Recommended Clutch Fan?

[tim_mc]

I went with this combo for my small block 350 with A/C:
Derale 17118: 18" fan, clutch type, 6-blade
Hayden 2705: Fan clutch, standard thermal, clockwise rotation

The 18" fan fits in the 4x4 shroud I'm using since my SBC is mounted in the 6-cylinder position. So far so good on the cooling.

[GASoline71]

I used the exact same combo as tim mc above, for my 1972 GMC C1500 with a SBC in the stock SBC location. Fits in the stock shroud perfectly and it all works flawless!

Gary

[FoxCustom]

Originally Posted by tim_mc

I went with this combo for my small block 350 with A/C:
Derale 17118: 18" fan, clutch type, 6-blade
Hayden 2705: Fan clutch, standard thermal, clockwise rotation

The 18" fan fits in the 4x4 shroud I'm using since my SBC is mounted in the 6-cylinder position. So far so good on the cooling.

Cool! Thank you for the info and feedback on the cooling.

Since I'm running a fan that's just over 19" now, I'm thinking this Derale 17119 standard rotation should work well in the stock shroud.
https://www.summitracing.com/parts/der-17119?rrec=true

[1968_K20_4x4]

Originally Posted by Stocker

Update, and I'll keep it brief. There are three types of thermal fan clutches -- standard duty, heavy duty, and severe duty. Good explanations / illustrations here: http://www.haydenauto.com/featured%2...s/content.aspx

My K20 uses a heavy duty unit but I could not find one. Virtually all are standard duty, and a very few are severe duty. Went to my local NAPA and another customer overheard us and suggested looking up the part for a slightly newer K30. Bingo! NAPA p/n 271303, fan clutch #2747. Made by Four Seasons in Lewisville, Texas.

Tom, I have to pass on yours. It is a standard duty and not recommended for my K20.

Hello Stocker,

I have a question for you regarding your fan clutch. How did you determine that your K20 required a heavy duty unit, as opposed to the standard duty one?

I am looking to install a clutch fan set up in my '72 K20 as well, and all my research so far has pointed me to the Hayden 2705 fan clutch (Standard duty) as being correct for my truck. Did you go with the heavy duty unit because your truck is an A/C truck?
Mine has no A/C and manual transmission.

I am looking to use the 18 inch Derale 17118 fan as mentioned above, but I am not sure if I should go with the 2705 fan clutch or the Heavy duty 2747 as you are running. I am setting up my truck to haul a 22ft camper trailer on occasion.

Thanks for any input!

[Stocker]

Originally Posted by 1968_K20_4x4

Hello Stocker,

I have a question for you regarding your fan clutch. How did you determine that your K20 required a heavy duty unit, as opposed to the standard duty one?

I am looking to install a clutch fan set up in my '72 K20 as well, and all my research so far has pointed me to the Hayden 2705 fan clutch (Standard duty) as being correct for my truck. Did you go with the heavy duty unit because your truck is an A/C truck?
Mine has no A/C and manual transmission.

I am looking to use the 18 inch Derale 17118 fan as mentioned above, but I am not sure if I should go with the 2705 fan clutch or the Heavy duty 2747 as you are running. I am setting up my truck to haul a 22ft camper trailer on occasion.

Thanks for any input!

You're on the right track! My K20 does have factory A/C. Also, the original fan clutch was a heavy duty unit. Interestingly, my local NAPA store listed only a standard duty unit for my truck, but their information was incorrect. Either fan clutch should work well for you, although towing your camp trailer *might* require additional cooling. I would also suggest considering a 7-blade fan. Mine is factory, and is quiet.

If you haven't already seen it, Hayden's website shows the differences between clutch types. https://www.haydenauto.com/en/produc...-types/thermal

[1968_K20_4x4]

Originally Posted by Stocker

You're on the right track! My K20 does have factory A/C. Also, the original fan clutch was a heavy duty unit. Interestingly, my local NAPA store listed only a standard duty unit for my truck, but their information was incorrect. Either fan clutch should work well for you, although towing your camp trailer *might* require additional cooling. I would also suggest considering a 7-blade fan. Mine is factory, and is quiet.

If you haven't already seen it, Hayden's website shows the differences between clutch types. https://www.haydenauto.com/en/produc...-types/thermal

Thanks for the reply and for that link- very good info there!

I think a 7 blade fan would be perfect for my truck, but when I did some looking I couldn't find one that specifically fit our trucks. Do you happen to have a part number for your factory original one that I could use to help me search?

[Stocker]

Originally Posted by 1968_K20_4x4

Thanks for the reply and for that link- very good info there!

I think a 7 blade fan would be perfect for my truck, but when I did some looking I couldn't find one that specifically fit our trucks. Do you happen to have a part number for your factory original one that I could use to help me search?

I couldn't find a number on my fan. Have been searching the web looking for a suitable fan, with limited success. I found one at Classic Industries that looks like mine, right down to the blade shape and rivet location -- but it doesn't appear to be asymmetrical (important for quiet operation). https://www.classicindustries.com/pr...B&gclsrc=aw.ds

Summit has this one https://www.summitracing.com/parts/oer-k193?rrec=true which looks like the one above. Might be worth a phone call to ask if the blades are evenly spaced (as pictured) or asymmetrical.

[1968_K20_4x4]

Originally Posted by Stocker

I couldn't find a number on my fan. Have been searching the web looking for a suitable fan, with limited success. I found one at Classic Industries that looks like mine, right down to the blade shape and rivet location -- but it doesn't appear to be asymmetrical (important for quiet operation). https://www.classicindustries.com/pr...B&gclsrc=aw.ds

Summit has this one https://www.summitracing.com/parts/oer-k193?rrec=true which looks like the one above. Might be worth a phone call to ask if the blades are evenly spaced (as pictured) or asymmetrical.

Thanks for those links, that 7 blade fan looks like it would work good. I appreciate the info!