Need Help on Flathead

I THINK it might be an older un-chromed Raptor piston.

You generally buy the piston kit and the book lists that number, but not the piston itself. Your number is on the top of the piston correct? That is the individual part number, not the set. The Raptor III piston (chromed) part numbers are all 55567- numbers and the unplated pistons begin with 55526-.

Either way, it's .010 over and definitely has a Briggs racing part number on it.
 
As long as the bore isn't worn, yes, a new set of +.010 rings is what you need. You may want to measure your bore/piston and make sure you have the correct clearances before buying rings, just in case you you need a larger piston.
 
I would not suggest putting over size rings in a motor. First off if you have two much ring end gap with the appropriate rings in this case .010 over the bore is worn out. If you got a .010 over bore you need .010 over rings. You should have to file them to make them work. It don't matter if they are Burriss or Briggs rings. If it already has ring end gap you need to bore your block to .015 over. Then use .015 over rings. Secondly, If you use oversize rings and set the ring end gap correctly , your ring is not round anymore. Its oval shape now. The problem with running an oval shape ring is that the tension is not consistent all the way around the bore. Another thing to consider if your bore is worn out its not straight anymore. The bore has to be straight from top to bottom so the ring end gap does not change from one end of the bore to the other end.. End result is you will not get optimum seal between you rings and the cylinder. Leak by the rings or valves and you will have less power. It shows on the dyno and the track.
 
You must log in or register to reply here.
Back
Top