Warsteiner, Wazzu70 and bmwman91 convince Norm he can build a smoking M42

[normboudreault]

Getting bored??? Are you nuts.. this is awesome! Learning about this stuff is why I decided to do this resto in the first place!!

And thank God for you guys, easily the most helpful bunch anywhere... 

I have no objections about porting my own head - just have to learn how its done first... man being a noob sucks... LOL

So which route to go? M44 or M47? Where would I get my hands on an M47 crank? Dealer sourced part not withstanding...
Would one make more low-down power than the other? Seems an M44 crank, being a direct "descendant" of the m42 would be a
better fit no? But again, what do I know... 

Im open to both but would like to know more what the primary differences between them are...

As for the cams I TOTALLY agree. A nice spread over the power band. Lets be honest - city driving is all about low down torque. I wont track this car - that's for rich people and their M3's  - but I do want to drive the hell out of it everywhere I go...and that means torque. I want whiplash everytime I leave a stop sign. And Im 42, not 18... We all age but some of us don't get any older... hehehe

So then your top recommendation is 250/250? From which supplier?

As for the transmission - as far as I know its the original, a Getrag 240, but as my car is a January '91, that means it would be an E34 518i unit. I have not found anything but a serial number on the unit so I can be 100% on that one. I never drove the car so I don't even know what condition its in... When you say close ratio, which models would fit the bill?

As for the diff, I've seen many 4.10s on ebay but man Im leary of buying one.. Who knows what shape they are in? If I do have mine rebuilt its about 800$ so I better be sure before I commit... Mine is the BIG LSD diff and I've read the smaller ones are actually better... what's a guy to do??

As for ITBs Ive read pros and cons regarding those. I do know thats too involved for now. But, when you sell me your M3 I'll let you know how I feel about them.... 

So, where does this all start parts wise - crank I imagine - then con rods and pistons?

Enough typing, I have to go work on the car, if I ever want to start on the engine....   

[wazzu70]

The M44 crank is a drop in replacement for the M42 since it was designed to be used with the same engine family. The M47 crank is from a diesel and must have custom machining to work properly.

The reason people go through the trouble to fit the M47 crank is it has a longer stroke. A longer stroke creates more low end torque. The M44 will have more toque than the M42 crank, but not as much as the M47.

Choose what crank you want to use first and that will help decise what pistons and rods you need.

The M47 cranks can be sourced from Europe, or bought new at the dealer. M44 cranks can be found almost free, M47 cranks cost a pretty penny.

[normboudreault]

Great explanation - thanks!

Looking on ebay I see m47 cranks as low as 200$... I imagine I should only buy new right??

Now the question becomes: how great is the difference in torque? (assuming similar setups)

[wazzu70]

You have to make sure its an M47 unit and not an M47N. The M47N will have a shorter snout and have a stroke greater than 88mm.

Otherwise, Id get a used crank if its available. Just have the machine shop check it out before using it and make sure there is no unusual wear. The machine shop needs to modify the snout of the crank anyway so you could just have them inspect it then.

Its a nice way to save a few hundred bucks!

[normboudreault]

Good to know. I haven't decided on one vs. the other yet...


Oh, and I just bought my parents house like 5 minutes ago, big double garage!! That will screw up my timetable for my build this summer but make working on the car and engine way easier...

[Warsteiner]

Wait...... what......Oh no......What's that?

[normboudreault]

That looks NUTS!!!

[Warsteiner]

Yes make sure its the M47 and not the M47N. They look totally different like Nick said. M47 is the way to go....

I had my cams cut at Dyno Spot Racing in Cali. Talk to Dick Chiang. Don't mention my name....Hahaha.. JK
http://www.dynospotracing.com
1798 Angela St, San Jose, CA 95125
(408) 271-9800 or maybe (408) 885-9988
Email:info@dynospotracing.com

I bought my crank new from the dealer $800 plus a $100 core charge. PN 11 21 2 247 514/reman. Get the remanufactured with bearing shells which is that 514 number. The 515 is a new crank which is probably way more money.

Stick with the stock transmission. No need to get all fancy and try to find and fit a close ratio for daily driving. If you want an upgrade then MM has the sport for our car which has larger bearings, more beefy, and a different gearing so one can hit 60mph in 2nd with 7100rpm. I think. Email them.....hahahaha

The diffs are small 168, to medium 188, to large 210. Most of us go from the stock 168 to either the M3 188 4.10 or 325 188 3.73
The smaller ones are lighter but not sure how they'll handle all that torque from the stroker.....

They wouldn't have given all the real E30M3's ITB's and the Euro M3's ITB's if they didn't make a difference. Notice how all the US M3 models got the single TB and hydraulic lifters and less compression, and ...... The Canadians got the good stuff with all the Euro models but noooo Not in the US!

Everything is for sale...for the right price

Decide on a crank and work your way up to the -.15mm sticking out of the block first. Then you can think about head work and A-N and exhaust and tuning......

Congratulations on the House!!!! Now maybe you'll have room for my M3 when you buy it? LOL

Well.... Nuts is good right? Lots of work.....Did I mention 33mm buckets and 6mm valves? Oh...I probably forgot those. Ooops...

Cheers,
~Ralph

[normboudreault]

Ralph, you're gonna bankrupt me before your done.... 

Hey thanks on the house - I cant possibly be the first guy whose bought a house so he can have more space to restore his E30 right?? 

Btw, Im printing this info to keep it all handy.. Hopefully the move doesn't set me more than 1 month behind on the build... 

[Warsteiner]

Headers to the left.....headers to the right.....

[Warsteiner]

ooops...the computer just happened to send the 33mm S52 cam tray pic too....hmmmm

Cheers,
~Ralph

[normboudreault]

Jeez, and I thought PORN was addictive...     

[normboudreault]

Hey youre smart - any ideas how to move this mess to my new home about 1mile away:



Aren't you in New Jersey... hmmm what you doing this weekend??...hahaha

[Warsteiner]

That's you and 3 big friends lifting it up and putting it onto your friends trailer after you have fed them pizza and beers....

Now.... Is that your, you're or youre smart? LMAO

[keflaman]

These cars are surprising light once stripped down to where you have it now. I loaded this myself using two jack stands, one car dolly and an engine hoist.