File Back rings are a high performance ring preferred by experienced engine builders and are designed to be fitted to the cylinder by filing back or removing some material from the ends of the rings. A ring filing tool is recommended. A good rule of thumb is to have .003" - .005" clearance for every inch of bore size plus an additional .001". In the case of the a 4" bore that would be .013" - .021" example 4 X .003" = .012" + the .001" = .013". However follow the instructions of the rings. Our high performance rings are designed for street or track use. Our top compression rings are made from Plasma-Moly coated ductile iron and are barrel shaped for superior compression and to prevent blow-by. Our second compression ring is a tapered ductile iron design to aid in oil control. The stainless steel oil control rings have expanders designed for proper tension against the cylinder wall for oil control without the loss of power.
- File Back Plasma-Moly rings
- Bore 4.0"
- Available in standard 0.020" 0.30" 0.40" and 0.60" over. Specify when ordering
- Thickness 1.5mm 1.5mm 3mm
- Set of 8