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Re: 2002 with an M3 crank?

>> What is the stroke on an M3 crank?
>
>84mm, for the standard 2.3 crank.
>
>> Anyone familiar with what is need to put an M3 crank in a 2002?
>> What is needed? rods? different timing/oil gears? bearings? flywheel?
>
>The main bearings are the same.  I think the rod bearings are also the
>same, although BMW lists a different part number for the M3 bearings.
>The main problems to doing this swap:  1) The M3 crank is substantially
>heavier, with larger counterweights. 2) The nose of the M3 crank is larger
>than the 1.8/2.0 cranks.  This means that the nose of the M3 crank would
>need to be cut down, and rethreaded and rekeyed, or you would need the
>M3 chain sprocket, crank pulley, nut, and front seal, with the front timing
>cover bored out to accept the larger front seal.  I'm not sure the M3
>pulley and sprocket will mate up with the 2.0 chain and ancillary equipment.
>At least the rear end of the M3 crank is the same as the 1.8/2.0 cranks.
>
>Also, the M3 rods are longer, 144mm vs. 135mm.  The M3 pistons have a much
>shorter pin to deck height to compensate.  The M3 bore is 93.4mm, which
>is bordering the limit that the standard 89mm 2.0 blocks can be safely bored
>out to.  The M3 uses a block with siamesed cylinders.  Also, the dish in 
>the M3 piston means that mating it all up with M3 pistons and an 8-valve
>head, the compression ends up somewhere around 7:1.
>
>Can you tell I've been researching this?  :) :)
>

Another thing to keep in mind wrt to a stroker configuration is an M10 block 
is the rod/stroke ratio.   I personally would try using as long as rods as 
possible, if I were doing a stroker configuration.  I also agree with Ben,  
its not worth putzing around with increasing the displacement.  Finding 
extra cubic inches in a 2002 is extremely expensive, and not cost effective. 
  There's nothing wrong with the stock crank (many good things, IHMO)   or 
the stock bottom end.

>> After my affair with the pistons not getting sold to me, I figured
>> I would measure my stroker setup and re-evaluate before I spend $400
>> for a new set of pistons.

I'd personally put that money into an injection system, or buying good 
valvetrain hardware. (in a performance application)

>
>I've been looking at this, and am not sure that the gain in displacement
>from 4mm of stroke would outweigh the increased mass and the trouble and 
>expense to make it all work.  Plus, I have a feeling that the resulting 
>motor would be more prone to vibrations and buzzing than a 2.0.  

A well balanced 2002 engine is pretty smooth, I think.   

> 
>> BTW, I don't know if I posted this, but my stroker set up is as
>> follows:
>> 
>> Crank -         88MM
>> Rods -          Stock
>> piston -        cut down. Yup, stock (Noral) pistons which were
>>                 cut down into pop-ups to make up for the stroke.
>
>Cheezy.  Amazing that the pistons are still strong with 4mm taken off of 
>the top.

And dangerous.  Minimum spec for most piston tops is .200" of material.  You 
already took off .158" if 4mm was really machined off.  (Hey---maybe 
Fillippo's discovered something about weight saving techniques that I should 
know about)

If I *were* doing a stroker kit, I'd definately have my pistons made by one 
of the U.S. suppliers.  Or Cosworth. (oh baby....)

That 7:1 M3 stroker setup sounds perfect for a supercharged application....:)

Erik
68 2002  - right on schedule