M42club.com - Home of the BMW E30/E36 318i/iS
PAPER OR PLASTIC => WTB/WTT => Topic started by: jeffrn1970 on July 05, 2015, 03:25:36 PM
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rebuilding a m42 on the cheap budget , needing some oversized pistons that I can have my block bored to . Thanks jeff text is easiest 479-531-5518
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Just be aware thst m44 pistons have a shorter wrist pin height and wont work withan m42 crank.
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I have no first-person experience with building an M42 on the cheap, so feel free to tell me to take a hike. This isn't a great car to start with if you really want to go fast. Cheapest way to do that is with an M52 probably. I've gotten about 10% more performance out of my motor just by running the mods I have listed in my sig (4-hole Ford injectors, high-quality/low viscosity synthetic lubes, thinner coolant mix, P/S & A/C delete, throttle heater delete, silicone rubber vac hoses, COP plate. You could go a lot further than I have with an electric radiator fan, lightened flywheel, shorter diff ratio, smaller circumference tires, etc..
But...did you check out Warsteiner's recipe yet? Here's a link. (http://www.m42club.com/forum/index.php?topic=17623.msg121382#msg121382)
Compression Height of Stock S50 Piston is 32.8mm with Honda 1.8L VTEC B18C (GSR) 138mm rod
. I know these parts aren't all that cheap but they're cheaper than custom parts by a long shot. It's a known and tested combination. IIRC he used an M47 crank (Euro-only diesel motor), so your mileage may vary with these parts.
Stalk R3v for someone that's blown up their S50, and there are probably a bunch of guys around with spare GS-R rods. You'll still need to do a good bit of machining, I guess that's the nature of the beast. There is some brilliant stuff in there, I promise. All for free! I'm buying Warsteiner a beer if I ever tear into my spare motor.
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Thanks Dave.... I had fun designing and building that motor.
So here's the quick down and dirty!
Internal bottom end components are all easy to find. M47 diesel crank with GSR 138mm rods and your choice of piston. I went with S50 because they were available to me. I used the M44 HG which supports the S50 piston but I'm not sure about the S52 piston. My rods are aftermarket GSR hence lighter but the proper measurements on the big end. You can re bush the small end.
That's really it for the lower other than replacing your oil squirters in the block and checking your oil anti-drain back valve between cylinders 2-3.
The top end is a completely different animal and has tons of possibilities. I did some of the no-no's that some say aren't possible but as a unit my motor supports them very well.
45mm ITB's, dual exhaust and porting the head. I have them all. Lol. Then I lightened the valve train with 6mm valve stems, 33mm buckets with cam trays. No more AFM. Then comes the pricey stuff.... Custom headers, E30M3 complete exhaust with SuperSprint muffler. This needed a custom down pipe from header to exhaust. The ITB's too. Lol. Custom cams but the these give an incredibly flat torque band from 4100-6900! Custom tuning that can snag you 212hp and 174ft/lbs at the crank on 10.9 compression.
There's probably much more I'm forgetting but that is the meat of it for my build.
Anything can be done. My limiting factor for HP are my cams. But I wanted a solid street car not a track car so my cams are great at 4100 and not starting at like 5500 and the compression supports them. Lots
Of things to think about. Lol
Cheers,
~Ralph