Fitting E30 (731) 2.0 head to E21.......

[OLE97P!]

It works, basically. I had to do a top end rebuild on an X plate 1981 320 which had a cambelt 'incident'. It had smoke on the over run so would have needed stem seals and possibly guides as well as a few bent valves replacing.
Found a mint E34 520i head for a few pounds (literally a tenner) with a recent new cam and rockers, zero corrosion and had never beed skimmed. Well, it was cleaned up and fitted with a new gasket and stretch bolts. the 731 inlet ports are quite a bit bigger than the original 200 ports so there was speculation as to whether the gasket would seal. Well it does, and it runs very well indeed - no more over run smoke!

Being a pre 10/81 car, it of course had the old square tooth belt with different pulleys. You can't buy these belts anymore but BMW sell a conversion kit to the later round tooth belt with three new pulleys. The same 520i that donated the head also gave up it's pulleys! I would use an L jetronic 320i/E28 520i cam pulley though as the E34 one isn't suitable due to having the rotor arm mounting lug. On this car we machined the 'ears' off the lug so it fits through the hole in the E20 top belt cover but an early pre Motronic top pulley would be easier.

I'd imagine good 200 heads are going to get a bit scarce but yes, the later head fits straight on and works fine.

[Jeroen]

Good to know and sounds well done... so she's running like new again now? Don't hesitate to post pictures!