Page 2 of 3
Re: m42/m44 conversion
Posted: Fri Jun 08, 2012 3:57 pm
by Irish_chris
wiz0r wrote:Pretty much all as above.
Option 1: No speedo
Engine, E30 sump, M42/M40 gearbox, custom gear linkage, E30 318is prop (custom prop mounts in trans tunnel), either subframe, custom engine mounts/subframe mods, M20 fly and clutch, E30 M20 starter
If you keep the gear linkage straight you won't need to mod the sump. Bad news is that you won't have a speedo, but you could bastardise an E30 speedo clock into your cluster with a custom chopper wheel setup
Option 2: Speedo
Engine, E30 sump, E21 M20 box, E21 M20 prop, E21 M20 gear linkage, either subframe, custom engine mounts, M20 fly and clutch, E30 M20 starter
Keeping the linkage/box straight will tilt the M42 more vertical and this will make the sump mods necessary. Everything else is much simpler IF you can get the bits, which these days will be costly.
Other considerations:
Custom exhaust, E30 in tank fuel pump (if carb), return fuel line (if carb).
thats given me a lot to think about thanks
I'll be doing this again and based on what I have laying around at the time.
Re: m42/m44 conversion
Posted: Sat Jun 09, 2012 3:46 pm
by drjim
For the effort of doing a swap, putting an M52 in is the best thing to do. Stick the battery and washer bottle in the boot and you're most of the way to the weight difference anyway. I suspect the quoted weights for the engines include all the ancillaries, and the e21 won't be having air con, or possibly PAS so without those pumps you have no weight issues. Nas has converted his 316 to an iron block M50 and had no issues, M52 is lighter than that.
Nas conveniently has the kit to do a conversion sitting in his garage including the M50 inlet stuff, custom made sump etc, it was supposed to be going in the slug when my M10 went into Marks track car, but everything got called off. I do therefore have a vested interest in him selling it as I need my money back! I'll not try to influence matters further
On thinking about it maybe you would like to buy my tuned/throttle bodied M10 instead, need to remove it from the car though!
Jim
Re: m42/m44 conversion
Posted: Sat Jun 09, 2012 4:24 pm
by e21-Mark
M52 transforms an e21. Not only does it make them properly quick, but you also get excellent MPG and reliability.
Re: m42/m44 conversion
Posted: Mon Jun 11, 2012 3:42 pm
by rob0r
I had known what I know now I wouldn't have done an M50 conversion in an E21. Without messing around with the rear axle the E21 driveshafts won't take the power. M52s deliver even more torque. Even if you have a rear E12 fritz conversion you are still keeping the weak link E21 driveshafts... I don't want to go on track and compromise my driving style to ensure my axle stays in one piece...
I think the M42 is the perfect choice for non 6 cylinder E21, also the sump is also easier to sort as it's two piece and needs less taking off than an M50 sump. M42s are debatebly more reliable than M52s and are definitely more economical than M50/M52s. For a 6 cyl E21 the M20B25 is a no brainer, but even then is still capable of destroying axles (Murran).
Edit: Also for M50/M52 conversions many people opt for an expensive rad (I didn't) and the ECU needs reflashing at an extra cost. M52s are often more expensive to buy in the first place.
Re: m42/m44 conversion
Posted: Mon Jun 11, 2012 5:18 pm
by Duracel79
If you can persuad Dr Jim to part with it, I think you best bet is the slugs engine. A well rebuilt M10 on TB's running about 160bhp.
Keeps the weight where you want it and more power than a std M42.
Ben
Re: m42/m44 conversion
Posted: Mon Jun 11, 2012 5:42 pm
by Irish_chris
Duracel79 wrote:If you can persuad Dr Jim to part with it, I think you best bet is the slugs engine. A well rebuilt M10 on TB's running about 160bhp.
Keeps the weight where you want it and more power than a std M42.
Ben
big money though? ive no idea on worth as my experience is in breaking e36/e46's
was considering stripping the car, 2 bucket seats, cage, m44/42 engine. theres an e36 318is with most of this local for in around 400 euro which is in my budget but im still considering what to do
as im sure some have read there is airbag suspension in the car hence the weight issue so i will be contacting the manufacturer to get the load ratings to see what my options are
Re: m42/m44 conversion
Posted: Mon Jun 11, 2012 8:22 pm
by drjim
My engine isn't cheap, 2L rebuilt with s14 throttles, dta ecu, 284 cam, ported head, forged je pistons with total seal rings, fully balanced bottom end, lots and lots of £££ spent, needs an offer over 2 k to tempt me to pull it from the car.
Sounds like quite a few people with ideas about m42 swaps, it is not a bad idea, and once you have it set up you can stick a new engine in easily if it goes pop. I'm hoping my m10 won't pop for a long time, as and when it does I will be going for m52, which is where the pile of bits in nas's garage came in!
Cheers
Kim
Re: m42/m44 conversion
Posted: Tue Jun 12, 2012 1:01 am
by nas80
M42 is weak. End of
Re: m42/m44 conversion
Posted: Tue Jun 12, 2012 10:52 am
by rob0r
E21s are weak, and there lays the problem.
I'm going to attempt to use my E21 M50 in anger for the forseeable future, I've been stock piling driveshafts and diffs...
Re: m42/m44 conversion
Posted: Tue Jun 12, 2012 1:24 pm
by nas80
No its not Rob. Its welded diffs which are the problem ..
I've not snapped a single one and I've been a hooligan plenty of times. In fact the e21 experts said i would but i say to them. Ha! Wrong!!!
Anyway my advice.... Don't bother with an M42. You'll do all that work for 50hp and your car will still be slow.
Re: m42/m44 conversion
Posted: Tue Jun 12, 2012 3:04 pm
by Duracel79
Same here, never had an issue with std driveshafts or differentials on my race car. Sticky tyres and between 185 and 210 bhp, no problems.
The only driveshaft i've seen break was Tommi's CV joint whilst launching at Santa Pod. It was probably a bit loose due to the previous drifting antics with the welded diff.
I've only upgraded my drivetrain as it'll have more like 350bhp and 270lbft going through it soon
Ben
Re: m42/m44 conversion
Posted: Wed Jun 13, 2012 9:25 am
by silver-stue21
Interesting comments on this, after reading all the recent posts and M52 installs (namely nas etc), i'm wondering whether i shouldnt bother with an M20 and go for the newer M52 engine now.....
Re: m42/m44 conversion
Posted: Wed Jun 13, 2012 11:29 am
by nas80
M20b25 makes the e21 good and for the cost your laughing.
Make no mistake. The 24v build threads make it look easy. Its a lot of work.
Re: m42/m44 conversion
Posted: Wed Jun 13, 2012 12:17 pm
by rob0r
E21s had a reputation for weak rear axles before people started welding diffs up, it might be true they are more prone to implode with a welder though.
Re: m42/m44 conversion
Posted: Wed Jun 13, 2012 12:41 pm
by Jason_323i
rob yet to try but e36 cv's joints look swappable, newer & stonger, also you want the drive shafts to be level as angle put load on the cv joint, time to raise the subframe?
Jsut for info what bits did you avtually break.