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..... I found an affordable performance water pump disguised as a stock replacement . Its a new pump by GMB available at Summit Part # GMB-130-1220 for about $55 . It comes with an aggressive 8 blade impeller (compared to the typical rounded 6 blade) . The pump on the top in the pic is what you'll find on the average parts store C4 water pump . Just thought I'd share with Y'all .....
Good find, but I hope they aren't for the same engine. Notice the pumps appear to run in opposite directions plus the fitting on both right sides are different. Just make sure they're right or risk overheating.
What a nice find, so what prompted you to do this type of research? Or were you replacing your waterpump and just stumbled on this.
Inquiring minds want to know....
D.
..... I had one of these GMB pumps a while back and couldn't find one when I redid the engine ... it cooled nicely , especially in traffic ... I bought a Stewart Stage 1 pump instead for around $85 , it has a 6 blade impeller and didn't cool as well as the GMB . Recently , I noticed a very small leak at the weep hole on the Stewart and decided to replace it so I looked for a GMB and found it at Summit . I have to grind the heads of the lower rear cover attaching bolts down a little because I'm using a timing cover that will not work with short water pumps (unless you use Summit .100" thick gaskets and grind the bolt heads) and because I loosened the cover , I take it completely off and seal it with RTV before installing it . That got me close and personal with water pump internals .....
Good find, but I hope they aren't for the same engine. Notice the pumps appear to run in opposite directions plus the fitting on both right sides are different. Just make sure they're right or risk overheating.
..... ??? ... No differences that I can see ... Rotation of both would be clockwise looking from the back side as viewed in the top pic ... I don't currently use the heater return hose pipe , I plug that hole in the pump .....
Good find although I just replaced mine 3 weeks ago with a $41 Autozone pump.
..... Great job , but was it a GMB ? ... or 8 vane impeller ? ... AZ , O'Reilly's , and Advance all had the one in the top of my pic with the 6 vane impeller and all were around $35-$40 .....
..... ??? ... No differences that I can see ... Rotation of both would be clockwise looking from the back side as viewed in the top pic ... I don't currently use the heater return hose pipe , I plug that hole in the pump .....
Based on the vanes, wouldn't the bottom one be designed to turn clockwise as viewed while the upper one would be counter clockwise as viewed? I know they can be used in the reverse direction, but space for coolant and efficiency is diminished. I know there are multiple water pumps to rotate in both directions on sbc engines based on application so you want the right one for your application.
Based on the vanes, wouldn't the bottom one be designed to turn clockwise as viewed while the upper one would be counter clockwise as viewed? I know they can be used in the reverse direction, but space for coolant and efficiency is diminished. I know there are multiple water pumps to rotate in both directions on sbc engines based on application so you want the right one for your application.
..... Both pumps pictured are C4 water pumps , the lower one IS closer to the camera .....
..... Great job , but was it a GMB ? ... or 8 vane impeller ? ... AZ , O'Reilly's , and Advance all had the one in the top of my pic with the 6 vane impeller and all were around $35-$40 .....
I don't know to be honest. This is the result of me going through the cooling system.
..... I found an affordable performance water pump disguised as a stock replacement . Its a new pump by GMB available at Summit Part # GMB-130-1220 for about $55 . It comes with an aggressive 8 blade impeller (compared to the typical rounded 6 blade) . The pump on the top in the pic is what you'll find on the average parts store C4 water pump . Just thought I'd share with Y'all .....
what they are saying is, see where the back of the blade is, that is what pushes the water. old one would have to turn counter to push water right, bottom clock wise to push right. The Vette used a reverse flow system, but other cars got standard rotation pump.
It can be easy to get the wrong one, and they only pump water well in one direction.
Now I have no clue which one is right per the pic, just read it can be a problem when buying parts.
If you want to boost it more, an old trick was to use a soup can lid and pop rivet it to it to, so the blades grabbed water even better.
Last edited by Buick350X; Apr 8, 2017 at 07:23 PM.
..... ??? ... No differences that I can see ... Rotation of both would be clockwise looking from the back side as viewed in the top pic ... I don't currently use the heater return hose pipe , I plug that hole in the pump .....
The eight vane impeller is a nice upgrade but its still a tin sheetmetal stamped "paddle wheel" and not a cnc machined impeller with curved vanes.
plugging the heater hose hole is a good idea; maybe better is an inline ball valve that would remain closed for maximum cooling but could be opened to provided a flow of hot water from the heater core when needed for cockpit heat.
another hole to plug, or at least greatly restrict, is the small hole (looking at the rear of the pump) on the right side; this hole short circuits hot water from below the thermostat directly back to the suction side of the pump...great for warming up the engine in subzero temps but probably not needed so much in Florida...if plugged completely, make sure the thermostat plate has one or two 1/8th inch "air bleed" holes drilled in it...most hipo tstats have one already.
what they are saying is, see where the back of the blade is, that is what pushes the water. old one would have to turn counter to push water right, bottom clock wise to push right. The Vette used a reverse flow system, but other cars got standard rotation pump.
It can be easy to get the wrong one, and they only pump water well in one direction.
Now I have no clue which one is right per the pic, just read it can be a problem when buying parts.
If you want to boost it more, an old trick was to use a soup can lid and pop rivet it to it to, so the blades grabbed water even better.
Actually it is not the back of front of the blade that matter. It is the angle of the blade and the drawn arrow goes the wrong way.
The top pump is a reverse rotation for the Corvette.
The GMB vanes go more or less straight out and probably works for both standard and reverse rotation.
First back to basics. ALL centrifugal pumps pull water into the center of the impeller and centrifugal force throws it outward. The "standard rotation" involves "traditional" small blocks circa 1955 up to, but not including the LT engines. The "standard rotation" was for older engines with fan belts and pulleys; when serpentine belt drives were introduced, the pump turned in the opposit direction, which cause a need for a different style impeller; hence the "reverse rotation pump".. The LT engines are completely different in the water pump design; the "reverse cooling" in an LT engine has nothing to do with the direction the pump turns; The LT pump housing is completely different and the pump is driven off upper timing chain sprocket, and only turns in one direction...ever. So if you have an LT engine, worry not, the pump is turning in the right direction (completely independent of the serpentine belt).
Didnt Edelbrock used to make one where the back of the impeller was solid? Guess it could help move more-
Bought a CAT hi flow at Pomona swap meet 15 yrs ago for 35..still on my camino. Almost moves too much water. Impeller isnt true so it cavitates get what you pay for
Didnt Edelbrock used to make one where the back of the impeller was solid? Guess it could help move more-
Bought a CAT hi flow at Pomona swap meet 15 yrs ago for 35..still on my camino. Almost moves too much water. Impeller isnt true so it cavitates get what you pay for
GMB Goo Mok bAng
It's called a "closed" impeller and is the most efficient design.
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