piston id required
 

can anyone tell me about the differences in these two pistons? I belive that they are both 930 pistons but im not sure about age. is the only difference between them in the skirt? and most importantly, can you use them as a mixed set? I have five of the pistons with the curved section and I have one with the more squared off section.

Thanks,

Andy

http://forums.pelicanparts.com/uploa...1119194613.jpg http://forums.pelicanparts.com/uploa...1119194625.jpg

sorry to bump this but im desperate for an answer!

Can anyone help me out?

Thanks,


Andy

Just a thought but the "square" one looks as if it started life as a "curved" one. Look just under the wrist pin; there seems to be a bit of radius left over on the "square" one. Could be someone removed a little weight from it. Take the five to a machine shop and have them modified like the "square" one.

fair point Jim, Ive looked at the surface of the square one but it looks as if its been milled. there are circular machine marks, similar to the marks on the curved one. im thinking that its a factory finsh but i could be wrong. anyone else got a view?

Andy

I have a set of 95mm 930 P&C's at home, I can take a picture of them and post it for comparison. What size pistons are these?

tim these are 97mm 930 turbo pistons. I just measured the crown diameters of both pistons. they came up at 96.57mm

Andy

anyone else? the guy is coming over to buy them tomorrow and it would be nice to be able to explain the two types of piston. (and hopefully explain that they can be used as a mixed set!)

Andy

If you used the pistons as they currently are, you would create an imbalance in the reciprocating mass. The five will have to be machined and balanced to the lighter piston. Have you checked the piston to see if it is in spec? Overall roundness, skirt wear, ring groove dimensions?

Dave they are all in spec but having the pistons machine to spec is not in the budget for selling these. ill let the guy know before he makes the trip and put the ball in his court i think.

Thanks for peoples help.

P.S. if anyone can i.d the pistons id still be interested to know what the differences are!

Andy