Your ideal build.

[benz-tech]

With so many asking what's the most power...I have little money...what bolt ons...need more power... I thought I'd start a thread where we could post our opinions on what would work the best- for a given requirement.
I'll start.

The perfect budget build for a daily driver, and this is very much my opinion, is:
M44 short block-don't worry the head will be cracked anyway. It has lighter internals, and piston oil squirters in the block and a better oil pump and timing case. you might need the late m42 timing cover to run 1.7 BUT I think the m44 crank sensor can be made to work with 1.7. Not sure tho.
Late M42 head, use the m44/S52 valve springs if doing 33mm buckets and trays.
Late m42 case will have the better timing stuff and a boss for the crank sensor.
'91 intake cam, late exh cam. It's a start. And prob perfect for a daily.
M20 lightened flywheel. There's a reason everyone says to do it.
I'd keep the dme and manifolds specific to the vehicle instead of diving in to an obd2 swap.
I really think the above is good for 160+ HP and a very useable torque curve.

There are some negatives. The  M44 crank is cast, and there's the whole crank sensor issue but IIRC they are both a 5v square signal and look to be timed correctly from the case on m42s to the crank on the m44s. The belt drives and dipstick are a challenge.

Just thinking about this makes me want to build one. One Saturday at the rancho picknpull and all those parts would be in my garage for the price of a used 'engine'. How do they know which engines the parts come from.

Others please chime in for your favorite build ideas. And the intended purpose. 

[Darky]

Always wondered about this.
All the m42 blocks that I have handled about a half dozen in Australia have had piston oil squirters.
Wondered if American m42 blocks did not have the squirters and euro blocks did?
Curious

[Warsteiner]

Darky...I have oil squirters in my M42 block. It came out of a US '94.

benz-tech....if you're located in NJ why don't you come and drive my car

I have plenty of ideas for people and you've mentioned a bunch.

The purpose: All out fun in keeping up with other faster cars.

Budget: hmmmmmm.....

Here are my goodies..

E46 320d M47 Crank with 88mm Stroke lightened
Ported Head
6mm valves and guides
E36 M3 trays and lifters
E30 M3 exhaust with M3 Supersprint muffler
Dbilas 45mm ITB's with no AFM
I do have a set of 45mm slide throttles that the S42 used to run as well.
Custom cams 250/250 or a 222/222 at 0.050'  Lift is 0.404"(10.3mm) centerline is 116.5 deg.  io-ic-eo-ec is -5.5, 47.5, 47.5, -5.5
S50 86mm pistons cut, pocketed, and dished for 10.9:1
Nick Arias NA3 138mm Rods 510 grams
M20 lightened flywheel and clutch
Custom 666 Header, slightly larger than stock


The recipe is S50 pistons 86mm bore with aftermarket Honda B18C (GSR) 138mm rods. You also have to rebush small rod end to 22mm.  Shave the piston 2.65mm and dish and cut relief valves to whatever compression you want. I used the S50 piston for 10.9CR.

This now gets attached to the M47 diesel crank with new keyway cut and nose turned down to fit the M42 crank gear.

Cams are your choice. I went for TQ for the street with a 250/250 with 10.3mm lift. 222* vs 215* for the Schrick at .050"
Dick Chaing developed these cams for me with my CR and power to 7500rpm. The cams are the limiting factor in power in this motor. More duration and lift will gain higher HP numbers and lower TQ but will also move the power band upward in the rev range. It's a trade off. All my power is made before 7K. These cams give a flat TQ curve from 4,100rpm to 6,800rpm.

Megasquirt II for tuning. Alpha-N/MAP

Exhaust is E30M3. from custom header back to M3 SuperSprint muffler.

Lightened the valve train to 6mm valves and used S52 M3 cam carriers which brings the buckets down from 35mm to 33mm with S52 springs.
There is some welding to do to make that all fit and some clearancing as well.

The final tally......212HP and 172ft/lbs at the crank in a 2045cc motor. That's US E30M3 territory, stock (192HP/177ft/lbs) and chipped (216HP/177ft/lbs) in a 2302cc motor. Figures are all Dyno Jet #'s.

Metric Mechanic claims 205HP with AFM and tuning, NO porting and stock TB. That's with Mark D'Sylva tuning over the internet and not having the car on his dyno. I hope that's true because then you can save a bunch of money on parts. I think that we need bmwman91 to get his car tuned!!

M42 which was the S42 in race trim made 315HP at the crank on a 2.0L. Mine is 2045cc's. If you use S52 pistons then you'll be around 2064. IF you go 87mm then I think it makes 2090+cc. 87mm?? Funny you should ask....LOL  try looking into the S54 piston:-)

Trivia.....did you guys know we have special exhaust valves that started on the Sport Evo M3? The BMW stock exhaust vales are sodium filled which is critical in removing heat from the valves.

Cheers,
~Ralph

[benz-tech]

Always wondered about this.
All the m42 blocks that I have handled about a half dozen in Australia have had piston oil squirters.
Wondered if American m42 blocks did not have the squirters and euro blocks did?
Curious

We might have an early vs late m42 issue here. My 91 rods had a hole to squirt but nothing in the block. Not my favorite design.

Oh and Ralph, if I only had your budget...

[wazzu70]

Benz had a good list.

FWIW the M42 blocks have squirters too. I have never seen one without.

My preference for a cheap performance engine would be M44 crank/rods/pistons, late M42/M44 lower timing case and oil pump. Late M42 head w early M42 cams. Block just depends on if you need the CPS signal from the crank counterweight or the front timing wheel.

Obviously there are better parts and combos out there, but this is all easy to source stuff thats readily available (in the US).

[Darky]

Hi

FYI My 1990 318is m42 had oil squirters.

Strange

[benz-tech]

Is it possible that I didn't look too closely at the block? The early m42 rods I had definately had holes to squirt the walls and I'm pretty sure the block didn't, but that was 2 years ago from an old engine I parted out. Didn't look at the last one, I just scrapped it.
Edit: yeah it was the block that had the boss to squirt, not the rods. The M44 has 4 screw-in squirters right at the base of each bore, just like all 98- Mercedes blocks fwiw. Same difference I suppose.

[jrw21]

The m42 is a fun engine. Amazing as it is shares the same characteristics of the m50, m52, s50, s52 concepts. There are so many options to build the m42 using any of the aforementioned engine parts. mix an match cranks, rods and pistons etc.. along with headgasket thickness to achieve any of your desired compression and liter goals. when I ever finish my build... I have enough spare parts left to build a second engine and definitely will be using my left over s52 pistons with bored block to match.

[wazzu70]

This is a picture of my 91 M42 when I disassembled it. you can see the oil squirters on the top of the main bearing journal slightly offset to the right in the picture. Its the little silver piece popping out When I took my engine apart I was under the impression the early M42s did not have them too. Glad I was wrong!

[varg]

The final tally......212HP and 172ft/lbs at the crank in a 2045cc motor. That's US E30M3 territory, stock (192HP/177ft/lbs) and chipped (216HP/177ft/lbs) in a 2302cc motor. Figures are all Dyno Jet #'s

Impressive.