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

[Herr Faust Schinken]

Yeah yours is an oem head the 885 casting mark on the sides proves it

[cabriodster87]

I just found that i have the AMC head. It's like my baby is sick now.

BMW how could you let this happen?

http://www.r3vlimited.com/board/showthread.php?t=232555

[MattAvino]

so if you have an 87 325i with a "2.5/2.7" embossed head and torx headbolts you know they were changed at some point.

The m20b25 I just pulled from my '87is has the '2.5' over the '2.7' stamped on the head. So has the head been replaced in the past?

[reelizmpro]

The m20b25 I just pulled from my '87is has the '2.5' over the '2.7' stamped on the head. So has the head been replaced in the past?

This or the entire engine.

[MattAvino]

Very interesting, my motor or head has under 200k then.

[reelizmpro]

Probably snapped a timing belt before or overheated.

[markt51]

87-88 cars came from the factory with 885 heads embossed with "2.5" only and hex headbolts. Even if your car was a super ETA 2.7 liter. 89-on heads had "2.5/2.7". These are the original specs, so if you have an 87 325i with a "2.5/2.7" embossed head and torx headbolts you know they were changed at some point.

I have a 1989 325i, manufactured in 9/88 and my head only has the 2.5 on the circle and not 2.5/2.7. Is this the original head? or was it replaced with an older one at some point?

[mr.vang]

my eta head doesn't show what you had presented

[reelizmpro]

I have a 1989 325i, manufactured in 9/88 and my head only has the 2.5 on the circle and not 2.5/2.7. Is this the original head? or was it replaced with an older one at some point?

Probably was changed but I'm not sure of the exact cut off date. Take a pic of the engine bay for me. Does it have torx or hex headbolts?

[blueapplesoda]

I'm assuming for those of you who have the machined down nub where it should say 2.5//2.7 or 2.5, the reman co machined the exhaust manifold mating surfaces down.

Sort of like the tell-tale casting dots on the bottom of the cylinder head, block mating surface, to tell you roughly how far the head is machined down. I believe there are 3 stages of dot depth, but I may be wrong. I have to look, i just know that once all those dots are gone, the head has been "used up".

[actletpone]

There is a head at my local bone yard which has the circle like the amc head. It does not have the other cast circle with 2.5/2.7 stamped on it, instead it has a bit like the eta at about cylinder 2 which just says 2.5. On the intake side it has 885 and the BMW enmblem. It is on a 1986 325.

What does this mean? Is it a 2.5 eta?.. can it be put on a 1990 325i ?

[702pjc]

I too have both the indentation mark and the 2.5/2.7 nub

[meengreene30]

My 731 head i'm running.

[whodwho]

Those are not the intake ports of a 731 head unless it has been port matched to a 325i manifold

[meengreene30]

Those are not the intake ports of a 731 head unless it has been port matched to a 325i manifold

Porting might have been done not sure. we were stumped with this motor too, came with a 272 cam, hd valvetrain. After a lot of searching we came up with it being a modified 731. Either way i'm really happy with this setup whatever it turns out to be, pulls a lil harder than my buddies 2.7i with same cam and valvetrain running headers.