What pistons for 2.7 ?

[12345kevin]

Ok

If I had an early 2.5 engine from an '86 car and had the following parts, which pistons would I need ?

324TD Crank & rods

I don't really want to get into machining the block & head etc.

If I can't use standard BMW parts, what would I need ?

Please don't fill the post with if's & buts.

Hoping to do this soon, so will do a fully documented build with photo's etc.

[Ant]

Cant use the TD rods without some major mods to the gudgeon pin area, they are simply massive when compared to the M20 B20/25 units

Crank goes in ok, needs M50 bearing shells, not ETA !

you'll have to machine the block dude, no getting away from it unless you use the Alpina pistons ( @ 120 each + rings) with the B25 135mm rods.

[ed325i]

Use your early 325 pistons.
If you dont want to get in to machining the block/ head go 2.8

[12345kevin]

Thanks Ant

It's going to have all new shells, bearing and rings anyway.

So, if I use 324TD Crank, Alpina Pistons, M50 Shells, standard 325 rods, block & head. This will create a 2.7 without any machining ?

Part no. for the alpina pistons ?

[daimlerman]

Where did you find the crank?

[Andyboy]

Thanks Ant

It's going to have all new shells, bearing and rings anyway.

So, if I use 324TD Crank, Alpina Pistons, M50 Shells, standard 325 rods, block & head. This will create a 2.7 without any machining ?

Part no. for the alpina pistons ?

Or use standard 325i pistons for a lot less money and spend £30 decking the block. Alternative number 2 is to use 525e pistons. They work fine with the 325i head and still give a decent compression ratio.
325i rods won't work with 325i or Eta pistons as they are too long so use 320i/323i/Eta rods.
Your early pistons will need 10mm taking off the bottom skirt to clear the crank webs.