FYI: 4106 Radiator Fans 6 blades vs. 8

OneLapper · May 13, 2010, 07:12:52 PM

These fans came out of two different 1964 PD4106s that happen to be only 102 serial numbers apart, both delivered new to Connecticut, both spent their lives in New England.

I didn't even notice the difference until they were side by side!!

My bus had the 8 blade fan, and I've never seen temps over 190 degrees. Interesting!

zubzub · May 14, 2010, 03:39:57 AM

unless you cleaned up the 8 blade I would guess the 8 is an upgrade from stock...maybe installed later?

chris4905 · May 14, 2010, 10:57:39 PM

Anybody know why the fan blades have a "notch" on all of the blade tips

zubzub · May 15, 2010, 01:10:30 AM

seems like a simple way to reduce blade flex/tune the blade. As the tips will turn faster than the middle. notching them stops them from distorting as a result of trying to move more air than the center? Maybe equalizing the flow over the entire fan area reduces turbulance/increases flow? 2 guesses from someone who has no idea.

OneLapper · May 15, 2010, 04:37:22 AM

Quote from: zubzub on May 15, 2010, 01:10:30 AM
seems like a simple way to reduce blade flex/tune the blade. As the tips will turn faster than the middle. notching them stops them from distorting as a result of trying to move more air than the center? Maybe equalizing the flow over the entire fan area reduces turbulance/increases flow? 2 guesses from someone who has no idea.

The notches in the fan allow it to fit closer to the core of the radiator.

Here's a pictures of the radiator and shroud.

Mrbill4108 · May 19, 2010, 05:17:32 PM

Anyone have one of those 8 bladed fans they want to get rid of/sell/swap?

Mrbillh

Lee Bradley · May 19, 2010, 05:25:27 PM

The title reminds me of the joke about the guy picking up a pizza. The pizza man asked if he wanted it cut into six or eight slices after a moments thought the customer said better make it six I'm not hungry enough for eight. Sorry back to your regularly scheduled discussion.

Barn Owl · May 19, 2010, 09:27:34 PM

Two ways to cool:

1. More fan blades. Cheaper and easiest of the two solutions. If you look at the charts for radiators, you see they rate their cooling by graph according to how much air flows over them. Down side is they eat hp/fuel for lunch.

2. Bigger radiator. Very costly, but the better of the two solutions if you can afford the upfront cost.

The 4106 came with a four core radiator, but there is enough room there to add three more, for a total of seven. If you ever re-core I would recommend the upgrade. If you ever put in an auto with the oil/water cooler you will probably not have a choice.