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I've been toying around with possible fixes for leaking Harley knucklehead and panhead oil pump inlet check valves. When these cast iron pumps age, many develope what appear to be corrosion-related pockets in the cast iron seat that the spring-loaded inlet check ball rests upon. This seat/ball seal is important as improper sealing allows the old from the oil tank to leak through the oil pump into the motor's lower end when the motor is not running.
I first used a 3/8" ball bearing that I brazed to a rod as a lapping tool. I would use this tool with valve grinding compound in an atempt to lap the old seat smooth again. Aside from providing a very good cleaning of the seat area, this generally does not work, as many pitted seats need a deeper cut to get them smooth again.
Next attempt was to use the commercailly-available aftermarket inlet seat cutter. Again, very little success. Unless mine was mis-manufactured, even when lightly turning the cutter against the inlet set manually, the cutting surfaces go dull after one use (at best). Maybe they're only supposed to be used on aluminum pumps? If so, they don't tell you that. One would also think that the cutters would be hardened - even slightly?? More hard-earned money down the drain. Very frustrating.
Tom Cotton then suggested a burnishing tool of his own making that has worked out well for him. A very interesting concept that uses a hardened ball that is forced and twisted onto the inlet seat thereby burnishing the cast iron seat material smooth again. I tried it on my '47 FL pump with no success. Knowing of Cotton's abilities, I'm sure it works in most cases. But I must have a really damaged pump body, as the lower end still fills up with oil when it sits for a week or so and the pump shaft-to-bushing clearance isn't excessive. Unacceptable.
I am now consdiering contacting a tool Manufacturer to cut a piloted cutter similar to the one that is currently available, but with three removable carbide blades similar to those that one might use on a boring bar.
Another possibility is having a removable 3/8" wide, 45-degree cutting stone mounted on the piloted shaft with an upper handle that one would spin manually (similar to a valve lapping tool), thereby slowly grinding in and smoothing a new seat surface. This surface would have to be lapped afterward, as describe above. I really like this idea, but making the small stone would probably be a problem. Maybe a permanent stone using a diamond grade abrasive for long use?
Third possibility might be to machine a pocket into the pump body and press in a seal or O-Ring upon which the spring-loaded inlet ball would sit and provide the necessary oil sealing.
After rambling above ad-nausia, I finally get to ask my question - do any of you know of a good (and affordable) tool house that might make the tooling proposed above? Do any of you have other suggestions. No ego here - I'll experiment with whatever works.
I first used a 3/8" ball bearing that I brazed to a rod as a lapping tool. I would use this tool with valve grinding compound in an atempt to lap the old seat smooth again. Aside from providing a very good cleaning of the seat area, this generally does not work, as many pitted seats need a deeper cut to get them smooth again.
Next attempt was to use the commercailly-available aftermarket inlet seat cutter. Again, very little success. Unless mine was mis-manufactured, even when lightly turning the cutter against the inlet set manually, the cutting surfaces go dull after one use (at best). Maybe they're only supposed to be used on aluminum pumps? If so, they don't tell you that. One would also think that the cutters would be hardened - even slightly?? More hard-earned money down the drain. Very frustrating.
Tom Cotton then suggested a burnishing tool of his own making that has worked out well for him. A very interesting concept that uses a hardened ball that is forced and twisted onto the inlet seat thereby burnishing the cast iron seat material smooth again. I tried it on my '47 FL pump with no success. Knowing of Cotton's abilities, I'm sure it works in most cases. But I must have a really damaged pump body, as the lower end still fills up with oil when it sits for a week or so and the pump shaft-to-bushing clearance isn't excessive. Unacceptable.
I am now consdiering contacting a tool Manufacturer to cut a piloted cutter similar to the one that is currently available, but with three removable carbide blades similar to those that one might use on a boring bar.
Another possibility is having a removable 3/8" wide, 45-degree cutting stone mounted on the piloted shaft with an upper handle that one would spin manually (similar to a valve lapping tool), thereby slowly grinding in and smoothing a new seat surface. This surface would have to be lapped afterward, as describe above. I really like this idea, but making the small stone would probably be a problem. Maybe a permanent stone using a diamond grade abrasive for long use?
Third possibility might be to machine a pocket into the pump body and press in a seal or O-Ring upon which the spring-loaded inlet ball would sit and provide the necessary oil sealing.
After rambling above ad-nausia, I finally get to ask my question - do any of you know of a good (and affordable) tool house that might make the tooling proposed above? Do any of you have other suggestions. No ego here - I'll experiment with whatever works.
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