E21 323i and E30 323i engine differences?

[Dod]

I know the injection system is different and so is the power but when it comes down to it, what exactly are the differences? Like could an E30 engine be of use to rebuilding an E21 item or could it be used as a bare spare (head and block?)

[PeteK]

Same basic design, but loads of detail differences. There's some good info on "M20 - e30 Zone.net". Google away.

[luke]

I ran an e30 block in my e21. The only major difference that made a problem was that there is nowhere to mount the K-Jet warmup regulator on the block. I just drilled and tapped appropriate holes in the block to suit, and it worked out fine.

There are plenty of other detail differences, but this was the only one that really matters much if you're using mostly e21 bits on an e30 block.

[horstl]

Hi,
so far I understand:
besides the missing hole for the WUR the E30 bottom end has a higher CR.
E21 has 9.5 whereas E30 have 9.8 - so different pistons.
Probably the head flows better too, on a E30 engine.
Slightly ported intake / outlets - but same valves.

Not sure about the cam.

Bottom line is: better to use a E30 323i engine and make the K-jet working on it.

rgds

Horst