would like some opinions

[Dave-ger]

So my 83 E21 has an M10 that may seems to be seized (put PB in the cylinders, going to see if it turns over tomorrow), and it's missing a freeze plug (going to see if I can get it to run before fixing that). anyways, I also have another M10 that I believe is out of a 77 so it was carbed and has a different head. the head on that one says "2.0 E21" or something like that and the one that's in my 83 says "1.8 E21" or something rather... does this mean the older one is a 2 litre and the other is a 1.8? I was also thinking of putting the 83 head on the 77 block if my 83 block is screwed, any issues with this? doesn't seem like it, but I figured I'd ask.


and for the opinion part: are M10's worth the effort? they are very non-repair friendly, that's for sure, and the parts for them don't seem to be the cheapest so far.

I rambled allot, I looked for an "FAQ" thread for M10 stuff like pirate 4x4 has for everything, but didn't find it... found other stuff for FAQ of course... anyways, if these are stupid questions and I annoyed you by posting this, sorry.

any input is much appreciated. Thanks.

[SoopaGhetto]

The head will fit the bottom end. i do believe it should clear the pistons as well.

if the heads were never switched out through the life of the engine, the "2.0 e21" designation on the head corresponds to the displacement of the engine: being 2.0

i honestly dont believe m10s are all that expensive to replace parts. it really depends on which route you wanna go though. I like the little m10 so i can justify spending money on parts some people would think is stupid/wasteful on such a "bad platform"

i go to bmw2002faq.com & iemotorsport.com for performance parts...

some times you can get good deals on ebay!

[Dave-ger]

thanks, very helpful. So that is interesting that my 83 is a 1.8 fuel injected setup and the old 77 that was carbed is a 2 litre.


I've got some research to do.

[SoopaGhetto]

thats how it is. also the carbed 2.0 put out a lot more hp than the 1.8

most people just swap in the 2.0 parts (crank, rods [thicker], pistons) into the 1.8 block and youd have a light-weight 2.0 engine in an already light-weight e30

[Dave-ger]

thats how it is. also the carbed 2.0 put out a lot more hp than the 1.8

most people just swap in the 2.0 parts (crank, rods [thicker], pistons) into the 1.8 block and youd have a light-weight 2.0 engine in an already light-weight e30

I don't have an E30 though, I have an E21. is the 2.0 block any heavier than the 1.8? seems about the same. This is something I could probably just research, but since I'm lazy right now (studying for finals and stuff), I figure I might as well ask.

[Tomslide50]

a 1.8 head on a 2.0 block yields low compression(~8.1:1). The 2.0 head would be a better choice.

[SoopaGhetto]

a 1.8 head on a 2.0 block yields low compression(~8.1:1). The 2.0 head would be a better choice.

on the contrary, its more dependent on the pistons. flat top pistons yields that cr number but i did some calculations and its more like 8.5~8.7

if you have pistons with some sort of bulge, the cr wouldnt be that low with the 1.8 head. but in general the cr is lowered slightly due to the 63cc almost hemi chamber of the 1.8 head.

the 2.0 block casting is physically heavier than the 1.8. also the 1,8 block design is better allowing less material and in turn less weight.

as long as you dont bore out the 1.8 block too much, it could take some nice hp!

[Dave-ger]

I'm going to keep it cheap if I stick with an M10 though, so boring out the 1.8 is out of the question, different pistons may be as well... hmmm. time to research.

oh yea, can't run the 2.0 head unless I can find a way to carb it, I was planning on using the fuel injection, which currently only works on the 1.8 head... unless it's somewhat easy and cheap to make the 2.0 head work for that, then the 1.8 head is what I'm using.


you have no idea how helpful this is, thanks.

[Dave-ger]

all this talk about lower compression got me thinking... TURBO! I have a turbo from a 5 cylinder audi, perhaps I can make that work.

[SoopaGhetto]

I'm going to keep it cheap if I stick with an M10 though, so boring out the 1.8 is out of the question, different pistons may be as well... hmmm. time to research.

oh yea, can't run the 2.0 head unless I can find a way to carb it, I was planning on using the fuel injection, which currently only works on the 1.8 head... unless it's somewhat easy and cheap to make the 2.0 head work for that, then the 1.8 head is what I'm using.


you have no idea how helpful this is, thanks.

you should be able to put all the 1.8i efi stuff onto the 2.0 head if needed (including manifolds). only thing you would need is a block off plate for the mechanical fuel pump thing on the head. they sell that at 02again.com or make your own...

[Dave-ger]

but my injectors go into the head, not the manifold... unless I could get a manifold that took the injectors, but I doubt that would be worth it if it even exists.

[Pinepig]

but my injectors go into the head, not the manifold... unless I could get a manifold that took the injectors, but I doubt that would be worth it if it even exists.

That manifold does exist and it was on e21s, I'm not sure what year the switchover was but they are pretty easy to come by at pick and pull around here.

[Slangbox]

all this talk about lower compression got me thinking... TURBO! I have a turbo from a 5 cylinder audi, perhaps I can make that work.

I like this plan.

[Dave-ger]

That manifold does exist and it was on e21s, I'm not sure what year the switchover was but they are pretty easy to come by at pick and pull around here.

must be the older ones then. according to whoever wrote on the valve cover of my spare engine, it was out of a 77 320i. the "i" means it's injected right? and there are no injector spots on the head, so it must have had the manifold you speak of. I wonder if I could modify my extra 82 manifold to fit the fuel injectors into the 77 2 litre head. that plan may not be worth it.

I'm also thinking I may see if I can have a dude I know machine the 83 1.8 litre head to gain the compression back plus some extra for if/when I put it on my 2 litre block. I do like the turbo idea, but I want this car to be super dependable, I'm not sure I can accomplish that with a turbo.