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Not really having an overheating problem- even with the 496. Just looking to improve a bit. The fan shroud I have does not cover the whole radiator, only the center directly in front of the fan. And it's basically just a sheetmetal ring that's slightly bigger in diameter than the fan. Any gain from fabricating a shell that would cover the outer edges of the radiator that are currently open? Not real crazy about spending $$$ for a factory shroud, but bending a sheet of aluminum/steel would be easy and cheap. Still running the engine driven fan too. Comments or ideas?
As long as the radiator is sealed to the radiator support forward motion of the car at speed will force air through the complete radiator. The fan comes into play when you have low or no forward motion. So how is the temperature at low speeds and when stopped?
No problem when stopped or going slow- it will very slowly get up to 200* but really never gets any hotter than that- at least on a 80*+ day. Just looking to improve, or maybe stop a potential problem before it happens. Part of the question comes from looking at both electric fans, DeWitt's radiators and factory shrouds- they all seem to pretty much cover all of the radiator, which would force more air thru the core when the fan(s) are running.
Having the shroud cover the whole radiator won't give you anymore cooling when moving but will direct more air through the radiator when stopped and the fan is running. In 68 the original BB radiator shroud design was just a sheetmetal ring that did not cover the whole radiator. After overheating problems on the early cars they quickly redesigned the cooling system and replaced the sheetmetal ring shroud with a full cover fiberglass shroud to help airflow over the radiator when stopped.
TimAT
Have you been following the Lincoln electric fan threads ?
Yes I have. Kind of thinking about going that way, but since I'm not really having a heating problem, it's a little tough to justify spending $$ on something that's not screaming for attention. I"m just looking to improve on the setup I have.
JC68-- that is exactly what is on m 69- a sheetmetal ring. Which is why I'm exploring other options.
Tim: For whatever reason, this is the shroud that came with my 69 small block from the factory. I also got the better radiator and I had thought it was the BB setup. It was a bear to get in and out but as you can see, it's no compromise. Worth chasing down rather than having to fab your own. It is some sort of composite ABS-like material, definitely not fiberglass.
1968 cars were the only year to use a true fiberglass shroud, in 1969 cars received either a molded plastic fan shroud or a sheetmetal ring depending on if a copper or aluminum radiator was used. Radiator usage was dependent on engine type and car options. For 1969 the general rule is BB cars, cars with auto transmissions, and cars with A/C used a copper radiator. Copper radiators used the plastic shroud. The others used a aluminum radiator and a sheetmetal ring fan shroud.
Thanks guys for the responses. A sheet of aluminum is easy to get, my neighbor has a brake to bend it with so that's no problem. I'll probably roll a couple of beads into it for strength, and then attach the ring I have to that. Or one of the Lincoln fans. Winter project for sure.
1968 cars were the only year to use a true fiberglass shroud, in 1969 cars received either a molded plastic fan shroud or a sheetmetal ring depending on if a copper or aluminum radiator was used. Radiator usage was dependent on engine type and car options. For 1969 the general rule is BB cars, cars with auto transmissions, and cars with A/C used a copper radiator. Copper radiators used the plastic shroud. The others used a aluminum radiator and a sheetmetal ring fan shroud.
JC: Just curious, how do you know this stuff? How might you explain my car? I know this is exactly how my car was delivered, L46, Ohio car, no AC, & no auto. Copper radiator. Early January build.
JC: Just curious, how do you know this stuff? How might you explain my car? I know this is exactly how my car was delivered, L46, Ohio car, no AC, & no auto. Copper radiator. Early January build.
I'm not sure of all the design criteria that drove GM to use what type of radiator with what engine and options but there were some rules they seemed to follow. The NCRS judging guides do a pretty good job of explaining what cars got what radiators, but a lot I just learned through observation as well.
The general rules for early c3 cars are:
The fan shroud choice is easy.
-Aluminum radiator cars used a sheetmetal ring fan shroud. -L88 cars are the exception as they did not use a fan shroud with the AL radiator.
-Copper radiators cars used a fiberglass or plastic fan shroud. Early 1968 cars are the exception to this, they used the sheetmetal fan shroud on copper radiator cars as well.
The basic radiator rules are:
- Aluminum radiators were used unless the car had one of the following options:
- BB engines used a copper radiator. -L88 cars are the exception
- Cars with auto transmissions used a copper radiator. - The copper radiator had provisions for a built in transmission cooler.
- Cars with A/C used a copper radiator.
1969 L46 cars are the ones that break the radiator rules. GM used both aluminum and copper radiators on cars with manual transmissions for no apparent reason.
BB Fan shroud
