Fan clutch bushing question

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71DodgeDemon340

71DodgeDemon340

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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?
 
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.
 
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
 
71DodgeDemon340 said:
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
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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
 
71DodgeDemon340 said:
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
Click to expand...

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.

69'Cuda Unmothballed OEM Rad 12.15.19-7.jpg
69'Cuda Unmothballed Radiator 1.19.20-3 (2).jpg
 
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.
 
AJ/FormS said:
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.
Click to expand...

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

EA17071B-0F40-49A0-BC5E-DE8924C98CDA.jpeg
 
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.
upload_2020-2-13_8-42-57.png


Fanclutch-Hayden2947-11.JPG


I turned my own reducer bushing in case need to use that clutch unit.
Glenray68-70b-032.JPG


Glenray68-70b-033.JPG

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.
 
2705 is another option. Shorter than the P-part clutch but longer about .3" longer overall than the 2947
upload_2020-2-13_8-58-36.png


upload_2020-2-13_9-1-2.png


upload_2020-2-13_9-2-11.png
 
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
 
Mattax said:
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
Click to expand...
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=joeychgo-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
 
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...:rolleyes:
 
Mattax said:
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...:rolleyes:
Click to expand...
Mattax said:
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...:rolleyes:
Click to expand...
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
 
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