Your pump above may be a "forever" pump (see below) as it has not stub beyond the impeller to contact the bridge in the head. Normal Model A pumps have this shaft extension which between bridge and brass rear bearing limit the end to end shaft motion.
Um. You don't say if your two blade fan is an original. If it is you may want to set aside BOTH fans.
Go buy an aluminum fan in the close to original airplane propeller pattern.
Or at least something other than original fans.
As to the water pump end play, have you tried the new pump in place to see how tight it is? It may be fine without ANY collar.
Many use the collars and report good success, but mechanically they're a dodge. Not part of the original design they're an adaptation created by need. Not to say they won't work - but just not my preferred.
You may have other options. The current breed of "Forever" pumps have a captive front bearing that does away with end play issues entirely. A little pricey though.
Or finding end play you can build up the shaft end with weld, grind it down, and re-establish the correct end play by trial and error.
Or tap the impeller end of the water pump shaft and sink a brass bolt there to take up space. You might even make it adjustable? Be sure to stake it AND use Loctite as you don't want it to move.
Or you can tap the bridge in the head for a cone head bolt, and screw it home on loctite and adjust it until the loctite sets in place. Even spot mill the head of the bolt if it is still too proud.
Or drop back 10 yards and rebuild a pump with the long shaft - and start over again.
Or use the collar...
Just try playing around with things. The thing to remember is to have NO MORE than 0.010 end play which will prevent the teardrop or square washer from getting out of it's recess in the impeller - and by spinning and wearing the shaft eventually cut your impeller off the end of the pump shaft.
Joe K
