Rebuilding a M73N

[PapaSmurfen]

Has anybody on here ever done a rebuild on a M37N, where they actually got into the bottom end, If so what kind of service manuals/info did you find/use for torque numbers or torque sequences etc... etc, I've heard the Bentley service manual is very lacking on this motor. I have a 1999 750il but ya know... same motor
Any help would be much appricated as I have not being able to find anything for a while

[CD05001CIA]

Cartoonz, TXGrtWht, you all wanna chime in here, I already told um to find an un-molested long block in a salvage yard, but ...

Cartoonz what's the cost / availability of bearings for the M73 crank & connecting rods? (ballpark) If at all . . .

Is wokke still following the e31 forum?

[cartoonz]

Bearings likely have to get sent off & recoated... last I checked they were unobtainable.

Bigger challenge is refinishing the cylinders to seat new rings... but really, unless your lower end has 200k+ on it, don't fix what ain't broke.

[PapaSmurfen]

My original block was overheated to the point that it's fucked by some idiots that didn't know left from right

I found a long block at a self serve junkyard, car was really nice, looks like it stopped running and was left out in a field, rats nests everywhere, I suspect it had an electrical issue and just wouldn't run and somebody gave up on it.
I robbed the long block out of that for 300 bucks, brought it home and tore it open to make sure it wasn't blown, bearings all look really good through-out, probably has less than 150k on it, so thinking of just re-using all the bearings (I can get them from my dealer but they're 30-40 bucks per bearing, plus a month to get flown in from Germany, so probably not going to do that). Cylinder walls look a million times better than my original block,

I bought all the gaskets to rebuild it I'm just looking for a service manual/tech sheet that goes over a full rebuild

[cartoonz]

Leave the pistons in it. Do not change the rings. Put all the bearing caps back and leave it be.

[cartoonz]

The point is, these engines are definitely not something for the casual mechanic to just "rebuild". Besides, it does not sound at all like it needs that. Take the heads to the machine shop, get them to do a full job and replace seals... maybe some exhaust guides too. Chase every bolt hole in the block with the appropriate thread chaser tap, get an account at BellMetric and get a supply of the upgraded harder bolts for all you can find. Use Reinzosil
There are torque tables around that show the appropriate settings for all the bolts. Note that you will need NEW head bolts and a degree type paper cutout to torque those. You cannot reuse head bolts.

The BMW factory manual can be found at www.Mwrench.com