Is this right?

[acolella76]

Got my pistons back from the machine shop and I noticed that the wrist pins are about 0.125" shorter than the snap ring grooves. I know the machine shop didn't mix the wrist pins up, and I doubt the person I bought them from mixed them up. But is this really normal? I know the wrist pin doesn't move side to side... just seems like a lot of play.

[spdracrm3]

they should be able to float but not that much ,it also means the pin is not fully supported by the bore and may wear a grove and then not float properly/bind

[328ijunkie]

Somethings going on...

[acolella76]

Dave do you have any S52 pistons lying around? tried to order a new wrist pin to measure. Apparently you can't order them and the dealership couldn't even give me the part number.

I'm starting to realize that a stock rebuild on these motors is really uncommon. Or just undocumented.

[328ijunkie]

Yes i do. Wrist pins are sold with pistons from B<W

[LJ851]

The only time i have seen a piston with circlips and that much end float resulted in a destroyed piston from the pin hammering the circlips.

I'm used to seeing several thousandths of an inch end float on a pin like that.

[acolella76]

Yes i do. Wrist pins are sold with pistons from B<W

Do they have wrist pins and do you want to sell them to me for cheap? :D:D I'd rather not spend money on new pistons considering I just had the valve pockets cut on these.

The only time i have seen a piston with circlips and that much end float resulted in a destroyed piston from the pin hammering the circlips.

I'm used to seeing several thousandths of an inch end float on a pin like that.

Yeah that is what I figured. Dang.

I wonder if these pins are from an M50 and maybe the PO got them mixed up

[328ijunkie]

Txt/call us

[Sh3rpak!ng]

Do they have wrist pins and do you want to sell them to me for cheap? :D:D I'd rather not spend money on new pistons considering I just had the valve pockets cut on these.

Sorry for an unrelated question, but:

I'm guessing you cut the valve pockets to retain full function of vanos with those cams? (rather than shimming the vanos)

[acolella76]

Yeah, the cams aren't crazy (just regrinds) but the head was skimmed past BMW's spec so it was a little close on both sides. So since I couldn't find any thicker OEM gaskets for the S52 I figured cutting the pockets was the best option.