Feuling M8 oil pump
Thread Starter
|
Cruiser
Joined: Jul 2024
Posts: 149
Likes: 57
From: Washington
Feuling M8 oil pump
If anyone is planning on doing their cam chest, upgrade to the oil pump, cam plate, installing a cam on the M8, DO NOT go with Feuling. I did, less than 500 miles ago, and today I had sumping, big time. So now I have to go in and do the job again. Im going back to the stock pump and plate. Don't drink the red cool aid. Now, they make beautiful stuff, Ive run them on Twin Cams for years, never had any issues. There's something wrong with their M8 pump and plate.
Seasoned HDF Member
Joined: Apr 2015
Posts: 10,001
Likes: 5,266
That sucks. For some reason, they do have an awfully long Troubleshooting Guide on sumping. Makes you wonder why, doesnt it?
https://www.feulingparts.com/tech/troubleshooting
https://www.feulingparts.com/tech/troubleshooting
Road Master
Joined: Jun 2013
Posts: 1,057
Likes: 953
From: Sarasota Florida
Could be an install issue. Feuling oil pumps, including the HP+ and Race Series for Milwaukee Eight (M8) engines, are designed to mate directly to the engine case with precision machining, relying on O-rings for sealing rather than a separate rear gasket. Specifically, the oil pump uses an O-ring in the scavenge port and another sub-seal O-ring on the engine case side to ensure a proper seal and prevent leaks or wet sumping issues.
However, due to customer demand and inquiries, Feuling added an optional O-ring groove to the back cover of their M8 oil pumps starting around May 11, 2021. This was in response to concerns about sealing in certain conditions—like engines with higher cylinder leak-down, poor sub-seal O-ring fitment, or looser tolerances. Feuling’s in-house testing on healthy engines didn’t show a significant benefit to adding this O-ring, but they included the groove as an option. If you choose to use it, you’d transfer the O-ring from the stock Harley-Davidson oil pump cover to the Feuling pump’s groove. This isn’t mandatory, though—it’s more of a precautionary measure for specific scenarios.
In practice, whether you need this extra O-ring depends on your engine’s condition and how well the pump seals without it. The Feuling pump’s billet construction (6061 for HP+, 7075 for Race Series) and tight tolerances are intended to work effectively with just the provided O-rings, assuming proper installation. If the pump is installed correctly—centered to the pinion shaft, with well-lubed O-rings and no damage—you shouldn’t need an additional rear gasket or O-ring beyond what’s supplied. Always double-check the scavenge port seal, as any compromise there can lead to oiling issues, regardless of an extra O-ring.
However, due to customer demand and inquiries, Feuling added an optional O-ring groove to the back cover of their M8 oil pumps starting around May 11, 2021. This was in response to concerns about sealing in certain conditions—like engines with higher cylinder leak-down, poor sub-seal O-ring fitment, or looser tolerances. Feuling’s in-house testing on healthy engines didn’t show a significant benefit to adding this O-ring, but they included the groove as an option. If you choose to use it, you’d transfer the O-ring from the stock Harley-Davidson oil pump cover to the Feuling pump’s groove. This isn’t mandatory, though—it’s more of a precautionary measure for specific scenarios.
In practice, whether you need this extra O-ring depends on your engine’s condition and how well the pump seals without it. The Feuling pump’s billet construction (6061 for HP+, 7075 for Race Series) and tight tolerances are intended to work effectively with just the provided O-rings, assuming proper installation. If the pump is installed correctly—centered to the pinion shaft, with well-lubed O-rings and no damage—you shouldn’t need an additional rear gasket or O-ring beyond what’s supplied. Always double-check the scavenge port seal, as any compromise there can lead to oiling issues, regardless of an extra O-ring.
Thread
Thread Starter
Forum
Replies
Last Post
98hotrodfatboy
Twin Cam Motors
7
Feb 22, 2023 03:10 PM
