General Dentside Chit-Chat

[NOCO77]

I will be driving mine through the winter and maybe do some simple things to it.

Damn I'd like to just finish mine so I COULD drive it this winter! All stripped down and too many chunks in cheap primer to go puttin' lights and mirrors back on it, and risk letting corrosion set in under the cheap primer. I want to get back onto it now that I'm back to work - its nearly ready for color.

 

[LEB Ben]

Good to see ya post up again Brad...does that mean it's getting too cold to be outside?

 

[LEB Ben]

Hey fellas...been meaning to ask this. When I swapped over to the 400 in the Bronco, I used the fan that was on the old 351M...it was a 6 blade fan that had slots that bolt to the water pump pulley. The one that was on the 400 was a 5 blade fan and has a 'spacer' to bolt to the WP pulley. Can someone explain the differences, and which would you use:

The one I am using:

The 5 blade:

and the pulley it mounted to:

I figured more blades equaled more flow??????

 

[1985 Ford F-150]

Well ones a clutch fan and the others a flex fan for one thing. I always ran flex fans just cause they were easier and I didnt have to worry about the clutch goin out. In your case it really wont make a differnce till ya buy a fan shroud.

 

[LEB Ben]

Well ones a clutch fan and the others a flex fan for one thing. I always ran flex fans just cause they were easier and I didnt have to worry about the clutch goin out. In your case it really wont make a differnce till ya buy a fan shroud.

Thanks Dan...guess I better go do some research, cuz I've never really known the difference. As for the fan shroud...I know I should have one, but I haven't had any cooling problems...the highest temp it ever gets to is right around 185*...but usually stays at 180.

 

[1985 Ford F-150]

More blades will move more air but the fan clutch just keeps it from goin as fast as the motor revs.

 

[LEB Ben]

Alright...thanks Dan. So the clutch is the big silver thing, and allows slippage at speed?


If anyone feels like posting the cliff notes version, I'd appreciate it.

 

[1985 Ford F-150]

Yeah thats what it is. If youve ever reved the 351 while your under the hood then youll hear the fan pushin air change pitch with the motor rpm. A clutch fan wont do it as much.

 

[DNFXDLI]

There is a silicone fluid in the center that heats up as the engine heats up...that in turn causes a bimetal spring to move out and causes the fan to turn faster. Even when the engine is cold the fan will turn...just nowhere as fast as the pulley is turning...and as far as I know with those kind, it never does turn at the same speed as the pulley, there is always a little lag. Overall will use less power to turn it when the engine doesn't require fan cooling..eg...out on the highway just driving normally.

 

[LEB Ben]

There is a silicone fluid in the center that heats up as the engine heats up...that in turn causes a bimetal spring to move out and causes the fan to turn faster. Even when the engine is cold the fan will turn...just nowhere as fast as the pulley is turning...and as far as I know with those kind, it never does turn at the same speed as the pulley, there is always a little lag. Overall will use less power to turn it when the engine doesn't require fan cooling..eg...out on the highway just driving normally.

Thanks Duncan...exactly what I was looking for. Learned something new today, thanks fellas. I just always thought it was either clutch fan or efan...and never knew the differences between a clutch/flex fan.

 

[1985 Ford F-150]

Yeah I just prefer the flex fans.

 

[UNRULEE]

I've been through many cooling set-ups, the stock spacer and fan, Taurus electric fan, flex fan, and the stock fan with a stock fan clutch.

I never thought of it but i spent a lot of time/money on my cooling issue.

What works best, and what's on the truck for good? Stock fan and fan clutch with the "correct" thermostat.

 

[m78]

Mine has the flex fan. I wonder if it has something to do with what gearing determined what fan .

 

[LEB Ben]

Great input Lee.


And I got to thinking about the amount your oil pan holds. Since you said yours holds 7 quarts, I have noticed a few places that said the econolines of the era had 7qt pans. Dunno what engines came in the e-lines, but if they came with a 335, any chance of a swapped pan some time in the last 30 years?

 

[LEB Ben]

Mine has the flex fan. I wonder if it has something to do with what gearing determined what fan .

Sooooooo...you're saying a flex fan or a clutch fan were both available from the factory?

 

[UNRULEE]

Great input Lee.


And I got to thinking about the amount your oil pan holds. Since you said yours holds 7 quarts, I have noticed a few places that said the econolines of the era had 7qt pans. Dunno what engines came in the e-lines, but if they came with a 335, any chance of a swapped pan some time in the last 30 years?

I doubt it, but who knows? I bought the truck wth 38,000 original miles on it from the second owner, and the second owner was real good friend's with the first owner. The seller swore up and down that the truck was stock (and it was EXTREMELY stock), and there where no real signs of any major wrenching on it. That being said it seems that every oil change I can go through 1-2 quarts before the next one. Maybe I should experiment with 6 quarts and see if the comsumption goes down.

Sooooooo...you're saying a flex fan or a clutch fan were both available from the factory?

I think all that was availible was the fixed fan and spacer or the fixed fan and clutch.

 

[m78]

I think all that was availible was the fixed fan and spacer or the fixed fan and clutch.

Thats what I meant

 

[Ranger429]

There is a silicone fluid in the center that heats up as the engine heats up...that in turn causes a bimetal spring to move out and causes the fan to turn faster. Even when the engine is cold the fan will turn...just nowhere as fast as the pulley is turning...and as far as I know with those kind, it never does turn at the same speed as the pulley, there is always a little lag. Overall will use less power to turn it when the engine doesn't require fan cooling..eg...out on the highway just driving normally.

Correct, there are two types of fan clutches, centrifugal and thermostatic. You have described the thermostatic. A centrifugal fan clutch spins faster with higher RPM's untill it starts to free spin.

 

[LEB Ben]

Damn fellas, I swear if it weren't for bad luck, there would be no luck at all. I started out on my trip back to school yesterday, and about an hour into it I hear a decent thud...turned out being my alternator belt flying off. Luckily, there was a parts store about 10 miles up. I get there, get a new belt. Head back out to put the belt on...low and behold, the head apparently sheered off the lower bolt on the alternator bracket that goes into the block. Luckily, there was still enough there to get a vice grips on it, and I had a spare bolt. But daggon, Murphy must really like me...I mean seriously, what are the odds.

 

[1985 Ford F-150]

Hmm never heard of that happenin before maybe it was just a weak bolt.