Question: Resoring back to factory cooling fan

[Ozziljian]

New member, 1st post

Ive recently bought a 73 Corvette w/ a 350 4 speed that has alot of modifications (that's saying it nicely). The modifications seemed to have been done with whatever was on hand or easily obtained. One thing I'm trying to set right is the cooling system and mainly because the temp creeps up past 230 degrees towards over heating. I'm not sure how high it will go as I shut it off before 240. It has an electric duel fan that is in "front" of the radiator and pushing air into it. I could move it to the other side like it should be (pulling in air), but I'd like to return it to the fan/fan clutch assembly it had from the factory. The problem is, is that somewhere along the line the motor was swapped out for a 1983 350ci (ive been told). So I'm not sure of which year clutch and fan to buy for. Does anyone know if fan clutches different much between the 73 - 83 350s? The shroud ill have to buy along with a clutch and fan is going to be expensive and I'd hate to have parts that arent going to fit because of a bigger waterpump or something. Any one have ideas on how they would go about doing this?
Thanks in advance

 

[bill81vette]

1st...Welcome to CAC!!!
enjoy!!!
2nd...is the air flow going thru the radiator or over it???
is the all of the air dams in place,to force the air thru the radiator??
get your self an assembly instruction manual,and a factory service manual.
these are the bibles for our vettes.
it will give you info you need for your vette.

 

[Antz81]

If it does have a motor from a 1983 swapped into it you may need to find out what it was off. It certainly won't be from a Vette.

 

[frank_nesta]

New member, 1st post

Ive recently bought a 73 Corvette w/ a 350 4 speed that has alot of modifications (that's saying it nicely). The modifications seemed to have been done with whatever was on hand or easily obtained. One thing I'm trying to set right is the cooling system and mainly because the temp creeps up past 230 degrees towards over heating. I'm not sure how high it will go as I shut it off before 240. It has an electric duel fan that is in "front" of the radiator and pushing air into it. I could move it to the other side like it should be (pulling in air), but I'd like to return it to the fan/fan clutch assembly it had from the factory. The problem is, is that somewhere along the line the motor was swapped out for a 1983 350ci (ive been told). So I'm not sure of which year clutch and fan to buy for. Does anyone know if fan clutches different much between the 73 - 83 350s? The shroud ill have to buy along with a clutch and fan is going to be expensive and I'd hate to have parts that arent going to fit because of a bigger waterpump or something. Any one have ideas on how they would go about doing this?
Thanks in advance

I agree with you that pusher fan in front of the radiator is not as efficient as a puller. But, there are many other reasons that could cause your over heating problems.
If this were my problem I would start by flushing the system. Then I would check to see if there is a thermostat and if the thermostat is working correctly. If they check out I would then check to see what I have. Do you have a long or short water pump. Once you know that then you can proceed. If you have a short water pump then the shroud, clutch, & fan for a 1973 should work.

 

[Ozziljian]

Long or short's difference?

I agree with you that pusher fan in front of the radiator is not as efficient as a puller. But, there are many other reasons that could cause your over heating problems.
If this were my problem I would start by flushing the system. Then I would check to see if there is a thermostat and if the thermostat is working correctly. If they check out I would then check to see what I have. Do you have a long or short water pump. Once you know that then you can proceed. If you have a short water pump then the shroud, clutch, & fan for a 1973 should work.

Im not sure what the difference is or how to tell if I have a long or short waterpump. What would I look for?

I was told the 83' motor was rebuilt (only 5miles when I bought). It was overheating when I bought it. There wasnt a thermostat in it (I put a 195 degree in), nor heater core connected(installing new one today). Im also flushing radiator today by letting straight vinegar sit in it (I saw it done on youtube, i hope it helps cuz i can see) Im not sure if it would be good for the block too. (If it was rebuilt correctly it should have been dipped).
I'm thinking the timing might have something to do with the overheating too. I bought a new timing light and installed a timing tab on balancer (there wasnt one of those either) but now am in a dilema because I dont know how to find stats on a motor that I cant fully read the block numbers on (the stamped number's tops are clear but the bottoms are very faint like the stamper was at an angle).

Thanks for the help!

 

[Ozziljian]

If it does have a motor from a 1983 swapped into it you may need to find out what it was off. It certainly won't be from a Vette.

Yeah, I know, right? .... It figures it was from that particular year. lol

 

[Vettehead Mikey]

I wouldn't worry too much about what the engine was when it was built. It's been rebuilt with who-knows-what components. I'd start with determining the current ignition timing and advance curve and go from there.

 

[Ozziljian]

1st...Welcome to CAC!!!
enjoy!!!
2nd...is the air flow going thru the radiator or over it???
is the all of the air dams in place,to force the air thru the radiator??
get your self an assembly instruction manual,and a factory service manual.
these are the bibles for our vettes.
it will give you info you need for your vette.

Thank you, after looking air dams up, I now know what they are. I didnt know how important they were. I dont have one on mine. Ill post a picture because Im not sure if I buy the original air dam if it would help on my vette since it has an after market front spoiler. Unless you think it would help anyway. Or if I can find out who made the spoiler and order one made for it.
Thanks for your help!

 

[frank_nesta]

The short water pump is about 6" from the block to the outside of the flang.

 

[kpic]

Welcome to CAC.

 

[Vettehead Mikey]

C3 Corvettes have neither a short or long pump. It's unique:

Chevy Water Pump Specifications

------------------------------------------------------------------------
Short-Style Pump for most 1955-72 cars & trucks (5/8" pilot shaft)
• Fits all 1955-68 S/B Chevy passenger cars, 1969-70 350 c.i.d. Corvettes and 1955-72 light duty trucks. Has 3/4" ball/ball bearing.
• Dimension from block surface to hub: 5-5/8". Inlet diameter: 1.80".
------------------------------------------------------------------------
Long-Style Pump for 1969-87 V8, 90° V6 & 1973-86 truck (5/8" pilot shaft)
• Fits all 1969-87 S/B Chevy or 90° V6 passenger cars and 1973-86 light duty trucks. Does not fit Corvettes (use #8810 or #8812) or late-model vehicles with serpentine accessory drive belts (use #8881). Has heavy-duty 3/4" ball/roller bearing.
• Dimension from block surface to hub: 6-15/16". Inlet diameter: 1.80".
------------------------------------------------------------------------
Short-Style Pump for 1971-82 Corvettes 3/4" pilot shaft)
• Fits all 1971-82 S/B Corvettes. Comes with heavy-duty 3/4" ball/roller bearing.
• Dimension from block surface to hub: 5-13/16". Inlet diameter: 1.80".
------------------------------------------------------------------------

 

[Ozziljian]

C3 Corvettes have neither a short or long pump. It's unique:

Chevy Water Pump Specifications

------------------------------------------------------------------------
Short-Style Pump for most 1955-72 cars & trucks (5/8" pilot shaft)
• Fits all 1955-68 S/B Chevy passenger cars, 1969-70 350 c.i.d. Corvettes and 1955-72 light duty trucks. Has 3/4" ball/ball bearing.
• Dimension from block surface to hub: 5-5/8". Inlet diameter: 1.80".
------------------------------------------------------------------------
Long-Style Pump for 1969-87 V8, 90° V6 & 1973-86 truck (5/8" pilot shaft)
• Fits all 1969-87 S/B Chevy or 90° V6 passenger cars and 1973-86 light duty trucks. Does not fit Corvettes (use #8810 or #8812) or late-model vehicles with serpentine accessory drive belts (use #8881). Has heavy-duty 3/4" ball/roller bearing.
• Dimension from block surface to hub: 6-15/16". Inlet diameter: 1.80".
------------------------------------------------------------------------
Short-Style Pump for 1971-82 Corvettes 3/4" pilot shaft)
• Fits all 1971-82 S/B Corvettes. Comes with heavy-duty 3/4" ball/roller bearing.
• Dimension from block surface to hub: 5-13/16". Inlet diameter: 1.80".
------------------------------------------------------------------------

Awesome thanks!
I do have a short water pump, and with that, I have about 5 inches to spare for a fan, clutch, and shroud assembly(taken into consideration the near 55 degree radiator slant.
Speaking of slanted radiator.... is my vette supposed to have a radiator with sloped cooling fins since it is angled mounted? It just would seem to make more sense for air flow, idk
Anyhow, thank you Vettehead Micky and everyone else! What a great helpful site!