Six Blade 20" Fan

[Rustyshackelford]

In the cooling upgrade thread I read about a 6blade 20" fan upgrade. I'm interested in this can y'all help me with some questions?
1. Where can I get the fan
2. Is it direct fit?
3. Can I use the same fan shroud?
4. Any other info appreciated.

 

[Rustyshackelford]

I did some direct messaging of the people who mentioned this fan and I found out it is a Derale 17120. It is supposedly a direct fit and will work with the existing shroud.

 

[scottladdy]

Does anyone know the diameter of the stock fan?

Thanks ...

 

[ken]

I measured it at 19 inches. Here is a pic of the 20 inch 6 blade on my M1028. As you can see there is plenty of clearance with the shroud. It doesn't rub off road either.

 

[scottladdy]

Is it louder than stock? Notice a difference in airflow?

I wonder if their 19" 6 blade would be enough? Would keep the factory clearances.

Thanks!

 

[ken]

I haven't noticed it being really louder. You can tell when the clutch locks up though. My 82 GMC came from the factory with a 20 inch 7 blade fan like this one in the pic. The clearance is not a issue. It has not rubbed at all even when hauling firewood off road.

 

[Jozseph]

Is it louder than stock? Notice a difference in airflow?

I wonder if their 19" 6 blade would be enough? Would keep the factory clearances.

Thanks!

FWIW review the following articles / commentary / sales ad;

"9 Blade Fan and Clutch"

at https://www.kennedydiesel.com/fansclutches.html

"Cooling System Upgrade"

at: https://www.kennedydiesel.com/waterpumpkit.html

You may also get ideas from a sales ad / copy:

"6.5TD C/K Trucks > Cooling System Upgrades & Components > 6.5 Turbo Diesel Cooling Fan Upgrade (early)"

titled;

"6.5 Turbo Diesel Cooling Fan Upgrade (early)"

at http://www.ssdieselsupply.com/p2_6.5_turbo_diesel_cooling_fan_upgrade_early.html

Regards

Joseph

 

[ken]

I have purchased many parts over the years from Kennedy. But he is up in Wisconson and Not in 100+ deg temps towing heavy loads. He prefers 195 thermostats. I can understand that, being that far north. When the clutch fully engages A bigger fan with more blades will move more air. I swapped to a severe duty clutch. You can easily "adjust" any fan clutch by drilling a new pin hole and moving the roll pin that the bimetal strip hooks on. The civi engines with a/c were 7 blades and 180 thermostats for good reason. Running coolant temps above 200 is too close to critical temp. Look at all the scrap Humvee engines. Most diesels were run at 180 before we were worried about emmissions. They also lasted a lot longer. My 6.5 runs between 180 and 190 99% of the time now. I put too much money in it to chance cracking something at 215.

 

[dezertdemond]

What's the brand and part number of the 6 blade 20" fan? Was it a direct fit on the 4 bolt fan clutch in the m1009?

 

[scottladdy]

What's the brand and part number of the 6 blade 20" fan? Was it a direct fit on the 4 bolt fan clutch in the m1009?

Mentioned a few posts back:

I did some direct messaging of the people who mentioned this fan and I found out it is a Derale 17120. It is supposedly a direct fit and will work with the existing shroud.

 

[dezertdemond]

He said that it supposedly fits. Just trying to confirm before purchasing. From my research it appears that the clutch bolt pattern is 3.25" and the fan is double drilled for 3 And 3.5"

 

[ken]

Here is a pic of it on my truck. I didn't measure the bolt circle but it bolted right up.

 

[dezertdemond]

Perfect! Thank you. Just confirming that is an original fan clutch?

 

[ken]

It is the clutch I got from Oriley's. I told the parts guy I needed one for a 86 K30 with a 6.2. Severe Duty. It worked with no problems.

 

[ken]

Ok I just went out to the Garage and measured a fan clutch from a 1009 I pulled the engine from. The Bolt circle on that clutch is 3.25. It is a little thinner and smaller than the clutch on my truck. I suggest getting a severe duty clutch for it. I never noticed a difference since I replaced them together at the time. Sorry This was a difference I didn't know. This set up has worked well for me in the Texas heat.

 

[dezertdemond]

Great info and thanks for checking on that. This California heat along with the ats turbo heat it up pretty quick

 

[corelokt]

There is modification to the spring on it as well.
Basically you make the spring a little longer by straightening the end and bending it a little further out.

 

[ken]

Dez, Get you a Robert Shaw 370-180 thermostat also. You can also get a MR Gasket #4367 Thermostat. It's the same one. They are The balanced sleeve high flow type. With this fan, clutch and thermostat overheating will be a thing of the past.

 

[Rustyshackelford]

Well Ken is just a wealth of information here! Now all we need is for joeblow to finish the cooling kit.

 

[scottladdy]

There is modification to the spring on it as well.
Basically you make the spring a little longer by straightening the end and bending it a little further out.

One brand, Hayden, advertises 170 degree F. engagement temp. Supposedly 25 degrees lower than stock, although the 195 figure is not fully confirmed. This is for their 2799 severe duty clutch.