decadamsinzim
Junior Member
- Joined
- Jan 12, 2013
- Posts
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- Zimbabwe
Greetz all,
I'm in the process of designing my own outdrive and I want to include an oil pump at the end of the drive shaft just inside the rearmost seal.
In other words, inside the casing, just in front of the prop.
Reasons for this are;
1) I want oil circulation through the whole leg assembly so the CV joint at the transom and associated bearings are always running in "fresh" cooled oil.
2) It means I can do an oil change on the outdrive without removing the boat from the water.
3) I have a quick visual way of seeing if any of my seals are leaking.
4) Include a magnet in the system for easy inspection for wear particles. Again, without removing the leg or boat from the water.
So, the idea is, the pump forces oil up a pipe to the front of the system then the oil makes it's way back down the leg through all the bearings and back to the pump. All the time, being cooled through contact with the casing which is obviously submerged. As there are no gears in the whole leg unit (except for the pump if I use a gear pump), I'm thinking along the lines of running the unit on ATF or engine oil which is resonably thin compared to traditional gearbox oil.
I have two ideas on pump design and this is where I need some opinions please.
Gear pump or impellor pump.
Which would be better?
Which one would use less horsepower?
The oil isn't under any pressure, it just has to move from the back of the unit to the front. So, all the pump has to do is circulate the oil.
The volume needed to be pumped is minimal. A gallon a minute would circulate the oil more than enough.
I'm concerned about creating a vacuum in the rear section of the leg and sucking water past the seals in to the leg if the oil can't return through the various bearings fast enough.
I think the idea is a real winner though, imagine to change the oil, all you have to do is disconnect the return hose from the front of the leg assembly, place in container. Put unit in drive and wait for it to pump all the oil out of itself. Reconnect hose. Refill with fresh oil. Job done. No drain plugs, no spillage. no fuss. no boat out of water!
Just thinking about it, I guess an impellor pump would pump oil in forward and reverse whereas a gear pump wouldn't work or would reverse the flow in reverse?
Your Ideas and thoughts most appreciated.
Thanks
Dave
I'm in the process of designing my own outdrive and I want to include an oil pump at the end of the drive shaft just inside the rearmost seal.
In other words, inside the casing, just in front of the prop.
Reasons for this are;
1) I want oil circulation through the whole leg assembly so the CV joint at the transom and associated bearings are always running in "fresh" cooled oil.
2) It means I can do an oil change on the outdrive without removing the boat from the water.
3) I have a quick visual way of seeing if any of my seals are leaking.
4) Include a magnet in the system for easy inspection for wear particles. Again, without removing the leg or boat from the water.
So, the idea is, the pump forces oil up a pipe to the front of the system then the oil makes it's way back down the leg through all the bearings and back to the pump. All the time, being cooled through contact with the casing which is obviously submerged. As there are no gears in the whole leg unit (except for the pump if I use a gear pump), I'm thinking along the lines of running the unit on ATF or engine oil which is resonably thin compared to traditional gearbox oil.
I have two ideas on pump design and this is where I need some opinions please.
Gear pump or impellor pump.
Which would be better?
Which one would use less horsepower?
The oil isn't under any pressure, it just has to move from the back of the unit to the front. So, all the pump has to do is circulate the oil.
The volume needed to be pumped is minimal. A gallon a minute would circulate the oil more than enough.
I'm concerned about creating a vacuum in the rear section of the leg and sucking water past the seals in to the leg if the oil can't return through the various bearings fast enough.
I think the idea is a real winner though, imagine to change the oil, all you have to do is disconnect the return hose from the front of the leg assembly, place in container. Put unit in drive and wait for it to pump all the oil out of itself. Reconnect hose. Refill with fresh oil. Job done. No drain plugs, no spillage. no fuss. no boat out of water!
Just thinking about it, I guess an impellor pump would pump oil in forward and reverse whereas a gear pump wouldn't work or would reverse the flow in reverse?
Your Ideas and thoughts most appreciated.
Thanks
Dave
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