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Author Topic: E30 M3 Flywheel conversion  (Read 6348 times)

e30nut

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E30 M3 Flywheel conversion
« on: May 23, 2007, 08:30:58 AM »
Gruppe:
Well into the engine swap/teardown/buildup (Thanks again to AK96SS!). Perfect time to address flywheel upgrades. I've floated the idea of this swap in various BMW forums and could not get a definitive answer.

I have a newly machined S14 flywheel (19lbs/228mm) that SEEMS to be a drop-in replacement (with the 228 clutch kit and M3 flywheel bolts...shorter) for the massive twinmass...what a beast that is! Just due to stupid US A/C cars. The gear rings of the two FWs mesh perfectly, so I'm assuming the starter will just drop right in with no mods! Thank goodness for 4cyl BMW lineage and smart engineers (re-use, don't re-design).

I'll let y'all know how it turns out!

Cheers!
« Last Edit: May 23, 2007, 08:32:32 AM by e30nut »
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gearheadE30

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E30 M3 Flywheel conversion
« Reply #1 on: May 23, 2007, 04:47:04 PM »
huh....this could save a lot of money and time versus the M20 swap...Can't wait for results!
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dude8383

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« Reply #2 on: May 23, 2007, 06:02:36 PM »
Interesting.

Keep us posted please!
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zav3n

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« Reply #3 on: May 24, 2007, 04:04:14 PM »
yes please keep us posted as soon as you finish post some pics specs and how shes running. i would really liek to see how the s14 flywheel would compare to the m20 and if it truly is a droop in mod. if so Im so doing it asap.!
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e30nut

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« Reply #4 on: June 03, 2007, 07:14:15 AM »
can't find my damn digi camera...

Finished assembly yesterday. Physically, fit was fine. Only mod I had to do was cut the 50mm M12x1.5 (12.9) bolts (8) down to 40mm. My initial thought was that I'd just use the M3 bolts (M12x1.5 22mm), but they were WAY short. The 28mm (M20 stock) might have fit, but I didn't have any.

Why do we toss those expensive 12.9 bolts anyway? They can't possibly stretch, right? New loctite 270 on clean threads should be just fine methinks.

Hand-turning the motor is fine. ope to fire it up once the rear tranny seal comes in Tues...fingers crossed.

One more thing...you lose the nifty flywheel lock. The e30m3 FW requires one of those tooth locks...or...just hang a 1/2 breaker bar off the front crank (22mm) when the engine is sitting on a pallet, to lock the drivetrain while securing the flywheel and rear tranny flange (89 ft-lbs final torque...w/ loctitie 270 on the nut collar).

The final assembly is about 1.25" shorter that the twinmass beast...still kinda odd about the bolts...

cheers!
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dude8383

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« Reply #5 on: June 03, 2007, 01:17:04 PM »
Wow, sweet.

Keep us updated!! I think I would be interested in purchasing an E30 M3 Flywheel if this works out.
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gearheadE30

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« Reply #6 on: June 03, 2007, 07:32:38 PM »
I don't know if it would make the balance haywire, but could a hole be drilled in the flywheel to match the bell housing(?) hole?

Otherwise, sounds great. Looking foreward to the results and PICS!! ;)
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e30nut

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« Reply #7 on: June 08, 2007, 01:49:21 PM »
not worried about recreating the nifty FW lock...

Got the motor back in and every plumbed up. Starter gear does not engage the flywheel. Seems to not be reaching it. This would be consistent with the 40mm FW bolt length, which of course was odd...

Coming apart again next week for further review...guess I need an M20 FW, or spend $$ at metric mechanic.
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e30nut

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« Reply #8 on: June 08, 2007, 01:52:59 PM »
oh yeah, one more thing. I used the 228mm clutch and PP from an S14. The whole assembly is shorter as compared to the twin mass setup....so much so that my shifter has move forward noticeably, which is not good.

On the M20 conversion, is the assembly shorter like this as well?

cheers!
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cecotto

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E30 M3 Flywheel conversion
« Reply #9 on: June 08, 2007, 05:04:50 PM »
Quote from: e30nut;27412
oh yeah, one more thing. I used the 228mm clutch and PP from an S14. The whole assembly is shorter as compared to the twin mass setup....so much so that my shifter has move forward noticeably, which is not good.

On the M20 conversion, is the assembly shorter like this as well?

cheers!


The shifter has moved forward??  Why..?

Your gearbox has not movet just because the stack height of the flywheel assembly is shorter?

Or am i reading this the wrong way?
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e30nut

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« Reply #10 on: June 09, 2007, 01:31:01 PM »
duh....my stupidity...shifter was connected 180 degrees backwards. Of course the length is the same, as it is determined by the housing.
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e30nut

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« Reply #11 on: June 09, 2007, 01:42:19 PM »
When I tried to fire up the car after initial assembly with the S14 FW the starter just spun, and did not engage the FW. So I thought the FW might have been too far back for it to reach the FW ring.

Got it all disassembled again. Getting good at this procedure ;)

The S14 FW ring is exactly 1" behind the block (ie: the mounting position of the starter)....same as the M42 twin mass FW...so that's not why the starter gear was not engaging.

I have 2 M42 starters, both were working prior to engine swap/re-assembly. Both seem to be physically release the gear w/o any problem (I pulled on the gear with some pliers and it moved up into position just fine...on both starters)

....what would cause the starter gear to not pop out during cranking? Is that even possible? Sounds like I got a 'lectrical problem now....

Also, I'm wondering if I need a different TO bearing, but we haven't gotten that far yet!
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e30nut

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« Reply #12 on: June 09, 2007, 02:16:20 PM »
Also, I'm wondering if I need a different TO bearing, but we haven't gotten that far yet![/quote]
OK, responding to my own posts...how pathetic!

I'm using the S14 TO bearing which is 25mm tall, same as the M42.

The e21 323 TO bearing is 30mm tall. I'm thinking that basically, the S14 FW is the same as the M20 single mass FW...with a ring gear that matches the M42 starter. The ring gears of both these FWs meshed perfectly when I had them side by side.

So, if the clutch was engaged because of a TO bearing issue, then I would expect the car to lurch when cranking...perhaps I had it in neutral when I cranked it? Don't remember...

The M42 twin mass + clutch/pp stack is ~3.25" deep.
The S14 + clutch/pp stack (228mm) is ~2.75" deep.

5mm = 0.2"

Any thoughts?
« Last Edit: June 09, 2007, 02:27:00 PM by e30nut »
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e30nut

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« Reply #13 on: June 09, 2007, 03:06:12 PM »
the S14 FW is just like this one...
« Last Edit: June 09, 2007, 03:10:58 PM by e30nut »
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e30nut

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« Reply #14 on: June 09, 2007, 05:52:11 PM »
OK, I think I've cracked the code....

It's the FW ring...

My initial thought on the need to change rings or starter gear was that they were different sized teeth. Not that holding them together is a scientific way of measuring a difference in diameter of about 2-5%...doh.

Rings off, little one in the oven (the little M42 ring that is), hopefully re-assemble (again) before dark!

But wait...I'd better wait for that e21/M20 throwout bearing to come in from BavAuto. Should be ready to fire it up again on Tuesday. I will report back...again.

All these findings lead me to believe that the stock S14/M3 FW and clutch is exactly the same as the M20 e30's. And I thought my e30/M3 was so exclusive...:p...heck, yet another sign of good engineering=>re-use!

cheers!
jpg
« Last Edit: June 09, 2007, 05:53:11 PM by e30nut »
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