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Correct fan clutch?

Old July 4th, 2019, 03:10 PM
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Correct fan clutch?

Once again, Iím having issues getting the fan shroud to fit. I bought the correct 4 core radiator top plate from OldsPackRat, and a new fan shroud from the parts place. The shroud fits better than it did with my modified top plate, in fact, itís a better fit than it ever has. My issue is with the bottom. I canít get the shroud to fit without the fan hitting at the bottom. Itís very light contact, but im also spinning the fan by hand. Im seriously beginning to wonder if this is the correct fan clutch. The fan seems to be tucked into the shroud a little further than it should be. Opinions? Anyone in readerland with a 69 Cutlass, 455, who cares to post a picture of their setup?





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Old July 4th, 2019, 03:41 PM
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When mine hit at the bottom it was because the motor mounts were sacked, new motor and tranny mounts and it no longer hit. Also I think there was a 19 and 19.5 " fans if your fan is too big that could contribute.
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Old July 4th, 2019, 03:51 PM
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Solid engine mounts, no sag with those. I have another fan clutch coming tomorrow for comparison. Iím going to be really pissed if the reason for all these hassles is the wrong clutch. I stuck my phone inside the shroud, itís obvious where itís hitting.
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Old July 4th, 2019, 03:54 PM
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My clutch fan notes from 1966 big cars with big blocks

Hayden clutch fans 2705 SD, 2747 HD, 2765 SD, all fit my 66 big cars with shrouds. Hayden 2747 HD has .5" radiator clearance and is both cool and very noisy. The 2765 runs quieter but hotter. Also check Hayden 2772, 2797, but they may be too long in overall length.

Hayden HD = heavy duty; SD=standard duty. HD spins the fan starting at lower temperature than SD. They have an online catalog you can review for overall length and other dimensions.

In the end I used an 18Ē 7 blade fan from the boneyard and one of the clutches listed above. I wasnít real religious about which GM the fan came from.

I think GM made 17.5, 18 and even 19Ē fans along the way all with the 4 5/16ís bolt interface. Dorman makes a few replacement fans but be sure you check the spin direction before buying. I went boneyard since It was cheap and easy.

In 1966, Olds only made one shroud which covers only 70% of the big car radiators. Itís ugly to admit it, but I cut up a later Toro shroud and just zip tied the drivers side wider edge to a cut up 66 shroud that connected the mounts. Ugly, but it works well.

Point is a dremel and a little creativity may get you the clearance you need. At the cost of originality.

Hope this helps

cf

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Old July 4th, 2019, 04:59 PM
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My fan measures 19 inches, 7 blades. I removed the shroud again, I noticed the body clips at the bottom of the shroud werenít bottomed out completely. By slotting the mounting hole up, the body clip will now sit flush with the mounting bracket. Iím guessing that will lower the shroud maybe 3/16, 1/4 inch at most. The distance from the mounting surface of the clutch to the fan is 7/8 inch, figure 1 inch if the fan was removed.

This is the only number I can find on the clutch. Ring any bells?

From the back of the fan, to the water pump mounting flange. Measures 7/8
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Old July 4th, 2019, 05:07 PM
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Hayden offers a low profile heavy duty fan clutch, I may try this and see what happens. If I wasnít so stubborn, Iíd put electric fans on it. 😡

https://www.haydenauto.com/en/ecatalog?partdetail=2947
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Old July 4th, 2019, 05:09 PM
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Maybe I am missing something, but why would the fan clutch have anything to do with the vertical alignment of the fan in the shroud? As said above, the engine or transmission mounts would have an impact of the vertical position of the fan. The fan clutch would only affect the fore-aft (horizontal) position of the fan in the shroud, not the vertical position.

Since you say you have solid mounts that won't compress, are you certain that they, along with the frame mounts, are the correct height?
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Old July 4th, 2019, 06:28 PM
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Matt, I've got a 1969 with that setup. I'll try to get some pictures tomorrow.
John
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Old July 4th, 2019, 06:29 PM
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I think the fan is too close to the radiator, too deep in the shroud. The engine mounts and frame mounts are correct. The fan is fairly centered in the shroud. The clearance issue is at the bottom, where the shroud kinda flares out.
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Old July 4th, 2019, 06:39 PM
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Originally Posted by matt69olds View Post
I think the fan is too close to the radiator, too deep in the shroud.
I still don't see how that would make the fan blades contact the shroud.
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Old July 4th, 2019, 09:11 PM
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I think what you’ve got is the Hayden 2705 standard duty. Just a few opinions:

1) If you can find a shorter fan clutch, or one that moves the fan backwards toward the motor, you’ll be better off. If I recall, you want half the fan blade in the shroud, half out.

2) My favorite fans are the 18” 7 blade fans from 70’s cars. My hunch is the 70’s ones pulled more air than the 60’s 6 blade fans to deal with emissions and higher engine temps. I suspect, but don’t know, that GM played with a lot of fan blade angles to optimize fan noise vs. fan CFM. I further suspect that they used different angles for Cadillacs vs, say, Chevy trucks. Also if you drop back from 19” to 18”, you get an inch of margin in case of motor mount failure.

3) A full radiator shroud really helps. So do the rubber covers in front of the radiator tanks which force the air through the radiator core. I’ve put these covers on the sides, bottom and top of my core for max. cooling. Fusick sells the masticated rubber in bulk for not too much money. Easy summer project with tangible results.

4) Electric fans are great, but they use high amperage so they need fairly heavy duty wires and maybe a relay. And a bomber alternator. Cuz you’re using them on hot days maybe with a/c running at low speed. I like factory style fan clutches better. Just simpler.

Good luck, with a bit of persistence, this is very solveable.
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Old July 5th, 2019, 09:33 AM
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Matt, I hadn't had my head under the hood of that car in a while. Sorry, I'd forgotten it doesn't have a clutch fan on it.
John
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Old July 5th, 2019, 10:57 AM
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Originally Posted by 2blu442 View Post
Matt, I hadn't had my head under the hood of that car in a while. Sorry, I'd forgotten it doesn't have a clutch fan on it.
John

Great big steaming piles of horse excrement!!! Ok, a new clutch is coming (according to the catalog itís the correct part). If itís the same as what I have now Iíll probably try the low profile Hayden part. Iím hoping that will position the fan in the textbook acceptable ď halfway in the shroud
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Old July 5th, 2019, 11:32 AM
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Mix/match is sometimes the order of the day - for my '72 350 I have finally settled on a GM p/n 342715 17.5" 7-blade fan (correct for mid-70's Corvette) and CARQUEST p./n 215046 thermal fan clutch (the p/n I believe is universal for other brands as well, like Hayden and Imperial).

the assembly fits perfectly with spacing right up to the inside of the shroud. This is combined with a Cold Case aluminum radiator.

This fan/clutch combo I'd presume could fit your motor as well, all else being equal as to the shroud and radiator spacing
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Old July 5th, 2019, 12:15 PM
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I just remembered that many years ago I had an issue with the fan rubbing the lower part of the shroud. For whatever reason (maybe the replacement radiator was too tall?), the shroud was being pulled up a bit too high by the upper mounting bolts and distorted it, so the bottom / center of the shroud was too close to the fan. I put some spacers between the shroud upper mounting holes and the radiator top plate to prevent the shroud from being pulled upwards when the bots were tightened and that corrected the issue.
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Old July 10th, 2019, 06:43 PM
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The UPS truck finally delivered the fan clutch! I got it bolted on, everything seems to fit better. I have about a 1/2 inch of clearance all around the fan, maybe a bit more at the top. Iíll finish it up tomorrow, 4 am comes to early in the morning.

Btw, Hayden part number 2947. I tried for 2 days to get one from the local stores, both NAPA and OíRiley said they could get it, when it came in it was the 2747, identical to what I had on the car. Iím not sure what is different with my car that the ďcorrectĒ parts wouldnít work, maybe a bunch of little things stacking up to create a headache. Whatever the reason, seems like this will work.
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