BBC piston and ring questions
 

Scuffed 3 pistons in one motor, pretty sure I know what happened. Another story for another day. I am going to most likely put new rods and pistons in both motors.

454's .030 over, cureently 8.9:1. Replacing with flat top forged (prob probe) pistons. 088 heads Should equal 8.4:1 roughly.
B&m 420 megablowers with chillers about 6lbs of boost. Mild hyd flat tappet cam.

What should I run for piston to wall clearance ? Was thinking .0055-.0065?

What ring package should I go with? 1/16 or 5/64?

Thanks

stay away from probe,,look nice but?? i have seen problems with them on some race motors..some of the pistons were.003 off from each other..stick with J&E or srp..worse case ross also makes a great piston..also spend the money on total seal rings..

Thanks for the input, I'll look into srp's

I am Refreshing my 540's right now... Daryl from Nortech did the machine work to my blocks and set the piston to wall at .006" with the 2618 JE pistons.

I was told by Daryl to use .026/.028 ring gaps... .0026 to .003" Bearing Clearance

Mine is supercharged and I am adding chillers and boost this time!! Also switched it from a solid flat tappet cam to a hyd roller.

I have the same blowers as you have in your boat mark. The chillers were on yours once before from what the previous owner had said. That boat should really fly now! Be careful with those drives!

there is no magic number for piston to wall clearance,blown or not,it differs with piston maker and material used.i recomend j&e pistons for blown application,with 1/16 1/16 3/16 ring package,also,if going over 950 hp,i always go with a thicker wrist pin.

Go with some JE blower pistons. Really not much more than the SRP line, I think I paid about 650 a set for mine. The pin they come with will work just fine for your setup.

If your on a tight budget, go with the JE Blower piston and a good set of Speed Pro file fit plasma Moly rings or Childs and Albert. Total seals are nice, but carry a nice price tag. id rather go that route than a cheaper piston and total seal rings. File Fit plasma moly been working just fine for many years. Just be sure the ring gaps are set to spec and proper honing is done.

Hell Fire rings are bad a$$, but wouldnt use them on a production block. They will wear the bores before they wear themselves. I'd rather keep the bores and lose a few hp. It just wont matter in a 40ft boat anyway.

Well it's looking like I only need 4 pistons, so instead of buying a whole set and rebalancing the entire assembly, I'm thinking just buy the srps I need and start putting together parts for a pair of 502's or 540's to swap in about 150-200 hours from now.

Sounds like a plan! Who knows, maybe a set of 572's for that Hawk???.....wait, maybe 598 by then...:party-smiley-004: