Guys currently building a 2 ltr zetec turbo and have got some low compression Vauxhall Calibra pistons, but i understand the conrods have to be altered to accomodate these pistons. How have people carried this out or what do people consider the best way to fit these pistons

 

The little ends on the zetec rods need opening up from 19-21mm i think. someone else will know

 

Standard silver-top small end is 20.63mm.. calibra pistons are 21.00.. you may have to machine the inside of the piston too to clear the rod, depending on which you use.. also need to machine some off the skirt to nicely clear the oil squirters.

 

Do you know if anybody as done this, I have an engine company doing this work for me and they feel that doing this to the con rods will weaken them to much.

 

Yes, everyone and their brother has been doing this for the last 10 years. None of this stuff is new.

 

you're only removing 0.37mm, thats about 15 thou in old money. It dosen't hurt the rods at all. The pins need to be an interference fit into the rods and need .0015" to .0025" nip. If they're still unsure, just send them to me!