M-8 Rocker Arm Tower Stud and Beehive Racing Valve Spring Kits
Pacifica, California based Kibblewhite Precision Machining is offering what it describes as a "premium" rocker tower solution for '17-'19 M-8 engines.
The kits include nuts machined from heat treated high tensile billet steel and heat treated 180,000 PSI aircraft alloy steel studs - both have rolled threads for the greatest possible strength and are black oxide treated for enhanced corrosion resistance.
Company President Will Kibblewhite explains that "because the stock M-8 rocker shaft bolts can stretch, the shaft can move in the saddle, leading to deformed saddles, cracked rocker towers and broken rocker shafts.
"KPMI M-8 rocker tower studs are made from 180,000 PSI yield strength, fine grain, heat treated aircraft grade steel; the lower portion of the stud is 0.810" long, which maximizes the length of the thread engagement.
"The threads are rolled, not cut. Rolling gives the threads a superior surface finish and compresses the material, making the threads denser, for the toughest and strongest possible thread, and the studs are black oxide treated to increase corrosion resistance.
"The combination of the material, thread type and the length of the thread engagement maximizes clamping force, makes the assembly more stable than stock, and reduces the chance of failure due to the stretching and flexing that the factory bolts are subject to."
The nuts are single point machined from high tensile strength aircraft alloy steel. During the machining process, close tolerances and smooth surface finishes are maintained - two critical factors for achieving correct fit and torque. After machining, the nuts are heat treated to a specific depth. This creates hard, wear-resistant working surfaces, while retaining a ductile core to prevent cracking under load. The premium black oxide treatment provides excellent corrosion resistance and appearance.
Also seen here is Kibblewhite's 0.625" lift beehive racing valve spring kit for '17-'19 M-8 engines. The company says that its R&D team conferred with some of the best known builders in the world to arrive at a consensus for the characteristics of this new kit.
"Combining feedback from these builders with our engineering team's stringent design criteria for wire stresses, fatigue life and manufacturing processes has allowed us to create a unique spring, designed specifically for the M-8.
"The progressively wound, ovate wire, beehive springs undergo proprietary heat treatment and shot peening processes. These complete kits provide the spring forces required for high lift camshafts and sustained high rpm."
The kits are supplied with either tool steel or titanium retainers to minimize reciprocating mass, special M-8 high lift beehive valve springs, heat treated steel bases and steel clad top hat seals with a Viton sealing element.
KIBBLEWHITE PRECISION MACHINING