piston questions

[marksmopars]

I would expect the bore size/piston clearance to be different for a cast piston versus a forged piston. I would suspect this must be a consideration if you don’t bore the engine specifically for the replacement pistons. Specifically forged pistons utilize a tighter clearance in general.

 

[NC Engine Builder]

I would expect the bore size/piston clearance to be different for a cast piston versus a forged piston. I would suspect this must be a consideration if you don’t bore the engine specifically for the replacement pistons. Specifically forged pistons utilize a tighter clearance in general.

Actually forged pistons normally require MORE clearance, especially a 2618 alloy. A 4032 has more silicon content, and runs a bit tighter, but a cast piston is sometimes fitted as tight as .001

 

[volaredon]

This block was bored for the exact pistons that are in it now with about 3 hours of run time since that was done. Reasons for a redo are all over in the past pages of this thread.

 

[TT5.9mag]

I would expect the bore size/piston clearance to be different for a cast piston versus a forged piston. I would suspect this must be a consideration if you don’t bore the engine specifically for the replacement pistons. Specifically forged pistons utilize a tighter clearance in general.

Cast pistons don’t grow with heat like a forged piston does. Hypereutectic pistons are still cast but with a little different alloy and grow a little more than cast and a little less than forged. Forged pistons will grow the most and require more clearance as @NC Engine Builder said.

@volaredon show us a few pics of the pistons that hit valves. At this point I think you’d be a fool to spend the money on new pistons.

 

[volaredon]

Maybe after work. I don't have any currently