E36 M42 into E30

[Johal E32]

Hey guys, I have a 91 318is with a cracked head. I had replaced the timing chain and all components associated 100 miles ago.

I have been offered a 1995 M42 from a E36 for a decent price, I know I need to run my E30 intake manifolds, do I need the E30 harness for the E36 motor? Or Do get the donor car harness and make that work in my E30 chasis for the E36 engine.

OR, I could pull the head and swap it onto my E30M42 thats in the car right now?

Thanks!

- Jordan

[TobyB]

The head should bolt up- keep it all e30, with all E36 head metal parts- as in, keep the mechanical stuff
(cams, trays, bolts, etc) together, but use all the rest of the E30 parts (electrical, in, exhaust)

The place where I get a little hazy is the timing chain setup-
I don't THINK the head drillings changed, but I've never looked at them side- by- side.

If it was me, I'd get the E36 engine, look at it carefully, maybe pull the covers off the engine in your car, and see what I thought then.

hth

t

[oldmann]

Swap the 95 M42 into your E30.

E-36 M42 would be a bolt in replacement, as johal32 said, use E30 intake, exhaust, all sensors from E30.

Not sure if 95 M42 had knock sensors, but they can just be eliminated, for E30.

If the engine is sound, but needs new timing stuff, swap your newer components over to the 95 M42.

Up to you if you want to do just a head swap from one to the other, A lot of work either way you go.

[TobyB]

95 M42 does have a pair of knock sensors, just for the record...

I agree, rereading, I'd try to get the E36 engine in, complete.
But it means going through the timing guides/tensioner again...

t

[Johal E32]

Hey just to update for anyone with a similar question.

I got the 1995 M42. I am going to swap over my brand new timing chain guides, rails, tensioner, cam gears and reseal it all. Swap the exhaust manifold, both intake manifolds, valve cover, oil pan and E30 pick up, runn a metric mechanic M20 LTW flywheel with stock 325 clutch and stage 2 disc (Craigslist find ftw), 325i starter, z4 3.0 SSK with all new delrin shift bushings, stock 325i TOB, also going to swap the water pump, thermostat and belts from the old engine since it only has <100 miles as well. Might as well take the NGK spark plugs too. I plan to run the stock 1991 DME and wiring harness.

So far I pulled the valve cover and the cam sprockets look like new, pulled the oil pan and looked up at the cylinder walls and saw a nice cross hatch pattern with no scoring. Coolant came out clean and blue, oil was dark but had no sludge. Compression was 225-230 on all 4 with a hot motor.

I have asked a friend of mine to help me and pretty much take over the project, I have my new semester starting tomorrow so I need to focus on school. I will report back and update as we go along.

[Johal E32]

http://www.e30zone.net/e30zonewiki/index.php/Engine_Swap_-_M42

This is what I read before I bought the engine BTW.. Good info.

How do I delete the knock sensor? Do I just not run them or something? They were not included with the new engine and obviously my E30 wiring harness will not have the other ends for them to connect into..

[RCtheRed]

I'd image since there is no wiring or relay for the sensors you'd be able to just leave it alone and not have to connect or delete any wiring.

Also your compression numbers seem a little high, maybe the head was skimmed a little before but that is good results when it's even.

[TobyB]

I am going to swap over my brand new timing chain guides, rails, tensioner, cam gears and reseal it all.

You may run into problems IF you have an idler sprocket in the timing chain system.
The E36 eliminated this sometime early on, and sometime after that the bosses for
it were (changed? Left undrilled? Drilled differently? I forget)
So you may not be able to use the timing components... this is not a bad thing, as the
E36 system's a lot more durable.

Let us know what you find when you get the front covers off!

t

[Johal E32]

Good stuff, thanks guys. The main reason I went with the late model M42 is that they seem to have more updated parts on them and seem really robust, not that the 1991 M42 isn't but it needs attention for the chain somewhere between 100-200k or something like that..

I checked some part numbers, I can swap my timing chain tensioner, tensioner rail, upper guide (the one near the cam gears), and the camshaft gears will interchange, and the chain itself. So that is good.

I will find out more when I pull the timing covers.

Thanks

[Johal E32]

Sweet all done.

Big thanks to my fellow member and good friend Drewdown.

So the '95 motor is in, I am running all 1991 accessories, ECU, harness, manifolds, oil pans, you name it. temp sensors in the head etc..

Seems to run really good, I have not had a chance to really wind it out but it was revving really fast with the 11 pound flywheel. Get this, no gear lash rattle!

Clutch is nice and stiff using the stock G240 trans, 318 slave, 325i clutch and pressure plate. I ran a stage 2 clutch disc and the engagement point is really really high. I might try bleeding the slave some more and maybe adjust the eccentric bolt on the clutch pedal itself. I am used to engaging at halfway or lower so it was weird moving the car out of the garage for the first time.

[TobyB]

Good to hear! On the clutch, use it a bunch- mine will self- bleed once I get it working,
and after a few days I realize that it's settled down to where it should be all by itself.

t