need advice...want extreme duty clutch fan for cooling

[rage'nrat638]

ok.....they did not offer h.d. or extreme duty fan clutch's in 69

i want the mother of all fan clutches.....

what year fan and clutch do i want to fit on my 69 and use the stock fan shroud......

any body been here?????

thanks mark

[gregsplace]

buy a clutch for a '87 454 suburban, truck, etc. That'll be exactly what you're after. Thats what I use(also what my 87 burb uses)

[rage'nrat638]

Originally posted by gregsplace
buy a clutch for a '87 454 suburban, truck, etc. That'll be exactly what you're after. Thats what I use(also what my 87 burb uses)

that will work with my 5 blade fan on the truck already???
thanks mark

[gregsplace]

yes, it'll work. Has alot of torque to it. Have to have a good alt. belt and pullies have to be in good shape,not worn to where there isnt any "V" left, otherwise alt. belt will squeal alot when accelerating hard. I use this fan clutch on all my BB trucks. I can take some pic's of it tommorrow if you like on 7-blade and 5 blade fans, Greg

[rage'nrat638]

THAT WOULD BE GREAT I WOULD BET THERE ARE SOME OTHER'S THAT WOULD LIKE TO SEE IT AS WELL....

looking for max cooling....running 4:11 gears 3/4 ton hauling a trailer....with the a/c blasting

is that a non thermal or thermal...fan clutch.....

maybe even a parts number would be great.....

thanks gregsplace

[gregsplace]

go to www.advanceautoparts.com search 87 454 burb/truck. yes, it's a thermal. cost $50 to $60. check with any of your local parts stores for that application, they should have it.

[68 Suburban]

What is the difference between thermal and non-thermal?

[rage'nrat638]

thermal is controlled by a spring activated by heat....
non-thermal in just a very stiff fan ......i think

[68 Suburban]

ok, which is better?

[68speedalert]

Dont' mean to step on toes, but if you put a MAX fan clutch on low pitch angled fan blade, you might as well buy a staight fan w/o any kind of clutch. The clutch will NEVER cycle out. You will sound like a jet plane going down the road and suck even more gas.

A non-thermal clutch just slips on higher rpms, no matter what the temp of the radiator coolant.

A thermal clutch senses the temp, locks up the clutch when it needs it. But you have to have enough resistance in the fan turning to force the silicon in the clutch to alow it to slip untill the temp calls for cooling.

You may not notice the fan noise on our trucks because the pitch is not very deep. The newer rear wheel drive vehicles operate llke this. When cold, you hear the roar of the fan. Engine runs a few minutes, fan noise cycles in and out a few times, Finally cycles out and stays out untill engine is HOT.

If your having problems overheating, you need to find a higher pitch fan blade and heavier clutch, maybe even a bigger radiator.

[rage'nrat638]

anybody else got something to add to this topic......

[69 air cab]

well..............about the time I thought I was catching on to this 68 SpeedAlert really gave me a good education. I too am wondering which way to go with my 69. Say Rage.........was the 5 blade OEM for the 69?..........I've heard it was 6 and even 7 blade. ALso I have had several people tell me not to use a flex fan because the rivits come out over time.

[gregsplace]

68speedalert is right about the fan pitches. The extreme duty fan clutches that I am referring to were used with 7-blade fans. I've used them on 6-blades too, but 7's are the best way to go. 5 blade fans usually were use on earlier 283's and 327's without all the assesories and had little fan clutches usually non-thermal( at least thats what I've seen, not saying that is 100%correct) Greg

[rage'nrat638]

WELL.......yes as far as i know it's the stock fan....looked at the LMC book and it's right there 18" 5 blade.....
i did learn someting about clutches......
i want a thermal type........
i can see where the pitch play's a part...not real sure how much...

talked to a instructor at UTI.....UNIVERSAL TECH. today and he said the same as 69speedaleart on the two types...
but added that i should have no problem...running the heavy duty clutch.....

so i took greg's advice on the model to get.....

fit's perfect.....87 sub. 4x4 454.....
so............this summer went i pull into indy..with the 85 on the trailer...and it sounds like a stelth bomber flying in,,, you will know who it is
and yes i did not really want to run a flex fan on the 69....
running one on the 638....because i feel i have too.
7200 RPM'S no problem's yet....

THANKS MARK

[rage'nrat638]

forgot the picture

[68speedalert]

rage'nrat638 said:

talked to a instructor at UTI.....UNIVERSAL TECH. today and he said the same as 69speedaleart on the two types...

That would be 68 speedalert. I save my 69ing for other things

Good move not to use a flex fan. You'll never have any problem running a heavier clutch than the fan can handle, except it will pull 100% air all the time. It sounds like that is what you want.

Glad I was able to cloud the issue, good luck!

For what it's worth, I have a 6 blade (I think) fan on ole yeller. It came off of a '68 Caprice if I remember right. It had a/c on it.

Steve