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Tuesday 6 September 2022

Feuling Parts

Feuling M-8 'Gorilla' Rocker Shafts

California based performance parts engineers Feuling wrote to AMD recently to tell us about its new 'Gorilla' brand rocker shafts.
"After having a rocker shaft failure road-racing our Milwaukee-Eight Road Glide at Laguna Seca in 2020, we decided to design the best possible rocker arm shafts and create a method to tighten up excessive rocker arm end play to help reduce further cylinder head thrust wear."
An ambitious brief and a tough engineering challenge. Awesome if they can get it right, but if it was easy, everyone would be doing it, right?

Well, two years later and after more testing than you could imagine, here's the 'skinny' - "precision- ground from 4140HT steel, gas nitrated and final surface treated, these shafts are designed with strength in mind.
"They have over double the strength of the factory (or our competitors') shafts, and we can now fully recommend our 'Gorillas' for all M-8 engines, and especially for engines running higher lift camshafts and heavier valve spring pressures."


Also seen here, Feuling says that its rocker shaft shims for M-8 engines will "help quiet your engine by tightening the rocker arm to cylinder head end play clearance.
"We recommend an ideal side clearance of 0.035 - 0.005 for optimum rocker arm oil psi and noise reduction. M-8 cylinder heads also have excessive wear on the rocker arm standoff thrusting surfaces.
"When a hardened shim like this is placed on the thrusting side, it will assist in reduction with further wear and reduce cylinder head damage risk."