# Solid Fan, No Clutch - is that like, ok?



## Ebartone (Aug 18, 2019)

Oh, so this is a bit of a tricky question, looking for your opinions. I’ve recently built a 462 stroker and it’s been running great for me, knock on wood. A couple hundred miles on it now and I’m very happy. My background, like many of us, is overheating has always terrified me! My previous engine had heating problems, and I’ve spent a lifetime with various fixes. So going into this one of course I was paranoid. The fellow at a local, very reputable shop that swapped out the engine for me swear by the idea of literally direct driving a fan to the water pump, and I decided to go for it, at least to start. Just as simple as that, an extension, and hard connection. So now I must say this engine stays very cool, and I’m very happy with it. I have 160° thermostat, rarely goes above 180, and once in a while at idle will stay at 200. So, you probably know where I’m going with this, the clutch. I’ve recently bought a Hayden and I’m considering putting it on, to try it out, but I’m asking myself, if it ain’t broke, why fix it? I hear no belt squeal, and I’m probably losing a few horsepower I know, but what do you guys think? The person that recommended this is fairly reputable, so please don’t jump too hard on him, and there are lots of his cars in my area running like this. Again, I know the immediate response, but what do you guys think? Has anybody lived with a direct drive like this? I know, I know, just try it, and I might, but still thought it was a fun conversation. Thanks.


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## O52 (Jan 27, 2019)

Four and five blade direct drive fans were standard for Pontiac models. When A/C or heavy duty cooling was optioned then a clutch fan was ordered.
There was also a seven blade direct drive fan available


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## Ebartone (Aug 18, 2019)

Here she is…… 6 blades


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## O52 (Jan 27, 2019)

Looks like five to me Lol. Never seen a six blade Pontiac fan.


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## Ebartone (Aug 18, 2019)

Yea its hard to get a good picture from the lighting, but its six all right. But not necessarily a Pontiac fan! The builder purchased it, I’m not sure from where.


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## O52 (Jan 27, 2019)




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## Lemans guy (Oct 14, 2014)

The shroud looks good and if it is cooling well then why change it. I would keep the clutch close on the shelf. Looks great…..


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## Mine'sa66 (Oct 30, 2019)

Direct drive fans have been around forever for good reason. I've run plenty over the years in countless applications. The nothing special 400 in my '66 GTO has a direct drive fan and a stock 4 core. Thermostat has to work to keep the temp up. I do live in Maine....


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## Ebartone (Aug 18, 2019)

Well, as a bit of an update, I mentioned that I have no belt squeal, and it turns out I don’t, until I hit 3100 RPM! Whether I’m on the freeway or idling in my driveway it’s the same thing, I get a pretty awful belt slip and squeal. And I’ve got a decent serpentine belt and I can tell you it’s in extremely tight, and it’s dry. So I think it’s time to try out the Hayden! I’m assuming the clutch will give me some slip as I hit higher RPMs and help with this problem? It’s the Hayden 2797 Severe duty.

The funny thing is when you look at the picture of my water pump pulley above, it seems like the belt is only touching maybe 15 degrees, which seems kind of small.


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## Lemans guy (Oct 14, 2014)

Serpentine belts have a specific tension; the pulley makers tell you just get it tight, but really you need a belt tension gauge. The gates cricket gauges are only about $14. Depending on whether your belt is 6 rib or 8 rib the spec is different.

On a new 8 rib belt for example, you put a very high tension to begin, like 200lbs. Then you idle the engine for 5 minutes and recheck the tension and it will be about 100 to 140 lbs.

then you can drive it and it will loose a bit more, I lie, the 8 rib about 100 lbs. Go by the Gates website numbers. They have specs for used belts too.

Also perfect alignment of the pulley’s will help to prevent belt squeal, you can use a straight edge but a “belt laser tool” is better.

The right tension, checked by a gauge, and the right alignment bystraight edge or laser tool will usually eliminate the squeals.


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## Ebartone (Aug 18, 2019)

Thanks LG, is this the one:









Amazon.com: Gates 91132 Krikit V-Ribbed Belt Tension Gauge, Black : Automotive


Buy Gates 91132 Krikit V-Ribbed Belt Tension Gauge, Black: Serpentine - Amazon.com ✓ FREE DELIVERY possible on eligible purchases



www.amazon.com


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## PontiacJim (Dec 29, 2012)

Lemans guy said:


> Serpentine belts have a specific tension; the pulley makers tell you just get it tight, but really you need a belt tension gauge. The gates cricket gauges are only about $14. Depending on whether your belt is 6 rib or 8 rib the spec is different.
> 
> On a new 8 rib belt for example, you put a very high tension to begin, like 200lbs. Then you idle the engine for 5 minutes and recheck the tension and it will be about 100 to 140 lbs.
> 
> ...



BUT, at these above numbers, is it too tight for the Alt/water pump bearings on our older cars? I don't know what the V-belt tension loads are, but I know based on pushing down on the belt and getting "deflection." I have had a couple garages that have over tightened the serpentine belts only to burn up a water pump and had to replace it way early. They did the same thing to me after the replacement, but I checked behind them and it was so tight I could stand on it and it would not flex. I backed off the adjustment screw (did not use a spring loaded roller to maintain tension like some others).

So just pointing this out. 

However, looking at the picture, you may be correct in that the belt does not make enough contact on the pulley and that is indeed causing it to slip. You might want to see if you could add a small tensioner/roller between the Alt. and WP so the belt will go over the WP pulley, then down under a roller, and back up and around the Alt. pulley.


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## Ebartone (Aug 18, 2019)

Thanks guys, but do you think that assuming the belt is tightened properly, that adding a clutch will help lighten the load at higher RPMs?


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## Lemans guy (Oct 14, 2014)

Yes, they have 2 models one goes to 250 or 300 lbs the other lower, I use both.

The V-belt tension spec is about 75 or 76 lbs. The aftermarket v-belts are fixed tension ,outlying, like March and CVF, so they have to be correctly adjusted.

Good point about the bearings on the WP PS etc. It can happen, but if done as Gates saysthat excessive tension on the belt lasts 5 minutes, streets the belt and immediately drops to a way lower level.

About 100lbs on an 8 rib serpentine runs quiet with no bearing issues. Not too far above the 76 lb factory spec on the v belt.

76 Would be a bit loose on the serpentine as Gates knows what their belt tension should be.

Best I recall Gates calls for a 120 to 140 lbs spec on their 8 Rib belt, I run that a bit lower at 100 lbs, taking into consideration Pontiac’s factory V-belt spec of 76 lbs.

So I split Gates and Pontiac specs, for this aftermarket serpentine belt phenomenon, seems to work great. Pulley companies could never get me a spec, just the 3/4 inch deflection thing, twisting the belt etc. done those but got lots of squeal.

Only the Gates procedure and the correct gauges and laser fixed it, and then use 100 lbs.


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## Lemans guy (Oct 14, 2014)

Clutch will not effect tension, as the WP spins either way. It may have more load, but not more tension. Tension is determined by the stretch of the components. It will have the same tension parked as running, once stretched out from new.

clutch is not the answer, gauge and laser and proper tension fix squealing


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## Ebartone (Aug 18, 2019)

I understand, what I’m trying to do is loosen the load and in turn loosen the slip, by at least slightly disengaging the fan when I’m over 3000 RPM. It doesn’t seem like a fan ever needs to run over that RPM to me, and I think it’s just severely loading the belt making it slip. But I’m working on tension too.


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## Old Man Taylor (May 9, 2011)

I've had a solid fan on mine for about 50 years. When I raced it I shifted the 428 at 6400 RPM. I've never had a problem.


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## PontiacJim (Dec 29, 2012)

Ebartone said:


> I understand, what I’m trying to do is loosen the load and in turn loosen the slip, by at least slightly disengaging the fan when I’m over 3000 RPM. It doesn’t seem like a fan ever needs to run over that RPM to me, and I think it’s just severely loading the belt making it slip. But I’m working on tension too.


The flex fan blades flatten out as RPM's increase. They cut the air pretty good at lower RPM's and then slowly flatten as RPM's increase, so thinking that the clutch fan slips at around 3,000 RPM's and then goes along for the ride will in essence be the same as a flex fan.

I used an aftermarket 6-bladed flex fan - and they will usually have an RPM rating as to how fast they can be spun up. It was noisey, you knew it was spinning, so they do have a "sound" to them. It did cool my engine well (pulling a lot of air at lower speeds), and it replaced a factory steel (I believe 4-bladed fan), and I did not use/add a clutch. Mild build 8.4 compression 400CI, nothing fancy or big HP.


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## BearGFR (Aug 25, 2008)

Couple things... One is be very careful about going all King Kong on belt tension. It's not difficult to get the belts so tight that it causes abnormal wear on the upper half of the front main bearing. Ask me how I know that 

Another thing: think about what your radiator "sees" as you're driving. Around town at city speeds, you need that fan to pull air through the radiator so that it can transfer heat into that air. The natural airflow through the radiator that's due to vehicle motion isn't sufficient to keep things cool. But what about buzzing down the freeway at 70+ mph? There's so much air piling up in front of your car that you don't really need a fan at all. If it weren't for needing that belt to spin the water pump, you could probably run just fine with no fan. Have you ever stuck your hand out the window at 70+ mph?That's a bunch of air moving, quite a bit more than that fan is pulling. Now consider this: The faster that fan turns, the less it looks like a fan and the more it starts to "look like" a solid disc. Especially in our cars that tend to have non-overdrive transmissions and also tend to be geared for acceleration, while you're driving at highway speeds turning 3000+ RPM, it's not too hard to see how it could be that as that fan spins faster and faster, it can start to >impede< air flow instead of generating it.

My opinion - take that for every nickel it's worth  - is that the fan RPM is just like nearly everything else on a car. More isn't always better. You've got to 'tune' things for your operating conditions, whatever they might be.

Bear


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## Ebartone (Aug 18, 2019)

Well, as a follow-up I tightened up the belt, and now there is no screeching sound whatsoever and the fan seems to be doing fine. Thanks everybody!


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