It is always interesting watching threads like this when others have the problem.  One system seems to be more or less doing well and not an issue, out of the picture.  Other problems are aired that look to be safely removed from the good system, and everything ends up turning back.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Opps. Question should have been addressed to Frank. Sorry.

6 VOLTS/POS. GRD. NW INDIANA

Dan,

        I attempt to get the clearance between .020 & .030" this is an arbitrary number I chose to eliminate as much leakage between the impeller and the casting as I could. Need to keep some clearance because the impeller will grow with heat more rapidly than the timing cover. I've seen rebuilt iron pumps with over .060" that still pumped water. 

      All of the timing cover castings will show evidence of grinding. This is to remove a core to pattern mismatch. The clearance issue always seem to be at the start of the volute, which is the closest point of contact.  

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank,



It would seem that pre-assembling/sealing pump to spacer before final installation on cover is dictated (if impeller-to-spacer clearance IS truly critical)?

I had assumed the impeller-to-pump body spec. was important, but since the impeller is so far from the cover volute on a T-Bird, and the larger impeller-to-cover volume space has apparently been proven moot by past testing of the once touted backing-plate accessory(?), this is indeed a revelation.

6 VOLTS/POS. GRD. NW INDIANA

Dan,

       I've had this discussion with a number of folks, including some from the Classic T'Bird club. The area behind the impeller, or the size of the plenum has no effect on how the pump works. The pump works by spinning the impeller, this throws the water out of the area betweem the blades. That is replaced by more water from the supply side (the radiator). Exhausted water, after it is thrown out of the impeller, is forced into the plenum and then the engine. The only restriction to this flow should be the thermostat.

      The plate that you refer to, has only one purpose, to make money for whomever sells it. 

Frank/Rebop

Bristol, In ( by Elkhart) 

Dan  

     Casco has a very interesting article on that plate,  Had one on my bird.. didn't work worth beans!!!  Now have large impeller, smaller pulley, clutch fan and large hole 170 thermostat--  also have A/C condensor under right front fender with elect fan. Even in parades never goes over 190.  Hope this helps!!     God bless    Eddie

Eddie

Lake Forest, Ca. 92630

[quote]pegleg (6/15/2009)

---

Ted,







I intentionally kept the impeller to the timing cover dimensions tight,



Ted,



Description of pump action exactly as I had assumed. So, am still puzzled by your previous statement re: impeller-to-cover clearance?

If pressure source comes from under the impeller vanes, aside from minimum clearance, why should it matter?

6 VOLTS/POS. GRD. NW INDIANA

Crap! Did it again! NOT Ted, but FRANK.

6 VOLTS/POS. GRD. NW INDIANA

Dan,

     Look at the timing cover, and remember the pump was designed for the car, not the Bird. The volute and the shape is designed to direct water into the the TC passage.  

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank,



So, due to the fact that the impeller is so far from the cover volute with the T-Bird spacer, I should assume that only safe minimum impeller-to-casting clearance is important in my case (?), and your "tight" design specs. were intended for max. efficiency when the cover alone is used?

6 VOLTS/POS. GRD. NW INDIANA