Author Topic: Some DEFINITIVE pics of M42 vs M20 FW conversion options (Read 33148 times)

thedguy · « **Reply #15 on:** November 16, 2012, 12:27:41 AM »

Quote from: irish44j;117697

You could always also have a new "divot" milled into the M20 flywheel. You could actually just do it with a drill (though the FW would have to be re-balanced afterward, probably)

That was the idea, seeing as I gotta have it shaved to get the weight down anyway.

I'm no where near buying any of this, but it's nice to get some of this cleared up finally.

romkasponka · « **Reply #16 on:** November 16, 2012, 12:29:42 AM »

Quote from: irish44j;117696

Did you use the spacer? If not, then that may be why you had to shorten the pinion throw, in theory, since it may not retract enough to clear.

Problem was that I was not able to install it on m42 starter shaft. Pinion was just longer...

Warsteiner · « **Reply #17 on:** November 16, 2012, 07:06:50 AM »

When you do this conversion, you might have to shave down the area where the ring gear sits on the M20 FW so that the M42 one will fit. The ring gears/flywheels are not the same size in all cases. This is the problem that I ran into when I did mine. Everyone says they are an equal swap and they are absolutely NOT. Everyone keeps talking about a "spacer"? If you're talking about the plate/big ass washer that has the holes for the FW bolts, well that's exactly what it is, a Big washer for the bolts. Other than that it's a pretty simple swap.

1. heat M20 and M42 ring gears and remove from their original FW's
2. cut M20 FW to desired weight
3. cut ring gear seat if needed
4. heat M42 ring gear and let it fall onto the M20 lightened FW

Done!
HTH

Cheers,
~Ralph

romkasponka · « **Reply #18 on:** November 16, 2012, 11:51:04 AM »

and I think balancing after that is must!

irish44j · « **Reply #19 on:** November 16, 2012, 02:55:00 PM »

Quote from: Warsteiner;117704

When you do this conversion, you might have to shave down the area where the ring gear sits on the M20 FW so that the M42 one will fit. The ring gears/flywheels are not the same size in all cases. This is the problem that I ran into when I did mine. Everyone says they are an equal swap and they are absolutely NOT. Everyone keeps talking about a "spacer"? If you're talking about the plate/big ass washer that has the holes for the FW bolts, well that's exactly what it is, a Big washer for the bolts. Other than that it's a pretty simple swap.

Cheers,
~Ralph

good advice.

we're using the term "spacer" because it is being used to space the flywheel back from the engine, and if we say "washer" people will probably be looking for something small

And in an engineering sense, it is actually not really a washer since it's not there to distribute load or allow rotation

thedguy · « **Reply #20 on:** November 18, 2012, 12:45:33 PM »

Can we get pics of said spacer seeing as you have the parts all out Irish?

irish44j · « **Reply #21 on:** November 18, 2012, 09:54:01 PM »

Quote from: thedguy;117799

Can we get pics of said spacer seeing as you have the parts all out Irish?

here you go. It's on the transmission-side of the M42 dual-mass, held on by two silver rivets. You drill out the rivets to remove it. Also you have to enlarge one of the holes to fit around the locating collar on the crankshaft if you use it as a spacer for the M20 FW.

sorry, for some reason I only took a pic of half of it last week...I'll take another if I think of it.

you can see on the left where I drilled out the rivet. The photo is showing the enlarged hole.

nickmpower · « **Reply #22 on:** November 18, 2012, 11:58:39 PM »

I am using a m20 JB racing flywheel, m3 pressure plate, m20 clutch disk, and 323 TOB. No spacer, because the jb flywheel

Warsteiner · « **Reply #23 on:** November 19, 2012, 08:01:29 AM »

That is the "washer" I was talking about and you get them when you get the M20 flywheel, or at least you should.

irish44j · « **Reply #24 on:** November 19, 2012, 08:02:44 PM »

Quote from: Warsteiner;117826

That is the "washer" I was talking about and you get them when you get the M20 flywheel, or at least you should.

Mine wasn't new, so it didn't come with one (they come with them new?). But if people with M42s are doing this conversion, it's easy enough to just take the one off the M42 FW.

Warsteiner · « **Reply #25 on:** November 20, 2012, 07:07:44 AM »

I never bought one new either. Every used flywheel that I have bought always had that "spacer/washer" with it.

~Ralph

Balkanac · « **Reply #26 on:** November 20, 2012, 11:14:26 PM »

did you guys ever get m40 engines in e30s or e36s? I got my SMFW off one of those engines and a M40 clutch kit. Eveything fits perfect, all i needed were m40 flywheel bolts. M20 stuff seems too complicated

romkasponka · « **Reply #27 on:** November 20, 2012, 11:50:07 PM »

Quote from: Balkanac;117910

did you guys ever get m40 engines in e30s or e36s? I got my SMFW off one of those engines and a M40 clutch kit. Eveything fits perfect, all i needed were m40 flywheel bolts. M20 stuff seems too complicated

It depends what you are looking for, because M20 clutch is much stronger and m20 clutch plus flywheel is lighter. The only thing what you can do is to make single mass m43/m40 lighter but that it is all.

irish44j · « **Reply #28 on:** November 28, 2012, 09:55:37 PM »

well, everything went together nicely....

ohne lader · « **Reply #29 on:** December 04, 2012, 07:59:28 AM »

Hi All!

I did a little research in the weekend. I measured M42-M44 DMF and M20 L-Jet FW which is 2,5 kgs lighter than average M20 FWs, so it's 6.090 kg. M42 DMF with pressure plate and clutch disc: 16.93 kg, M20+pressure plate+clutch disc: 12.790 kg! And another advantage: the L-Jet FW's crankshaft side is thinner, and at this swap you don't need the spacer/washer removed from M42 FW.

ps: I'm a new member, don't really know how to attach pictures, but I have a lot about this swap.