Ktholin

My 55 (283ci with fuel injection) has a 5 bladed fan and clutch which I believe is a a 1959/60. I'm installing a new upper and lower fan shroud, which the car has never had since I have owned it. Since I discovered the fan clutch will not fit in the existing shroud (after I had it restored), I am replacing it with the original 4 bladed fan.

My question is what am I giving up, if anything, by removing the fan clutch and going with he stock fan/shroud? I understand with the clutch the fan doesn't turn as fast, depending upon the temperature, but what does this translate to in terms of performance? Am I better off sticking with the higher tech fan without the shroud?

wraplock

While the 5 blade fan will pull more air than a 4 blade, It will not live up to it's full potential without the use of a shroud so you may not lose much by using the 4 blade with a shroud. If you chose to go the 4 blade/shroud route seal around the shroud to insure that your fan pulls max air through the core and not around or under it. Pay attention to the placement of the fan into the shroud. If it is to deep it won't work properly. The fan blades should be sticking out of the shroud about an inch or so. I think you may find that the 4 blade fan sans clutch makes a bit more noise than a clutch fan does. In my 60 I run a 5 blade with clutch and the stock shroud. I took the time to seal off anywhere that air could be drawn into the fan without passing through the core first. Very happy with the results.

Don

Ktholin

Thanks, although I never had any overheating issues, I think it looks better with the shroud in place. There are some areas I could probably seal on the top and sides (black foam weatherstrip with adhesive?).

I checked the clearance and my fan is perhaps 1 inch outside the shroud so I should be OK. I don't see any way I could adjust it.

GTOguy

What wraplock said. Always run a shroud with these cars. A fan clutch will free up power and fuel mileage, but also puts more weight on the water pump bearing. I run fan clutches in most of my cars, but always with a shroud. As long as it doesn't overheat with your fixed fan and shroud combo, you'll be just fine.

Ktholin

By the way, is there anyway to run a fan clutch with the 4 blade stock fan? I'm not sure its feasible, since the fan would be located well inside the shroud.

MikeM

I've never seen a Chevy clutch fan with four blades. That's not to say it couldn't be done but I can't think of a single reason why you would want to invest the time and money?

AZDoug

A fan clutch will let your accelerate faster, if the clutch isn't locked up. Less rotating mass to spool up.

This was readily apparent on my 4.3L V-6 S-10, the truck was freakin dog when the clutch had locked up, it felt like i had an extra 700 pounds in the back.

Doug

jim lockwood

The 4 blade fan and no clutch absolutely does make more noise.

I added a 5 blade fan and a clutch to my bride's '59 (which previously had the 4 blade and no clutch). The reduction in engine noise was dramatic! Nothing subtle about it.

Jim

Ktholin

Well, I guess i'll find out this weekend when I get it running again. Like I said, I really didn't have overheating issues without the shroud and the 5 bladed fan.

I wonder if I could fit a 59 or 60 fan shroud to accommodate the 5 bladed clutch fan I have. Not sure about the clearance with my 55.

Frankie the Fink

I run a fan with a fan clutch eliminator (see red arrow) on my otherwise stock '61 with no ill effects; put it on 6 years ago and run in Orlando heat with zero problems.

Ktholin

OK, I'll bite. What's a fan clutch eliminator, or is it self-explanatory?

Frankie the Fink

Its basically a spacer that directly drives the fan (show above)..

Ktholin

OK, that's what I thought. No fan clutch, just a spacer to achieve the proper fan depth in the shroud.