M50 conversion flywheel and block options

[lukasbmw]

I currently am running:

1999 M3 Tranny
1995 M50 engine

E30 325i flywheel and clutch

Recently my rear main seal started leaking and I began to explore block options.

QUESTION1:
I currently have M3 cams installed in my head and just need to install the M3 springs and retainers to make my head M3 spec. I also have a m52 aluminum block and 3.0 1995 M3 crank. I could easily make a 2.9 all aluminum S50.

OR

Should I just buy a 3.2 block and throw that together to make a 3.2 OBD1 E30? Latley I've been leaning towards this option as I never track my car and probably never will. I love having torque and straight line accleration. I'm thinking a 3.2 is better in my case.

Question2:
I need to ugrade my flywheel as it come within hairs of rubbing on the oil pan bolts. The flywheel is actually so close to the oil pan bolts, in order to remove the oilpan you need to remove the flywheel. Huge pain in the ass. Time to get a real flywheel. The only problem is all E36 flywheels are dual mass correct? Are there any options for performance flywheels other then a $900 M5 clutch/UUC flywheel combo? I don't want to put a dual mass in my car BUT I also don't want to spend $900 on a damn flywheel.

-ELUK

[erik325i]

Don't get an e36 flywheel, as they are dual mass.
Just take your e30 flywheel to a machine shop and have them shave some material off the back of it. That way, you get more clearance, and a lighter flywheel.

-Erik

[lukasbmw]

Even with a super slim line socket and shaving of the rear of the flywheel, there would still be problems.

I guess my only option is a LTW flywheel. I'm not cofident the stock flywheel and clutch will handle 260hp+

As a matter of fact, I remember a bmwe30.netER with a supercharged m20 having flywheel/clutch problems.

[NickP]

I'm running a shaved single mass m20 flywheel with a sachs heavy duty clutch on my s50 for a couple years now. I don't abuse the clutch but I don't take it easy either. Its holding up great.

So yeah its possible and it holds up; if you're planning on forced induction or any other power adders obviously look at another flywheel option.

[Brew]

Don't get an e36 flywheel, as they are dual mass.
Just take your e30 flywheel to a machine shop and have them shave some material off the back of it. That way, you get more clearance, and a lighter flywheel.

-Erik

As far as I know, the e30 flywheel/pressure plate/clutch assembly does not work with the e36 tranny.

Lukas- Turner sells JB racing flywheels that will work for your setup. I'm going to be getting one within the next month, but since I'm using the 260 tranny, I'm getting the e30 325i flywheel.

As far as your engine plans...
I was planning to do a 2.9L non-vanos stroker myself, but I ran across a deal on a 3L shortblock that I couldn't pass up. At this point my plan is to use the S50 bottom end with my s50-cammed non-vanos head. I feel a little more confident with a bottom end that was put together in a factory than one pieced together from 'junkyard' parts.
Do you know the history of your aluminum block? They are very easily damaged by overheating. You'll know its been overheated if the head bolts strip out when you torque them. I've also read that there -may- be an issue with putting an OBD1 crank in a OBD2 block, specifically with the crank pulley and timing chain. There also -may- be issues with using a OBD1 head on an OBD2 block. I'm sure someone else can clarify.
Basically if I were you, I'd bring the alloy block and all your other engine parts to a engine machinist who is familiar with BMW stuff.
Honestly your best bet might be to find an S50 short block.

[CarsSuck]

If you do go the alum. block route, write a few big posts about it. I've considered this engine but i am told the cooling passages dont line up between the head and block. I wonder if another M52 head from an iron block motor would work (both are M52, alum. block is M52tu).

[NickP]

As far as I know, the e30 flywheel/pressure plate/clutch assembly does not work with the e36 tranny.

Lukas- Turner sells JB racing flywheels that will work for your setup. I'm going to be getting one within the next month, but since I'm using the 260 tranny, I'm getting the e30 325i flywheel.

As far as your engine plans...
I was planning to do a 2.9L non-vanos stroker myself, but I ran across a deal on a 3L shortblock that I couldn't pass up. At this point my plan is to use the S50 bottom end with my s50-cammed non-vanos head. I feel a little more confident with a bottom end that was put together in a factory than one pieced together from 'junkyard' parts.
Do you know the history of your aluminum block? They are very easily damaged by overheating. You'll know its been overheated if the head bolts strip out when you torque them. I've also read that there -may- be an issue with putting an OBD1 crank in a OBD2 block, specifically with the crank pulley and timing chain. There also -may- be issues with using a OBD1 head on an OBD2 block. I'm sure someone else can clarify.
Basically if I were you, I'd bring the alloy block and all your other engine parts to a engine machinist who is familiar with BMW stuff.
Honestly your best bet might be to find an S50 short block.

The e30 single mass flywheel works just fine with the ZF tranny as per my post above.

There's no issue with an OBD1 head on an OBD2 block as long as they're both single VANOS.

[Brew]

If you do go the alum. block route, write a few big posts about it. I've considered this engine but i am told the cooling passages dont line up between the head and block. I wonder if another M52 head from an iron block motor would work (both are M52, alum. block is M52tu).

The aluminum block that we're talking about is the M52 from the Z3, not the double vanos m52tu.

Nick, thanks for clarifying that stuff. I ASSumed that the overall thickness of the pressure/flywheel assembly would be different, and the clutch wouldn't engage/disengage properly.