WTF did i buy? (lower timing case)

[erb326]

i bought an M42 from an e36 >94 or so the guy said.
motor busted the idler sprocket (flaw in the casting) so i bought a new one but the new one doesnt have an idler sprocket so... WTF did i buy? was there a change in the timing system over the years or is this completely the wrong part. how do i make the one that i bought work

[Dj Buttchug]

the m44 and m42 timing cases are different. i just looked up the part numbers on realoem.

m44 rear timing case is 11141739699
m42 is 11141727191

fwiw i have an m42 case i can send you

[erb326]

so the lower timing case i have is for an m44?

[Dj Buttchug]

yes. from what i can tell.

[rjcaptsean]

It will work, you just need to purchase a different chain guide set, and use an M44 oil pump (the rotor is much thicker than the M42 unit). The chain guide set does not use an Idler pulley so you have one less moving part to worry about breaking.

There are a few threads on this, but I can't remember which site. Do a search here and on M42club.com.

[monty23psk]

m44 is better to m42 design, but either will work, just need matching parts.

[erb326]

Does it NEED an m44 oil pump or is it just a good idea to have it?

[rjcaptsean]

It NEEDS one. The M42 pump is thinner and will not work.

[erb326]

so the older models have the idler spocket, what is the part for the new models? is it the timing rail deflection plate? is this the part im looking for? http://www.pelicanparts.com/cgi-bin/...C%20Each%20%20

[Rustee21]

I am about to do this but I think there’s some misinformation in here. M44 would not have the crankshaft position sensor tab that the one you have has. I think you picked up a late model m42 case without the idler sprocket which is supposedly much better. Should be the same oil pump. How did this work out for you?

[bmwman91]

M42 timing case up to some point in mid or late 1993 has the idler sprocket.
M42 timing case from late 1993 to 1995 has a plastic guide instead of the idler sprocket, as well as the crank position sensor holder.
M44 timing cases have the plastic guide as well, but no holder for the crank position sensor since the M44 has the toothed wheel on the back of the crank.

Early M42 timing cases also use a different main tensioner rail and pivot pin arrangement which is not compatible with the later ones.