*Urgent* Forged Piston Ring Gap..??

Just putting my engine back together and have got stuck on what the ring gap should be.

The pistons are forged Ross with a 4" bore.

Does the rule of 4 thou per 1" of bore still apply with forged pistons?

Should I go for 16 thou gap?

 

I would call Ross for that answer.

 

Get the word from Ross and the ring man. When in doubt always call customer service.

 

Been a while since I cut rings.... but it seems like it was determined by the type of ring, and not the piston... since they expand at different rates. Like ole Don says ... call the manufacturer.

Kamp

 

Ok, Ross states the 4 thou rule on there site.

 

It also depends on the engines application, IE: Street, Race, High Heat, Blowers, Turbos,etc.
.016 on the top ring can be marginal even on a street engine with todays fuel.

 

yup, use has more to do with it than anything else, nitrous requires a lot of gap, blowers a bit more than unblown, etc. It has to do with how much heat gets to the rings, which determines how much they expand. If it's just for normal naturally aspirated use, then figure .016" for a mild engine to .020" for a screamer.

 

I figure not having enough gap is definitely disasterous, so when in doubt go bigger (gap).