I am planning on re building a head over the winter. I know the 1.8 head flows better but any particular year i should be looking at? The yard i would get it from has M10s ranging from as far back as the 2002s all the way up to the E30 318s so i have alot to choose from. Also is porting and or polishing worth it on these motors? I would be doing it myself but i do not have a flow bench so if anyone knows the good areas to remove material from and areas to stay away from that would be great. chris

There is more to a good head than max air flow...

Each head has + and -.

1.8L casting head, MAY flow a little more than other heads due to the open chamber, I doubt it personally because these heads have canted valves that unshroud as they open because they move towards the center of the combustion chamber. They do come with the largest valves used in stock heads. Other heads use the same valves and some use smaller valves. These heads have injector hole in them. 1.8L pistons have a slight dome I believe (never had the head of my 1.8L so not positive) that won't work with other heads. Largest combustion chamber volume of all the m10 heads. Might be a great head with custom pistons with domes that match the combustion camber edge closely as often done with Harley Davidson Sportster Evo heads.

e21 casting head, Semi open chamber with one "quench pad". Quench pads promote turbulance and better combustion if the piston comes within .050" of the pad, any more clearance than that and the benifit deminishies greatly. Largest valves also. No injector holes. Won't work with 1.8L pistons-the dome will hit the quench pad. 2.0L engines with this head have a small dome.

121 casting, Closed chamber with two "quench pads" for even better combustion efficency but MAY not flow as well due to the closed chamber. I have not measured the valves from this head, they may be slightly smaller than the e21/1.8L valves but that's a pretty easy fix if you are redoing the head anyway. Personally, I would like to use this head myself, I think it would work great with a 92mm bore and flat top pistons.

These are 3 of the castings available that I have looked at, there are others out there also. Early 1600 and 2002 heads have smaller valves and closed chambers from what I have heard.

For info on head porting visit my page:

http://www.e21motorsports.com/kendanielson/cylinder%20head.html

hope this helps some,
ken

Bumping this, i have a 79 2.0 head that i will be redoing until i make the swap to a new engine

Bumping this, i have a 79 2.0 head that i will be redoing until i make the swap to a new engine

What are you swaping another m10?

Not for a very long time, but i will be swapping heads shortly. I wanted to have a motor to rebuild for a snail so i can just swap motors but first i want to have my elcamino drivable at the very least.