Leakless water pumps...

THE1ANDONLY

THE1ANDONLY

Member
Can anyone tell me if there is a difference in a 1928-1929 and a 1930-1931 water pump? I ordered a new pump from Macs but did not realize they offered two. The one i ordered is for 28-29 and my engine is a 31. Thanks... Shaun
 
The packing nut is brass on a 28-29. The 30-31 has an aluminum or whatever they are making new packing nuts out of these days. Otherwise they are interchangeable.

You will have no problem putting that pump on your '31 motor.
 
They are mechanically interchangeable. The 28-29 had a copper alloy packing nut, the 30-31 had a zinc nut, plus other minor differences. Unless you're into judging, nothing to worry about. Even if you were into fine points, the replacements from parts vendors have numerous tiny differences a judge would notice, so neither would be perfect.
 
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Besides the packing nut, the only other difference is the hole in the casting at the bottom of the pump. E28 had a dime sized hole, whereas 28/29 and 30/31 have a much larger hole, about 1" by 2".
 
Isn't there also some minor casting differences between pump housings, not by year to year but by different casting plants. I have about twenty water pumps and not all are exactly the same.
 
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