OT: Finding a mechanical engine fan by dimensions

[b***@www.zefox.net]

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

[Jim Wilkins]

wrote in message news:v097p5$1rgi9$***@dont-email.me...

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
--------------------------

Or a metal fan adapter plate?

[b***@www.zefox.net]

Post by Jim Wilkins
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

[Snag]

Post by b***@www.zefox.net

Post by Jim Wilkins
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 ...

[b***@www.zefox.net]

Post by Snag

Post by b***@www.zefox.net

Post by Jim Wilkins
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

[Leon Fisk]

On Thu, 25 Apr 2024 01:32:29 -0000 (UTC)
<***@www.zefox.net> wrote:

<snip>

Post by b***@www.zefox.net
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.

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:

https://html.duckduckgo.com/html/?q=fan+clutch+eliminator&kd=-1&kp=-2

Pretty sure it's still around somewhere in my stuff along with a couple
fan clutches and likely the original fan blade too...

[b***@www.zefox.net]

Post by Leon Fisk
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

I'd prefer to use a clutch if possible. The Scout's gas mileage is
bad enough already, I'd rather not make it worse 8-) But, if the
blade I ordered won't fit, and the blade I have won't fit, I might
opt for a clutch eliminator as a temporary fix.

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.

Thanks for writing!

bob prohaska

[Leon Fisk]

On Thu, 25 Apr 2024 21:40:17 -0000 (UTC)
<***@www.zefox.net> wrote:

<snip>

Post by b***@www.zefox.net
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.

Well, at least you're gaining on getting it running again👍

Probably already found this stuff, but just in case...

Description for this clutch mentions you'll likely have to replace the
fan:

https://scoutparts.com/Bolt_On_Fan_Clutch_500202c2_Scout_II_Scout_800_Travelall_Travelette_Pickup_Metro/p11856

Same place sells a fan that I suspect is what you need now. Has a
wicked price though.

https://scoutparts.com/18_Fan_Blade__Scout_II/p18325

This place seems to have the same fan but a bit cheaper:

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🙂

[b***@www.zefox.net]

Post by Leon Fisk
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

I ended up ordering the fan (Derale 17118) from Amazon, it came in yesterday.
Stamped "Made in USA". Didn't fit 8-)

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.

A few carefully counted strokes of a rasp got the fan to fit the clutch.
The centering seems no worse than the blade runout so I'll try to use it.

The most impressive discovery so far is the teflon valve stem packing. I
bought it years ago to seal a flange on an espresso machine boiler, only
to discover the bolts were merely loose. It sat in the toolbox for years
until saving my bacon on this project. I'll be tempted to try it the next
time there's a leaky valve or differential cover to seal.


Thanks to all for reading and writing!

bob prohaska

[Leon Fisk]

On Sun, 28 Apr 2024 01:19:05 -0000 (UTC)
<***@www.zefox.net> wrote:

<snip>

Post by b***@www.zefox.net
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.

That would be about the right size for it to get a final machining
operation after punching to true it up nice🤔

Sounds like you've got this problem handled now and will soon be tooling
around again in vintage style🙂

[Jim Wilkins]

Post by Snag
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

-------------------

If you can get a spare OEM or similar fan perhaps you could open up the
center hole and drill new bolt holes.

[Snag]

Post by b***@www.zefox.net

Post by Snag

Post by b***@www.zefox.net

Post by Jim Wilkins
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

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 .

[b***@www.zefox.net]

Post by Snag
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
.

[Snag]

Post by b***@www.zefox.net

Post by Snag
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
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
.

OK , if I understand correctly the 4 slot flange bolts to the pump
and the fan bolts to a surface that is hidden by the fan . Got a mill
and a boring head ? Is the current fan's base circle diameter big enough
to drill the bolt pattern of the new clutch ? I could adapt that fan to
that clutch in my shop .

[Jim Wilkins]

"Snag" wrote in message news:v0f1g9$3edci$***@dont-email.me...

OK , if I understand correctly the 4 slot flange bolts to the pump
and the fan bolts to a surface that is hidden by the fan . Got a mill
and a boring head ? Is the current fan's base circle diameter big enough
to drill the bolt pattern of the new clutch ? I could adapt that fan to
that clutch in my shop .
Snag

-------------------------

Two notches in the fan hole might get it over the flange without losing
centering. Does the clutch body size allow you to tilt the fan and slip an
edge of the hole into one of the slots to gain clearance?

Perhaps you could make an adapter disk on the lathe large enough to attach
to the fan with the proper center and mounting holes and rough out the fan
hole to a scribed line with hand-held tools, as I have to do to mount a
round meter in a panel too large for the mill. Also make a 1 or 2 piece
stepped plug to center the fan on the adapter plate and drill the matching
hole pattern before opening up the hole.

[b***@www.zefox.net]

Post by Snag
OK , if I understand correctly the 4 slot flange bolts to the pump
and the fan bolts to a surface that is hidden by the fan . Got a mill
and a boring head ? Is the current fan's base circle diameter big enough
to drill the bolt pattern of the new clutch ? I could adapt that fan to
that clutch in my shop .
Snag
-------------------------
Two notches in the fan hole might get it over the flange without losing
centering. Does the clutch body size allow you to tilt the fan and slip an
edge of the hole into one of the slots to gain clearance?

I think the answer is "yes", but the clutch centering boss is 2 5/8", while
the fan bore is 2 3/8". There's enough metal on the clutch to turn down the
centering boss to 2 3/8", if that runs true enough a new bolt circle on the
fan can be made with hand tools. If the new fan arriving today won't fit it
might be worth a try since the clutch will fit in my lathe.

Thanks for everyone's help!

bob prohaska

[Jim Wilkins]

Post by Jim Wilkins
Does the clutch body size allow you to tilt the fan and slip an
edge of the hole into one of the slots to gain clearance?

I think the answer is "yes", but the clutch centering boss is 2 5/8", while
the fan bore is 2 3/8". There's enough metal on the clutch to turn down the
centering boss to 2 3/8", if that runs true enough a new bolt circle on the
fan can be made with hand tools. If the new fan arriving today won't fit it
might be worth a try since the clutch will fit in my lathe.

Thanks for everyone's help!

bob prohaska
-------------------------------
Did I not explain that clearly enough? If you angle the fan until it
contacts the clutch body and can slide one edge of the hole into a notch on
the flange, the other side of the now offset fan hole may clear the flange
enough to pass over the high spot and let you remove the fan from the slot
and seat it in place.

[Leon Fisk]

On Tue, 23 Apr 2024 21:04:37 -0000 (UTC)
<***@www.zefox.net> wrote:

<snip>

Post by b***@www.zefox.net
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

[b***@www.zefox.net]

Post by Leon Fisk
On Tue, 23 Apr 2024 21:04:37 -0000 (UTC)
<snip>

Post by b***@www.zefox.net
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.

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

[b***@www.zefox.net]

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.

Thanks for everybody's patience!

bob prohaska

[Leon Fisk]

On Wed, 24 Apr 2024 04:11:21 -0000 (UTC)

Post by b***@www.zefox.net
I decided to order a fan from Amazon, based on a few words on
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.

[b***@www.zefox.net]

Post by Leon Fisk
On Wed, 24 Apr 2024 04:11:21 -0000 (UTC)

Post by b***@www.zefox.net
I decided to order a fan from Amazon, based on a few words on
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...
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.

I thought about a flex fan, but it would require yet more hardware
to reach the fan shroud. The fan from Amazon comes to $60, if it
fits, problem solved. If it does not fit maybe I'll reconsider...

Thanks for writing,

bob prohaska

[Clare Snyder]

Post by b***@www.zefox.net

Post by Leon Fisk
On Tue, 23 Apr 2024 21:04:37 -0000 (UTC)
<snip>

Post by b***@www.zefox.net
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.

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

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????

[b***@www.zefox.net]

Post by Clare Snyder
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????

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.

Now that I've got the pump in and fan on the clutch after a little freehand
file work I'll try to stuff it back together tomorrow to see what else
goes wrong....

Thanks for writing!

bob prohaska

[Leon Fisk]

On Sun, 28 Apr 2024 01:49:45 -0000 (UTC)
<***@www.zefox.net> wrote:

<snip>

Post by b***@www.zefox.net
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

[b***@www.zefox.net]

Post by Leon Fisk
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

Indeed, and note that they're used. Already have one of those 8-)

If the design permitted servicing I'd have been tempted to keep the
screw-on style. As a crimped assembly there's no obvious hope of repair,
even if wear parts like bearings and seals could be bought or adapted.
That's what motivated replacing the clutch along with the water pump.

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.

Thanks for writing,

bob prohaska

[Leon Fisk]

On Sun, 28 Apr 2024 19:10:30 -0000 (UTC)
<***@www.zefox.net> wrote:

<snip>

Post by b***@www.zefox.net
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.

You can buy both, water pump and fan clutch from Rockauto for $100 or
less depending on which variety you want. The only thing I couldn't
find there was the fan blade you needed...

In the description for the Screw-On clutch I previously linked to they
suggest buying their "kit" that contains the water pump, clutch and fan
blade. I doubt they sell many of those screw on clutches at that price😉

[Clare Snyder]

Post by b***@www.zefox.net
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

No idea what the clutch fits??