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#21
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I've had a water pump let go and dimple the hood, lol.
It also took out the radiator, the fan shroud, the fan, the belt, the clutch on the fan, and the overflow tank for the radiator. New hood, hood insulation, radiator, clutch and fan, fan shroud, overflow bottle, belt, and $2,000 later, it was back on the road. Would have been more if I had to pay a shop to repaint a new hood. Luckily this car uses an OEM plastic fan, so instead of going through things or piercing the hood, they tend to just break off. |
#22
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Mu buddies 70 flaked the paint off, my 78 the polyurethane stayed on but that big flat surface in black the dimple is obvious-at least to me. Not sure if one of those paintless dent removal things would work on it.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#23
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IT IS NOT A FIREBIRD, IT IS A SHARK.
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The Following User Says Thank You to aceaceca For This Useful Post: | ||
#24
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There was a thread I was reading advising not to use a clutch but instead a flex fan directly coupled and run it at rpm to improve cooling. Sounds like it could be trouble at a certain rpm
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#25
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I don't believe there is anything that does a better job of cooling than the factory clutch fan setups Pablo. The added benefit is that they aren't huge HP suckers either.
I have a slew of fans on the wall and on the mezzanine and have tried a lot of stuff over the years. Most recently dual electric fans. I've found out here in the Arizona heat that the factory clutch fan, with a good clutch, and a proper shroud has been the best at cooling hands down, even on big HP large CI engines. Here's a fan test you might find of interest if guys are worried about HP. I can't think of any other reason someone would switch over to those tiny aluminum flex fans unless they thought they would gain some HP, because they don't really pull much air. As you can see, those little fans don't even add HP. In fact it killed 11 hp over the stock clutch fan. |
#26
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Looks like there’s under hood insulation. Slowed it down some.
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🧩 Burds Parts, Finding those Hard to Find PCs, no Fisher Price Toys Here Just Say No To 8” Flakes F ire B irds 🇮🇱 |
#27
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The clutch fans have a known RPM limit, about 4800 rpm if I remember right--it's on the Hayden web site if anyone wants to look it up.
Since the water pump is typically spinning faster than the crank...the fan clutch is turning faster than the tach suggests, by whatever the pulley ratio happens to be. The saving grace here is that the fan clutch is also slipping some, the fan clutch is turning faster than the crank, but the fan isn't due to fan clutch slippage. Yet another reason to NOT use the "Heavy Duty" or "Severe Duty" fan clutches (that don't slip properly when used with typical automotive fans) in a performance application. |
#28
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I don't know if I buy into all that. These clutch fans are what GM used on nearly all the high performance solid lifter engines and we zing those things up repeatedly. I don't think GM would have engineered them this way if that clutch fan was going to be a problem above 4800 rpm.
My little DZ loves 7,000 rpm. 51 year old stock clutch fan in place, works just fine. I have the heavy duty unit on my 454 chevelle and can't tell you how many times I've buzzed that thing to 6500 over the last 35 years, lol. Dad can't stay off the rev limiter set at 6300 in the GTO, with a heavy duty clutch fan on it. |
#29
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From the circle track world...
The crate engine (sealed engine) series all have the same engines so anthing that frees up power or reduces friction/drag is always being sought after. Those engines max out at 7000 RPM. Anything riveted or "flex" fails in short order. Fan/pump are usually driven 1:1. Front of cars are completely closed so high draw fan is imperative. The only two viable choices are; https://www.race-fan.com/ Crates LAtes and Super Late Models (turning 9000 RPM) usually use this: https://gorsuchperformancesolutions....ir-6-blade-fan YFLMV! On a side note, my factory Ford 428CJ fan/clutch let go on me last summer, ~ @ 6K...it's over driven.... "only" junked a new OEM rad. Haven't opened the hood since! (not fixed) Last edited by STEELCITYFIREBIRD; 07-15-2020 at 02:10 PM. |
#30
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Quote:
I tend to believe that's why the carnage wasn't so bad on my sons mustang. Being plastic, it never did puncture the hood. I believe if that was metal it would have certainly went through. When it hit other stuff like the lower radiator hose, the shroud etc...the blades just broke off, didn't even cut through the lower hose. It was the clutch that did most of the damage, mainly to the radiator. |
#31
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I'm guessing very few of these let go at ide but more likely at revs. meaning nothing but bad news..!! Easy sometimes to take for granted the amount of engineering $$ a cars manufacturer puts into its vehicles to insure stuff like this won't happen and make them liable. The lack of this engineering is why some aftermarket parts can be less expensive, sometimes you do get what you paid for....
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#32
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The Racefan blades are the same material huge semi truck fans are made of. Quite aggressive blade pitch and surface area, VERY light. Heavy fans toss belts. We drive ours with a HTD belt/pulleys ...no slip, ever.
My 68 likely will be getting one in 19". |
#33
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#34
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#35
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Quote:
Heavy-duty and Severe-duty clutches slip less, though. (Unless they're used with fans having big pitch/high drag.) Quote:
https://www.haydenauto.com/en/techni...q-fan-clutches Quote:
But it will suck a lot of air, so guys use 'em and think they're "great for added cooling". Duh. The thing will never properly disengage. Might as well scrap the clutch and just use a solid spacer if you think you need a "Heavy duty" clutch on a wimpy fan. Don't forget to armor-plate the under side of the hood. What I did not see was any mention of Hayden selling fans other than electric fans any more. There used to be three part numbers for clutch-style fans, two in the normal direction, and one for reverse rotation. None of the non-electric fans are in the catalog any more. Last edited by Schurkey; 07-15-2020 at 10:39 PM. |
#36
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No. I've NEVER seen a water pump pulley smaller than its crank pulley.
__________________
Anybody else on this planet campaign a M/T hemi Pontiac for eleven seasons? ... or has built a record breaking DOHC hemi four cylinder Pontiac? ... or has driven a couple laps of Nuerburgring with Tri-Power Pontiac power?(back in 1967) ... or has a Pontiac born the same year as Jim Wangers? (1926} |
#37
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Just to add to the confusion Hayden themselves indicated to use the heavy duty clutch for my application.
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#38
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I put a factory judge flex fan on my car with a/c pulleys. At about 3000 rpm`s, I thought the fan might come apart. I got the factory judge pulleys for it. Turn it 5600 to 6000 all the time with no worries. Ya gotta slow those direct drive fans down.
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#39
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I can’t get a pic to load correctly from smartphone. Last edited by PunchT37; 07-16-2020 at 07:49 AM. |
#40
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IIRC... that is SOP on A/C equipped Pontiac's, over driven water pump....under driven pump on non A/C cars.
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