M20 Distributors?

[Gooneric]

Are all M20 dizzes the same? Could i use a Distributor from any 6 cylinder model E30 and fit it to an early model car? Does it make a difference if i am running M20B25/M20B27/M20b20 engine?

Reason for asking is my dizzy is bollocked and i want to fit a replacement from a used car here rather than importing one, mine is M20B20 but the other models i have options from are all B25/B27 engines.

[vpilarrt]

According to bmwfans its the same cap and rotor for all 3 engines you listed.

[kronus]

Do you have a distributor (behind the alternator) or a distributor cap (on the front of the head)?

All distributor caps are the same, and were fitted to all B25s and B27s. Distributors are less common by far, were fitted to L-Jet e30s like the 323i, but I'm not sure what management the B20 got.

[Farbin Kaiber]

B20 is like the B23, there are three or four different Distributors there. The exterior difference I've found is the two prong connector for signal to the computer. Pull the P/N off the distributor and start hunting for the same number, if you get a different one, you'll have a headache, ask me how I know.

[LJ851]

I have dists out of all the m20 variants and they are all visually the same and you can put them in any M20 (except IX). The only difference between the various mechanical M20 dists is their advance curves as far as i can tell.

I have not personally plotted the advance curves on any but i do now have M20 electronic internals inside my 1986 911 dist. :o

[Gooneric]

Its a distributor and the car is L-Jet .. i'll see if i can get the P/N.. realoem has different part numbers for the 320 and 323 , but they all look the same to me.. however now that you mentined the connector that throws me out a bit. Will have to check that as well.
I dont want anymore headaches lol , i did all the checks and could not figure out what was wrong until i pulled the cap rotor and the covering and found part number 4( impulse sending wheel ) in this diagram with a broken prong :

http://realoem.com/bmw/showparts.do?model=1132&mospid=47257&btnr=12_0011&hg=12&fg=05

[Farbin Kaiber]

I think I have a spare if that's all you need.

[LJ851]

I also have a spare #4 in the diagram you linked to. Dont loose the locating dowel when you pull it apart.

[Gooneric]

I can get Part number 4 , but i would rather have a spare dizzy just in case.
Sent PM

[Earendil]

I have dists out of all the m20 variants and they are all visually the same and you can put them in any M20 (except IX). The only difference between the various mechanical M20 dists is their advance curves as far as i can tell.

Wait what, why not an ix? It uses a M20B25 like the 325i. Is it a fitment issue?

[LJ851]

Wait what, why not an ix? It uses a M20B25 like the 325i. Is it a fitment issue?

The oil pump is driven reverse compared to all other M20 engines. The distributor does not approve.

[Earendil]

The oil pump is driven reverse compared to all other M20 engines. The distributor does not approve.

What does the oil pump direction have to do with the distributor cap?

[LJ851]

This thread is about mechanical distributors that were used on the early 323 and 320/6 M20 engines. They mount on the left side of the block and are driven off the layshaft that drives the oil pump.

[Earendil]

This thread is about mechanical distributors that were used on the early 323 and 320/6 M20 engines. They mount on the left side of the block and are driven off the layshaft that drives the oil pump.

Except that you said "you can put them in any M20 (except IX)". Would that not be the case then? I guess I haven't seen a mechanical distributor, but are you saying I can put one on my US Spec 1989 325i M20B25 that would otherwise use an electronic one?

[LJ851]

... but are you saying I can put one on my US Spec 1989 325i M20B25 that would otherwise use an electronic one?

Yes.

There is a plug that covers the hole were the mechanical distributor used to go. It is that way because the layshaft that drives the oil pump is what the dist was driven off of. All those pieces are still required dist or not. If you remove the plug and install the dist it will function just like the early M20 although the dist cap might hit the B25 intake manifold.

The gear on the IX layshaft is cut reverse because it spins the oil pump the other way so the mech dist does not mesh and it would not want to spin backwards anyway.