Chevy 350 Water Pump
Discussion
My Chevy engined race car is overheating. The fan develops 2,835 cfm, it is front mounted. I can replace the rad to one with a much deeper core and fit a heavier duty fan, I'm also thinking about the pump.
The existing pump is standard, I see that there is also a high-volume pump, the other option would be electric. I would prefer not to go down the electric route as I need to retain originality for historic racing, but I need to get the temperature under control. Which option would make generate the biggest improvement?
Any other suggestions?
The existing pump is standard, I see that there is also a high-volume pump, the other option would be electric. I would prefer not to go down the electric route as I need to retain originality for historic racing, but I need to get the temperature under control. Which option would make generate the biggest improvement?
Any other suggestions?
My experience is 20+ years keeping a BBC powered '68 C3 Vette cool. '68/'69 being introductory years did have cooling issues. Some may be similar to yours.....there are similarities.......
Water pump - if the engine still has a stock pump......does it have a metal pump impeller? if yes and the engine has been run historically without anti-freeze corrosion/cavitation could have eroded the vanes, obviously affecting cooling.....simply replace with a high volume new short/long pump as appropriate. Source yourself a OEM spec viscous coupled fan. These will have 5 and 7 bladed versions. 7 blade will usually be found on BB A/C powered cars.
The viscous fan unit itself was available in different spec's for different years and applications, whether 'standard' duty, 'heavy' duty and 'extreme' duty (perhaps BB powered trucks?). You will need to source/fabricate a fan shroud attached to the rear of the radiator, enclosing the fan blades with a 'plenum' in between rear of the radiator and the fan blades. Affixed to front of the radiator you'll need another 'plenum' inbetween it and the grille opening, effectively sealed so that all incoming cooling air passes through the radiator, applying the same logic to the shroud and sealing to the rear of the radiator.
Perhaps do this before considering thicker radiator, remembering there is a balance between water flow/water temperature through the radiator vs potential reduced air flow through rad core if using a multi cored unit.
Stock GM mechanically driven fans (although CFM's were not published by GM) generally draw more air through the radiator than most aftermarket units.
A hi-po electric fan will have a high electrical load generally needing heavier cabling and alternator.
BTW a 'pusher' type fan as mounted on your Gilbern will potentially 'stall' if asked to push large quantities of air through the radiator.
The same type of fan mounted to the rear of the radiator will only cool an area of radiator the same diameter as the fan blades, whereas a same sized 'puller' fan set well back in a correctly designed shroud will pull cooling air across the whole radiator surface.
Ever seen the size of grille opening on an early C3 Vette? - try keeping close to 600 hp cool in heavy urban traffic in summer!
Water pump - if the engine still has a stock pump......does it have a metal pump impeller? if yes and the engine has been run historically without anti-freeze corrosion/cavitation could have eroded the vanes, obviously affecting cooling.....simply replace with a high volume new short/long pump as appropriate. Source yourself a OEM spec viscous coupled fan. These will have 5 and 7 bladed versions. 7 blade will usually be found on BB A/C powered cars.
The viscous fan unit itself was available in different spec's for different years and applications, whether 'standard' duty, 'heavy' duty and 'extreme' duty (perhaps BB powered trucks?). You will need to source/fabricate a fan shroud attached to the rear of the radiator, enclosing the fan blades with a 'plenum' in between rear of the radiator and the fan blades. Affixed to front of the radiator you'll need another 'plenum' inbetween it and the grille opening, effectively sealed so that all incoming cooling air passes through the radiator, applying the same logic to the shroud and sealing to the rear of the radiator.
Perhaps do this before considering thicker radiator, remembering there is a balance between water flow/water temperature through the radiator vs potential reduced air flow through rad core if using a multi cored unit.
Stock GM mechanically driven fans (although CFM's were not published by GM) generally draw more air through the radiator than most aftermarket units.
A hi-po electric fan will have a high electrical load generally needing heavier cabling and alternator.
BTW a 'pusher' type fan as mounted on your Gilbern will potentially 'stall' if asked to push large quantities of air through the radiator.
The same type of fan mounted to the rear of the radiator will only cool an area of radiator the same diameter as the fan blades, whereas a same sized 'puller' fan set well back in a correctly designed shroud will pull cooling air across the whole radiator surface.
Ever seen the size of grille opening on an early C3 Vette? - try keeping close to 600 hp cool in heavy urban traffic in summer!
Edited by roscobbc on Tuesday 7th May 00:01
roscobbc said:
My experience is 20+ years keeping a BBC powered '68 C3 Vette cool. '68/'69 being introductory years did have cooling issues. Some may be similar to yours.....there are similarities.......
Water pump - if the engine still has a stock pump......does it have a metal pump impeller? if yes and the engine has been run historically without anti-freeze corrosion/cavitation could have eroded the vanes, obviously affecting cooling.....simply replace with a high volume new short/long pump as appropriate. Source yourself a OEM spec viscous coupled fan. These will have 5 and 7 bladed versions. 7 blade will usually be found on BB A/C powered cars.
The viscous fan unit itself was available in different spec's for different years and applications, whether 'standard' duty, 'heavy' duty and 'extreme' duty (perhaps BB powered trucks?). You will need to source/fabricate a fan shroud attached to the rear of the radiator, enclosing the fan blades with a 'plenum' in between rear of the radiator and the fan blades. Affixed to front of the radiator you'll need another 'plenum' inbetween it and the grille opening, effectively sealed so that all incoming cooling air passes through the radiator, applying the same logic to the shroud and sealing to the rear of the radiator.
Perhaps do this before considering thicker radiator, remembering there is a balance between water flow/water temperature through the radiator vs potential reduced air flow through rad core if using a multi cored unit.
Stock GM mechanically driven fans (although CFM's were not published by GM) generally draw more air through the radiator than most aftermarket units.
A hi-po electric fan will have a high electrical load generally needing heavier cabling and alternator.
BTW a 'pusher' type fan as mounted on your Gilbern will potentially 'stall' if asked to push large quantities of air through the radiator.
The same type of fan mounted to the rear of the radiator will only cool an area of radiator the same diameter as the fan blades, whereas a same sized 'puller' fan set well back in a correctly designed shroud will pull cooling air across the whole radiator surface.
Ever seen the size of grille opening on an early C3 Vette? - try keeping close to 600 hp cool in heavy urban traffic in summer!
Thank you, that is really helpful. I was in the paddock parked next to a Camaro, it had a rad the size of a barn door! Water pump - if the engine still has a stock pump......does it have a metal pump impeller? if yes and the engine has been run historically without anti-freeze corrosion/cavitation could have eroded the vanes, obviously affecting cooling.....simply replace with a high volume new short/long pump as appropriate. Source yourself a OEM spec viscous coupled fan. These will have 5 and 7 bladed versions. 7 blade will usually be found on BB A/C powered cars.
The viscous fan unit itself was available in different spec's for different years and applications, whether 'standard' duty, 'heavy' duty and 'extreme' duty (perhaps BB powered trucks?). You will need to source/fabricate a fan shroud attached to the rear of the radiator, enclosing the fan blades with a 'plenum' in between rear of the radiator and the fan blades. Affixed to front of the radiator you'll need another 'plenum' inbetween it and the grille opening, effectively sealed so that all incoming cooling air passes through the radiator, applying the same logic to the shroud and sealing to the rear of the radiator.
Perhaps do this before considering thicker radiator, remembering there is a balance between water flow/water temperature through the radiator vs potential reduced air flow through rad core if using a multi cored unit.
Stock GM mechanically driven fans (although CFM's were not published by GM) generally draw more air through the radiator than most aftermarket units.
A hi-po electric fan will have a high electrical load generally needing heavier cabling and alternator.
BTW a 'pusher' type fan as mounted on your Gilbern will potentially 'stall' if asked to push large quantities of air through the radiator.
The same type of fan mounted to the rear of the radiator will only cool an area of radiator the same diameter as the fan blades, whereas a same sized 'puller' fan set well back in a correctly designed shroud will pull cooling air across the whole radiator surface.
Ever seen the size of grille opening on an early C3 Vette? - try keeping close to 600 hp cool in heavy urban traffic in summer!
Edited by roscobbc on Tuesday 7th May 00:01
At the moment the plan looks like:
- Replace the pump.
- Replace the rad taking thickness from 70mm to 100mm and adding 100mm to height by setting it lower.
- Scrap the 14 inch pusher fan and replace either with an engine side fan and shroud, either elec 16 inch or manual.
I used some of that corregated plastic sheeting that estate agent use for their 'for sale' signs to make-up fillet pieces to add-in around the radiator, glueing into place with Sikaflex body sealant/adhesive. My inclination would be to start with the high volume water pump and perhaps try a budget 'puller' electric fan. Before I sourced a DeWitt alloy radiator I would add some Redline Water Wetter to the coolant........regarded perhaps by some as 'snake oil' I found it it actually reduced the running temperature by about 3 degrees F......not a lot but enough in my case back then to stop it boiling over.
Car gebnerally now runs between 165 in winter, 175/185 in summer and about 190 in extreme heat.....never boils over.
Car gebnerally now runs between 165 in winter, 175/185 in summer and about 190 in extreme heat.....never boils over.
roscobbc said:
I used some of that corregated plastic sheeting that estate agent use for their 'for sale' signs to make-up fillet pieces to add-in around the radiator, glueing into place with Sikaflex body sealant/adhesive. My inclination would be to start with the high volume water pump and perhaps try a budget 'puller' electric fan. Before I sourced a DeWitt alloy radiator I would add some Redline Water Wetter to the coolant........regarded perhaps by some as 'snake oil' I found it it actually reduced the running temperature by about 3 degrees F......not a lot but enough in my case back then to stop it boiling over.
Car gebnerally now runs between 165 in winter, 175/185 in summer and about 190 in extreme heat.....never boils over.
Your further comments are much appreciated, thanks. Looking at pumps, I think my best option might be Moroso part number 63500. Would you agree?Car gebnerally now runs between 165 in winter, 175/185 in summer and about 190 in extreme heat.....never boils over.
Keep it stiff said:
roscobbc said:
I used some of that corregated plastic sheeting that estate agent use for their 'for sale' signs to make-up fillet pieces to add-in around the radiator, glueing into place with Sikaflex body sealant/adhesive. My inclination would be to start with the high volume water pump and perhaps try a budget 'puller' electric fan. Before I sourced a DeWitt alloy radiator I would add some Redline Water Wetter to the coolant........regarded perhaps by some as 'snake oil' I found it it actually reduced the running temperature by about 3 degrees F......not a lot but enough in my case back then to stop it boiling over.
Car gebnerally now runs between 165 in winter, 175/185 in summer and about 190 in extreme heat.....never boils over.
Your further comments are much appreciated, thanks. Looking at pumps, I think my best option might be Moroso part number 63500. Would you agree?Car gebnerally now runs between 165 in winter, 175/185 in summer and about 190 in extreme heat.....never boils over.
Stewart seem to have a good name stateside.......plenty of higer performance options......are they China made
'today'? don't know. https://www.stewartcomponents.com/product/chevrole...
A few options here on Rock Auto -
https://www.rockauto.com/en/catalog/chevrolet,1971...
I’ve got a Moroso pump on my race car, works fine. They don’t have an integral bypass so you’ll need to drill your thermostat or add one
You didn’t say when it overheats. Is it when moving at greater than 40mph or when going slowly/stationary. This will tell you where to improve things.
You didn’t say when it overheats. Is it when moving at greater than 40mph or when going slowly/stationary. This will tell you where to improve things.
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