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TR2/3/3A Replacement or rebuild kit for water pump

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bobhustead

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I got a new Moss water pump. OEM pump shaft and pulley are slotted at .125. The new pump has a metric slot and key. OEM slot is .125 and OEM key is slightly less than .126. New metric key is .018. ANSI specifies key width from +.001 to .000 in relation to the key slot. Moss is working on this, but meantime I need a water pump compatible with my OEM pulley. Does anyone have recent experience with another vendor?

Thanks, Bob
 
Not too recent, but the pump & pulley I got from TRF a few years back seemed to fit and work fine. No problems yet.

I did notice some noise while changing coolant yesterday, but it turned out to be a belt that was about to go. New belt solved the problem.

But I didn't check the fit of the key particularly. I know it's important for the pulley to be a tight fit on the shaft (and to be careful when driving it on so the impact doesn't get transferred to the bearings); but as long as it's tight on the shaft I don't see where clearance to the key would be an issue. Unlike some keyed drives, the force is always in the same direction.
 
Given that the taper is not an interference fit, I fear that inertia will cause the key to slowly abrade the slot in the pulley. I will talk to my machinist about cutting a 1/8 slot in the shaft or regrooving the pulley to the metric dimension.
Bob
 
What taper? AFAIK it's a straight shaft, and should be a light interference fit. If not, the wiggling action (from the sheave being so far away from the mounting surface) will tear up the joint no matter how tight the key is.
 
bobhustead said:
...I will talk to my machinist about cutting a 1/8 slot in the shaft or regrooving the pulley to the metric dimension.
Click to expand...

If you're willing to involve a machinist perhaps they could just cut down the upper half of the metric key to be .125" -- shouldn't have to do that of course but then the modified key would fit both parts (shaft & pulley). I would be reluctant to modify the pulley.
 
The metric key is thinner and its arc of a much smaller radius than the OEM key. Thus any machining would need to be of the bottom of the OEM key and leave little depth of penetration by that key into the shaft.
 
My micrometer agrees with Randall on the lack of shaft taper. I had thought a slight taper because they don't start to tighten up until the pulley is slid almost all the way on. The fact that it is straight makes me more dedicated to proper fit. Decided to buy the Moss replacement pulley, so I called to check dimensions. They tell me the slot is 1/8. So much for that idea.

Bob
 
One millimeter = about .0394, so the metric key is 3mm. Machinist can recut the key pocket one of 3 ways without even removing the shaft from the housing. Sorry for the typo. .118 is the number
Bob
 
Not the answer you are looking for but wanted to share. I did recently....one month ago.....replace the water pump on my TR3A. I purchased the moss water pump. I also purchased a new pulley. I know the pulley was not free, but not too expensive. If you are considering this route, just wanted to let you know the new water pump and pulley from moss did fit.
 
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