Mentor, Ohio based Wiseco Piston has unveiled a new line of pistons for late model Harley applications – their Black Edition pistons – featuring two new proprietary coatings.
They feature what Wiseco describe as an “industry first” ArmorFit coating on the piston skirt, as well as an ArmorX coating on the entire piston. Said to offer superior protection against wear, higher compression, smooth and quiet operation, and maximized efficiency, they are available for M-8s and popular Twin Cam and Rushmore model engines (SE heads).
Wiseco’s ArmorX coating comes from a proprietary electrochemical process using high strength materials that create an armor-like coating on the piston dome and ring grooves, providing resistance to extreme heat and detonation, while also providing a distinctive black color.
The ArmorX coating acts as a shield around the piston, keeping the forged aluminum protected against potential damage from extreme conditions.
The ArmorX coating is also said to add support to the vulnerable areas of the piston. “Machine work done on a piston, such as the piston ring grooves, can create vulnerabilities. After machining, these areas could potentially display reduced strength and wear resistance, especially in V-twin engine applications. However, the ArmorX coating covers every nook and cranny it’s applied to, adding its strength and wear resistance qualities where the piston needs it most and providing even more longevity to the life of the piston.”
The patented Wiseco ArmorFit coating is a product of their in-house R&D department. Wiseco say their R&D team “went through a thorough process of testing, developing and benchmarking with the in-house dyno, as well as with thousands of on-road miles to perfect the ArmorFit skirt coating.
“The coating comes from a ‘moly’ (molybdenum) based dry film. Moly is naturally a dry lubricant, providing great lubricating qualities, even in the presence of zero liquid lubricators.” Wiseco mixes the formula in-house, and uses a patented process to permanently apply this moly based dry film to the piston skirt. It is bonded to the skirt surface, and is designed to become the piston's sliding area against the cylinder wall. The result is the piston operating quieter and smoother than stock, with reduced friction throughout operation.
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| Wiseco R&D Manager Dave Fussner: “The challenge has been developing a robust skirt coating that could be applied thicker and allow the forged piston to be installed at the same or less cold clearance than a cast piston” |
Dave Fussner, Wiseco Research and Development Manager, said: “The challenge has been developing a robust skirt coating that could be applied thicker and allow the forged piston to be installed at the same or less cold clearance than a cast piston. Simply applying the standard skirt coating material thicker to receive the desired result is an unsatisfactory method and yields unsatisfactory results.”
During engine motion, the coating will adapt and actually fit itself to the cylinder wall, eliminating the need to measure clearance or worry about noise and wear that comes from piston rock with some traditional style pistons.
A very important note regarding the ArmorFit coating is that Wiseco does not change the piston’s outside diameter to accommodate for the coating. Proper clearance between the piston and cylinder wall is always necessary, to allow room for expansion at operating temperature. Proper piston dimensions are maintained during production of Black Edition pistons, and the ArmorFit coating is applied after these dimensions are met. As a result, the user can simply choose the proper piston to fit their bore, and let the ArmorFit coating worry about the rest.
Black Edition pistons offer higher 11:1 compression, as well as much quieter operation. The Black Edition pistons will improve lubrication of the piston and the piston pin to combat wear, and offer a better ring seal thanks to optimized ring grooves.
Also, the CNC-machined dome shape, along with the ArmorX coating, is said to allow for more efficient power delivery and fuel use thanks to improved flame travel during combustion. This means that the engine will operate smoothly and quietly throughout the entire rpm range.
Black Edition piston kits include the piston, rings, wrist pin and locks. Milwaukee-8 applications will be available in 107 ci and overbore and sleeve in options, including 114 ci, 117 ci and 124 ci.
For Twin Cam and Rushmore models Black Edition pistons will be available in 103 ci, 106 ci and 117 ci ranging from 9:1 to 10.5:1 compression ratio for Twin Cam 96 and SE heads, and 103 and 106 ci with 10.5:1 compression ratio for ’15 and up Rushmores.
www.wiseco.com