WTF...Water Pumps!
06-01-2009, 08:01 PM
#151
Rennlist Member
As I mentioned above, it has both. A roller to take the radial load and a ball bearing to take the axial load of the impeller trying to push the shaft forward.
06-01-2009, 08:15 PM
#152
Team Owner
Greg did you read post 150??
06-01-2009, 08:18 PM
#153
Nordschleife Master
support
Here's a wacky idea. Now, recall that I don't know these cars inside out so this may be an obviously infeasible solution or it might be a feasible non-solution.
The timing belt pulling the shaft up with a lever must be causing some issues, as noted above. If we can reduce this force, then the problems will presumably be reduced.
How about having another bearing on the outside in front of the pulley? Make a pump with a longer shaft that sticks out of the pulley. Fabricate a plate that has a bearing housing in it and a bearing in it. After installing the timing belt, bolt on the plate with the bearing such that the shaft end is supported by the bearing.
The shaft-bearing fit wouldn't have to hold much torque because there's no torque in the direction of rotation. The only load would be the timing belt pulling the shaft up. So it doesn't have to be pressed in with a press or anything.
If the shaft is supported from both ends, there belt doesn't have the leverage to pull up the shaft and wreck havoc inside the pump.
See the doctored picture.
If this is obviously stupid, please feel free to ridicule me!
The timing belt pulling the shaft up with a lever must be causing some issues, as noted above. If we can reduce this force, then the problems will presumably be reduced.
How about having another bearing on the outside in front of the pulley? Make a pump with a longer shaft that sticks out of the pulley. Fabricate a plate that has a bearing housing in it and a bearing in it. After installing the timing belt, bolt on the plate with the bearing such that the shaft end is supported by the bearing.
The shaft-bearing fit wouldn't have to hold much torque because there's no torque in the direction of rotation. The only load would be the timing belt pulling the shaft up. So it doesn't have to be pressed in with a press or anything.
If the shaft is supported from both ends, there belt doesn't have the leverage to pull up the shaft and wreck havoc inside the pump.
See the doctored picture.
If this is obviously stupid, please feel free to ridicule me!
06-01-2009, 08:26 PM
#154
Rennlist Member
isnt the impeller getting pulled into the engine? If the ball bearings dont have races designed for axial loads, they will fail. the design obviously has flaws. too bad as it is SO important.
mk
mk
06-01-2009, 09:29 PM
#155
Race Director
Here's a wacky idea. Now, recall that I don't know these cars inside out so this may be an obviously infeasible solution or it might be a feasible non-solution.
The timing belt pulling the shaft up with a lever must be causing some issues, as noted above. If we can reduce this force, then the problems will presumably be reduced.
How about having another bearing on the outside in front of the pulley? Make a pump with a longer shaft that sticks out of the pulley. Fabricate a plate that has a bearing housing in it and a bearing in it. After installing the timing belt, bolt on the plate with the bearing such that the shaft end is supported by the bearing.
The shaft-bearing fit wouldn't have to hold much torque because there's no torque in the direction of rotation. The only load would be the timing belt pulling the shaft up. So it doesn't have to be pressed in with a press or anything.
If the shaft is supported from both ends, there belt doesn't have the leverage to pull up the shaft and wreck havoc inside the pump.
See the doctored picture.
If this is obviously stupid, please feel free to ridicule me!
The timing belt pulling the shaft up with a lever must be causing some issues, as noted above. If we can reduce this force, then the problems will presumably be reduced.
How about having another bearing on the outside in front of the pulley? Make a pump with a longer shaft that sticks out of the pulley. Fabricate a plate that has a bearing housing in it and a bearing in it. After installing the timing belt, bolt on the plate with the bearing such that the shaft end is supported by the bearing.
The shaft-bearing fit wouldn't have to hold much torque because there's no torque in the direction of rotation. The only load would be the timing belt pulling the shaft up. So it doesn't have to be pressed in with a press or anything.
If the shaft is supported from both ends, there belt doesn't have the leverage to pull up the shaft and wreck havoc inside the pump.
See the doctored picture.
If this is obviously stupid, please feel free to ridicule me!
06-01-2009, 10:12 PM
#156
Rennlist Member
As I said, they have bearings to handle both axial and radial loads(from a previous thread on the subject):
Last edited by SharkSkin; 06-01-2009 at 11:13 PM.
06-01-2009, 10:23 PM
#157
Former Vendor
Thread Starter
Greg I was wondering if you checked the belt tension prior to removing the belt after the WP got damaged?
Second what type of tensioner are you using??
If a factory type then have you verified that it is correctly assembled and full of oil??
By correctly assmbled I mean the sequence of the Belville washers.
When i rebuild the tensioner i clean all of the washers then reassemble them then fit them to the tensioner piston, then fit the piston in a vice and gently squeeze them together , you can see the washers deflect slightly then release, this gets all of the play out the washers prior to installation, it is best to the have the engine see a heat cycle and then recheck the tensions as heat will also change the belville washer preloads and possibly reduce it
Second what type of tensioner are you using??
If a factory type then have you verified that it is correctly assembled and full of oil??
By correctly assmbled I mean the sequence of the Belville washers.
When i rebuild the tensioner i clean all of the washers then reassemble them then fit them to the tensioner piston, then fit the piston in a vice and gently squeeze them together , you can see the washers deflect slightly then release, this gets all of the play out the washers prior to installation, it is best to the have the engine see a heat cycle and then recheck the tensions as heat will also change the belville washer preloads and possibly reduce it
Set at 5.2 "belt units" using the factory tool. After initial run in, rechecked and retensioned back to 5.0 "belt units"....all measurements "cold".
06-01-2009, 10:23 PM
#158
Team Owner
Nice, destructive testing , very interesting internals
06-01-2009, 10:29 PM
#159
Former Vendor
Thread Starter
Here's a wacky idea. Now, recall that I don't know these cars inside out so this may be an obviously infeasible solution or it might be a feasible non-solution.
The timing belt pulling the shaft up with a lever must be causing some issues, as noted above. If we can reduce this force, then the problems will presumably be reduced.
How about having another bearing on the outside in front of the pulley? Make a pump with a longer shaft that sticks out of the pulley. Fabricate a plate that has a bearing housing in it and a bearing in it. After installing the timing belt, bolt on the plate with the bearing such that the shaft end is supported by the bearing.
The shaft-bearing fit wouldn't have to hold much torque because there's no torque in the direction of rotation. The only load would be the timing belt pulling the shaft up. So it doesn't have to be pressed in with a press or anything.
If the shaft is supported from both ends, there belt doesn't have the leverage to pull up the shaft and wreck havoc inside the pump.
See the doctored picture.
If this is obviously stupid, please feel free to ridicule me!
The timing belt pulling the shaft up with a lever must be causing some issues, as noted above. If we can reduce this force, then the problems will presumably be reduced.
How about having another bearing on the outside in front of the pulley? Make a pump with a longer shaft that sticks out of the pulley. Fabricate a plate that has a bearing housing in it and a bearing in it. After installing the timing belt, bolt on the plate with the bearing such that the shaft end is supported by the bearing.
The shaft-bearing fit wouldn't have to hold much torque because there's no torque in the direction of rotation. The only load would be the timing belt pulling the shaft up. So it doesn't have to be pressed in with a press or anything.
If the shaft is supported from both ends, there belt doesn't have the leverage to pull up the shaft and wreck havoc inside the pump.
See the doctored picture.
If this is obviously stupid, please feel free to ridicule me!
The pulley would have to be "trued" up, but I see no initial reason that would not work. If cleverly designed, the "new" support bearing could also ensure that the pulley could not "walk" off.
06-01-2009, 10:34 PM
#160
Former Vendor
Thread Starter
Hard to say for sure, I suppose. Generally though, on centrifugal pumps the pressure on the back side(where the seal is) is less than the pressure on the front side(where the vanes are). Certainly there is very low pressure at the inlet and there is relatively high pressure at the circumference of the impeller as it pumps. Maybe the ground blocks are evidence that it gets pulled rearward, after all.
As I said, they have bearings to handle both axial and radial loads(from a previous thread on the subject):
As I said, they have bearings to handle both axial and radial loads(from a previous thread on the subject):
If you go out and start looking at water pump bearings, you will see that they are offered in both styles....why they didn't spend another $2, on this pump, and use the proper bearing is just silly.
06-01-2009, 11:26 PM
#162
Team Owner
Thanks Greg, so its safe to figure that the bearing /belt wasnt overtightened to start the failure chain.
PT does have an interesting suggestion to support the shaft from the other side of the pulley.
I wonder how it could be fabricated, some of the holes on the front of the WP are already used so a spacer might have to come into play for the mount plate, and a longer pump shaft also installed
PT does have an interesting suggestion to support the shaft from the other side of the pulley.
I wonder how it could be fabricated, some of the holes on the front of the WP are already used so a spacer might have to come into play for the mount plate, and a longer pump shaft also installed
06-01-2009, 11:56 PM
#163
Nordschleife Master
I'll name this wacky device concept the "double fist." I have business undergrad degree, which leads me to believe that the name is critical part of the commercial viability of any design. ;-)
Without any engineering background, I am going to babble about my design ideas a bit. It would be nice to know whether the pump's thrust loading is towards the block or away from the block, seems important to me. If the thrust force pushes away from the block, maybe use a tapered roller bearing in a cartridge as the second fist? That would allow for both the radial and thrust loadings without a problem. The steel plate in which the bearing is housed could be designed to provide the right spring force against the shaft.
Coming back to my comfort zone, if the double fist can be installed on an existing water pump while the engine is in the car, the sales potential is much higher.
If someone who has an engineering background designs the double fist and then produces it, I'll buy one or two.
Without any engineering background, I am going to babble about my design ideas a bit. It would be nice to know whether the pump's thrust loading is towards the block or away from the block, seems important to me. If the thrust force pushes away from the block, maybe use a tapered roller bearing in a cartridge as the second fist? That would allow for both the radial and thrust loadings without a problem. The steel plate in which the bearing is housed could be designed to provide the right spring force against the shaft.
Coming back to my comfort zone, if the double fist can be installed on an existing water pump while the engine is in the car, the sales potential is much higher.
If someone who has an engineering background designs the double fist and then produces it, I'll buy one or two.
06-01-2009, 11:57 PM
#164
Nordschleife Master
Thanks Greg, so its safe to figure that the bearing /belt wasnt overtightened to start the failure chain.
PT does have an interesting suggestion to support the shaft from the other side of the pulley.
I wonder how it could be fabricated, some of the holes on the front of the WP are already used so a spacer might have to come into play for the mount plate, and a longer pump shaft also installed
PT does have an interesting suggestion to support the shaft from the other side of the pulley.
I wonder how it could be fabricated, some of the holes on the front of the WP are already used so a spacer might have to come into play for the mount plate, and a longer pump shaft also installed
Would be interesting to see a prototype made by "rebuilding" a new Laso pump with a longer shaft and a bracket.
If you've looked inside the S4's Bosch alternator, the rear bearing is the type of thing I suspect ptuomov is getting at - a plastic cup-shaped bushing to accomodate the bearing, to allow for tolerance and avoid press fit, inside a metal housing.
That way the pump could have the extra front bearing pressed onto the shaft and left there permanently - for good axial alignment.
06-02-2009, 01:20 AM
#165
Former Vendor
Thread Starter
I'll name this wacky device concept the "double fist." I have business undergrad degree, which leads me to believe that the name is critical part of the commercial viability of any design. ;-)
Without any engineering background, I am going to babble about my design ideas a bit. It would be nice to know whether the pump's thrust loading is towards the block or away from the block, seems important to me. If the thrust force pushes away from the block, maybe use a tapered roller bearing in a cartridge as the second fist? That would allow for both the radial and thrust loadings without a problem. The steel plate in which the bearing is housed could be designed to provide the right spring force against the shaft.
Coming back to my comfort zone, if the double fist can be installed on an existing water pump while the engine is in the car, the sales potential is much higher.
If someone who has an engineering background designs the double fist and then produces it, I'll buy one or two.
Without any engineering background, I am going to babble about my design ideas a bit. It would be nice to know whether the pump's thrust loading is towards the block or away from the block, seems important to me. If the thrust force pushes away from the block, maybe use a tapered roller bearing in a cartridge as the second fist? That would allow for both the radial and thrust loadings without a problem. The steel plate in which the bearing is housed could be designed to provide the right spring force against the shaft.
Coming back to my comfort zone, if the double fist can be installed on an existing water pump while the engine is in the car, the sales potential is much higher.
If someone who has an engineering background designs the double fist and then produces it, I'll buy one or two.
I envision your bearing to be a sealed ball bearing that fits over the "nose" of the pulley, not on the shaft. With a little bit of play in the mounting plate, the bearing could "slide" over this nose piece and then be bolted down to the mounting points.