The Stovebolt Site Forums The Shop Area Engine Shop 2nd series 6 blade fan

Is anyone aware of a six blade fan for later 261 engines? I read posts where it is eluded to as an option, but cannot find any more info or pics.

I see them come up on eBay from time to time, but not very often. I have never found one at a swap meet or salvage yard.

I saw this one that sold that purpotedly was for a 261.

Fan

I saw some 6 blades for the later small block. Could I use that?

So it's either a 19 in. four blade or 18 in. six blade not using a shroud. I would like to hear what others are using on their 261.

Four blade fan with a shroud keeps my 235 cool.

I found a four blade 20 in. Hoping it helps.

Fans are just for idling/not moving. Needing bigger/more blades generally are not the fix for an overheat. But not sure of the mission objective.
I do read a clue "hope it helps" ??

FYI. Previous discussion on fans:
6 Blade Fan

The actual truth is there are three factors involving fan performance. None of which are "get a larger/more blade" fan. These factors are assuming, without a shadow of doubt, that you have a "necessary" shroud. "Necessary" if you have a cooling problem and can fit one.
1. Tip of blade to shroud clearance and depth into shroud.
2. Blade pitch angle
3. Distance from Radiator

An upgraded or re-cored radiator, a good water pump and proper thermostat are very important. A rusty clogged system/motor can't be cooled.

Lots of opinions and unsubstantiated BS from automotive electric fan companies.

Topical Tid Bit: Ceiling fans produce less air movement with more blades but are quieter.

A radiator fan is a static pressure style axial fan. Wiki says: Axial fans operate at specific speed i.e., high flow rate and low head and hence adding more blades will restrict the high flow rate required for its operation.

The confusion and false info is caused by hype, misunderstanding the many different types of fans and use requirements. Some users may mix up electric static pressure fans and air flow fans and their blade-to-flow characteristics.
In belt driven auto fans, shrouds and spacing are the trick with 4 blades. The clutches and flex o lite blades have no effect on cooling. They are for more engine power, better gas mileage, possible bearing wear savings at cruise speeds. Ram air cooling takes over at cruise speeds.

Great info Bartamos.

TF trucks 3/4 ton and larger with sixes had a heavy duty cooling option that included a larger radiator, a fan shroud and a 20" five blade fan with eccentric blades. I think it might have been stock on some of the larger trucks, but I am not sure.

The heavy radiators are about 1/2" thicker and 2" wider, but fit into the same mounting holes on the core support as the regular radiator. If you look at a standard radiator on a TF pickup, the mounting brackets on the sides are angled at about 45 degrees to fit the mounting holes on the core support. The ones on the heavy duty radiator are not angled to accommodate the wider core and tanks. The heavy duty radiator also has mounting clips for the fan shroud. The larger radiator was not offered on 1/2 ton trucks, but it does fit. US Radiator makes replacements either with standard size tubes or smaller tubes for even greater capacity. They are available with or without a transmission oil cooler.

The fan shrouds for the sixes are very hard to find, kinda like hen's teeth. Repops and originals can be found for the V8's, but not the sixes.

The five blade fans are hard to find, but they are out there. I have found two or three over the years when searching boneyards. All of the ones that I have found have been on big trucks. I have never found one on a pickup.

Here are a couple pictures of the five blade fan and shroud installed in my '57 3600 with a 261. As Bartamos pointed out, note that the exposed tips of the fan blades are key to making the shroud work.

http://s844.photobucket.com/user/ma...4868_zps1d3zlhee.jpg.html?sort=3&o=1

Here's a few pictures of the heavy duty cooling option with the five blade fan, shroud and larger radiator in a '57 6400 cement truck with a 261. That's the engine, fan and shroud that are now in my '57 3600 pictured in the above link.

http://s844.photobucket.com/user/ma...1172_zps8qvgngj2.jpg.html?sort=3&o=5

Matt

Matt, get out of Photobucket as fast as you can. It was a sinking ship. Now it's sunk. Maybe you can see your stuff but we can't. I have posted many times about this bad hosting company. Photobucket has left thousands and thousands of internet posts now worthless. Just a big black round speedo logo. Use something else or our own attachment manager. Maybe Photobucket will fix it someday.

Bartamos, we can keep preaching it but for some reason they just won’t listen. Guess they don’t want us to see their photos.

NOTE to EVERYBODY.....DO NOT POST PHOTOBUCKET LINKS HERE. The majority of us can’t see them. Use this sites image hosting procedures or a user friendly site like Google. Help us help you.

I’ll get down from the pulpit now. 🤨

I can see them. Maybe a settings thing for you guys? I no longer have a PB account and don't like PB but I can see them. I agree with Bart about using our own Attachment Manager. If you're not sure about how to use it click the link at the bottom left of any page.

I first see them 2-3 seconds before they are overwritten with PB stuff. Not enough time to really see what is being shown. I would like to see the shroud though. I have a PB account but have essentially abandoned it because they made it so unfriendly.

Dennis

My experience on all PB is the same as DennisM. I believe a lot of folks will have the same issue. It could be setting as Tiny says but I'm not going to investigate and change settings on my computer. (Tiny, I'm on Windows 8.1) I did not have a problem with seeing PB a few years ago. I wrote a greasy spoon about it recently. I never did like putting pix, with addresses that lead back to my computer, on there anyway. I trust the Stovebolt.

Attached are some of the pix mentioned in my post above. I can't attach all of them because we are limited to five pictures, so if you want to see more, you'll need to try the links and endure the pop-ups on PB.

I have a friend who is an excellent fabricator who specializes in making aluminum fan shrouds for hot rods. He has developed tools and techniques such as rolling the edge to allow the exposed fan tips to catch and channel more air just for making fan shrouds. He makes them for high end projects on the West Coast including doing the custom ones for SoCal Speed Shop.

A couple months ago, he was in my garage looking for ideas for a '56 big window that he wants to begin. He saw my factory shroud and scratched his head because he had never seen one before. I explained the high capacity option discussed in my above post. I also mentioned that there isn't one available for sixes with a standard radiator and that I occasionally see requests for them on Stovebolt, especially when someone is adding AC.

He took that as a challenge. Using my shroud as a guide and a spare standard radiator that I had laying around, he fabbed a shroud to fit the standard radiator and either the stock four blade 20" fan or the optional five blade 20" fan on either a 235 or 261.

I am going to install the shroud with a standard radiator this weekend so that we can test it.

When I have some results and pictures, I'll begin a new topic to share the info.

Matt

"I can't attach all of them because we are limited to five pictures, so if you want to see more, you'll need to try the links and endure the pop-ups on PB."

Just post 5 photos in different replies?

I fabricated a similar shroud as Matt's buddy. It made a hot running 235 engine run cool.

That's the proof we were looking for. Thanks Paul.

Thanks Matt for posting those pics.

I have been to Matt's house and seen his beautiful truck. He really has got some great ideas and is a great fabricator and motor builder. Not to mention a nice guy. Nice to know him.

P.S. Matt: I passed on the burb tank to someone who needed it. Thanks.