Cheap/Basic M42 Mods.

[freeride53]

inspiration, yo!

[pbr87]

What do u guys think about spray maybe like a 75 shot?

Don't do it.
It's bad for piston rings and head gaskets, and it puts harmful sudden load changes on your drivetrain components.

If you're going to build a car for nitrous, to reliably handle a 200+ shot, props to you. But this requires a built motor, metal head gasket, special piston rings (there's a company called Hellfire that makes them), and strengthening/upgrading almost every piece of your drivetrain.

[2002maniac]

When I put in my medium case 4.10 with the turbo car I didn't even have to shorten the driveshaft, it just fit in.

yeah, what's this talk of shortening the driveshaft? I'm positive the input flange is in the same place.

[Asbradley21]

I wouldn't put nitrous on an m42 period. Get a real FI system.

[KenC]

Had those and are great for top end power. I dyno'd 136 to the wheels with those, delete parasitic fan (efan), 4 pintle injectors (mustang), ebay proformance chip, and cleaned up vacuum lines. Warning though, you do lose a good bit of low end torque. When I put my stockers back in for the turbo setup, gained ALOT more torque below 3000rpm.

do you remember what regrind it was? 256? 270?

[getouth]

what about hi comp pistons?

[e30guydownunder]

yeah, what's this talk of shortening the driveshaft? I'm positive the input flange is in the same place.

The driveshaft is telescopic. The flange on yours may have been loose and you without noticing adjusted the length of the tailshaft. It is a very minor change in length.

Plus shortening the driveshaft excessively and putting it out of the way makes it a bit easier to get the diff in position.

[thedguy]

To the guys talking about regrinding the cams

What are a safe set of specs to go with an what can the factory valve train even handle? I know a little about cams, but never ordered a custom grind and about the only thing I know to do is to get in contact with Delta cams.

[decay]

To the guys talking about regrinding the cams

What are a safe set of specs to go with an what can the factory valve train even handle? I know a little about cams, but never ordered a custom grind and about the only thing I know to do is to get in contact with Delta cams.

i don't have anything about specs for you, but a friend has an intake cam from these guys:

http://www.webcamshafts.com/

in his m42 and seems happy with it. you could check with both; even basic info on lift and duration would let you make something of a judgment call on which you want.

edit: also found these:

http://www.deficarsport.com/touring-bmw-m42-4cyl.htm

i would be very interested in the specs on the stock cams myself, if anyone has them.

[z31maniac]

dk, Metric Mechanic and VACMotorsports have M42 cams as well as Webb and possibly DBilas.

[decay]

yeah, looking at the retail for my ITBs i don't think i'll be going with dbilas. not raking in the iraq money any more, which is why progress on my car has slowed so drastically. :)

i was asking about stock cam profiles because a trick i've seen used on VW and nissan twincams is buying a "sport" cam for the intake and then swap the stock intake cam over to the exhaust side. asked robert (peerless) about this and he thinks we could do the same on the M42.

anyway someone on m42club found the specs for me:

Application: O.E.M.
Duration [0.1mm+cl]: 255/255°
Duration [1.0mm+cl]: 207/207°
maximum lift [cl=0]: 9.70/9.70mm
Lift at TDC [cl=0]: 0.90/0.65mm

so everything is the same except the lift @ TDC. am i reading it right when i think that means they're basically the same except the intake cam has a more convex ramp? or is it just that TDC just falls on a different place in the "bump"?

looks like it might not be worth the trouble but i thought the idea was worth investigating.

i will probably just go with delta regrinds like 2002maniac did. i've done enough weight and parasitic-drive reduction (ps/ac/clutch fan all gone) that losing a bit of low-end would probably just make it feel like it used to before; and another ~100lbs is going to come out of the car before i get around to this anyhow.

[Voluted]

www.catcams.com has cams for the m42 as well but i have no idea about cost (check out the chart below). They sell more agressive cams but they require different springs/lifters to install.


O.E.M.
255 / 255°
207 / 207°
9.70 / 9.70mm
0.90 / 0.65mm
O.E.M.
HYDR: O.E.M.

1301411
257 / 257°
215 / 215°
9.90 / 9.90mm
1.30 / 0.95mm
O.E.M.
HYDR: sport

1301413
269 / 269°
225 / 225°
10.00 / 10.00mm
2.05 / 1.55mm
O.E.M.
HYDR: sport

[fiftytakedowns]

o0o0o sounds fun!

[fiftytakedowns]

Even after the ltw flywheel I feel like I need some more oomph....
DK hows the PS loss? Im getting sick of it . but Im wondering about the safety (like hydroplaning, spinning out ETC.

I really wonder How much power we can get out of the m42 without doing internals.

[Cyrix2k]

I wouldn't put nitrous on an m42 period. Get a real motor.

fixed. The m42 has its place, but overall, it's near the top of its game barring expensive mods and even afterwards is largely gutless. I'd much rather have a torquey motor than a high revving one. In race applications, I can see a built M42 being nice. For the street... I'll take an I6.

Oh, and I own an M44 powered e36. It sounds like a lawn mower and just never idles as well as the I6s. I *much* prefer the M20 or M5x, neither of which are all that expensive to swap in and yield much more usable power.