M44 Camshaft in M42 with solid lifters?

[totheredline]

I may be slightly off my rocker on this one but I wanted to see if anyone had any information. SO, dont flame me for this, Im just curious. :stupid:

I am currently rebuilding an M42 ( that will see autocross/track use) using the stock bottom end an M50NV pistons but Ive found out pretty quick that there are very few upgrades for this motor that are cheap.

I was origionally going to replace the OE lifters with VW hydro lifters but I also found out there are solid VW lifters that will also fit in the M42. If you know anything about mechanical lifters, you know that they require a camshaft with a more "gradual" lobe profile. While you can get camshafts for the M42 that are ground for solid lifters, they cost wayyyy too much money to justify doing a solid lifter conversion.

I know that the M44 uses rocker arms instead of the lobe directly on bucket design in the M42. That being said, from what I can see, the M44 camshafts have a much more gradual lobe profile suitable for solid lifters. they also have slightly more lift and duration 252 on the M42 vs 258 on the M44. I also assume the cam trays are different so would they even fit?

Has anybody tried this? I suppose Im probably just crazy.

[bmwman91]

Not going to work well at all. Cams with a rocker profile used in a tappet application is a real shot in the dark. You might as well stick with the stock M42 ones.

To get to any kind of point where you NEED solid lifters on an M42, the cost of custom cams is going to be less than 20% of the build. I'm running a 205bhp 2.1L M42 on late-model M50 hydraulic lifters (smaller oil reservoir, lighter than early ones) and some custom cams developed by Metric Mechanic & ground by Cat or Web (I forget who). MM says that the engine can take 9000RPM without mechanical failure, and certainly without valve float being an issue on the hydraulic lifters. I had them limit the chip at 7700RPM since a) I want to get 100,000 miles out of it, and b) power starts dropping off above 8000RPM. Really, unless you are building an M42 with a mega peaky power curve and lousy mid-range torque, there is no way that you will need solid lifters. You'd be hard pressed to get an M42 to breathe above 8000RPM and still have an engine that is tolerable on the street.

This is assuming that you are looking to build for a street sport / autoX application. If you are building for a dedicated track racing application, then yeah you'll have slightly different criteria.

You know what would be REALLY cool? Swap on the M44 valvetrain with the M42 bottom end. Supposedly the M44 valvetrain had 25% less frictional losses from the rocker/finger lifter design. I am not sure if that can take high RPM abuse as well as the tappets of the M42, but it would be a sweet build.

[TobyB]

seconded- it's not going to fit. If it fits, it won't turn.

Honestly, I think your biggest bang- for- buck is to send a pair of cams to Delta
(or another performance regrinder) and see what they can do for you.

The fabled S42 is REALLY hard to find... there is a thread on here somewhere, a while back,
from a guy in SA who was trying to do it.

t

[Ryann]

Get yourself a 4.27 diff. Then remove everything from the car you don't regularly use. Like the spare and the jack and the lug bolt wrench and the passenger & back seats.. side glass and window motors? ;) Get a tiny battery. 14" weaves are pretty light but get something lighter. TR C1s? Trunk trim, tool kit contents. Eat less, starve yourself. It'll be like adding 75 ft/lbs for $250.

[wazzu70]

As mentioned using M44 cams, even if they could fit would not allow the engine to breathe enough at high RPM. Since the engine would not be a high RPM motor, there would be no benefit to the solid lifters.

There are no real cheap valvetrain upgrades for the M42. Your best bet is getting a hotter intake cam ground by Web cams. Delta does not do grinds for our cams anymore.

[totheredline]

Thanks for the insight guys, much appreciated. :)

As mentioned using M44 cams, even if they could fit would not allow the engine to breathe enough at high RPM.-

There are no real cheap valvetrain upgrades for the M42. Your best bet is getting a hotter intake cam ground by Web cams.

The M44 cams have a slightly more agressive profile so it would help a little at higher RPM.
From what Ive seen, (and experienced for the couple times I drove my car before i tore down the motor) the M42 seems to fall on its face after 6500 RPM. Im not trying to build a race motor but I would like it to make power all the way up to 7 grand.

Ill check out web cams for sure. A decent regrind and VW lifters would probably fit my needs.

I suppose I could adjust timing for more overlap. Does timing really help these motors as much as people say it does?

[wazzu70]

Advancing the intake cam will help mid range torque at the expense of high end power.

It all depends on where you want the heart of your powerband.

[bmwman91]

totheredline,
The M42 head just isn't going to breathe better with bolt-on type changes alone. You need to look into more aggressive cams and/or do some work on the ports and valve seats. My Metric Mechanic M42 pulls hard all the way to 7700RPM with hot cams, a multi-angle valve seat grind, shorter valve guides and their custom "grooved" valves. I'd bet that most of it is from the shorter valve guide (less obstruction) and the hot cams with both longer duration and higher lift. All of the lighter components in the head and block are there as much to improve longevity as to help it spin up faster.

I wouldn't bother adjusting the cam timing. Unless you do that and then go pay $$$ for a dyno tune, you aren't going to run well. I screwed around with the timing many years ago and it didn't feel good.

That reminds me...if you do end up changing the cams and doing any porting, you'll need a custom tune done to actually take full advantage of it. That'll probably run you another $1000.

As many have mentioned in the past, the M42 is an expensive engine to mod. A chip and lightened M20 flywheel/clutch are the only worthwhile mods in the "cheap" category.

[totheredline]

totheredline,
The M42 head just isn't going to breathe better with bolt-on type changes alone. You need to look into more aggressive cams and/or do some work on the ports and valve seats. My Metric Mechanic M42 pulls hard all the way to 7700RPM with hot cams, a multi-angle valve seat grind, shorter valve guides and their custom "grooved" valves. I'd bet that most of it is from the shorter valve guide (less obstruction) and the hot cams with both longer duration and higher lift. All of the lighter components in the head and block are there as much to improve longevity as to help it spin up faster.

I wouldn't bother adjusting the cam timing. Unless you do that and then go pay $$$ for a dyno tune, you aren't going to run well. I screwed around with the timing many years ago and it didn't feel good.

That reminds me...if you do end up changing the cams and doing any porting, you'll need a custom tune done to actually take full advantage of it. That'll probably run you another $1000.

As many have mentioned in the past, the M42 is an expensive engine to mod. A chip and lightened M20 flywheel/clutch are the only worthwhile mods in the "cheap" category.

I really, really LOVE how light the car feels with the m42. Ive driven a couple other E30's with 6 pots and they feel heavier. I dont care what people tell you, theres a noticeable difference in handling.
That being said I want to keep the M42 and retain the car's purity somewhat. (I also think 318's with the origional M42 will be valuable someday) You obviously feel the same way sice you spent the money on that screamin MM m42. Im jealous BTW.

SOLUTION TO MY PROBLEMS: forced Induction.

In reality I should probably spend money on an awesome suspension setup instead of trying to get a couple horses out of the M42.

stock cams, VW lifters and MarkD chip will proably satisfy me untill I have the money to purchase or build a hot M42

[bmwman91]

Truthfully, just get the chip. Lighter lifters won't do much for you on an internally stock engine. And do an M20 flywheel conversion, with the flywheel turned down to 11-12lbs. That really wakes the car up (although, you will get some heinous tranny rattle with that light of a flywheel).

I hear you on the balance thing. It's a big reason why I like the M42 in there. That and the fact that it is already set up with electronic ignition and a timing chain (that's a real love-hate thing).

If the roads in your area are pretty good and you stay on paved roads, a suspension can be a lot of fun. I ran with Bilstein Sport + H&R Sport springs and all poly bushings for many years. A busted oil pan in the middle of nowhere and a shift in my interests to rock climbing required me to return the car to stock height though. It turns out that Bilstein HD shocks with the stock springs, and brand new OEM rubber bushings everywhere makes for a car that handles very well while still being comfortable.

[totheredline]

Truthfully, just get the chip. Lighter lifters won't do much for you on an internally stock engine. And do an M20 flywheel conversion, with the flywheel turned down to 11-12lbs. That really wakes the car up (although, you will get some heinous tranny rattle with that light of a flywheel).

The M20 fly mod is on my list since the DM flywheel in the car is shot.


So little update with the engine. I took the bare block and head to the machine shop to have a machinist take a look at it. I had noticed some scaring on the #3 cylinder wall but I thought it would come out if it was honed and it recieved larger rings. Well, upon further inspection he estimates it will need at least a .20 overbore to get it out. SO, this means I will need larger pistons. I really do not what to spend a lot of money on performance pistons.

Are theyre any OE pistons from an M5x S5x that will fit correctly? and possibl give me slightly better compression.

[totheredline]

HMMM. looks like I have a couple options. Euro s50B30 or S50B32 US s50B32 OR M44 pistons.

Now, with the S5x pistons, I wil have to deck them or use 135mm rods so I dont have an insane comp ratio. M44 pistons will give me a slight boost in comp ratio but I wont have to modify them in anyway

[benz-tech]

I'm pretty confident that the deck on an M44 piston is too low for M42 use and would drop your compression ratio significantly, but I have a set that I'll be selling cheap in the near future if you want them. I have a set of 135mm M3 rods as well that I'm offing. But don't take my word for piston fitment, get the correct part numbers off realoem.com and then enter them in this site: autopartoo.com
they seem to have some of the needed info for comparing deck and bore variations.

[totheredline]

Yeah, I've been looking at maxsil pistons. That's probably my best bet.