Head games

[Jroc81]

Long story short, I have an 87 325e that supposedly had an i(m20b25) engine swapped into it shortly before I got it. If this is true, the gauge cluster must have been left stock, because its got an e(m20b27) redline. are there any casting marks on the head that I can look for, which will tell me definitively which engine I have? Just to clarify, the engine is complete in the car. Were it out i'd know by the piston/chamber shape, but i'm not about to go through pulling it to find out.

[NC325iC]

what does the intake manifold look like?



This is an i motor, if the intake runners are smaller diameter than these its an e (also slightly different in shape)

[Jroc81]

Well yeah it pretty much looks like that, but I was sort of hoping for a more technical answer, because numbers are easier to deal with than trying to judge subtle shape and size differences from a picture. Also. I dont think the PO was the type to "do it right the first time" and may have used e parts, if any i parts weren't present, just to make it run.

[StereoInstaller1]

Do you think he left the ETA engine management?

Do you have a sensor at the 11:00 position on the front harmonic balancer, or do you see teeth on it?

the head on a 2.7 is a 200, on the 2.5 it is 885. the intake manifold is quite different, it is an easily visible thing, not subtle at all, IMO.

See if you can find a knowledgeable local R3V member locally to help you.

Luke

[Jroc81]

the head on a 2.7 is a 200, on the 2.5 it is 885. the intake manifold is quite different, it is an easily visible thing, not subtle at all, IMO.

Thanks! This is what I was hoping for. Where, on the head are the casting marks located?

[NC325iC]

Do you think he left the ETA engine management?

the intake manifold is quite different, it is an easily visible thing, not subtle at all, IMO.

that was something i was thinking about too, if it stops revving at 5k you may still have an e ecu. if it revs past 5k then its i electronics, just the tach doesnt match.

and i agree, thats why i mentioned that

[Jroc81]

My fear that the b25 could run on b27 management is part of the reason I created the thread. the PO def would have left that in, if he thought it'd work, and didn't have an ecu/harness to complete the swap. Also the information of head casting numbers/location is at very least, difficult to find.

[Jroc81]

Anyone know exactly where to look on the head for the casting numbers?

[SpecM]

Anyone know exactly where to look on the head for the casting numbers?

on the exhaust side, look for a quarter-sized flat spot with a number. It wouldn't be the casting number, but it will say 2.5 or 2.7 (or both on a late casting)

[lennon]

OP, you could just take a picture and post it. we can help you identify it. of course if the previous owner mixed and matched parts its going to be harder to figure out. report back with photo of engine and the number on the ECU.

[Jroc81]

on the exhaust side, look for a quarter-sized flat spot with a number. It wouldn't be the casting number, but it will say 2.5 or 2.7 (or both on a late casting)

Thanks! You know what i'm hoping to find...

[Jroc81]

OP, you could just take a picture and post it. we can help you identify it. of course if the previous owner mixed and matched parts its going to be harder to figure out. report back with photo of engine and the number on the ECU.

Well we've discovered that it may be possible for the intake mani and the ecu to work on the b25 head so the casting numbers are the end all for this thread. If i find that it has a b25 head i'll post pics/video to prove that it runs lol

[lennon]

edit- okay. i was just trying to help you figure out what youve got since you made it sound like the PO did a hackjob swap. thats why i mentioned the ECU and people are mentioning the intake manifold. knowing what head you have doesnt mean its a b25 bottom-end and complete b25 management.

[Jroc81]

edit- okay. i was just trying to help you figure out what youve got since you made it sound like the PO did a hackjob swap. thats why i mentioned the ECU and people are mentioning the intake manifold. knowing what head you have doesnt mean its a b25 bottom-end and complete b25 management.

True! but if i have an i head and an e bottom end, then the PO made me a nice 327i. Which if it has flat top e pistons(8.3-1), makes my pants tight, because i'm starting a turbo build for it, which is why i'm trying to figure out what head I have.

[jlevie]

A SuperETA engine also has an 885 head, but different cams and valve springs.

To really find out what block is in the car you need to know what the tops of the pistons look like, which can be determined w/o pulling the head with a borescope. If those are M20B25 pistons then the engine is probably a full up M20B25. A quick peak at the DME will what engine is is for.