Oil pump replacement gears

Conaway2

Conaway2

Well-known member
Does anyone know of a supplier who offers replacement oil pump gears that are machined and not sintered ?

Thanks - Jim
 
sintered
/ˈsin(t)ərd/

adjective
produced by or subjected to sintering (the process of coalescing a powdered material into a solid or porous mass by means of heating without liquefaction).
"a mosaic made from sintered glass"

co·a·lesce
/ˌkōəˈles/

verb
gerund or present participle: coalescing
come together to form one mass or whole.
"the puddles had coalesced into shallow streams"
Similar:
unite
join together
combine
merge
fuse
mingle
meld
blend
intermingle
knit (together)
amalgamate
consolidate
integrate
affiliate
link up
homogenize
synthesize
converge
commingle
commix
combine (elements) in a mass or whole.
"to help coalesce the community, they established an office"

Hey I can't be the only one that didn't know...... I hope!
 
I believe most of the suppliers we mention in this forum sell sintered gears. I’m thinking seriously about just re-using the original gears.
 
Do you know of problems with PM gears? If originals are in good condition and check to have minimal wear then they can be reused. Model A engines run at a lower rpm level than a lot of others and I haven't heard of problems yet.

Sintered iron and steel gears have been tried in several applications on different helicopters that I've worked on over the years and they had troubles with them. It seems that the PM technology works well for automotive connecting rods and other structural engine parts but not so well with some gears. On Lycoming engines they first used sintered iron with problems, then they tried aluminum ones that didn't work well, and finally they changed to a nitrided steel gear for one and a carburized steel gear for the other and this worked OK. On the Rolls Royce/Allison 250 military turbine engines, they tried a sintered steel gear for the output shaft and they started failing right & left till they took them all out of service.

The technology is getting better but that's due to the intense need of auto & auto parts manufacturers to make parts cheaper. They are easier to manufacture with no hobbing technology required and they are easier to heat treat but you never know how the ones for model A engines are made. If they cut corners, there is a lot better chance for problems.
 
rotorwrench said:
They are easier to manufacture with no hobbing technology required and they are easier to heat treat but you never know how the ones for model A engines are made. If they cut corners, there is a lot better chance for problems.
Click to expand...

Great read and info, I wonder if I missed a bullet bt using NOS or NORS kits from the 30s & 40s.

Can sintered gears be identified visually?

BTW I have seen ads for that process in bronze by 3D painting and a furnace for hard to find parts.

Another era scene fro SHORPY.COM
 

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If they cut corners, there is a lot better chance for problems.
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And on the Model A, a lot less chance of catching it. As in no oil pump pressure indication.

One positive check would be to remove the side oil pipe and see if oil leaks out.

Joe K
 
The oil pump is a simple displacement pump...not a pressure pump. Only lifts oil about 6 inches. If the gears fit well and not bind, I would think all should be good?

Brian W.
 
I just pulled the original pump gears from the degreaser bath, cleaned them up and inspected them. They are clearly machined, as the marks are very visible on both ends of each gear. There is also hardly any wear on the gear teeth or shaft. I think I’ll replace bushings and gaskets and reassemble the pump with the original gears.
 
Conaway2 said:
I just pulled the original pump gears from the degreaser bath, cleaned them up and inspected them. They are clearly machined, as the marks are very visible on both ends of each gear. There is also hardly any wear on the gear teeth or shaft. I think I’ll replace bushings and gaskets and reassemble the pump with the original gears.
Click to expand...
There you go!
 
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