Author Topic: Norm's e30 M42 Rebuild: Input needed! (Read 7162 times)

normboudreault · « **on:** November 06, 2014, 02:19:54 PM »

Alright guys, those following my rebuild thread know Ive been talking about rebuilding my m42. Its from a 1991 318iS with 235000kms. Ive found a shop with lots of experience in high performance rebuilds and they are keen on taking on the project. Im not planning anything crazy but I need to have an A-Z idea of how this project will proceed. The car is a summer driver for fun, no racing, no tracking.

Since Im doing a rebuild I want a wee bit more power and torque. Ive never driven the car but I know it needs more power!

Bottom End
Crank:
I know I can go stock on the crank, M44, M47. My preference is for the M44 for simplicity and cost. 83.5mm stroke
Internals:
Here I want to lighten things up to reduce the recip. mass.
Connecting rods: What will I need and what should I get and where should I buy them? MM, VAC etc..
Pistons: Same considerations as for the connecting rods.
Overbore: Planning on a slight overbore (nextsizeup) if block specs ok.
Bearing shells: What are my options?
Flywheel: Planning on an aluminum flywheel with uprated clutchkit from Vac...Seems less hassle than the m20 route...
Anything else?

Top end
Was planning on a Vac head but im thinking I will have this one rebuilt. Will be way cheaper. MM offers some tasty upgrades but are they worth it? What should I do?
Camshafts: Expensive.. not sure about these.... Options?
Fuel injectors?
Water pump?
Is the single timing chain conversion worth it? Any considerations with this setup?
Is the m44 chain tensioner change worth it?
Planning on the throttle body heater delete too...

Do I need ARP bolts? Where should I use them and which ones to order? The ARP site doesnt list the M42...

Will I need new engine management for tuning?

What should I ask of the engine shop? The owner seems really friendly and relaxed.. This is a small shop away from the big city with 25+ years and recommended by other shops... No stress...

I initially wanted to do more but now that I have a 2nd iS with an engine that also needs work and an e30 M3 I will buy one day I am more restrained. Im hoping for 170hp with around 5000$ to budget.

Gentlemen, thanks for the help!

DesktopDave · « **Reply #1 on:** November 06, 2014, 03:34:51 PM »

Wish I knew more about these engines. Never been tempted to build one. I am told that the later M42 & M44 rods are lighter. The entire M44 cam chain system is much improved. I'm told that NA E36 M3 pistons can be persuaded to fit.

Instead of a new standalone, I'd focus on upgrades that can fit within stock Motronic constraints. I'd certainly consider a stainless dual-pipe exhaust, along with a newer catalytic converter to eliminate the expensive OEM units. A nice WBO2 could help. PM Barrie (Midnight Tuning) or talk to Mark D'Sylva. Both are members here, and both might offer you excellent suggestions.

The alu flywheel is a tempting upgrade, but I've heard they're perhaps a bit too light. Personally, I'd go with the smaller M40/M42 non-A/C flywheel instead of the M20 unit, unless you're planning on a lot more power. You should be able to find them in Canada, as the non-A/C cars were more popular up north.

I'd skip the ARP studs...unless you're doing forced induction.

I'd also be on the lookout for updated injectors. The newer plastic-bodied types are superior. The Mustang 19# units work well, but after having used them I'd go a wee bit bigger. Maybe 22#-ish? I'd also be tempted by the "showerhead" Denso types. I haven't gotten a lot of info on them, once I get a set I'll post my findings.

Mimikrakra · « **Reply #2 on:** November 07, 2014, 11:17:11 AM »

Hi, you don't need ARP studs. When you change these engine part you do need an engine management.
Why do you change the crank if you don't put a new camshaft ?
My daily M42 is stock with just a ship. with 330000 km it sort 147HP.

Tgoode318 · « **Reply #3 on:** November 07, 2014, 01:10:23 PM »

Hey Norm! With 5,000 you could go down a number of different paths. Based on what you said you were looking for this is what i would recommend.

Your main focus here is going to be increasing displacement and stroke as this will give you the much needed torque that this engine lacks stock. If you were going for a track type set up you would have massive cams & extreme compression itbs port & polishing mass reduction etc, but the problem with this set up is around town you would have to rev the nuts off of it and look like an ass in doing so. Even if you did that you would never fully utilize the power band :_( .

Here's what i would recommend.
Crank: m47 Can be had from BMW N/A new for 800 Or you can find one on euro ebay/ junk yards etc.
Pistons: Cp Pistons From vac $699
Connecting rods : Arrow vac $1,200
Cam's: Vac's in house cams -$750 or get yours reground $250-300
Engine management: Go standalone. This in the end with proper dyno tuning will give you the best driveability custom tuned for you modifications i would recommend haltech $1,000 or Vems
Light weight flywheel: $600. As dave said you dont want to go to light here but 8-9 pounds Again vac's JBR is a great option
I would also go for performance coated rod bearings $179.
& Performance coated main bearings $149
Total cost 5.3k Not including putting every thing together.
That would be a bad ass engine and it would be very torquey and fun to drive around town
My 2c ; )
-TG

keflaman · « **Reply #4 on:** November 07, 2014, 03:29:42 PM »

No affiliation, but I've been watching this ad pop up and down on CL for over a year (or two?). Maybe it's something you could use.

http://charlottesville.craigslist.org/pts/4681887858.html

Maybe not.

Warsteiner · « **Reply #5 on:** November 07, 2014, 03:55:17 PM »

I agree with what everyone is saying so I'll add a little more....

Norm, why don't you just buy mine? LOL

So here's my rundown....
Crank...definitely do the M47... no question
Pistons....go for the US S50 because they are cast not forged. Forged will be slapping around your cylinders until they are warm up in street motor. If your machine shop is good, then there is no issue with giving you the exact compression you want. By the way...What compression do you want?Also..going with S50 86mm pistons let you use the M44 1.9L HG. Not sure that the S52 86.4mm piston will fit without modifying the HG or going cometic HG in which case you will need to go ARP studs.
Connecting rods...GSR B18C 138mm rods...choose whatever aftermarket company you want
Cams...I can hook you up with my guy out in Cali that made mine with less duration 250* but more aggressive all around compared to MM and Schrick equivalent
Engine Management...you could go with a stand alone or... go see Barrie or Mark
LWF....M20..make it any weight you want and you'll never have any issues...mine is 11-12#'s , Clutch kit is a stock E30 325
I used stock bearings on my build.
Port the head. Add 6mm valves with some S50 33mm cam buckets and beehive springs.
Ditch the AFM and run MAP or A-N or a blend. You can ditch the ICV too.
Now you need a custom header thats slightly larger than stock with a custom transition piece to mate up with the E30M3 dual pipe exhaust!
The only thing I didn't mention was the ITB's which are a must to make this all work....LOL
When all is said and done, you'll have my engine and drive-train in your car

Don't forget about the E30M3 diff to handle all that new torque which will last you forever...

You could always go with slide throttles as well with the custom intake plenum to make the engine really scream...PS I have one of those too...ssshhhh

So when you're done building all that, you won't need the E30M3 anymore... You'll have that and some E36M3 in your motor as well! And if your good with resin and plastics you can make the E46 intake plenum fit as well.

That congfig should yield you 2045cc. If you can get 205HP then thats 100HP/L which is very respectable.

Heading out to tune my car right now....

Cheers,
~Ralph

DesktopDave · « **Reply #6 on:** November 07, 2014, 05:45:38 PM »

Quote from: keflaman on November 07, 2014, 03:29:42 PM

No affiliation, but I've been watching this ad pop up and down on CL for over a year (or two?). Maybe it's something you could use.

http://charlottesville.craigslist.org/pts/4681887858.html

Maybe not.

I remember the first time you posted that....definitely a lot of bang for the buck. If I wasn't restoring the E24 I'd be considering it myself.

Darky · « **Reply #7 on:** November 08, 2014, 02:57:32 AM »

Hi Norm
Great idea starting this now!

Big decision time.

Bottom End
Using a m44 crank with 83.5 mm Stoke great idea for NA build, not recommended for forced induction or large compression being cast but for the 170 hp mark. Neat!!
I also believe that it is the lightest crank for these engines.
Connecting rods shouldn't be a massive concern even m44 rods would do, no need to spend huge down here when your not going large compression, but most are around the 500g area. Which does save you a bit of mass.
Pistons would probably be cp 86 mm s50 US or similar, that way you can use m44 head gasket any larger and you have to get a exotic type of head gasket!$
With that crank and Pistons you will be at 1939 ml.
Bearings I would use MM tri metal, very nice gear. (I find it interesting that xrallyparts also sell tri metal bearings, hmmm)
Flywheel does not really matter weather it's aluminium or steel as long as it's around the 6 kg mark.

Top end
The e30 m42 head has good points and bad.
Springs are quite good
The 7 mm valves have got to go! While your there may as well go oversize no price difference.
So with this you will also need new valve guides.
Obviously get the head ported and polished while your there.
You should do the s50 cam tray mod, I used m52 trays same part numbers. Again this lightens the mass and is reliable and inexpensive!
Camshafts, what inlet manifold are you going to use? You see the standard e30 m42 is undersized 38 mm, they did this improve torque down low. Ideally it should be 41.8 mm. So if your going to use this go 250-270 deg <10 mm. Long duration will get the air there.
M44 timing chain conversion is definitely worth it for 2 reasons larger oil pump (strong heart) and deflection rail rather than wheel. Less mass.
Single row timing chain conversion there is a lot of mass to be saved here but it's single row. But if you go single row you have to do the m44 timing chain conversion for the stronger oil pump. Ie more pressure on the chain.
Throatle body heater in Australia is useless. It's bloody 40+deg c outside why the hell are you heating the air even more, but Saying that not so sure about Canada.

As for arp bolts, not necessary MM makes some m3 bolts and there cheaper.

Hope this helps Rohan

normboudreault · « **Reply #8 on:** November 08, 2014, 08:31:14 AM »

Gentlemen lots of good ideas!! Thank-you.

Tgoode318 - I like your thinking but I think the m47 crank will be quite the hassle, not only to source but to fit and ensure all else fits..
Flywheel - Vac is the front runner here -good call..
Performance coated main and rod bearings - I like it - who sells 'em?
Cams - expensive and Im wondering how much its worth bothering with.. Opinions??

Dave - I agree with staying with the Motronic but mostly out of fear of dealing with a stand-alone! Once we've squared away the
details on this build I will speak to Barrie and figure which route is the way to go. I am also planning the stainless steel
exhaust (sans-cat) and a twin tip muffler (remember my double cut-away rear end I welded in!)

Ralph- I don't need to do anything you said cause I will buy your M3 from you anyways...

But, going with the M44 crank what are your recommendations?

Darky- Always appreciate hearing from you Rohan! I am planning a NA build - keep it stock!
If I use the m44 is there a required/recommended connecting rod length? Never ordered any, not sure how that will work..
Bearings, I have looked at the MM ones, very nice.
Top end - I agree, 6mm (oversize??), new guides, new springs.
Never heard of the s50 cam tray mod - details please!!
Inlet manifold - never had plans to change it - where do I get a 41,8mm one??
Camshafts - again, expensive...recommendations??
I agree with the M44 timing chain conversion - what do I need parts wise??
Single row on the timing chain as well Ive learnt is a good idea.. What do I need for it?
Throttle body heater will be deleted - its a summer car!

Darky · « **Reply #9 on:** November 08, 2014, 08:51:08 PM »

Hi Norm

Your connecting rods will need to be selected at the same time as your Pistons! To hit your desired compression ratio. Which is?
Valves are standard 7 mm stem and 33/30.5. But if your buying new ones to get 6 mm stem go 34/31.5 mm (oversize). More air more power good

Valve springs on the e30 m42 are really good if your planning on going to 8000 rpm change them otherwise wouldn't bother.
The s50 cam tray mod is the same as Ralph 33 mm lifters. You need to do it to use the smaller lifters. M42 lifters are all 35mm. But pictures speak a thousand words and video is even better. YouTube s50 m42 cam tray mod, you'll find it!
Inlet manifold your new donk will need a 47.5 mm manifold but there ways around this, ie long duration cams or itbs. There's 42 mm set getting developed on this site. S50 itbs are 48 mm and there's companies that make 45mm around.
Parts for the m44 timing chain conversion mabeer did a great write up on it, In his build.
All you need for the single row timing chain is a timing chain from MM. You can get you camshaft wheels ground down too, lightens things up again!

Cheers Rohan

Warsteiner · « **Reply #10 on:** November 09, 2014, 07:33:33 PM »

I have no idea about the M44 crank Norm.... It's really all a numbers game to make it all fit. Check with someone who has done the swap because I think the pick ups for the sensors are in the rear of that crank? Not sure though.

I would sell you my M3 if you're serious about it

I'd even sell you my M42 stroker car....

Nothing is a problem if your machine shop is good at what they do. Is this going to be a street car?

Cheers,
~Ralph

wazzu70 · « **Reply #11 on:** November 09, 2014, 11:47:58 PM »

The M44 crank has the pickup on the counterweight between 3 & 4. All OBDII BMWs have it here as far as I know. This is not an issue though as the harmonic damper has the trigger wheel, and that fits all cranks. Just don't remove the trigger wheel on the crank as its part of the balance.

The M44 crank is a nice upgrade and its readily available so its cheap. Its the best budget crank IMO.

The rods are 140mm long and the GSR rods Ralph mentioned are good substitutes. They are slightly shorter at 137.9mm but there are a lot of cheap options due to the engines popularity. If you go this route make sure the rod length difference is taken into account when ordering pistons.

Truthfully, I would just use the factory rods. Just make sure the machinist makes sure the caps arent tweaked. Stock pistons are probably just fine too, but if you want to change compression or add bigger valve reliefs custom are the way to go.

Late M42 front cover is a must have upgrade for the chain deflector versus the idler gear that always seems to break. Make sure there is a provision for the crank position sensor (not sure if late M42 and M44 both have it). Replace the oil relief valve with the updated composite version.

IMO the single row timing chain is a good way to spend money for little gain. Its only worth it if you want every last little hp. Spend the money on a good set of cams. Thats what really is needed to make these motors shine from what I have seen. The VAC 269/269 cams seem to work well. Since you are outside the states you might be able to get catcams cams cheaper (VAC uses them and is the US distributor).

Just my thoughts for a budget performance motor. I dont have enough money to dream really big...I have to stay practical!

normboudreault · « **Reply #12 on:** November 10, 2014, 03:05:42 PM »

Guys, thanks for the input!! My head is spinning a bit.. This is a lot of information!! But I've made my crankshaft decision:

M44.

Didn't know about the sensors - has anyone done this - what do I need to know??

Connecting Rod - still debating... I want to make this decision with a matching piston in mind. Is a couple hundred grams weight savings worth around 1500$.. If I can use the stock con rods but get new, lighter pistons is money better spent on the cams??

I think I agree with Wazzu on the timing chain... I just remembered the PO told me he had just changed the chain and sprockets...I have the receipts...Should be good for a while.. but I will price the new timing chain from MM just to see...

Valves: New 6mm... If I go oversized - can I use these in the std tray? Darky, I checked out the cam tray conversion video - I think its a bit of overkill for what Im aiming for - but neat as hell though!

Ralph - its a street car... just want more power without spending 10Gs... However, if you sell me your M3 for 20G's Im on the next flight to your place... you mentioned 40-50Gs but youre negotiable right???

Warsteiner · « **Reply #13 on:** November 10, 2014, 03:39:43 PM »

Norm...
You can get new rods for $300-$400. They don't have to be super special. You're not building a forced induction motor with oodles of power.

If you want more power than stock, get a chip for free or $200 That should get you close to 150HP if you have a good motor to start off with. Do the M20 #12 LWF for a minimal as well, maybe like $400 with the Clutch kit. That will make it feel alive!

You should save your money for my M3..LOL I"ll let my M3 and M42 Stroker go for $50K..

Cheers,
~Ralph

normboudreault · « **Reply #14 on:** November 12, 2014, 09:23:08 AM »

50k?? Lets meet halfway and call it 20k...

Author Topic: Norm's e30 M42 Rebuild: Input needed! (Read 7162 times)

normboudreault

Norm's e30 M42 Rebuild: Input needed!

DesktopDave

Re: Norm's e30 M42 Rebuild: Input needed!

Mimikrakra

Re: Norm's e30 M42 Rebuild: Input needed!

Tgoode318

Re: Norm's e30 M42 Rebuild: Input needed!

keflaman

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Warsteiner

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DesktopDave

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Darky

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normboudreault

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Darky

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Warsteiner

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wazzu70

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normboudreault

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Warsteiner

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normboudreault

Re: Norm's e30 M42 Rebuild: Input needed!