E36 M42 vs E30 M42 key differences

[josephb983]

I've done a bit of checking, and the main differences between the E36 M42 and the E30 M42 are:

1) different belt system (uses 1 belt)
2) knock sensors, which will not be used after the swap
3) cast internals, vs forged internals on the original E30 engine

For the swap, these items will have to be replaced using the original E30 M42 engine parts:

4) air intake
5) oil pan

These are the only differences. Correct?

I will be swapping in an E36 M42 soon I think. Anything relevant to this swap would be appreciated. I was not able to find much info on this swap, I guess because it is fairly self-explanatory.

Thanks.

[kristofer_turner]

hi mate
oil pan is offcourse different and the intake too and the camshaft is differenent aswell, thats were the later m42 got its extra bit of power from. It flowed a lil better.

 all m42s were double chain driven. internals were the same in both later and earlier engines. and offcours the later engine had a knock sensor added to it.

 Would you not just like to leave the e36 m42 as it is when you put it into your e30?

[josephb983]

hi mate
oil pan is offcourse different and the intake too and the camshaft is differenent aswell, thats were the later m42 got its extra bit of power from. It flowed a lil better.

 all m42s were double chain driven. internals were the same in both later and earlier engines. and offcours the later engine had a knock sensor added to it.

 Would you not just like to leave the e36 m42 as it is when you put it into your e30?

From what I understand, if you do not swap the air intake the hood will not close on the E30's?

[tony92ic]

I think it is the other way around.  The later air intakes were shorter to account for the more aerodynamic design of the e36.

You can put an e36 intake into an e30, but not an e30 intake into an e36.

I have seen an argument that the e30 intake is actually the better of the two, but the topic was hotly debated.

Hopefully someone can more definitively weigh in.

And when they do can they explain why we have to swap the serpentine belt to the V belt when putting a late M42 into an e30. It seems to me if you are using the later accessories you should be able to leave the sepentine configuration, but from reading posts it seems that most people backdate to the v belts.

[kowalski]

from looking at the one in my garage (e36) and the one i've taken apart thats in my car (e30)

the e36 intake is variable length which is good, can be short or long runners looks ugly though.

the valve stem diameters were 1 mm smaller on the e36 head. 6mm vs. 7mm

oilpan

serpentine belt

knock sensors

the internals are all the same other then that (pistons, rods, crank, etc...)

[strypt]

You cannot use the E36 intake because the M42 E30 engine harness wont fit then, and if you are planning on using the E36 harness it wont fit the E30 firewall connector. And the E36 intake will also be very close to the brake fluid tank. (if I recall correctly) ---> use the E30 intake. You'll also need to change to M42 E30 valve cover as the E36 crankcase ventilation will hit the E30 intake otherwise.

[josephb983]

And when they do can they explain why we have to swap the serpentine belt to the V belt when putting a late M42 into an e30. It seems to me if you are using the later accessories you should be able to leave the sepentine configuration, but from reading posts it seems that most people backdate to the v belts.

Is this really true? You have to swap to the v-belt system? You can't stay with the single belt?

[HaNasich]

check out my thread - i've plant an 1996 M42 from E36 in my E30.
i used an 1991 M42 E30 Harness.with the H-U-G-E help of Vlad from this forum...


the main issue was to adopt the C101 connector, but beside that - all connection went fine, the harness fit perfect.
the only thing i came across was the cam position sensor connector - that has four teeth in the newer M42 engine, and the old M42 has 3 teeth.
i solved this by griding the lower teeth and connecting it.

p.s. - the E36 internals are forged as well.
it is the M44 that are cast only.


Ron.

[josephb983]

check out my thread - i've plant an 1996 M42 from E36 in my E30.
i used an 1991 M42 E30 Harness.with the H-U-G-E help of Vlad from this forum...


the main issue was to adopt the C101 connector, but beside that - all connection went fine, the harness fit perfect.
the only thing i came across was the cam position sensor connector - that has four teeth in the newer M42 engine, and the old M42 has 3 teeth.
i solved this by griding the lower teeth and connecting it.

p.s. - the E36 internals are forged as well.
it is the M44 that are cast only.


Ron.

Was the original engine in your car an M42, or was it an M40? Are you here in the United States?