JRrev
Well-known member
Heard a sound and then vibration in my '72 Towncar. Yep, broken off fan blade. Fortunately, no other damage.
Widowmaker
- Thread starter Dave Mellor NJ
- Start date
Heard a sound and then vibration in my '72 Towncar. Yep, broken off fan blade. Fortunately, no other damage.
Model "A" Fords
Senior Member
While looking into fan problems years ago I called Bert's and Steve went through all the issues. Surprisingly he said the 1931 design also failed.
I owned a pile of fans but still ordered eight more including the 1931 design from Bert's stock of "decent looking ones". Steve cautioned me on actually using them.
To check them they were cleaned to bare metal. Most had visible cracks near the center hub while others were on the blades and around spotwelds. Once cut open, one previously oily one was still smooth while others had rust and pits including bulges caused by expanding rust. One pulley was quite worn as if the belt was too tight?
My car radiator was destroyed with a broken blade even though no crack was visible. Once separated a microscopic dark spot was visible on the edges where the break had initiated. At about 100 years old fatigue may not be visible even though the fan looks good.
I owned a pile of fans but still ordered eight more including the 1931 design from Bert's stock of "decent looking ones". Steve cautioned me on actually using them.
To check them they were cleaned to bare metal. Most had visible cracks near the center hub while others were on the blades and around spotwelds. Once cut open, one previously oily one was still smooth while others had rust and pits including bulges caused by expanding rust. One pulley was quite worn as if the belt was too tight?
My car radiator was destroyed with a broken blade even though no crack was visible. Once separated a microscopic dark spot was visible on the edges where the break had initiated. At about 100 years old fatigue may not be visible even though the fan looks good.
CT Jack
Well-known member
I am not completely familiar with the judging standards pertaining to Model A engine parts but it seems to me it would be very wise to relax the requirement for the 2 bladed fan and permit substituting it with a 2 bladed cast aluminum fan. This would help the purist to understand that safety is more important than originality. I have worked as an engineer in the field of high-performance gas turbine engine component development. These engines all utilize numerous rotating components called blades which have a limited amount of usable life. Once the life or safe usage cycle of these parts has been reached, they are discarded and replaced. The primary reason for replacement is the high potential of a blade breaking causing a catastrophic engine failure. The main mode of failure is caused by internal cracking within the metal and metal fatigue.
An original 80+ year old Model A fan is a sheet metal fabricated weldment. Welding in general produces very tiny internal cracks that are non-visible to the naked eye. Under normal engine use the blades flex or bend with the change in engine speed. Over time the small cracks can grow as the blades are continuously flexed. Once the crack growth reaches the point where the strength of the material is dramatically reduced, blade failure will occur.
An original 80+ year old Model A fan is a sheet metal fabricated weldment. Welding in general produces very tiny internal cracks that are non-visible to the naked eye. Under normal engine use the blades flex or bend with the change in engine speed. Over time the small cracks can grow as the blades are continuously flexed. Once the crack growth reaches the point where the strength of the material is dramatically reduced, blade failure will occur.
ModelA29
Well-known member
When I first joined the Cobra club a guy had a 66 GT350 that the fan had tossed a blade through the hood. Cheap enough to fix in 1975 but today an original HiPo fan is over $750 not to mention an all steel Shelby hood pulling 12 grand.... https://bringatrailer.com/listing/a...ll-1966-shelby-hoods-were-made-of-fiberglass/
Model "A" Fords
Senior Member
Sorry for the paranoia but this has become a more common occurrence. During a week long club event of approximately one hundred cars a blade destroyed a hood and a second pierced a radiator. Of all the cars less than fifteen were Model "A"s. Not a good average! Fatigue will only increase with time.
I spent a few hours on the internet looking for the aluminum fans and saw this ad at gaslightauto.com :
A-8600
$59.95
Two Blade Fan Assembly. USA. 4 cyl. each, 1928-34, shipping added when packed and weighed.
I didn't notice any reference to not in stock so I clicked to buy it. When I continued their standard note showed:
A hold will be placed on your credit card for order total, but not charged. Your full payment will be processed once your order ships for the total amount with shipping charge added. You will be emailed your paid invoice at that time. Please note that not all parts listed online are in stock. If you are concerned about availability, please call before ordering at 937-652-2145 or 1-800-242-6491 or email sales@gaslightparts.com
All other ads read not in stock. There was somewhere a reference date for new stock arrival but sorry I didn't think to write it down and I can't remember where it was. Surely someone on this sight has that information and will share it.
This was available at Snyder's. Along with the ad they discuss what fan to buy. Give them a call and they may know when the aluminum ones will come.
FAN PLASTIC/STEEL HUB
Part # A-8600-P | Model Year 28-31
This is a modern style fan for your Model A. It uses a black plastic blade and a machined steel hub. The blade bolts to the hub using four bolts. U.S.A.
$89.95 EA
Hopefully the new ones will be available soon.
I had heard about these incidents but assumed they were few and far between. Based on the small sampling we have here, this is NOT uncommon.
Very useful cautionary advice. Not just for our own cars but for the countless times we've stood over someone else's while the engine was revved.
Very useful cautionary advice. Not just for our own cars but for the countless times we've stood over someone else's while the engine was revved.
Bruce of MN
Well-known member
Any details on how to adapt a clutch fan and which one to use?
Pete
BANNED
I used to use one called "Fanomatic". They made models for most late model cars. I don't remember which one I used on an "A". It did require some machine work though.
That one had centrifugal weights that operated the fan disconnect and they were adjustable for RPM. There are some now that have a viscous type clutch. I don't think they are adjustable.
Synchro909
Well-known member
There is a company here that goes one better than an electric fan and thermostat. They make a setup that replaces the water pump with an electric unit that varies its speed according to the temperature of the engine. The same with the fan. All of that means that when running at any decent speed outside an urban area, the motor is not loosing power driving the water pump and generating more electricity for the fan than is absolutely necessary. That means more power for driving and less fuel.
A motor setup with a system like that has no fan belt because there is no constantly running fan. The front belt only drives the generator/alternator from the crank shaft.
As I have said before, my cars are drivers and the non original look doesn't greatly bother me. This sounds like a good arrangement, IMO.
stickshift
Senior Member
A setup like that works very well. My Prius has no belts, and an electric water pump. 350k miles and it has never been to the mechanic. I just do simple maintenance.
David in San Antonio
Well-known member
Synchro 909 - Name of company that does electric water pump and fan? Thanks from Texas (110 degrees F / 43 C yesterday)
Chris in WNC
Well-known member
that's remarkable.
Toyota should be using your car for an advertisement.
In a previous life I had a grandson who abused his Honda Accord severely but it kept right on going. His mom leased it for him new on his 16th birthday. He drove it like a maniac and probably only changed the oil every 50,000 miles if that. When it was traded a few years later, the Toyota dealer only gave them $100 for it- it looked like hell but was still running with over 200K miles. I thought this could have been a great opportunity for Honda to promote how bulletproof their cars are.
Without a picture, can someone describe the basic construction of the stock 2 blade widowmaker fan? Mine has been media blasted and inspected for cracks, but I read that is not enough. Are the blades formed around, past the center and overlapped/layered around the center tapered mounting hub?
Thanks!
Thanks!
Model "A" Fords
Senior Member
The propeller section is made from two pieces running the full length (outside diameter) of the fan. They are stamped from steel that's approximately 0.037" thick. They are formed to the propeller shape including the outer surface of the hub. When the front is combined with the rear piece they result in one double layer on each end of the blade that are spot welded together in a couple places to hold them together for the next step. Now the propeller ends are resistance welded around solid up to the point where the pieces part to form the outer hub.
The inner hub is made up of a stubby steel section that was machined with the tapered hole and key way.
The rear side of the pulley is formed including the inside hub. The front of the hub is resistance welded to the stubby steel part completing the hub.
The front section of the pulley slides from the front to the rear until it stops to complete the pulley shape then spot welded to the rear pulley.
With the hub and pulley assembled the propeller assembly is slipped over the hub until it bottoms against the front of the hub. Now the fully assembled fan is spot welded at the back of the propeller hub just in front of the pulley.
This leaves hollow sheet metal parts that have little integrity. These sections are prone to rust not easily noticed along with plenty of stress risers where cracks initiate.
I won't get into the late 1930 early 1931 improved one piece fan. It to had flaws and known to fail.
Sorry for the big ramble, I just realized I had the photographs which explains better than from my memory.
