BMW vs AMC head

[reelizmpro]

im thinking it was a factory item, maybe bmw couldn't meet the demand and had AMC make them for them. there is just too many around to conclude that people changed heads.

I disagree. It's not factory. These "spanish" heads have been around a long long time since the cars were new. They were a cheaper alternative to the then very expensive BMW cylinder head. Everybody sold these heads as alternatives. These cars are 25+ years old. That's why there's a lot of AMC heads out there but they are far less common than the stock 885 BMW head.

Also, 87-88 original heads had "2.5". Even the 88 325 although it was a 2.7 liter. 89 on up say "2.5/2.7". This is true for original heads. If you have an early car with "2.5/2.7", then you know the head has been changed at some point. Over the years things get switched around alot. I've seen early engines in late cars. One vert i saw at the junkyard yesterday has a super ETA engine in it.

[Cabriolet]

i have all the receipts from my car and no where in any of the papers does a head change happen. only papers i dodnt have are from the first owner in 1991-1993. is it possible that bmw couldn't meet the demand, with them starting production of the m50?

[Cabriolet]

so dose the amc head give more power than the stock head

i really doubt it, the ports are poorly designed. they have a sharper angle on the runner and arent 100% the same size.

the exhaust side is identical 30mm in diameter and same port shape.

[Jand3rson]

Oh wow I never knew about these AMC heads. Gonna do some searching now. Thanks for this.


Learneded somfen new today!

Same, I had no idea that there was something like this out there!

[reelizmpro]

AMC website..

http://www.amc.es/

http://www.fcpeuro.com/products/bmw-cylinder-head-11127514540

http://www.firstfives.org/faq/cylinder_head/cylinder_head_faq.htm

http://www.e30tech.com/forum/showthread.php?t=65287

http://www.perfectengine.com/product_p/pck-bmwm20b25-chb.htm

Cabriolet...your head was changed at some point.

[einstein57]

im thinking it was a factory item, maybe bmw couldn't meet the demand and had AMC make them for them. there is just too many around to conclude that people changed heads.

BMW had to change a lot of heads back in the 80's. The timing belts were not made as strong as they were supposed to be and were "prematurely" failing. The original interval was somewhere between 60-80k miles. After bmw paid the bill on replaceing a couple thousand heads and motors they reduced the service intervals for the timing belt.

[HR2L]

This thread made me go out and look at my cylinder head. Thanks for the photo's and comparison, amazing how shitty the AMC cast is when next to a genuine BMW 885. Glad to see that my replaced motor has a genuine BMW cylinder head.

[Cabriolet]

BMW had to change a lot of heads back in the 80's. The timing belts were not made as strong as they were supposed to be and were "prematurely" failing. The original interval was somewhere between 60-80k miles. After bmw paid the bill on replaceing a couple thousand heads and motors they reduced the service intervals for the timing belt.

good to know thx

[e30m20TurbO7]

i recently just found a amc head off a parts car
it came of a sedan 325i it looks to be in good condition i can have it checked out a local shop
if any one is interested in buying it 125+ shipping
pm me if your interested
btw im new to Revlimited but obsessed

[fporro]

Just pulled a new AMC off (euro 3/91 325iC) parts car, this thing looks like it was just bolted on.
I'll post pics in a few.

I thought Metric Mechanic liked AMC's over 885's, no ?

[reelizmpro]

They had good experiences with the AMC heads and they were a good low cost alternative at the time. today u can get either head from the junkyard for the same price. I'd stick to the original 885.

[e30leigh]

wow!!! interesting about the amc. im about to start looking around for an m20 to build. ill deff be looking for an 885 head for my car. i dont want any of that amc crap at the business end of my engine.

and id say hands down there is a little gain to be had using the obviously better quality bmw head.

[fporro]

from my euro 3/91 325iC

[e30leigh]

looks like oil in the water? or that the tried and true, rust is better then coolant approach? haha

[Cabriolet]

wow, bumped i see. anyways it has been a few months and tbh i cant tell the difference in power at all, course no dyno runs, but my amc head's valves were a ton quieter than the 885 head i put in, might just need new eccentrics. fporro's amc head looks just like mine. the oil return port looks poorly formed and the lower have of the intake valve has an odd shape.

p.s. thx reelizmpro for all the info contributed here.