rich5962

Here we go again with changes to our reproduction parts that DON'T FIT as one would expect them to.

A while ago I acquired a few new rebuild kits from my supplier. When I rebuild the WP's, I like to use the original cast iron impeller and hub. I feel they are a better grade of impeller over the stamped steel, and the hubs are higher quality as well.

Here's a cast iron impeller....




and original hub...





Here is the rebuild kit sold today by most suppliers.....



Now, here is where the changes to these kits become problematic. The new kits include bearing/shaft assemblies that are incompatible in size versus original shafts. This prevents you from using your original impeller and hub.

The shafts are approximately 0.005" smaller diameter than original spec. You MUST use the included impeller and hub with the new kits. As you can see, when comparing the original parts to the reproduction parts there is a substantial difference in size.


Please note that my caliper wasn't perfectly zeroed when i took these measurements. Add a few thousandths to each of my numbers below.




Additionally, the ceramic seal and steel disc is now an assembly. It MUST be used with the new shaft as the assembly includes a swedged inside collar. This collar is pressed onto the shaft which seals water out of the exterior bearing cavity. Original type seal discs incude a rubberized internal seal, which presses against the flat face of the cast iron impeller. The new type seal has NO rubber seal to fit against the stamped steel impeller.


Also notice the quality of the stamped steel impeller and hub included with these kits. When installing the impeller, a tolerance of apx 0.015" is typical as spacing of the blades to the pump housing. I like to use a snug 0.013". When checking this tolerance, you MUST ensure that each impeller blade, a much softer steel, is exactly the same distance to it's hub. If not, one or more blades can be out of spec. You MUST use your feeler gauge on EACH impeller blade to ensure correct tolerance. I have had to bend a few blades to get them correct on a recent rebuild.







Here are some telltales for reference of the original to reproduction parts differences..........

This is the stamping number on top of a stock size earlier(same as original spec) shaft included with this "correct" kit. Top of shaft is marked W6468

This is the earlier "CORRECLY" sized shaft kit. W6468 shaft stamp on top.




Here is the identifier on top of the shaft of the reproduction kit, marked W2468. This is the smaller shaft diameter part.






Here are some close ups of the seal differences.

These photos are the original type 2 piece seal. The part of the seal with the spring incudes a ceramic disc. The steel disc in the 2nd photo has a rubber sleeve to mate with the face of the impeller to seal water out. When the ceramic seal compresses against the steel disc face, it seals water out.







Here is the new seal assembly. There is a rubber seal an the steel disc, but it is a different ID than originals. The steel disc has the same OD as originals, but the ID is larger, to accommodate the steel sleeve to hold the ceramic seal and steel disc together as an assembly. Therefore, one cannot use the new steel disc over a original type shaft. It's too small with it's included rubber sleeve.






Note the steel collar is swedged to hold the assembly together. This collar is the ONLY deterrent to keep water out of the pump bearing assembly.


I decided to use a original type seal pair on the new impeller. I machined the face of the stamped steel impeller flat. Then using the original type rubber backed disc, pressed the assembly on as original designed assemblies. This sealed the pump assembly properly, just like the original design.

Once complete, this pump worked fine with it's rebuild using the newer kit, but it required a little variation of the original methods.





As an addendum, I spent much time with several suppliers of these kits. I spoke to a major pump kit supplier/manufacturer in Tampa, Classic Reproduction Parts, and was told that ALL of their rebuild kits for GM water pumps are now like this. They measured a few kits for me and confirmed they are NO LONGER supplying shafts sizes as original. One MUST use the new hub and impeller supplied with the kits.

If you locate a supplier of ORIGINAL specification kits, please let me know.

Rich

Frankie the Fink

Yeah - seems I vaguely remember something about this whole issue
Between this nonsense and the C1 steering box rebuild kit mods; folks working at this level need to pay REAL
close attention.

65tripleblack

I rebuilt my pump years ago using a kit made up for me by a NASCAR vendor in the Carolinas. I specified that I wanted to use a F.A.G. shaft/bearing assembly. The bearing/shaft came to me and was marked "Canada", as I expected. I asked the supplier if I could get the identical shaft/bearing ***'y with needle bearings instead of ball bearings (larger annulus cut into the shaft and less chance of breakage at high RPM). I ordered and received a needle bearing assembly. This was in 2009. Here is a picture of the components:


I can try to dig for the supplier if you need him now.

rich5962

Thanks for the info and photo. Yes if you find the info and share it here that'd be great.

Rich

65tripleblack

This information was compiled in August 2010:


Howard Stuart Race Pumps
6006 Ball Park Road
Unit G
Thomasville NC 27360
336 476 9720


F.A.G. Cust Service
200 Park Ave
PO Box 1933
Danbury CT 06813
203 790 5474
800 243 2532

Bearing/Shaft Assembly..................F.A.G numbers
Needle: WR-2548-1
Ball: WB-2548-1

Overall Length: 5.485"
Shaft Diameter: 0.6267"