TDI M42

Post Sun Oct 30, 2005 1:00 am

http://www.tdi-plc.com/bmwE36318iS.htm

Anyone know what've they done to achieve the 2l? Judging by the bore/stroke it looks suspiciously like e36 s52 pistons (86.4mm bore) and M44 crank (83.5mm). seem to remember on bimmerforums them saying something about these pistons and the m42. If there's sufficient distance between the cylinders, boring it seems like a cool way to 1.9l and yes i know 4 pot wrongness, easier to put in an m50 etc. i'm not about to do it just intrigued.

Post Mon Oct 31, 2005 8:58 am

to add to my own post, it seems pretty likely:
http://staff.connect.com.au/lheather/31 ... 00624.html
anyone know where i can find piston specifications on the web?

Post Tue Nov 01, 2005 1:06 pm

whilst looking for 1.9l conversion pistons for my golf 16v a few years back, i downloaded the mahle and ks catalogues..

They had all the specs you'll need, assuming they do the pistons you're after. Should do. oem for lots of german apps..

jai

Post Tue Nov 01, 2005 4:21 pm

i still dont quite understand what you gotta do to achieve 2litres out of an M42 lump??? is it possible?

Post Tue Nov 01, 2005 5:36 pm

bore and stroke it

Post Tue Nov 01, 2005 7:49 pm

tdi are extortionate prices and rip off merchants!!!

Post Wed Nov 02, 2005 12:03 pm

that tdi stuff does seem well pricey, but i guess it would be big-time labour and they are marketing it as a complete fitted engine etc.
you had experience with them karan? i've never used them, rest assured I'm not about to either.
i found out some more info on cylinder spacing, its 91mm c-c, the same as M50/S50, and the cylinders are siamesed. should be ok to go out to 86mm (a la e36 M3) or 86.4mm (e36 m3 evo). 87mm (a la S54) is pushing it imo.
AC Schnitzer and Hartge used 86.4 on their M42/4 conversions apparently (and they had longer strokes!), and the S42 was 86.4mm bore.
Still a few things i haven't figured out yet:
dunno about the compression ratio using M3 pistons.
what rods to use, guess the m42 ones could be re-machined if nec.
also not sure about head gaskets, whether using a stock M44 head gasket (for 85mm pistons) would match up to an M42, and whether it would be ok with 86mm pistons (think it would be pushing it with 86.4mm pistons). otherwise custom head gasket, not keen on that.

links:
http://staff.connect.com.au/lheather/31 ... 00525.html
http://forums.bimmerforums.com/forum/ar ... 11269.html
http://www.dtmproductions.net/forums/ar ... /t-51.html

Post Wed Nov 02, 2005 3:06 pm

you would need a custon head gasket.. one for an 85mm bore will be too small..

Post Wed Nov 02, 2005 7:56 pm

that's what i thought but in one of those links above (http://staff.connect.com.au/lheather/31 ... 00525.html)
the chap says he used an M44 head gasket with his 86.2mm pistons and seems to suggest that the bore on the head gasket is 86.15 (and that if using 86.4mm pistons a custom gasket is reqd) if i understand him correctly, though i'm not quite clear. I think i'd need to see an M44 gasket and measure up. I can't see why the stock gasket wouldn't quite meet the edge of the cylinders. Any ideas?