"Pinking" and other problems

[duffusdipspinner]

Hi guys

we need help.

Got the e36 M42 engine into the e30 and it's running.

The problem is that under load the engine is knocking/pinking etc and sounds like a diesel at tickover.

Now the e36 version uses different cams from the e30 version, so I'm wondering if it's the different cams causing the problem seeing as the e30 ECU will not be timed properly for the newer cams therefore causing the problem. Any ideas

Also, we can't bleed the cooling system properly, basically can't get the coolant to go through to the heater matrix. The engine seems to be running very hot, although we can't tell because we don't have a working guage now. That could cause the pre-ignition I know. Where is the thermostat on the M42 lump ?? Maybe it's stuck closed ??

Any help appreciated.
Thanks

[strad]

Thermostat is where you'd expect, behind the housing that has the two main radiator hoses coming out of it.  

Not a swapper yet, so can't help with the other q's.  Edit: if I had to guess though, I'd say that running the correct ECU might help.  The E36 M42 has knock sensors, the E30 M42 doesn't.

[bmwman91]

If you are running the E36 motor from the E30 ECU, that is your #1 problem.  Did you put the E30 intake manifold on it?  The E36 one is a dual-track one that is completely incompatible with an E30 ECU.  The cam differences do not help either.  You will need to run it from an E36 ECU, OR put an E30 intake manifold on (+ E30 fuel rail & injectors, the E36 used different ones) and swap in some E30 cams.

As for the overheating...
Did you use any gasket sealer on the thermostat housing gasket?  If so, it can gunk up the air-bleed passage in the housing, causing a lot of issues.  Pull the cover off again & check to make sure the little groove between the 2 "chambers" is not plugged.  As far as the heater core business, I have never bothered with that on the M42 when bleeding the system.  From the design of the water system, it looks like any additional air in the system can bleed out on its own into the expansion tank.  Of course you should do everything you can to get air out yourself, but the heater core is not as big a deal as it is on other cars.