M42 build for E36 Compact

[MrPhatBob]

You should see the mismatch on the stock manifold - they're barely even the same shape!  I reckon there's good gains to be made for those who are sticking with the standard manifold if they were to port match.

[MrPhatBob]

Okay so Wossner are not interested in splitting a set of 6 pistons, so I need to find another piston set

[wazzu70]

CP, Wiseco, Diamond, JE, ect. all make pistons. You can even buy a set of 4

[MrPhatBob]

Cheers, trouble is it only looked like Wossner did the S42 two ring slipper piston

[timothymcn]

Unless you can convince two other M42 guys with much deeper pockets than I to go in on a set of 12 pistons...

[wazzu70]

Any of those companies can make anything you want. They make two ring pistons as well. Not sure what a "slipper" piston, but Im assuming you are meaning less friction from one less compression ring.

[MrPhatBob]

I've been speaking to a UK distributor for JE Pistons about getting 4 US S50 pistons, but I can most likely get a UK manufacturer to make them for less than the cost + freight + import duty + tax.  Especially as the piston for the GM C20XE is close to perfect all except for the valve angles.

One of the engine builders pointed out that OEM S50 pistons are not exactly "standard" in the sense that they're pretty high spec in comparison to lowly engines.  So we're getting prices on Mahle 86.4mm S50B30 pistons.

In the good news section of the program, Jondel Race Engines have taken a look at the M42 head, quoted me a good price and say that my BHP predictions are more than achievable.

Slipper Pistons are an established term http://en.wikipedia.org/wiki/Piston#Slipper_pistons you'll know what they are when you see them.

[wazzu70]

Thanks, I looked up slipper piston and I knew what it was from looking at the pictures. Its essentially maximum reduced weight. Learn something new every day!

CP, JE, ect. Offer slipper pistons they all have their own unique name for them

[MrPhatBob]

Well I'm now waiting on prices for a set of JE Pistons from Cambridge Motorsport, they're the UK dealer and work with MASS Race Engines who're kind enough to let me use all of their equipment.  We'll see how that pans out.

BTW I just realised that you used to be on the VEMS forum I ran.

[wazzu70]

I figured there wernt that many PhatBobs out there!

The VEMS is working nice on my car. Just need to keep it together long enough to rack up some miles!

[MrPhatBob]

So I got prices from the Mahle supplier near me and the price for standard S50B32(EU) pistons was close to the same as JE Pistons - so I ordered a set of 11.5:1 S50B32 US pistons as they have the 22mm piston pin.

According to the scales at Mass Race Engines my current piston and rod assembly weighs 1032.1gm
Using the JE pistons with ZRP rods I'm looking at a weight of ~788gm

Resulting in a reduction of 244.1gm each, meaning 976.4gm for all four - that's a good reduction in weight for the whole rotating assembly.

My next concerns are: front pulley and water pump cavitation at higher than standard RPM

[colin86325]

You could switch to an electric water pump (EWP) and never have to worry abut cavitation, regardless of rpms.

[MrPhatBob]

Yeah that's one option I was thinking of, there are underdrive pulleys available for the M4x engine to avoid cavitation.  Then we'll have a cost benefits analysis to work out which option to go for.

I've seen that Mocal do a take off plate for the oil filter so that I could use a remote filter and oil cooler setup.

[MrPhatBob]

Now for lifters...
From what I've read these should be the right type:
http://www.ebay.com/itm/Audi-VW-1-8-2-0-16V-racing-solid-lifters-cam-followers-tappets-set-16pcs-/111142281592?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19e098a178

Am I correct?  I hope so as they're really well priced.

[wazzu70]

IIRC the lifters were from an 8v VW engine.

Websites like Catcams have the BMW lifter dimensions and you could compare to the 16v VW to see if its a match