I've decided to build a fan shroud for my old Plymouth using examples shared here on the HAMB. The fan I'm running is 19" in diameter and my radiator is 20" tall and 18" wide. The fan is a traditional viscous type, not an electric deal. I'd like to go with a smaller fan so that it will fit neatly in the shroud, but I don't want to loose any cooling efficiency that I may gain by adding the shroud. Do y'all think going with the smaller fan, say 16", and adding the shroud would be better than what I've got now, no shroud and a 19"fan? Thank y'all for the help.
Squirrel, You're on top of these cooling questions, I read alot of your stuff researching....the fan is currently 2" from the radiator.
2" is too far a way all it does is recycle the air in the engine compartment and not pull any air through the core. 3/4" is the desired distance. I never have assumed a problem until it actually popped up. I'd get an 1 1/4" spacer for the fan and give it a try before going off the deep end. My cars don't have A/C so I've never built a hotrod that required a shroud to keep it cool. I've built a lot of hotrods using stock radiators in front of stock late model V8 engines and never had an over heating problem. I have had to use a thermostat to get the temp up to 180 where I like it in the spring and fall.
That all sounds good to me. The only difference might be being in Texas vs. being in Maryland. Have you driven the car? does it get hot in traffic? if so, how hot? and what engine is in it?
Yes, I drive the car. It's a mild 318, no ac. Temps run around 185 normally and they start to creep up to 200 in traffic. I haven't driven in the heat of a summer afternoon (100+), but would like a setup to where I could without worrying about overheating. I did the paper test on the front of the radiator and the fan sucks the air through good enough to hold the paper, for what that's worth....
I'd still get a spacer to get the fan closer to 3/4" but I agree with squirrel that those temps are not dangerous.
It has a clutch on it, I'd be wary of a spacer in addition to a clutch. Although I run a really long shaft clutch on my 55....not sure if I can get a replacement for it, it's for a Buick with a V6 from long ago.
I thought about this on my way to the nursing home this morning. This is exactly what I was going to say. Aside from that you can get away with a slightly smaller fan and a shroud. A common misconception is that a fan needs to cover the radiator. Not the case, a fan only needs to be efficient and move air across the fins. If your shroud is sealed up around the outer edges if of the core a fan 2/3 the size of the face of the core is sufficient. One other thing if you are going to run a clutch fan you are best off a temp controlled fan as opposed to one that is regulated by RPM.
Actually what I see more than that is if it aint broke fix it until it is. I am working on one of those right now but that is a different story all together.
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