Question. 69 camaro Z/28 with a non-stock 350-300hpish engine. It currently has a single 4 blade fan with a spacer versus the fan clutch with a 7 blade fan like the 302 has.

What's the difference? Advantages, cautions? Can I run a clutched setup as long as I have sufficient clearance? Do other components require changes also? Like alternator, etc>?

Thanks

Clutch and fan bolt onto the end of the water pump, no need for mods
If u have the correct shroud the fan blades will be just inside or about 1/2 out of the shroud
Clutch fans are very efficient and reliable.

Well, I have a high pitch 4 blade fan on mine. I know for certain that as long as there is a belt on there, it will spin and cool. I have seen clutches go bad...

Never had a problem keeping mine cool with the 4 blade. JMHO.

I have seen clutches go bad...
I have to...after 200,000 miles and bearing has been stuffed for 50,000 miles of that.
Oh and one on my car, new about 6 months old, then car got stolen, and engine spun up well over the 10,000 rpm mark according to the forenseics guys....also destorying a near new water pump, cam lobes, broken valve springs, trans bearings and torque converter.

Ya just gotta trust the engineers at GM, they had been using non clutch fans and then invented the fan clutch. They had to be more costly to produce so the payoff had to be worth it. Why go backwards?

alan

Most mechs that I have talked to in the past had discouraged them... but that's just heresy on my part. My engine rebuilder said to keep it simple... so I did. No clutch, but to each his own,eh?

capt

I have seen clutches go bad... JMHO.

Lots of parts can go bad. That doesnt mean using one wont benefit you. And replacements are only about $25. FWIW I used one on my HP BBC build.

Most mechs that I have talked to in the past had discouraged them
And then run thru old postes here, check out those who have the same +ve opinion as Alan...then go read some of there other posts, PRACTICAL expericance and advice
You will find these HARD core guys know what the hell they are talking about ...and are not just experianced home mechanics of often 30 or 40 yrs hands on, but also top professionals also of decades of experiance...

Most mechs that I have talked to in the past had discouraged them
lets face it, most nechanics are under 30, grew up with a different technolgy and 99% of there work is on modern cars post 80s or 90s..with very little experiance of pre mid 70s on a regular daily basis.
And those older guys, in the day dumped fan clutches, but in retrospect, and decades of experiance, endorse them...

Most mechs that I have talked to in the past had discouraged them
And then run thru old postes here, check out those who have the same +ve opinion as Alan...then go read some of there other posts, PRACTICAL expericance and advice
You will find these HARD core guys know what the hell they are talking about ...and are not just experianced home mechanics of often 30 or 40 yrs hands on, but also top professionals also of decades of experiance...

Most mechs that I have talked to in the past had discouraged them
lets face it, most nechanics are under 30, grew up with a different technolgy and 99% of there work is on modern cars post 80s or 90s..with very little experiance of pre mid 70s on a regular daily basis.
And those older guys, in the day dumped fan clutches, but in retrospect, and decades of experiance, endorse them...

I have a flex fan on my '68. It's not something I would have bought (it was on the car when I bought it), but it works very well. It moves a lot of air a low RPMs and is pretty quiet. At higher RPMs the blades flatten out to use less power.

As pointed out in my post, I said my info was heresay. The mechanics were all pros in their field, and the majority of them had shared a common belief with me, that given the chance, they would avoid a clutch fan application. These people were not home mechanics.

My engine rebuilder was into oval racing/drag racing with many years of experience and I took his advice as well, based on his experience.

As in any field of endeavour, there will always be differences of opinion, and no one, I think has the definitive truth within them. This is why we have these posts, so that we can all learn and... share.

capt

If you worried about a clutch fan going back install a water temp gauge. I took off my 4 blade fixed and went with a flex a lite nonthermal clutch and 6 blade fan. haven't had any cooling problems since the upgrade.

My take on it is, in the real world, switching to a flex fan you gain a few HP and also gain a few degrees at idle. For some cars a few extra degrees means overheating for others they are no where near the danger zone anyways. So often a flex fan works fine and you gain a few HP. Im running a modified BBC and I live in South Texas so my car is closer to the edge of overheating. I NEED the extra cooling.

As pointed out in my post, I said my info was heresay. The mechanics were all pros in their field, and the majority of them had shared a common belief with me, that given the chance, they would avoid a clutch fan application. These people were not home mechanics.

My engine rebuilder was into oval racing/drag racing with many years of experience and I took his advice as well, based on his experience.

As in any field of endeavour, there will always be differences of opinion, and no one, I think has the definitive truth within them. This is why we have these posts, so that we can all learn and... share.

capt

And let's all agree that the racing environment is totally different from the city street driving environment. In racing, there is no need for a/c, cigarette lighters, stereo systems, automatic transmissions, power windows, power seats, hide-away-headlight systems.......and many more "optional" systems that too can break down and be a PIA to fix.

alan

As pointed out in my post, I said my info was heresay. The mechanics were all pros in their field, and the majority of them had shared a common belief with me, that given the chance, they would avoid a clutch fan application. These people were not home mechanics.

My engine rebuilder was into oval racing/drag racing with many years of experience and I took his advice as well, based on his experience.

As in any field of endeavour, there will always be differences of opinion, and no one, I think has the definitive truth within them. This is why we have these posts, so that we can all learn and... share.

capt
Well,,,,,, how do I say this? Oh OK! I disagree.
Virtually all high performance engines built with a conventional fan/water pump have a clutch and lots of blades, not just four. Hotrod Magazine tried to find out why and also settle the controversy. They tested every setup available for cooling and horsepower demand. Hands down winner of cooling was the factory setup like our cars originally came with. Horse power? Same. They took zero, none, just like they were not there when pulling on the dyno. Hard to beat perfect. And they look kinda good too.
:thumbsup:
http://epitomesrebuild.com/images/138.JPG

Fred, that would make perfect sense. As smog regulations kept playing a larger and larger role for manufacturers to deal with, the cars had to run hotter to have a more complete combustion therefore they had to improve the cooling systems to keep up. A thermostatically controlled fan allowed the engine cooling demand to dictate "how much fan" was needed at a given time. On the track, yes, who cares about that, it's all about hp and performance.

I was always impressed when I read that manufacturing costs were figured out to the penny. A thermostatic clutch costs more than a slug of aluminum with 4 holes. Add in the cost for warranty failures/replacement and you just have to believe that the benefits outweighed the costs as far as GM was concerned.

alan

My engine rebuilder was into oval racing/drag racing with many years of experience
THAT is the issue...the diff between a pure show car, street and pure track is like night and day...from pistions, cylinder to wall gaps, cams, pumps, and even chroming sumps and valve covers.
One doesnt go to a leg bone specialist for a spinal injury