Where the hell do you get Main Bolts (crank shaft to block)?

[Jon K]

Guys I cannot find "main bolts" on any autohaus, bma, bimmerparts, etc., website. Whats up? Where can I get main bolts for my M50 motor... or re-use old?

[yaofeng]

Try this site. I think you want part #11241713342.

http://www.bmw-auto-parts-dealer.com/

This is a dealership which also does mail order. They are located 40 miles from where I live in NJ. There is no free shipping. I wish they move out of state. Paying both shipping and sales tax is not good.

[yaofeng]

Sorry the previous part# was for the con rod. It should be part #11111735525.

[Jon K]

Thanks Yaofeng

[Bill R.]

You don't replace the main bearing bolts on the m50. and don't forget about the 9 possible size variations on the main bearings according to the color code




Thanks Yaofeng

[Jon K]

You don't replace the main bearing bolts on the m50. and don't forget about the 9 possible size variations on the main bearings according to the color code

Ah, well the torque PDF I got said "replace, oil, and torque" main bearing bolts. I guess she's getting new ones :)

As for the main bearings - Autohaus and BMA and all those places only offer "stanard" or "oversized". I went with standard. We'll see I guess.

[Dave M]

You don't replace the main bearing bolts on the m50. and don't forget about the 9 possible size variations on the main bearings according to the color code

phew.......jon had me a bit worried. Did I replace mine? Uhmmmm, nope :D

[Jon K]

phew.......jon had me a bit worried. Did I replace mine? Uhmmmm, nope :D

Dave what did you do as far as bearings are concerned?

[Dave M]

Jon, it was a while ago and I don't remember whether I got the bearings from the dealer of BMA. It would have been one of the two. As the block I replaced mine with was a much lower mileage and everything looked A-OK (I had a machine shop look at it), I used stock sized everything. Are you at all worried about the wear on this thing?

Dave

[Jon K]

Jon, it was a while ago and I don't remember whether I got the bearings from the dealer of BMA. It would have been one of the two. As the block I replaced mine with was a much lower mileage and everything looked A-OK (I had a machine shop look at it), I used stock sized everything. Are you at all worried about the wear on this thing?

Dave

Not at all - this motor looks perfect, as does the head. So you just used +0mm bearings? Because that is what I purchased - I am going to fit them with plastigage to make sure, but I wanted someone who has done this to give me some insight - thanks much. Other than torque specs, are there any other documents you used?

[Dave M]

Yep 0+ bearings, the bentley, the torque specs and, believe it or not, a Haynes manual, which actually does a better job of explaining bottom end 'stuff' and has pics if needed. Doesn't take much to improve on bentleys bottom end ;) info as there isn't any. I didn't have a protractor or anything, just went by sight etc.

There was a downloadable Haynes on here, but I just checked and the link no worky.
Dave

[Jon K]

Dave how do you know which way to orientate the bearings ? The caps have notches and all.

[Bill R.]

in the Tis like so. And the tangs on bearings always go together. Also you don't just slap a set of standard bearings in there. As i mentioned before there are 3 different sizes of standard, Bmw holds everything to very close tolerances. The paint color code indicates how thick the bearings are in the standard size.




Dave how do you know which way to orientate the bearings ? The caps have notches and all.

[Dave M]

See, this is why I shouldn't be trusted. I forgot about the yellow paint and the associated question that was asked when ordering. OOOops.

[Jon K]

I'll check that out Bill. I don't have the crank here.



in the Tis like so. And the tangs on bearings always go together. Also you don't just slap a set of standard bearings in there. As i mentioned before there are 3 different sizes of standard, Bmw holds everything to very close tolerances. The paint color code indicates how thick the bearings are in the standard size.