Aluminum Fan blade...Breaking...

Steve Plucker

Steve Plucker

BANNED
While on a tour this last weekend, one of the participants had a nice surprise...one of the fan blades made a clean break. Put a dent in the left side of his hood.

Has there been other reports of this happening?

Pluck
 
I had one break in the late 90's.I actually didn't know what happened until I opened the hood.I was flying along at about 60 or so and then all hell broke loose.I hit the key and the clutch at the same time,everything smoothed out.When I opened the hood I spotted it right off.I wasn't expecting to see the aluminum fan broken,it had only been on for a couple of years.I had bought it in the 70's though,so it came from either JC Whitney or Ricks.The casting at the break was full of air holes.We had a terrible time trying to break the other blade off so I could drive off.I saved the pieces,they are in a coffee can somewhere.I drove that truck the rest of the summer without any fan,just the pulley section of it.
 
Steve Plucker said:
While on a tour this last weekend, one of the participants had a nice surprise...one of the fan blades made a clean break. Put a dent in the left side of his hood.

Has there been other reports of this happening?

Pluck
Click to expand...

Hey Steve,
It would be interesting to determine the year made of this alum fan.
Early such fans were poorly made as to balance and / or mounting hole taper.
I've never heard of a newer made alum fan letting go of its blades.
 
Let me assure you that this was not a materials failure. This was an impact brake. Once I got the car home I discovers a large chunk of my upper radiator hose missing and a flat spot on the inlet pipe. So please don't remove you aluminum fan! The fan is not more than 5 years old and has only been on my car less than a year.



There is a story behind this break which illustrates the flexibility of the power train. I was towing a 1930 Pickup back to our base camp and as I rounded a sharp turn my back wheels slipped in the loose gravel. When they grabbed the road there was a sudden and significant pull on my trailer hitch which caused a flex in the power train lifting the front of the engine long enough for the fan to strike the radiator inlet pipe at a high RPM. The ensuing POP and bang and then vibration were the result of that sudden pull on the back of my Tudor.


For those who will ask, the front motor mount is original style with all the proper springs in place so there is the possibility of lift!
 

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Tonight I replace the broken fan with a good original 2 blade fan. I repaired the inlet pipe and replaced the upper hose with a good used unit I had. I have the same problem of clearance between the tip of the fan and the hose. I already have 6 rubber shims on each side of the radiator to raise it high enough to clear the fan. Currently I have about an 8th of an inch clearance. When I accelerate there is enough torque to raise the engine and the fan strikes the hose. If I add more shims than the fan belt will rub the lower hose. Any suggestions?
 

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I would check to make sure your front engine mount lower spring underneath the crossmember is compressed enough. Does the crank line up or is the engine high? Some of the front spring mounts allow the engine to sit up too high .
The service bulletins have the proper dimensions.

I have on occasion had to slightly bob a new repro fan but would never do that to an original. Remove the original and go back to a new repro aluminum.

Report back on mount to fan clearance. Post photos of front mount on top and bottom sides of crossmember
Larry shepard
 
I had a break in an aluminum fan but it wasn't a blade. A chunk of metal broke out of the key way groove, making it about twice the size it should have been. Sounded like a bad timing gear or bearing. Probably, my fault for not making sure the bolt was kept tight but could have been a bad casting. After having a cracked blade on my '31 Chrysler about the same time, I went to a plastic fan on the "A" and have felt comfortable and safe with it since. Too many stories about broken blades and the damage they can cause.

Glen
 
I used the Plastic Fans, but on here, I heard of one breaking a blade. I "think" one broken blade would be "driveable", until you could get home???
Bill W.
 
It is / they are casting from crummy Aluminum and will fail from abrasion.
Any aircraft repair station has the dye penetrating fluids too check them,...which isn't a
bad idea!
Did the other blade show signs of hitting the hose?
 
There were some after market 28-29 radiators that the upper hose connection was at a too low angle. Under certain conditions the fan blades would hit the upper radiator hose and I could hear the sound . I soon found the problem and removed about an inch from each end of the fan blades and rebalanced the fan , before any real damage ocured . The radiator was very slightly used when I bought it. I'm pretty sure that some of these radiators are out there and still in use. I won't say who I think made these 28-29 radiators because I didn't buy it direct from the maker. If the fan continues to strike the upper hose it could cause problems with the fan blades .Slightly shortening the fan blades will reduce the horse power draw and the fan will still do its job . The fan is only needed at idle and speeds below 25 MPH
 
Many years ago (about 1960) I was driving my '30 Tudor on the Wilbur Cross Highway in CT at about 55 mph when a loud noise occurred followed by a violent shaking of the whole front end of the car. Came to a screeching halt, opened the hood and found that one blade of an original two-blade fan had broken off, cutting the radiator hose (lots of steam), putting a big divot in the top of the hood and taking a small slice out of the radiator. I taped up the hose with friction tape, cut off the other blade, put some chewing gum on the radiator and nursed it the rest of the way home to MA. An exciting trip!! Model A's are tough old birds!!
 
Castings like the aluminum fan can have internal defects not detectable by dye penetrant inspection. Dye penetrant inspection is for surface defects such as a crack in progress.



A crack in a casting will have less time to failure than in a non-cast part.


There is such thing as a good original fan because it is impossible to determine its remaining structural fatigue life.



In my opinion, Dave Wilton's plastic fan with its steel hub is the 2nd best there is for the Model "A" and Model "B." An electric fan is the utmost!
 

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Is it just the photo in post 13? Sure looks like that fan is installed backwards on the hub.

From the "Twilight Zone".
 
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I bought an aluminum 2-blade fan off of eBay many years ago. I've never
put it on a car. The blade castings just don't look right: they are not concentric (can't think of a better word?) to each other and the whole fan
looks unbalanced.:eek: I believe the fan was unused and will stay that way.;)


Bob-A:D
 
I am running an aftermarket radiator I bought at a swap meet in the mid 1980's I think I have always had this problem but I used to run the 4 bladed fan and they had shorter blades. It wasn't until I switched to the 2 blade fan that I started having the trouble. It is likely a bad radiator design. Thanks.
 
Purdy is right about those after market radiators having the incorrect angle in the top inlet pipe. I know, MY 28 Tudor had one. When I changed from a 4 blade fan to a new aluminum 2 blade fan, I had to add shims to the radiator to get sufficient clearance for the new fan. Fortunately I replaced the radiator recently with a new heavy duty one from Brattons. No more shims, outlet pipe on radiator lines up perfectly with outlet pipe on the head. Problem solved.
 
gibbdo said:
Tonight I replace the broken fan with a good original 2 blade fan. I repaired the inlet pipe and replaced the upper hose with a good used unit I had. I have the same problem of clearance between the tip of the fan and the hose. I already have 6 rubber shims on each side of the radiator to raise it high enough to clear the fan. Currently I have about an 8th of an inch clearance. When I accelerate there is enough torque to raise the engine and the fan strikes the hose. If I add more shims than the fan belt will rub the lower hose. Any suggestions?
Click to expand...

Just does not sound right with the clearances you are indicating! Is this an original Radiator? Is the front motor mount properly set up? Shimming is masking something else here!
 
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