M42 build for E36 Compact

[MrPhatBob]

Thanks mate, I am following the advice of people who've been building powerful 16v engines for years, John used to work for Cosworth building BDA and BDG engines. Richard comes by the workshop and often gives me advice, he used to build Toyota 4A-GE engines. And the guy who's been advising cam profiles etc, Stefan, works for BMW M-Division. On top of that we have Pete who's an aerospace machinist who gives me verbal abuse if I try to cut corners, and Stuart who's built more race engines than I've had hot dinners who often starts a conversation with "if it was my engine I'd be doing..."

As I have secured myself a new job I will not be further preparing the chassis - its already to Compact Cup spec @ ~1200kg, but now I am not going to compete in the cup, I can go lighter - so more weight is coming out, polycarb windows... So my mates at another garage will be paid to do this work.

[adam gardner]

Really interested in this one as I live in England and I'm trying to do a similar thing. I'm looking at building a 2.1 engine but without buying directly from the US as the import rules confuse me! Where abouts are you? pistons are the thing I'm unsure about as I will need some pistons making to get the correct deck height with the 88mm stroke crank. I'm wanting to build a torquey engine that will retain the standard inlet manifold for my class of rallying.

[Pelly82]

Hello Adam, I am interested in the same thing... I was thinking at 88mm crankshaft, 135mm rods (like these: http://www.ebay.it/itm/CXRacing-BMW-M20-H-Beam-Connecting-Rods-135mm-Rod-Length-/180820595258?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a19bf523a), and good S50B32 pistons like wossner... Maybe all will fit without extreme modifications... I read in other topics that we can use honda (engine B18C) rods, 138mm lenght, but you must work on pistons...

[wazzu70]

The 138mm rods will not work with an 88mm crank. The gudgeon pin would be into the piston crown!

The longer rods are for the 81mm (M42) and 83.5mm (M44) cranks.

[Pelly82]

Crankshaft + Bearings from Diesel: 88mm Hub (16.6kg) Stock 13.2kg
Eagle Forget Conrods: 135mm (22mm pin, 540g) Stock 532g
Wiseco/Mahle Forget Pistons: 86mm (22mm pin, 320g) Stock 446g
Headgasket M44: 1.74mm

=> CR = 13.06:1 /1.85mm over deck/
     Discplace: 2044.7cc = 8.6x8.6x8.8x3.14159  (511.17cc per Cyl)

88mm hub + EVO Piston + 140mm M44 Rod = 6.85mm over Deck
88mm hub + EVO Piston + 135mm Eagle Rod = 1.85mm over Deck

So, I think I have to use rods of 135mm lenght...

[wazzu70]

Correct!

[sh123]

cant wait to see this done!!

If you are expecting 200bhp, how much  would you expect on a standrard inlet and throttle body and maybe mustang injectors or similair? (looking at building something similair not to this extent though but have to run standard throttle body in race class)

cant seem to see what final cc this will be is it a 2.1? only getting into the process of building enginesso cant figure outs the calculations

[MrPhatBob]

Really interested in this one as I live in England and I'm trying to do a similar thing. I'm looking at building a 2.1 engine but without buying directly from the US as the import rules confuse me! Where abouts are you? pistons are the thing I'm unsure about as I will need some pistons making to get the correct deck height with the 88mm stroke crank. I'm wanting to build a torquey engine that will retain the standard inlet manifold for my class of rallying.

Hello mate, I'm outside Cambridge and will happily point you in any direction you need if you want to PM me.
I have the 86.5mm JE Pistons which will give you plenty more compression if you're going for a longer stroke - as I say PM me your number and I'll give you a shout - any info I have is free to share.
I'm sticking with an M42 crank because I want revs, so I am keeping it short stroke.

[MrPhatBob]

cant wait to see this done!!

If you are expecting 200bhp, how much  would you expect on a standrard inlet and throttle body and maybe mustang injectors or similair? (looking at building something similair not to this extent though but have to run standard throttle body in race class)

cant seem to see what final cc this will be is it a 2.1? only getting into the process of building enginesso cant figure outs the calculations

Its going to be a 1.9, I'm running a standard M42 crank as I wanted a short-stroke big-bore engine as I'm going for power through revs - I have a 4.3:1 LSD so torque is not an issue

[MrPhatBob]

These arrived

So I lapped my valves in

Fitted the new valve guide seals and the dual valve springs

Put the shims in place

Then tested the clearances of the cams


And the net result is that the inlet fouls the cam carriers, and the shims will need at least 2mm removed to get the clearances even close to right.
So there's a load of work more to be done - but that's the good part

[adam gardner]

Nice! That's a proper Xmas present

[wazzu70]

Did the inlet cam lobes hit the carriers? If so, thats some tall lobes

Better to have the shims too tall rather than too short... Much easier to remove material than add it!!

[Darky]

Crankshaft + Bearings from Diesel: 88mm Hub (16.6kg) Stock 13.2kg
Eagle Forget Conrods: 135mm (22mm pin, 540g) Stock 532g
Wiseco/Mahle Forget Pistons: 86mm (22mm pin, 320g) Stock 446g
Headgasket M44: 1.74mm

=> CR = 13.06:1 /1.85mm over deck/
     Discplace: 2044.7cc = 8.6x8.6x8.8x3.14159  (511.17cc per Cyl)

88mm hub + EVO Piston + 140mm M44 Rod = 6.85mm over Deck
88mm hub + EVO Piston + 135mm Eagle Rod = 1.85mm over Deck

So, I think I have to use rods of 135mm lenght...

Careful crankshaft stroke is the diameter not the radius so
Going from m42 crankshaft 81mm to m47d20 88 mm only increases the piston height by 3.5 mm using the same conrods.
Cheers Rohan

[sh123]

cant wait to see this done!!

If you are expecting 200bhp, how much  would you expect on a standrard inlet and throttle body and maybe mustang injectors or similair? (looking at building something similair not to this extent though but have to run standard throttle body in race class)

cant seem to see what final cc this will be is it a 2.1? only getting into the process of building enginesso cant figure outs the calculations

Its going to be a 1.9, I'm running a standard M42 crank as I wanted a short-stroke big-bore engine as I'm going for power through revs - I have a 4.3:1 LSD so torque is not an issue

ohh right ok fair enough, im from the uk aswell btw and ive built my compact up for road rallying so im looking for tourque rather than a revy engine! but im still at the starting stage really of my build so got plenty of time to view my options

what is involved in converting the m44 to m42? im guessing not a big job as youll be on thottle bodies?

also do you know what is the uk equivelent to the mustang injector upgrade they have?

cheers
sion

[Pelly82]

[/quote]
Careful crankshaft stroke is the diameter not the radius so
Going from m42 crankshaft 81mm to m47d20 88 mm only increases the piston height by 3.5 mm using the same conrods.
Cheers Rohan
[/quote]

Yes, I agree with you.
Today I will disassemble a m42 engine I bought, so I can try all the combination!!!