Best M42 Mods

[irish44j]

The whole starter will bolt on as long as it physically matches the M42 bolt locations. IIRC I got one off of an M50 car in the junkyard, but I could just be talking nonsense there.

You will see the area that needs to be shaved to clear, the flywheel will rub on it and you just take off as much as needed. Some M20 flywheels seem to be a bit different so YMMV. The other way to go is to take the spacer ring off of the M42 (riveted on) and put it between crank and M20 FW. Either way you will quickly see the issue, so just be a bit creative about solving it and you are all set.

M20 starter is direct bolt on, but it doesn't use the "nub" that the M42 starter uses as a third stud. Not sure why, but it seems fine without using it.

here's a view up the flywheel with the M20 starter pinion gear clearance.



here's the part you need to shave for the M20 FW to clear the motor. Note that I am using the M42 "spacer ring" on mine and still had to shave it a bit. You can do it with a file, grinder, dremel, whatever. It's not going to affect anything structurally...those are just ribs that hold the oil pan bolt bracket, basically.

[irish44j]

But do I have to get an M20 clutch as well, or can I still use the M42 clutch. Mine has less then 10k on it, don't want to waste it, lol.

The whole starter is direct bolt on? Or just the pinion? Every where I've read, people just swap the pinion on them.

Also, are there pics/ is there a write up on where exactly you're supposed to shave down? Searched but no in depth details. I'm considering this pretty soon..if its that easy, then I'll get the M20 FW.

Sorry for all the questions..I'm still learning the ways of the E30's!

yeah, M20 clutch. I didn't think much about that since mine came with a lightly-used M20 clutch that I just re-used.

M20 starter is direct bolt-on. Guys change the pinions so they can keep using their M42 starter I guess, IDK. I have a reman M20 starter on mine and it works/engages/disengages just fine, no problem.

[decay]

I've heard of the VW lifters...what VW in specific would I look up to find these? My lifters are fine right now, but I know I'm creeping up on 200k so it might be something to think about soon.

you are going to want to google there; VW lifters are the "same" for a lot of 8v/16v/etc engines but even within the VAG options they discovered some were lighter than others- i think they found the "best" ones were from a euro diesel. if you can't find the answer on vwvortex/etc, call rapidparts.com and tell them you're building a revvy engine and need the "good" lifters.

[InNeedOfBoost]

I've heard of the VW lifters...what VW in specific would I look up to find these? My lifters are fine right now, but I know I'm creeping up on 200k so it might be something to think about soon.

[bmwm42]

They are badass I love em was a cheap easy upgrade the car is even more r3v happy and they weigh allot less

[decay]

Vw lifters

hell yes. so badly want to do that & the MM single timing-chain conversion.

[bmwm42]

Vw lifters

[roguetoaster]

The whole starter is direct bolt on? Or just the pinion? Every where I've read, people just swap the pinion on them.

Also, are there pics/ is there a write up on where exactly you're supposed to shave down? Searched but no in depth details. I'm considering this pretty soon..if its that easy, then I'll get the M20 FW.

The whole starter will bolt on as long as it physically matches the M42 bolt locations. IIRC I got one off of an M50 car in the junkyard, but I could just be talking nonsense there.

You will see the area that needs to be shaved to clear, the flywheel will rub on it and you just take off as much as needed. Some M20 flywheels seem to be a bit different so YMMV. The other way to go is to take the spacer ring off of the M42 (riveted on) and put it between crank and M20 FW. Either way you will quickly see the issue, so just be a bit creative about solving it and you are all set.

[InNeedOfBoost]

^^ Thank you sir.

[decay]

I've got the single mass non ac fw lightened to 18 pounds with a stock clutch and it's great

yeah, i should have done that.

edit: no mix/match. m20 clutch and flywheel, or m42.

[InNeedOfBoost]

the "modifications" for the M20 setup are almost nothing. Take the spacer off your stock flywheel, shave about 2mm off the lower oil pan ribs, and use an M20 starter (direct bolt-up) and M20 flywheel bolts. It is really very simple and can be done in literally minutes..... Even with the starter, it's probably cheaper than what you'd pay for an M42 single-mass, since you can find M20 fW's dirt cheap - plus the M20 has more clutch surface area with the same weight.

But do I have to get an M20 clutch as well, or can I still use the M42 clutch. Mine has less then 10k on it, don't want to waste it, lol.

The whole starter is direct bolt on? Or just the pinion? Every where I've read, people just swap the pinion on them.

Also, are there pics/ is there a write up on where exactly you're supposed to shave down? Searched but no in depth details. I'm considering this pretty soon..if its that easy, then I'll get the M20 FW.

Sorry for all the questions..I'm still learning the ways of the E30's!

[AndrewBird]

Improved idle, but that's it. It might have a very minor effect on bearing wear as it would help dampen engine vibration, but I doubt it would be even measurably different.

[Simon S]

just for discussion's sake, I must ask the question:

Does a heavier, dual-mass wheel featuring vibration-dampening design help an m42 engine to last longer, as well as helping a g240 transmission last longer?

In other words: What are possible benefits to maintaining a factory dual-mass wheel on one of these cars?

[irish44j]

Yea, sorry...I was referring to the single mass M42 flywheel. From what I read in a few places, the M42 SINGLE mass + clutch + pressure plate weighs the same as the M20 setup.

Of course, it goes back to the M20 setup requiring modifications and the M42 SM being ridiculously hard to find.

the "modifications" for the M20 setup are almost nothing. Take the spacer off your stock flywheel, shave about 2mm off the lower oil pan ribs, and use an M20 starter (direct bolt-up) and M20 flywheel bolts. It is really very simple and can be done in literally minutes..... Even with the starter, it's probably cheaper than what you'd pay for an M42 single-mass, since you can find M20 fW's dirt cheap - plus the M20 has more clutch surface area with the same weight.

[irish44j]

yeah, i was unclear, sorry.

single-mass flywheel was an expensive bit. ask shops that have BMWNA connections.

yeah, I ninja-edited before I saw your post :)