RipJaws 3 Report post Posted December 15, 2015 Hi, been doing my research and it seems a few fly wheels can bolt up to the m52 but I have a m40 flywheel sitting out side (I am using the gear box for my swap) but can't really find if it will work or not, it's a pretty chunky little thing, it looks a lot different to the m20 one.. It seems the m42 can and I know the m20 one is preferred but it needs some machining? What does it need before it will be accepted? Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted December 15, 2015 probably can use it but not the best solution. depending on how much of your budget is still there, get an aftermarket one. M20 ones are hard to find now unless you are buying it brand new from BMW (if even still available) Quote Share this post Link to post Share on other sites
RipJaws 3 Report post Posted December 15, 2015 Why is it frowned upon to use an m40? I can get an m20 one from a friend but it's bugging me as to why they are preferred. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted December 15, 2015 is the M4o one you have dual mass? Quote Share this post Link to post Share on other sites
e30ftw 410 Report post Posted December 15, 2015 Because the M20 one is single mass and can be lightened, Better clutch options etc. The M40 one will be dual mass and will probably explode behind an m52 (not really) Quote Share this post Link to post Share on other sites
RipJaws 3 Report post Posted December 15, 2015 Ahh I see. Dual mass being quite a week mechanism then? Or only where the m40 is concerned? I didn't think about the choice of clutches and that alone is the rub. Quote Share this post Link to post Share on other sites
BM WORLD 1283 Report post Posted December 15, 2015 (edited) I have used the early solid mass m43 m42 m40 flywheels from e36 models etc approx. 9.5kg to 10.5kg , they have the recease clutch face, ( later m43 and m44 flywheels are dual mass type about 12.5kg but you cant do much with those etc ) I get the old clutch rebuilt by auto clutch . stronger clamping and new material put on the clutch disc , either std or carbon Kevlar etc. works well enough and you can retain the m52 starter motor etc and yes don't use the dual mass 4cyl ones with the 6cyl 2.5-2.8L early solid mass flywheel looks like this one http://www.trademe.co.nz/motors/car-parts-accessories/bmw/gear-boxes/auction-999166959.htm otherwise go the m20 solid mass type with a strong clutch Edited December 15, 2015 by BM WORLD 1 Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted December 15, 2015 heavier for a start, and also a two piece unit that does and will fail, particularly with hard launches, skids, burnouts etc if thats your thing Quote Share this post Link to post Share on other sites
RipJaws 3 Report post Posted December 15, 2015 (edited) Well that settles that then! Does anyone know a sweet clutch kit, for a good price that will work great with an m52. One that can handle launches and things. Also what machining needs to be done to the m20 flywheel precisely? Edited December 15, 2015 by RipJaws Quote Share this post Link to post Share on other sites
polley 916 Report post Posted December 16, 2015 M20 flywheel needs a skim off the back to clear the sump/block. Though you probably won't find a "decent" setup for what you'd call a good price Quote Share this post Link to post Share on other sites
RipJaws 3 Report post Posted December 16, 2015 OK that is some good info thanks people. Well what would be a recommended type of clutch to use for an m52? Something not insane like 5 puck or carbon Kev or is that what you want Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted December 17, 2015 I used a M20 flywheel, back shaved to the ring gear and balanced, with brand new but a bog standard OEM M20 flywheel and pressure plate on my M52B28 E30 way back when. I did everything a 17 year old does with a high power RWD car, and it held up just fine. There is no real need to get fancy if you are keeping the engine stock Quote Share this post Link to post Share on other sites