Fan clutch bushing question

[71DodgeDemon340]

That brass bushing that goes in the fan clutch to help center it on the water pump snout is it supposed to be slightly longer than the hole in the clutch itself? I just noticed it while mocking up my aluminum pulleys. The bushing has a split down the length of it but with it sitting in the fan clutch it protrudes about 1/16” maybe a little less. Does it mash flush when tightened up? I had it bolted up before to the steel pulley and didnt notice any issue. When the clutch is tightened up does it mash the brass bushing in and that split there for a relief when it gets tightened up?

 

[Hemioutlaw]

It's fine as long as where it mounts sits flush.

It's split to make up for the tolerance in shaft diameter.....IE: if it wasn't split it might not fit on the shaft.

 

[71DodgeDemon340]

It mates to the pulley but if you lay the fan clutch face down on the table and put the brass bushing in the pilot hole you can see the brass bushing sticks up some from the fan clutch, if you set the pulley on the fan clutch shaft the brass pushing allows the pulley to rock back and forth

 

[Scamp Rhonda]

It mates to the pulley but if you lay the fan clutch face down on the table and put the brass bushing in the pilot hole you can see the brass bushing sticks up some from the fan clutch, if you set the pulley on the fan clutch shaft the brass pushing allows the pulley to rock back and forth

I need a new fan clutch also. Where did you get yours? As far as the bushing goes I would try grinding a little bit off. But first I'd put it together and see if the brass bushing would crush down to make a tight fit. I'd like to know the outcome here because like I said, I've gotta do the same. Steve

 

[Hemioutlaw]

It mates to the pulley but if you lay the fan clutch face down on the table and put the brass bushing in the pilot hole you can see the brass bushing sticks up some from the fan clutch, if you set the pulley on the fan clutch shaft the brass pushing allows the pulley to rock back and forth

Is your setup similar to this one?

This pic is of my old clutch fan setup prior to replacing the rad and going with the Compact Hayden 2765.

If I recall on mine I thought that the bushing was actually a little too short and I installed it on the shaft and then mounted the clutch fan.

 

[AJ/FormS]

If it rocks when mounted on the pulley, then it is too long. If it doesn't sit flat, then it will wobble at speed.It cannot crush when it hits the bottom of the hole. if the mounting flange is stepped, then it only has to be no taller than flush to the outter ring.

 

[71DodgeDemon340]

If it rocks when mounted on the pulley, then it is too long. If it doesn't sit flat, then it will wobble at speed.It cannot crush when it hits the bottom of the hole. if the mounting flange is stepped, then it only has to be no taller than flush to the outter ring.

thats what i was thinking too, i never noticed it until now. it is barely sticking above the flange.

 

[Mattax]

Found the same thing. I didn 't like the 2947 clutch's reducer bushing. It sits proud of the casting. It's also a little loose.

I turned my own reducer bushing in case need to use that clutch unit.

The other thing I didn't like is how tight it is to get it mounted. With screws long enough to get 4+ threads to bite, its a PIA.

 

[famous bob]

thats what i was thinking too, i never noticed it until now. it is barely sticking above the flange.

View attachment 1715469487

Cur that to where it sits flush --but dont go any more .

I have an extra reg fan clutch , like the one pictured if anybody needs it --------------cheap. u pay shipping also.

 

[Mattax]

2705 is another option. Shorter than the P-part clutch but longer about .3" longer overall than the 2947

 

[mopowers]

thats what i was thinking too, i never noticed it until now. it is barely sticking above the flange.

View attachment 1715469487

Touch it on a belt sander and it'll be fine.

 

[71DodgeDemon340]

My dad took it to his work today and touched the bushing with a DA and some 80 grit paper, finished it off with 320 grit, he also laid a straight edge on the clutch and made sure it was flush.

i have a question though, because the aluminum pulley is thicker than the steel with the aluminum pulley slid on i had maybe 1/8” of water pump shaft sticking out, this should be enough for the bushing to contact right? After all it only centers the fan clutch. I spun the pulley and fan after i tightened it up and everything looks straight and no wobble. I should be able to start it tomorrow and really get a eye on it

 

[Scamp Rhonda]

2705 is another option. Shorter than the P-part clutch but longer about .3" longer overall than the 2947
View attachment 1715469507

View attachment 1715469508

View attachment 1715469509

Mattax, can yo tell where you got the Hayden 2705 from? I'm finding conflicting info on amazon. It says it doesn't fit my 72 Scamp.
Hayden Automotive 2705 Premium Fan Clutch https://www.amazon.com/dp/B000C3BAXQ/?tag=fabo03-20
I'm trying to find one that is narrow enough to fit my car which the original is 2.5" total width. Your measurement on the 2705 was just under 3 1/8". That would be fine and that looks like the one I want. Just trying to make sure be fore I order it.
Thanks Steve

 

[Mattax]

Bought both the Hayden's from Rockauto. If my locally owned store was still in business I would have bought from them, but they're gone.

Interesting that you're not finding an application reference. I took a lot of notes from an on-line Hayden and Four Seasons catalogs. (Turns out when I called them that they are both essentially the same company). Then made little drawings and bought the ones that seemed most promising.

If my notes are correct, the Hayden catalog showed.
1968-73 340 => 2707 thermal, 17107 non-thermal, 2747 Heavy duty
1968-73 318 => 2706 thermal, 1706 non-therrmal, 2747 Heavy Duty

But IIRC what happened is that I noticed the Four Seasons catalog had a listing for 1969 340 non-thermal clutch. When I called, they told me was equivalent to Hayden 1705 (Four seasons 36949). Then got the other cross references as well which is how I decided to try the 2705. My car probably has a little less room because it has the longer '70 up style water pump with the earlier bubble top style radiator.

The thermal units have the bimetal coil. Check the shop manual on whether your application should have it or not.

The catalogs say overall hts, and distance from pulley to fans are:
2706 3.3", 1.75"
2747 3.3", 1.62" (fan is closer to pulley)
2705 3.1", 1.53" (clutch shorter and fan closer to pulley)

I think I have another page of clearer notes in the to be filed pile...

 

[Scamp Rhonda]

Bought both the Hayden's from Rockauto. If my locally owned store was still in business I would have bought from them, but they're gone.

Interesting that you're not finding an application reference. I took a lot of notes from an on-line Hayden and Four Seasons catalogs. (Turns out when I called them that they are both essentially the same company). Then made little drawings and bought the ones that seemed most promising.

If my notes are correct, the Hayden catalog showed.
1968-73 340 => 2707 thermal, 17107 non-thermal, 2747 Heavy duty
1968-73 318 => 2706 thermal, 1706 non-therrmal, 2747 Heavy Duty

But IIRC what happened is that I noticed the Four Seasons catalog had a listing for 1969 340 non-thermal clutch. When I called, they told me was equivalent to Hayden 1705 (Four seasons 36949). Then got the other cross references as well which is how I decided to try the 2705. My car probably has a little less room because it has the longer '70 up style water pump with the earlier bubble top style radiator.

The thermal units have the bimetal coil. Check the shop manual on whether your application should have it or not.

The catalogs say overall hts, and distance from pulley to fans are:
2706 3.3", 1.75"
2747 3.3", 1.62" (fan is closer to pulley)
2705 3.1", 1.53" (clutch shorter and fan closer to pulley)

I think I have another page of clearer notes in the to be filed pile...

Bought both the Hayden's from Rockauto. If my locally owned store was still in business I would have bought from them, but they're gone.

Interesting that you're not finding an application reference. I took a lot of notes from an on-line Hayden and Four Seasons catalogs. (Turns out when I called them that they are both essentially the same company). Then made little drawings and bought the ones that seemed most promising.

If my notes are correct, the Hayden catalog showed.
1968-73 340 => 2707 thermal, 17107 non-thermal, 2747 Heavy duty
1968-73 318 => 2706 thermal, 1706 non-therrmal, 2747 Heavy Duty

But IIRC what happened is that I noticed the Four Seasons catalog had a listing for 1969 340 non-thermal clutch. When I called, they told me was equivalent to Hayden 1705 (Four seasons 36949). Then got the other cross references as well which is how I decided to try the 2705. My car probably has a little less room because it has the longer '70 up style water pump with the earlier bubble top style radiator.

The thermal units have the bimetal coil. Check the shop manual on whether your application should have it or not.

The catalogs say overall hts, and distance from pulley to fans are:
2706 3.3", 1.75"
2747 3.3", 1.62" (fan is closer to pulley)
2705 3.1", 1.53" (clutch shorter and fan closer to pulley)

I think I have another page of clearer notes in the to be filed pile...

Thanks so much for all that information. I have a 318 with air conditioning so I don't know if that makes a difference. Probably? Amazon didn't have much info. I should have checked out Hayden site first. Do you know what difference is between a thermal clutch and a non thermal clutch? Mine is thermal oem. I think I am going with the 2705, it looks like it will be about 3/4" closer to the radiator than the original. Again thanks much. Steve

 

[Icetech]

My dad took it to his work today and touched the bushing with a DA and some 80 grit paper, finished it off with 320 grit, he also laid a straight edge on the clutch and made sure it was flush.

i have a question though, because the aluminum pulley is thicker than the steel with the aluminum pulley slid on i had maybe 1/8” of water pump shaft sticking out, this should be enough for the bushing to contact right? After all it only centers the fan clutch. I spun the pulley and fan after i tightened it up and everything looks straight and no wobble. I should be able to start it tomorrow and really get a eye on it

@71DodgeDemon did you ever have any issues with that setup? I have the same thing.. Aluminum pulley with a hayden clutch and due to the pulley thickness the clutch barely engages on the pump snout.. Almost thinking of trying to find a steel pulley to make it safer. Was just curious if you had run it and no issues after a few years.. thanks

P.S. your mailbox is full

 

[71DodgeDemon340]

Hey sorry been mia lol. Yes it has worked flawlessly, no issues with it even up to 5000 rpm lol

 

[CRUZE 418]

I have the Hayden 2947 on my '72 318 with A/C.

 

[famous bob]

That brass bushing that goes in the fan clutch to help center it on the water pump snout is it supposed to be slightly longer than the hole in the clutch itself? I just noticed it while mocking up my aluminum pulleys. The bushing has a split down the length of it but with it sitting in the fan clutch it protrudes about 1/16” maybe a little less. Does it mash flush when tightened up? I had it bolted up before to the steel pulley and didnt notice any issue. When the clutch is tightened up does it mash the brass bushing in and that split there for a relief when it gets tightened up?

I turned mine down to fit exactly...jfyi

 

[CRUZE 418]

Boy, you guys had me going! I thought, damn, I have 2 #2947's on running cars, and this one not on the running Hemi yet. So I checked it, sure enough, it does protrude out a bit. Well, the water pump shaft has a little bit of a recess around it. I put it on by hand, it fits perfectly. So then I checked the shaft on a small block water pump, same thing. I do not see any reason to be modifying the bushing.