CP Forged Pistons Honda B16 B16A SC7116X 81.5mm 11.1:1

1. Deep valve relief depth accommodates high lift camshaft
2. Made for +1mm valve sizes
3. Custom skirt cam and barrel design
4. Accumulator grooves
5. High strength aluminum forgings
6. High performance rings
7. Fully CNC machined and balanced to +/- 1 gram
8. Wrist pins included at no additional cost
9. Double pin oilers, force fed oil ring
10. Pick lock grooves for easy lock removal
11. Pin fitting included

Radiused domes are used to maximize quench while eliminating possible hot spots that promote detonation.

Cam and Barrel: Extensive research has been done to find the optimum skirt shape for each piston. Having the correct cam and barrel on a part promotes the following:

1. Tighter clearances
2. Less noise
3. Better ring seal
4. More power
5. Durability

Lateral Gas Ports are channels drilled at the bottom of the top ring land that assist in ring seal. These channels allow combustion gasses to enter behind the top ring and improve ring seal by forcing the ring against the cylinder wall during combustion.

Skirt Coating offers additional lubricant in times of extreme heat or heavy wear situations. Coating can help by limiting the amount of friction on the skirt and providing a buffer between the piston and the cylinder.

X-Forgings are designed to minimize friction and reduce weight without compromising strength. With the use of bracing and ribs, the forging is configured by adjusting the weight balance between high and low stress areas. This design enables the use of a shorter pin for added strength and weight savings.

Accumulator groove is a Vshaped groove machined in the 2nd ring land to collect excess blow-by between the top and second ring. This groove collects residual gasses during combustion and alleviates top ring flutter while increasing ring seal.

Accumulator groove is a Vshaped groove machined in the 2nd ring land to collect excess blow-by between the top and second ring. This groove collects residual gasses during combustion and alleviates top ring flutter while increasing ring seal.

Double pin oilers, in conjunction with our dual fed reservoir, add twice the amount of oil from the cylinder wall to the wrist pin.

CP groove stands for Constant Pressure Groove. This groove works as a channel on the lower part of the top land that equalizes pressure to the back of the top ring groove. When used in combination with lateral gas ports, the CP groove helps keep gas ports clear of carbon build up. In addition, the CP groove prevents the top land from smudging into the top ring if the land rubs the cylinder bore.

Failure to check ring gap can result in severe engine failure. The following end gap recommendations are general guidelines. The best ring gap for any particular engine and application varies. Increased clearance is generally needed for forced induction, nitrous, filled blocks, endurance racing and other extreme applications. The final end gap suitable for the engine is the full responsibility of the engine builder. If you have any questions, please call us for technical support.

To determine the ring end gap look for your application in the proceeding table.

ALL BORES MUST BE CONVERTED TO INCHES.

Example: Bore size is 81mm – to find top ring end gap for a street application:
81mm/25.4= 3.189 inches
(3.189” x .005)= .016”
.016”is the minimum allowable clearance.

NOTE: If the ring gap is less than the minimum specified for your bore size, it will be necessary to file fit the rings to achieve proper end gap.

Ring Filing Procedures

1. Ring gap should be filed using a ring filing tool.
2. Ring gap should be filed in an inward direction and square to the sides.

1. A torque plate should be installed on engine (if applicable) and torqued to same specifications as machine shop.
2. Piston ring should be below and square to the deck.
3. Measure ring end gap with a feeler gauge.

GAS NITRIDED, CPN AND CPN2 PISTON RINGS
For use with gas nitrided, CPN and CPN2 piston rings. To identify a gas nitrided top ring the entire ring will be a light gray. These instructions must be followed for maximum ring seal. A torque plate must be used unless the bolt holes are not part of the cylinder. The first stone is a 525 (220 grit) stone, done until there is .001” left from final bore. The bore must be round to .0002”, checked 360 degrees from the bottom to the top of the bore. Then switch to a 625 (280 grit) stone, 50% load until .0002” is left from final bore. Then use the 625 stone at 20% load to final bore size.

CHROME RINGS
To identify a chrome top ring the face will have a chrome plating, the top and bottom of the ring will be a reddish-brown. Chrome on any of the rings is not compatible with nikasil bores. These instructions must be followed for maximum ring seal. A torque plate must be used unless the bolt holes are not part of the cylinder. The first stone is a 525 (220 grit) stone, done until there is .001” left from final bore. The bore must be round to .0002”, checked 360 degrees from the bottom to the top of the bore. Continue with a 525 (220 grit) stone, 50% load until .0002” is left from final bore. Then use the 525 stone at 20% load to final bore size.

ALL RINGS
The honing must be done slow to minimize heat build-up. No hand honing. Final bore needs to be less than plus or minus .0002” out of round, checked 360 degrees around the bore from the bottom to the top of the cylinder. This can only be checked with a dial bore gauge. The expertise of your machine shop is critical to the proper finish on your block bore. When you receive the block back from the machine shop it will appear clean, the block still needs to be cleaned. There will be material trapped in the honing grooves of the block that are not visible. Failure to clean the block will lead to premature ring wear and blow-by.