I need some help in understanding the choices there are in building a 96x78 motor.

1. If I use stock rods & 24mm pin pistons I have to shim the cylinders to accomodate the longer stroke(also pushrods, oil tubes, maybe head studs, etc) making the head-to-head distance 7mm wider.

2. If I use KB or JE 22mm pin pistons and T1 rods, I do not have to shim the cylinders, except for a small amount to set deck hieght. The basic head-to-head distance does not change.

If #2 is the case, then the 22mm pin seems to be the "easier" way to go???

Do you have to specify the "pin position" when you buy the 22mm pin pistons??

All "on topic" replies appriciated.

Ken

I'm new to this, but I thought the T1s used 24mm pins, and the T4s used 22mm pins. I could be wrong. Either way, it really depends on who you're getting the pistons from. I know Scat specifies what stroke the pistons are made for with a stock length rod; I.E. pin offset. However, some places don't, and YOU'LL have to tell them what pin height you need. Ussually in a situation like the latter, they'll have a few options (probably the same as everyone else) to choose from, unless you want to pay for completely custom made pistons. So yes, you do need to specify the piston pin height for the specific application, but some sellers take out a middle step for you by sorting out exactly what that height should be for a number of different strokes.
I hope I explained that right. I'm really tired and getting cross-eyed.
Mark D.

BTW (just for my own curiosity) what length rods are you planning to use in this hypothetical engine of yours?

You can't do a 78mm stroke with stock rods, the cam is in the way. You must use aftermarket Type 1 rods and even they need to be cleared and the cam must be ground on a smaller base circle.

FYI the type 1 uses a 22mm pin and the type 4 a 24mm.

Shims will be required any way you do it, period.

Thanks for the comments.

ken

Yes, thanks. I'm looking to build a motor soon and can use any info I can find.
Mark D.