m42 crank

[tim_s]

a long shot i know...
don't spose anyone has a crank loose that they can take some measurements off of have they? as many measurements as posible would be useful, length, big end dia etc, am scheming....
cheers
tim

[stuartgallafant]

you trying to get more horses outta your iS? thats what i wanna do so i'd be interested in hearing what you've got planned fella...

[tim_s]

hi stuart, yeah am considering various combinations of bore and stroke atm. am trying to get hold of a cheap spare block to work on at the mo so i can measure cranks up etc.
There aren't really any bolt-on parts, everything requires machining pretty much. but basically if you're prepared for hassles and cost, you can get anything from 1.9l-2.1l out of the bottom end. I'll probably end up with 2l and 10.8:1 CR with an engine not as square as i'd like, which is a bit of a compromise, but it should be a reliable setup. It'll probably cost a bit under a grand, and the door will remain open for bigger pistons later.

[Demlotcrew]

Dude i have a block

I also have your Cams in the box ready to ship, just need to get a quote for postage!

Will get them to you soon!

Andrew

[tim_s]

you have a pm andrew!

[jono]

Hello Tim, my name is Jon Finch, I am very interested in what you are doing - I currently rally an e30 318is which has had quite a few mods done to it, just bought a piggy back ecu unit from performance power to try to get more bhp that way (I hope!). Anyway enough of that - I have just stripped an M42 engine down to rebuild, head getting gas flowed as we speak, now I would love to increase cubic capacity to 2000cc or even 2100cc by changing the stroke, (I feel looking at the thickness inbetween the cylinder bores that fitting larger diameter pistons is a no no. I will help you as much as I can (you can ask ant how persistant I am as I spent 100 of hours getting a chip he had written to work) my knowledge of changing the stroke and what it entails is none existant, I have a guy how keeps my engine in top shape he has a rolling road / computer equipment etc. so if you are prepared to share your your knowledge I will build an engine and see how we get on. What are you going to do about conrods? as these will need modifing.

[tim_s]

hiya fella, no probs sharing info, its what we're here for! i'll pm you though, and a lot of things still need working out, if you hang on a few weeks i'll have much more for you!

[E30Mark]

I have a spare M42 engine and have too been thinking what to do with it!

a m44 crank will increase capacity to 1900cc,

What plans you got up your sleeve then?

[tim_s]

hi mark. m44 crank alone won't bring it out to 1900cc, only 1850cc, plus the pistons would need decking or something to deal with the extra stroke. could change to m44 crank and pistons though and get 1900cc. i'm looking at a longer stroke and bore than that with a bit of luck.

[stuartgallafant]

so if you put an M44 crank, rods and pistons into an M42 block, you get 1900cc instantly?

[E30Mark]

so if you put an M44 crank, rods and pistons into an M42 block, you get 1900cc instantly?

I believe so!

|Don't know the rod lengths on the M44, but i can't think of any reason why the piston would come any higher in the block, so it should fit OK.

The thing to remember is the M42 crank is forged, the M44 isn't... i also believe the rods and pistons in the M42 are lightened and balanced, don't know the M44 internals are.

[tim_s]

rods are both 140mm c-c, same big/small end dia, the m42 ones are a bit nicer though. mark, although the rods are a bit nicer, the m42 internals aren't really much better than the m44s (other than crank which i'll discuss below!), or any other bm engine for that matter. the m42's just not that special. also fyi the later m42s use the same rods as the m44.

the m44 crank and pistons should go - the compression height is correct.
having said that the block will need boring and honing + new sized head gasket, might need to deck lightly too, don't whether the valve pockets on the m44 pistons are correct either, and i reckon you'll need to do some machining to fit the crank. tbh as mark suggests its really not worth the bother. it's not just about the crank not being as strong, the m44 crank isn't fully counterbalanced. it's probably not too bad, it just doesn't make sense to swap the m42 crank for a cheaper item that gives such a minimal capacity increase.
by the time you've bought an m44 bottom end, had the machining done on the m42, swapped everything over, changed gaskets, rings etc, you'd be looking at a lot of money for under 100cc capacity increase and no increase in CR - you'll be lucky if it gives you a few hp and a tad more torque. only worth looking at if you're rebuilding anyway, and then probably still there's money better spent elsewhere imo.

on the other hand the 88 crank i've got is forged and fully counterbalanced and 2 litres is a much bigger step

I may be able to build one or two more 2, 2.05ish or 2.1 litre bottom ends after i've finished mine, as i'd like to try some different bore/stroke combinations, but they'd be pretty pricey. i could also put together a 2 litre bolt-on stroker kit that wouldn't require a rebore or even splitting the head from the block (if you're ambitious!), but again it would be pricey, prob Ԛ£800, and it would be a lot of grief for me to source and machine the parts.
its debatable whether its worth putting that sort of money into an e30 m42 really. having said that, compare that to tdi's 2 litre which appears to use the m44 crank and costs Ԛ£2,700 in kit form!
ultimately i am intrigued to see what power i'm gonna get with mine running a squarish 2l, cams and a higher CR (11:1 ish).
hope that helps, oh yeah i have pictures of m42/4 bits if reqd

[Jhonno]

here is some inspiration for you m42 guys...

http://forums.bimmerforums.com/forum/sh ... 471&page=1

Ignore the e36 wrongness of it

[E30Mark]

here is some inspiration for you m42 guys...

http://forums.bimmerforums.com/forum/sh ... 471&page=1

Ignore the e36 wrongness of it

OMG, only read the first page so far... but it looks interesting....

Anyone got a spare E46 320d crank....

[Stevin]

That guy is a mate of mine... can't wait to see how it comes out when 100% done.

His previous plans were, to Supercharge, then Turbo... now he built this.

He has built a Supercharged 4cyl M42 b4... hope this come out nicely... especially the thottles... Cause I may well copy his setup but with the M20

[Demlotcrew]

Good luck to the guy. Hope he gets good power from it.

Andrew

[tim_s]

yeah have been following that project, some impressive commitment to the m42.
there's a few other interesting m42/4s out there too, and a comany in the states who do lots to them. there's some out there with a bigger bore than that south african one (87mm is the furthest), and a few with throttle bodies. i think on e36coupe there's a chap with s50 throttle bodies on an m42, don't know whether its up and running yet though. i'm sure this will be very cool.
i'll try to find the link when i have time.
fyi the e46 m47 cranks are not a direct fit to the e30. there are also lots of variations of cranks - ones with different nose designs and some with drive mass compensators and crank wheels on the crank. even the 'correct' crank needs machining to fit. the e30 m42 pulley design is also a bit of a pain with the crank sensor being there really.

[Stevin]

I've always thought BMW 4cyl from factory had loads of potential, just cause, of what power they make when BMW Motorsport gets hold of them

[StreetSpec]

im following that thread on BFc too ... well, when BFc is actually online i am. Im really interested to see how it pans out. see if it really is worth the effort. Otherwise it'll be back to the FI brawing board.

On a related note ... although the crank is inferior, does anyone know what kind out cpacity you would reach with an m44 crank, + an overbore to fit the s50(86mm) pistons? probly something like 1950cc?

[stuartgallafant]

that is unbelievable!!

im glad somebody has finally gone all the way with a 4 pot, i knew they had potential!!