SBC water pump questions

[rfoll]

My long pattern Edelbrock water pump apparently killed the mechanical seal last night after 2 passes. Pretty solid stream of water draining from the weep hole. Its an older unit that I ran for a couple of years and eventually it started to show signs of leaking. Edelbrock said they would rebuild it for about $75, but I would have to pay to ship it. Automotive Friction In Damascus OR rebuilt it for me about 5 years ago for the same price without paying a shipping fee. I would have expected it to last longer, but maybe I'm expecting too much for a pump to last when it sees 6500-7000 rpm on a regular basis. Currently the pulleys are the same diameter, about 6 7/8". Looking at new aluminum pumps, prices start out at $82 for a Proform pump with a stamped steel impeller. Almost all of the pumps I looked at claimed to be high volume, and I'm not sure I need that as my cooling system never allows the engine to get hotter than 180 degrees. My question is, are the stamped sheet metal impellers inherently inefficient? I worked in the wastewater industry for 30 years and never saw that style impeller on anything. When the motor driving the pump is the size of a Suburban, efficiency is important. Is the Edelbrock pump worth rebuilding, or do they use a stamped impeller? My guess is the Stewart pump is likely to be the best quality unit, but their claim to be high volume is likely to be real, making me think it might pump more water than I need. I gave some thought to under driving my pump with a smaller crank pulley, but new pulleys start about at over $40. I am completely open to suggestions. Thanks, Rick.

[ClassAct]

My long pattern Edelbrock water pump apparently killed the mechanical seal last night after 2 passes. Pretty solid stream of water draining from the weep hole. Its an older unit that I ran for a couple of years and eventually it started to show signs of leaking. Edelbrock said they would rebuild it for about $75, but I would have to pay to ship it. Automotive Friction In Damascus OR rebuilt it for me about 5 years ago for the same price without paying a shipping fee. I would have expected it to last longer, but maybe I'm expecting too much for a pump to last when it sees 6500-7000 rpm on a regular basis. Currently the pulleys are the same diameter, about 6 7/8". Looking at new aluminum pumps, prices start out at $82 for a Proform pump with a stamped steel impeller. Almost all of the pumps I looked at claimed to be high volume, and I'm not sure I need that as my cooling system never allows the engine to get hotter than 180 degrees. My question is, are the stamped sheet metal impellers inherently inefficient? I worked in the wastewater industry for 30 years and never saw that style impeller on anything. When the motor driving the pump is the size of a Suburban, efficiency is important. Is the Edelbrock pump worth rebuilding, or do they use a stamped impeller? My guess is the Stewart pump is likely to be the best quality unit, but their claim to be high volume is likely to be real, making me think it might pump more water than I need. I gave some thought to under driving my pump with a smaller crank pulley, but new pulleys start about at over $40. I am completely open to suggestions. Thanks, Rick.

If Milodon doesn't make a pump for it, I'd call Stewart Components and buy their pump. Money well spent.

[allencr267]

If it's using the same size bearings & seal as stock, a rebuilding kit with a new shaft might be available locally on a dusty shelf. There's nothing to'em if you've got a puller & press, and even a swinging press(hammer) can do the job with a little care.

[BigBlockMopar]

I did some basic comparisons once on a few Mopar waterpumps and the ones with the old factory stamped steel impellers did a much better job of pumping the coolant around then the modern scroll wheel versions.

[peejay]

What are you using for coolant?

Are you 100% certain there isn't any chance of there being any dust/debris in the coolant?

I've seen water pumps killed after someone used a "cookie" to clean the gasket surfaces and the abrasive material got into the water jacket. The seals are just two pieces of plastic/carbon that slide against each other, they don't cotton to running in 1000 grit coolant.

Another thing to consider is if your fan is out of balance if you are running one. Or running a solid fan on a huge long extension. Although, this usually destroys the bearings.

[rfoll]

What are you using for coolant?

Are you 100% certain there isn't any chance of there being any dust/debris in the coolant?

I've seen water pumps killed after someone used a "cookie" to clean the gasket surfaces and the abrasive material got into the water jacket. The seals are just two pieces of plastic/carbon that slide against each other, they don't cotton to running in 1000 grit coolant.

Another thing to consider is if your fan is out of balance if you are running one. Or running a solid fan on a huge long extension. Although, this usually destroys the bearings.

None of the things you suggested applies. I'm running a thermal clutch to drive the fan so the fan never sees high rpm. The pulleys are 1:1 so the pump sees engine rpm. I'm pretty familiar with the small mechanical seal they use in water pumps. They are just a spring loaded carbon rotor running against a ceramic or hardened steel stator. From the amount of leakage I want to guess the rotor fractured. When the seal fails and the bearing starts using coolant for a lubricant, the end is near, I have never had one fail so dramatically and abruptly. No puddles on the floor when I put it on the trailer. I may install one of my new factory GM pumps to finish the season, assuming it doesn't rain every Saturday for the next month, and buy one of the Stewart pumps when Summit does one of their 10% off sales.

PICT0442.JPG

[Geoff2]

The gaps around the impeller, not so much the impeller shape, is what is important. If you remove the rear cover of the Edel #8810 Victor pump, the casting is TOTALLY different to the factory style. The impeller sits in a machined cavity with about 0.040" clearance to the casting. When you look at factory pumps, they have huge gaps, so that the coolant has plenty of places to 'escape'...& get recirculated inside the pump but not get pumped into the engine.

[Lizardracing]

Buy a Stewart pump and you'll have it the rest of your life probably.

You cannot move too much water. Not possible. Physics don't work that way.
Your thermostat will control the warm up period.

[rfoll]

In one of the pump classes I attended, the instructor had some data on what happened when the clearances were opened up. doubling the clearances dropped the efficiencies by something like 25%. I plan to remove the back cover on the pump, and if things are as you describe, I will send it to Edelbrock for repair.

[stealth]

I’m thinking at that RPM with a big heavy fan hanging out there is putting a huge load on those bearings... also consider that fan is likely not balanced all that well ...hammering the pump even more.

Might consider an electric fan to ease the stress on pump..and eliminate the blades chunking through the hood..

[77cruiser]

When I had the stock pulley sizes & I spun mine up over 6K with the pump going over 7500 I always had problems with reman pumps. One even pushed the shaft forward about 1/4 inch.

[rfoll]

I have been running the same fan and clutch for over 15 years. The stock pumps never had a problem. I put the Edelbrock pump on to save weight and assumed it was a more efficient pump. It was rebuilt in 2015, not much for longevity.

[77cruiser]

I bought a used Edelbrock pump 5 years ago, so far so good, pump only sees 64-6500.

[swampbuggy]

Rfoll, i have been messing with car engine stuff for almost 50 years and i have learned one thing for SURE, not everything in the aftermarket is high quality !!! Mark H.

[rfoll]

Never mind, the problem wasn't the pump. When I replaced the Chevelle big block radiator with a Summit 4 row aluminum unit made for the car model, the lower hose started to touch the balancer. It didn't leak until the engine was shut down, and the water followed the curve of the balancer to the bottom and dripped right off the very bottom. When I went to pull the pump I noticed numbers blurred on the balancer indicating a rub. It didn't leak when running because the hose is on the suction side of the pump. Thanks for the replies anyway.