m10 with volvo b21ft pistons

[38927]

what modifications are needed to put volvo b21ft mahle pisotns into an m10. I know thus far that the block is going to need to be bored a little larger to accompany the larger volvo pistons. My understanding is that volvo pistons are 92mm and another guy (good and tight) on e30 tech is running 91mm pistons...1mm over wouldnt kill the block (i'm assuming).

so whats the wrist pin bore diameter vs. the bore diameter of the volvo wrist pin diameter. I also wanna know how much of a height difference there is betweent the top of the m10 piston to the center of the wristpin nore. vs. the top of the volvo b21ft mahle piston to the center of the wristpin bore.

I know this has been done before...i searched and came up with nothing. volvo b21ft mahle pistons in combination with stock m10 rods=awesome, strong block. thanks in advance

[Guest Anonymous]

If you searched and came up with nothing, how do you know it has been done before?

92mm is not too big, but the wrist pin height is important. I would be curious if this works or not. Also what are the available bore sizes of these pistons?

[38927]

I'm not a bmw guy, but i frequently browse the bwm forums and have heard of people using these pistons.

[JohnW]

I would be interested to know if this would work. You might try searching (Roadfly?) forums for BMW 320s and e30s, as many U.S. 3 series cars from 77-85 also used M10 blocks. I do believe Mahle supplies pistons for both M10s and B21s, but whether or not there are very similarities, I do not know.

It really shouldn't make the bottom end any more durable, but it could make for a nice little bump in displacement. Keep us posted.

[Guest]

It's been our experience that a 92mm reboring in the M10 block is just about MAX. During the casting process of the blocks, the cylinder cores usually "shift". Thus, when you over bore, there is a very real possibility of a very thin cylinder wall on one side or the other of the cylinder. It would be best to have your machinist sonically measure the wall thicknesses before you go this route, Better yet, have the wall measured after you have bored.

mac.

PS. It might cost you more than one block before you get one that passes inspection.

[PatAllen]

i was not aware of this posisbility...

i do believe it is easier to do it like i did, with toyota 20R pistons.

pin bush is the same diameter, all you need is to overbore the block a bit, and deck the block to get zero deck. I bought 2 set of theses with rings and pins for 200$ cdn. call it cheap. Those are the pistons i run in my turbo 02 for nearly 5 years now.