M42 Turbo - Scandinavian style

[varg]

Interested to see this. I'm trying for ~300whp on a stock bottom end, don't know if it will end well. Why will you be machining pistons instead of just getting good custom pistons and doing a stroker build? 500bhp is no joke from a little 1.8!

As for the intake manifold, I am using the stock E30 M42 intake. It should hold together nicely. The stock M40 manifold can handle 2.5bars of boost, so it shouldnt be problem on M42.

I have been told, by people who have made much more power than I do, that the stock M42 intake is a restriction above 300hp or so.

[MVincken]

I use M50 crankbearings because they a 360degree oiltrack instead 200degree which the M42 have stock.

I don´t really see that as a plus.
2 jears ago i worked on calibration of Alfa Romeo engines and they all broke down because of these bearings
(i work at FEV GmbH, a big engine building/calibration company)

replacing your bottom bearing scale with one with a oil groove, also decreases (by +-20%!) the gliding surface of your bearing.
this increases the average surface pressure on your bearing what leads to bearing wear (due to a thinner oil film between bearing and crankshaft)

and because the load is the biggest on the bottom bearing, it´s best to not have a oil groove here.

[econti]

M42 aftermarket bearings are 360 degree thrust anyway
(so I'm told, by someone who has built a lot of them)

-edit-
You will also see a big difference with a good forward facing manifold and plenum

[23732]

If you're going to go through the work I would suggest buying 85mm CP pistons that are 8.5:1 compression ratio. you'll need to bore and hone the block, but then you could add a MLS head gasket or o-ring the block still. It would probably hold up to your goals.

Curious to see how this all works out though. You're talking a lot of boost too, what are your plan for an intake manifold?

I don't want to bore the block, as the walls are so thin from the factory. If the build doesnt hold up, I can always just another one together.

As for the intake manifold, I am using the stock E30 M42 intake. It should hold together nicely. The stock M40 manifold can handle 2.5bars of boost, so it shouldnt be problem on M42.

should be managable when u use 135mm conrods instead of 140mm ones?

but it´s like you say indeed, the cost will go up significantly.

why do you want to use m50 bearings?

I use M50 crankbearings because they a 360degree oiltrack instead 200degree which the M42 have stock.

[MVincken]

I've thought about it, but since I use so low compression I think it will be hard to find pistons that can handle to lathed that much. By increasing the stroke that much, you'll also increase the compression and therefore the pistons needs to lathed even more. Also, I want this to be kind of a budget build. I can always source another M42 and build it to a 2l. My brother have two or three M42s laying around. If my setup doesnt work well or the poweroutput is good enough, I will try a 2l instead.

should be managable when u use 135mm conrods instead of 140mm ones?

but it´s like you say indeed, the cost will go up significantly.

why do you want to use m50 bearings?

[ccsdo5]

If you're going to go through the work I would suggest buying 85mm CP pistons that are 8.5:1 compression ratio. you'll need to bore and hone the block, but then you could add a MLS head gasket or o-ring the block still. It would probably hold up to your goals.

Curious to see how this all works out though. You're talking a lot of boost too, what are your plan for an intake manifold?

[23732]

I've thought about it, but since I use so low compression I think it will be hard to find pistons that can handle to lathed that much. By increasing the stroke that much, you'll also increase the compression and therefore the pistons needs to lathed even more. Also, I want this to be kind of a budget build. I can always source another M42 and build it to a 2l. My brother have two or three M42s laying around. If my setup doesnt work well or the poweroutput is good enough, I will try a 2l instead.

[MVincken]

awesome build!
why not directly build a 2.0-2.1L stroker with a m47 crankshaft and m50/s50 pistons?

it´s definately a huge project, 2.5 bar / 37psi is a lot of boost :)
goodluck!

[23732]

Hello from Norway. Here I will keep some kind of log/build thread of my forced induction project. M42 turbo!

I chose the M42 because of the weight, weightdistribution and the potential.

The goal is around 400-450whp.

The parts I am going to use is:

- Stock M42 block with o-rings in the block. M50 crankbearings, and new bearings/gaskets on the whole engine.
- M42 head with grinded valves, ported intake/exhaust canals, with reinforced M50 valve-springs, stock headgasket, VAG lifters and custom camshafts by KMcams. I am thinking about a revlimit on 7500rpm.
- Lathed pistons down to 7.3:1 compression
- M20 flywheel, with 618-pressureplate and Sachs raceplate, springless.
- VEMS standalone ECU with Electromotive singlecoils.
- Garrett T3/T4e, 50trim turbo
- E36 325i aluminum radiator

Thats all I can think of at the moment. Pictures will come soon.

The engine has been disassembled and the block has been painted. After it has been o-ringed I am going to hone it.

At the moment I am calculating how much the pistons has to be lathed to lower the compession down to 7.3:1. The engine has to handle around 36-38psi of boost.

You guys can ask me questions in this thread if you want, and I'll try to answer as best as I can.