engine and drivetrain Flat pistons v domed

[Guest Anonymous]

I have to rebuild my engine and was going to stay stock. My supplier only has domed pistons. Will they work with my standard head or should I look for flat 8.3 pistons which were made for the head? The engine is apart and the machine shop is waiting on me.

[Guest Anonymous]

URL: http://www.geocities.com/karlkarlb/BMW.html

If you have a 121 head that takes the flat pistons, then stick with the flat ones. You don't want the valve to hit the top of the piston.

[Guest Anonymous]

there isn't just one dome piston.. there are three different kinds for three different heads... and there are even some small and large domes... and then there's custom pistons with domes on them and then the hemi piston... point is... all the dome does is increase the compression ratio and add power... you can run 87 octane on 9.5:1.. I guarentee you do it every day in your daily driver.. now the shape of the dome is dependent on your head... if you have a 121 head then it looks like a bath tub.. if you have a e12 head then it looks like a grand piano.. if you have an e21 then it looks like a grand piano as welll cept the angle of the dome in respect to the front of the engine is different... it's rotated so they're not interchangeable.. so first make sure you're supplier has the correct piston for your head... and then throw them slugs in and enjoy the power toss a schrick 292 in there as well and have go fast fun.. party on

kris

[Guest Anonymous]

The head says 121 T1

My concern was with the valves hitting however I am hearing that you should always go with domed for increased compression better performance. I assume if I get the bathtub pistons I will be okay. I just assumed the car was stock and I had an e12 head, glad I looked.