SB water pump rebuild kits

[Ed S.]

I am resurrecting an old subject that hasn't been discussed / updated in quite a few years - Small Block water pump rebuild kits. Threads in this forum dated 8 - 10 years ago indicate members were not all that happy with available rebuild kits. You could not use the original cast iron impeller with the new machined shaft that was part of the rebuild kit, the replacement impellers that came with the kits were stamped steel and.... there were concerns about the design and reliability of bearings and seals. I am attaching a great article written by Rich Mozzetta on these issues.

I have been looking at components in available kits, they all have stamped steel impellers and do not seem to have changed much in the last 10 years or so.

All that said, has anything changed, have rebuild kits improved in the last 8 - 10 years? Are there any recommended sources (vendors) for a SB water pump rebuild kit? Any recommendations on preferred rebuild kits would be appreciated. I am aware of the issues involved with supporting the pump body when pressing parts in.

Also, two specific questions re a 175 pump for a 64 L76 engine. 1. The plate on the back - should it have or not have recessed groves pressed in along the edges between the bolt holes, I am thinking no groves. 2. What is the correct markings on the heads of the 6 hex nuts that secure the plate on the back?

[Bob W.]

Re: SB water pump rebuild kits

Ed Check E-bay a few years ago I bought a kit with a cast impellers, it was like 45.00 for the kit

[Ed S.]

Re: SB water pump rebuild kits

Ed Check E-bay a few years ago I bought a kit with a cast impellers, it was like 45.00 for the kit

Interesting - never thought of that. I looked and..... I found 3 rebuild kits with cast impellers..... but.... I am a bit gun shy of E Bay merchandise where there is no info regarding the seller or the manufacturer ---- I would be concerned about the quality / precision of the main shaft and bearings and.....the impellers look a bit flimsy for cast iron.

[Bob W.]

Re: SB water pump rebuild kits

Ed I typed in chevy 327 water pump rebuild kits and that is how I found the kit. I think this is the same guy that Rich M told me about I think he sells kits for other cars also.

[Donald H.]

[Elliott P.]

Re: SB water pump rebuild kits

It looks like Rich Mozzetta has done some serious homework on rebuilding these SB water pumps. I am a retired engineer who tends to way overthink things. I have a C2 SB with AC that tends to overheat in hot weather when the traffic isn’t moving. It will overheat at idle with the AC off; however, I can race the engine to keep it cooler until I can find an exit to the traffic jam. I have been given reason to believe that the main problem is this 10-15% ethanol crap gas we have that burns hotter and runs hotter. (Thermostat, fan clutch, 15 psi cap, and tune have been checked.) A generous electric puller-fan is the optimal solution; but…, the car is a Top Flight Chapter car and the electric fan installation is a big no-no, and a pain in the rear to swap in and out with the fan shroud on these cars.

So…, how about a water pump impeller that produces more water flow? I realize this may only be a short term solution until the radiator-to-air heat exchange rate tops out. But, much can be done with impeller design, beyond the relatively crude cast iron impeller, and the absolutely primitive pin-wheel stamped metal repro-replacement impeller. Particularly at low-speed, clearances are critical. A proper die-cast (plastic?) impeller could be designed to minimize clearance tolerances and drag at high speed, with a more optimum RPM/volume curve. I’m just sayin. Has anybody looked into this?

BTW, that stamped metal impeller is an insult to my over-sensitive little grey cells. Was it designed(?) or just hammered out? Perhaps it wouldn’t mater in a 289 Mom and Pop overhaul in Cuba, but a high tuned performance engine deserves much better. The crude design will cause cavitation in near-boiling water and bubbles don’t conduct much heat. Oh well, that’s just me (the overthinking engineer).

[Joe L.]

Re: SB water pump rebuild kits


Elliott------


A higher flow waterpump will not necessarily improve cooling. In fact. in most cases it will be a detriment. That's because the real key to cooling is the amount of heat transfer that the radiator can accomplish. A higher flow waterpump may result in the coolant moving too fast through the radiator and, thus, insufficient residence time in the radiator.

I don't like the stamped steel impellers, either. However, virtually all modern cars use this type of impeller in the waterpump. GM began using this type of impeller in original and SERVICE small block waterpumps dating back to the mid to late 70's.

[Richard M.]

Re: SB water pump rebuild kits

Elliot,

I feel Joe has described it well.

Maybe what you're experiencing should be reviewed in a new topic, particularly with details of year, engine, hp and carburetor/distributor details. We could help you try to solve your issue.

It's possible that a ignition timing anomaly is going on and if ported vacuum, your heat buildup at idle/traffic could be corrected with a conversion to full-time manifold vacuum and a replacement VAC unit. There have been many discussions here revolving around Duke Williams' methods to do this conversion, all with excellent results to correct problems just like yours. When you raise your idle, a ported VAC will then become operational, adding timing which cools the engine.

I did this conversion on a 67 L71 (427/435) about 10 years ago resulting in a amazing difference. Since then many others.

Rich

[Elliott P.]

[Richard M.]

Re: SB water pump rebuild kits

Elliot,

Best to start a completely new Thread titled with your Overheating subject.

Describe your engine configuration as above and just copy/paste your info from your 2 posts here to the new thread. We'll follow up there.

Add this info.....

Distributor, if TI or Points system.

VAC # (stamped on mount base)

Carb type and Part#

VAC Vacuum source(ported or full time)

Rich

[Richard M.]

Re: SB water pump rebuild kits

Ed have you located the kit needed yet?

Rich

[Ed S.]

Re: SB water pump rebuild kits

Rich - thanks for asking. The answer is yes, I sent you a PM with details. I will post a follow up message on this thread with details for all after I get the kit, install it and observe its performance.