95 E36 M42 -- bad head, looking for options

[Jaredmac11]

So I took my M42 head out of an e36 95 sedan to a machine shop to have it tested and they confirmed its been overheated and has a crack and is donezo.

I have 2 E30 M42s in my garage from a friend who needed space.

I, foolishly and regrettably bought most of the parts I needed for the E36 m42; bearings, gaskets, valve stem seals, etc.  typical rebuild parts.  So I dont want to fully abandon the E36 M42 but I can.


What sort of options do I have here?

The options as I see it are:

• Acquire an e36 M42 head that is confirmed good from a shop ($300)
• Abandon E36 build with parts, find parts for e30 M42
• Possibly Frankenstein an engine and use an E30 head on an M42 block?  Is that even possible?

Just a note:  This is going in my E21 3-series.  I wanted to maintain OBD1 and not move up to OBD2/M44.

edit:  Found some more information, the core head between the E30 and E36 appear to be almost exactly the same, however, the valves are 6mm for the E36 and 7mm for the E30.  In addition the E30 use dual springs and the camshafts between the 2 appear to use different numbers.

I'd like to use my E36 valves, springs, lifters and cam but I'd have to swap out the valve guides and that does not seem feasible at a reasonable cost.

[benz-tech]

Run the e30 head and cams. Pay to have the 6mm guides and valve job done, it's worth it.

[Jaredmac11]

Run the e30 head and cams. Pay to have the 6mm guides and valve job done, it's worth it.

Just out of curiosity, what sort of difference does the lighter valve give?  Less weight = better in engines, but does it just allow the valve more clearance for better air/fuel mix or what?