board/for...ad#post9875136

[Camper Van Someren]

So many threads. It appears you have a "cheater" motor. It's common for crap-can racing for people who "think" they are gaining by using a stock eta and adding an 885 head. Sorry to say, but a 318iS will out-rn it.... You need to decide if you are going to run the car as an eta, or 325iS, and stick with your plan. The 325iS trim will produce about 150whp/50wtq on a good JY motor.. The eta will produce about 120whp and 165wtq, also in stock "racing" form. Nearly equal on the racing circuit. That being said, the "2.7i" combo puts about 135whp and 150wtq. If you go to user settings and turn on "signatures" you will fond links to dyno trials we have done on m20's at work. https://www.r3vlimited.com/board/for...ad#post9875136

Ok I’ll have to find those threads about cheater motors and do some reading. However the car has had a whole engine replaced (not just head) so probably more likely that it is a full 2.5 from a 325i rather than a cheater. It doesn’t have a separate gear on the front for the crank position sensor (why I originally thought it was a 2.7) but maybe they are running a full 2.5 motor with the sensors and ecu from the original 2.7? Is that possible? I looked for the “serial number” stamped on the block but there is nothing there. I guess my next step would be to pull a spark plug and see what pistons it has. Then I’ll know if it’s a 2.7i cheater or a bad 2.5 transplant. Sent from my iPhone using Tapatalk

[Camper Van Someren]

I found a VIN from a 1990 325i on the block. I talked to the prior owner of my car and he said he swapped in the motor, but he thought it was from a 1987. Said he kept the original 86 “eta” ECU and tried to use the new fuel rail from the donor motor but it ran like crap (probably because it was an eta Motronic 1.0 controlling a motor that should have 1.3) so he put the original fuel rail on. He also put on some pulleys and water pump from the original motor to make everything work. He said he swapped out the “2-stage” fuel pump for the newer pump. After doing some reading, it looks if I could get an ECU and engine loom from a Motronic 1.3 325i, then it would probably run better and make lots more power?