Greetings, working on my 2.9 stroker M50 swap.

[triggrhaapi]

Hey all, just thought I'd say hi. I'm doing a high comp 2.9L stroker rebuild of an M50 using a mish mash of parts:

Stock pistons with valve pockets machined .49mm to clear valves (11.4:1 from what I hear)
M50NV 135mm beefy ass conrods
S50 crankshaft
S50 cylinder head recently rebuilt by yours truly with 4 new valves and all new valvestem seals ( I got a deal on it because it met with the #6 cylinder)
Low mileage M52 VANOS unit out of a 50k mi 99 323 with a brand new solenoid
New bearings, rings, seals, ICV, Vacuum hoses, coolant hoses, thermo, metal thermo housing, fan clutch, secondary timing chain tensioner, secondary chain guide.

Waiting on my next paycheck to go send the block out for reconditioning for the new rings, so I'll be doing a mock buildup to test clearances. M20 comes out this weekend, then the chassis prep, then I get the block back from the machine shop and slap that shit back together, throw some good old fashioned BMW 15W40 oil in it and break in starts! I'm going to be using the G265 with a stock M50 clutch (believe it or not I have a friend who put 40k on one running an S50 swap and it never slipped once) and I've already flushed the trans and refilled it with Royal Purple.

[325Projectz]

I wish we saw more 2.9l rebuilds... Get it dyno'd when you're all done.

I'd like to see the power numbers because I have enough motors to build a couple of those things.

Whos tuning are you going to be running?

[BimmerToad]

sweet, keep us up to date on your status and figures

[triggrhaapi]

I wish we saw more 2.9l rebuilds... Get it dyno'd when you're all done.

I'd like to see the power numbers because I have enough motors to build a couple of those things.

Whos tuning are you going to be running?

For now I'm just running TMS S50 software, but ultimately I will be hand tuning with either an SMT 6 or switching to a standalone Link Plus ECU. I'm a hands on kinda guy.

Since the crank is the same and there is only a 2mm difference in bore, the ignition timing will be right (ish) for the squash characteristics (but not the CR, so I'm going to be relying on the knock sensors and good fuel to keep me safe) and the extra fuel will help keep the detonation down. I'm going to have to be careful on fuel (i.e. I'm going to be running half race gas half shitty 91 cali pump) but I'm expecting S50 numbers or better.

I know you personally won't need it, but I know these motors like the back of my hand so if you guys need any info about anything at all I'm a good resource.

[triggrhaapi]

Oh and I forgot to mention it, but the machining of the valve pockets is crucial since you're increasing piston thrust by .45mm (increase in stroke from 75mm to 85.9mm, minus 5mm piston thrust from 135mm conrods = .45mm extra) or you can just cut them down and remachine the valve pockets if you don't want to have to deal with the higher comp ratio.

[streetknight]

what headgasket will you be using?

[triggrhaapi]

Stock, I'm actually test fitting the new bottom end right now to check head clearance. Valve pockets are going to be machined to clear. .45mm is not much compared to the head gasket thickness.

[FredK]

Yeah, .45mm is very little material.

Sounds like a cool project and you should have no problems matching stock S50 output.

Any reason why you are going with NV rods? Yes they definitely weigh more, but I'm pretty sure the rods aren't the weak point on the S50/52 engines.

[triggrhaapi]

The real reason I went with the NV conrods was because I found them for cheap. I only discovered their beefiness later when I got them and compared them to stock. To be perfectly honest they actually weighed a bit less than the stock ones I pulled out of the M52 block that I was originally going to use. A few fractions of a gram, but less. I'm going to keep them when I go to boost in a few years. They'll take whatever two 16Gs will throw at them.

[streetknight]

yeah i slowly building my nv 2.9 but i was going to use a .98" vac mls hg to get compression to 11.4-1. im using all nv m50 stuff execpt for the later 2.5 piston and s50 crank. i have not test fitted the block and head with the stock hg yet should do that this weekend.also are you reliving the valves your self or having the machine shop do it?

[CarsSuck]

Low mileage M52 VANOS unit out of a 50k mi 99 323 with a brand new solenoid
.

I thought that was a dual vanos engine.

[E304life]

I thought that was a dual vanos engine.

M52 single vanos
M52TU dual vanos

[FredK]

I thought that was a dual vanos engine.

Yes, a 1999 323i was a sedan, and was an E46. However, the E36 coupe was still around and kicking, with the 323is, 328is, and M3 models out for the 1999 model year.

[triggrhaapi]

For the record this came from an early 99 E36.

[SiGmA_X]

Just so you know, the M50TU rods are the same strength and lighter... You can search on Techno550's handle over on BFC, he just had a thread about this....