The Oddfire Code

Ladies (please say there are some ladies here) and gentlemen: I believe we may have a decades-old automotive mystery on our hands, one tied to a certain balancing act that must be achieved by every internal combustion engine: The yin of the heat-generating explosion inside the cylinders must be countered, perfectly, by the yang of the fan and radiator's cooling effect.

All of which is a very long way of saying the Jeep (Buick) Dauntless V6 has both a distributor and a fan.

As we know, the Dauntless V6 does not fire its six cylinders evenly. There are longer pauses between some cylinder sparks than between others.

Now observe the cooling fan I recently removed my own Dauntless V6. The six blades are not spaced evenly. There are larger gaps between some blades than between others.

Why? Could this be some Buick or Jeep engineer or designer's inside joke -- a design cue that echoes the engine's inner oddness?

(Probably not, I admit. But why not space the blades evenly?)

 

Pretty sure that isn't a stock fan though. Most of these came with a standard GM 4 bladed fan.

 

That's no fun! (I have seen those four-blade fans in several photos, though.)

 

Mine looks exactly like that, and it's the original "heavy Duty" cooling fan.

 

Never seen a fan like that, only 4 or 5 blades.

 

I saw many vehicles running fans with unequal spaced impeller/vane changing fan belts. I first recall them when the fans with the clutch made an appearance. I worked in service stations back in the 70's and these were common. Boss said the unequal blade spacing reduced fan blade noise, particularly "chopping sounds" that ocured at certain rpm's. , I was....

 

look closer at the center hub.

 

Besides the 4 blade fan, I think these 2 were optional fans for the V6......

 

yep, for noise..

 

Mine's the 5-blade like Zoomer posted.

 

Zoomer's five-blader is crazy! Seems like it would be tough on bearings, but what do I know? (And maybe there is thicker metal on side to balance the weight?
Anyway, the noise-reduction/noise alteration theory makes sense. Which means they really are "oddfire" fans, just not for the reason I was hoping.

 

I had the 4 blade on the 71 and the 5 blade on the 67. The Orange tips keep the black paint from slinging off.

BTW.. I sold this to someone on this site about 8-10 years ago. Wonder where it is today...

 

Vintage mid sixties motors?.............don't think I've ever seen anything but a 4-blade on a factory Odd-fire?........maybe later in the Even fired era?

 

mine came with a 4 blade like Mark posted, but now it has a 4 blade off a junkyard Buick. The tips are rounded.

 

This is all further evidence of just how mix-and-match my Jeep is.

 

My Tux has the zoomer 5 blade and it's original.

 

Someone please paint a face, hands and feet on one of the five-blades.

 

I have 2 V6's 67 and 68. Both have the Zoomer 5 blade. I'm glad they have space. I figured was for access to the fan bolts? Naw engineers wouldn't do that. I know cause I is one.

 

I have yellow stripes on mine. Always wanted to be a pilot.