The water pump on my '72 Scout started to leak. Since the OEM fan
clutch is unfindable I decided to go with a pump that uses a bolt-
on clutch, but the clutch I ended up with has a larger bolt circle
and centering boss than the OEM fan.
On Tue, 23 Apr 2024 21:04:37 -0000 (UTC)
<bp@www.zefox.net> wrote:
<snip>
The water pump on my '72 Scout started to leak. Since the OEM fan
clutch is unfindable I decided to go with a pump that uses a bolt-
on clutch, but the clutch I ended up with has a larger bolt circle
and centering boss than the OEM fan.
Did you try Rockauto? Maybe:
https://www.rockauto.com/en/catalog/international,1972,scout+ii,4.2l+258cid+l6,1498398,cooling+system,radiator+fan+clutch,6812
Or a metal fan adapter plate?
Jim Wilkins <muratlanne@gmail.com> wrote:
Or a metal fan adapter plate?
Then I'd still have to find a fan. The OEM fan won't fit over the
mounting flange of the new clutch and has a too-small bolt circle.
Thanks for writing,
bob prohaska
I decided to order a fan from Amazon, based on a few words on
the manufacturer's website: >https://derale.com/product-footer/belt-driven-fans/fan-clutch-fans/standard-rotation/17117-17120-detail
Flange bolt circle: 3" / 3 1/4"
Flange diameter: 2 3/8" / 2 5/8"
After long reflection it crossed my mind that what they called "flange diameter"
might be the centering boss diameter. I'll find out in a week.
On 4/23/2024 5:28 PM, bp@www.zefox.net wrote:
Jim Wilkins <muratlanne@gmail.com> wrote:
Or a metal fan adapter plate?
Then I'd still have to find a fan. The OEM fan won't fit over the
mounting flange of the new clutch and has a too-small bolt circle.
Thanks for writing,
bob prohaska
If you have machine tools it should be quite easy to fabricate an
adapter plate . It doesn't have to be something as skinny as a piece of
1/4" plate ...
On Wed, 24 Apr 2024 04:11:21 -0000 (UTC)
<bp@www.zefox.net> wrote:
I decided to order a fan from Amazon, based on a few words on
the manufacturer's website: >>https://derale.com/product-footer/belt-driven-fans/fan-clutch-fans/standard-rotation/17117-17120-detail
Flange bolt circle: 3" / 3 1/4"
Flange diameter: 2 3/8" / 2 5/8"
After long reflection it crossed my mind that what they called "flange diameter"
might be the centering boss diameter. I'll find out in a week.
Hopefully this works out for you
Many years ago I installed a "Flex-Fan" on a big block that was having problems cooling during the summer. It was just a simple order from
Sears back then...
They are still around it seems and maybe they have one that might fit:
https://www.etrailer.com/search/Flex+Fan
They have a more universal fit than OEM. They work differently too. At
low speeds they scoop a lot more air. As the motor revs up the blades collapse (flex) becoming more efficient.
An adapter between the clutch BC and the fan BC? Unfortunately the mounting >flange of the clutch is too big to fit through the center hole of the OEM fan. >Apart from that little niggle the idea would work. It would definitely work >in a case where the fan was larger than the clutch.
Snag <Snag_one@msn.com> wrote:
On 4/23/2024 5:28 PM, bp@www.zefox.net wrote:
Jim Wilkins <muratlanne@gmail.com> wrote:
Or a metal fan adapter plate?
Then I'd still have to find a fan. The OEM fan won't fit over the
mounting flange of the new clutch and has a too-small bolt circle.
Thanks for writing,
bob prohaska
If you have machine tools it should be quite easy to fabricate an
adapter plate . It doesn't have to be something as skinny as a piece of
1/4" plate ...
An adapter between the clutch BC and the fan BC? Unfortunately the mounting flange of the clutch is too big to fit through the center hole of the OEM fan.
Apart from that little niggle the idea would work. It would definitely work in a case where the fan was larger than the clutch.
Thanks for writing!
bob prohaska
On that same old big block with cooling woes... I tried a "fan clutch eliminator" too. It was an adapter with lots of bolts that took the
place of the fan clutch. This took care of the spacing to shroud
problem. Search that has some results for this both pro and con:
I was visualizing a puck with the correct features for the water pump
on the back and the correct features for the fan/clutch on the front .
Maybe an inch thick , maybe a bit more ... unless that puts too close to
the radiator .
Snag <Snag_one@msn.com> wrote:
I was visualizing a puck with the correct features for the water pump
on the back and the correct features for the fan/clutch on the front .
Maybe an inch thick , maybe a bit more ... unless that puts too close to
the radiator .
The clutch fits the water pump correctly. The fan needs to fit _over_ the clutch mounting hub and mounts to the back surface of the clutch body.
Unfortunately the center hole on the fan is too small to fit over the
clutch hub and the fan bolt circle is too small to fit the clutch. Here
are a few images, hopefully they'll clarify the topological problem: http://www.zefox.net/~bp/scoutfan/
The obvious way to use the fan and clutch that I have together would be to bore out the ID of the fan and re-drill the bolt circle. That wouldn't
be impossible if I had an 18" swing lathe. I have only a 10" (maybe 11"
over bed) lathe, but taking the fan apart, doing the machine work and riveting it back together is a lot of work and not easy to get right.
At this point all fingers (and other appendages!) are crossed in hopes
the fan on order will fit the clutch on-hand.
Thanks for writing,
bob prohaska
.
Does anybody know of way to search for a radiator fan by mechanical >dimesions? Email to Dorman was replied to with a stern "no".
The water pump on my '72 Scout started to leak. Since the OEM fan
clutch is unfindable I decided to go with a pump that uses a bolt-
on clutch, but the clutch I ended up with has a larger bolt circle
and centering boss than the OEM fan.
The clutch I'd like to use has a four on 3 1/4" bolt pattern with
a 2 5/8" centering boss. The fan shroud is 19 1/4" ID, water pump
rotation is clockwise looking at the front of the engine.
Apologies for bending the "metalworking" concept, but Scouts are
mostly metal and I think I'm looking for metal fan 8-)
Thanks for reading,
bob prohaska
Leon Fisk <lfiskgr@gmail.invalid> wrote:
On Tue, 23 Apr 2024 21:04:37 -0000 (UTC)
<bp@www.zefox.net> wrote:
<snip>
The water pump on my '72 Scout started to leak. Since the OEM fan
clutch is unfindable I decided to go with a pump that uses a bolt-
on clutch, but the clutch I ended up with has a larger bolt circle
and centering boss than the OEM fan.
Did you try Rockauto? Maybe:
https://www.rockauto.com/en/catalog/international,1972,scout+ii,4.2l+258cid+l6,1498398,cooling+system,radiator+fan+clutch,6812
That looks broadly like the clutch I got with the new water pump.
But, no dimensions or even a good description.
If there's a way to search parts by category and description please
point it out, I couldn't find it.
Thanks for writing,
bob prohaska
One small discovery so far is that 3/32" teflon cord valve bonnet
packing seems to make a good water pump gasket. The paper gasket
wouldn't seal owing to warpage between pump and housing.
Which engine do you have? most 1972 Scouts used AMC engines - 194, 232
or 258 inch sixes and most 304 V8s were AMC - so AMC clutches and fans
dhould likely fit????
https://www.superscoutspecialists.com/fan-blade-for-bolt-on-fan-clutch-scout-ii
Some numbers in the description for the pump and clutch it fits, likely nothing that matches what you have though.
Thanks for the pictures, big help in better understanding the problem
you're having
The central hole has two diameters of centering boss, 2 3/8" and 2 5/8", each >clocked to its own bolt circle, I needed the 2 5/8" surfaces. To my surprise they
were about .015" undersize. The hole was clearly punched, since it wasn't round,
but how it got fifteen thou undersize baffles me. Only idea that comes to mind
is that over the years the punch and die wore, either from wear or resharpening,
and nobody noticed. Or, they noticed and didn't care.
It's an IHC v345. AFAIK only the sixes were AMC, 232 and 258, there was no >401 offered in Scouts. One oddity is that while the car contained a thread-on >fan clutch that's NLA, the manual refers exclusively to the bolt-on version >I'm presently trying to retrofit. Somebody had a last-minute change of mind.
This place claims to have some thread-on clutches but you'd
better sit down before looking at the price
https://scoutparts.com/Fan_Clutch_Screw_On_Type_Very_Rare__Scout_II_Travelall_Travelette_Pickup_Metro/p13305
The idea of having the old water pump rebuilt might make sense if it
can be done inexpensively, just to have a spare on hand. That would
require pulling and reinstalling both pulley hub and impeller, which
would take at least some fixturing.
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