Fan came apart!!

L

Lee Mitch

Senior Member
First time posting on this side of FB as I am a Model A guy.


I picked up this pretty nice stock '39 pickup a little over a year ago and just got it back on the road. Test drive #2 and the metal fan blew apart and really caused some ugly damage. I've heard of this happening in Model A's, so that it why some of us put on those ugly plastic fans.
The previous owner had upgraded to a 12V system and I think that is where the problems began.



I need your help. When switching to a 12V system, is there a conversion kit that includes a fan and spacer that attaches to the new alternator? Is this sold as a complete unit? I don't know where to start on this and could use some ideas, perhaps some vendors and or parts numbers.



Give me your ideas guys! Thank you!
 

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I hate to hear that this happened to you, but the damage in this picture is an absolute badge of honor that I would have to leave AS IS!! DD


436187
 
>>>is there a conversion kit that includes a fan and spacer that attaches to the new alternator? Is this sold as a complete unit?>>>


Maybe. But I made my own 10si/12si adapter to accommodate the original gen-mounted metal fan just like yours. Ran it for a short while. Then decided 'Nope, the risk is too great'. Currently running without a fan. But plan to mount a shrouded 14" electric just in case it gets too hot. 8^)



Jack E/NJ
 
>>>Just got it back on the road>>>


dd>>>this picture is an absolute badge of honor that I would have to leave AS IS!>>>


Agreed. Sort of like a christening including the radiator if it doesn't leak. If it were mine, I'd have to leave it be. Maybe touch up the bare metal spots with a bit of rust-oleum reformer to keep it from rusting and the paint from peeling further. Jack E/NJ
 
Thanks Jack. I was thinking electric plastic fan too, but ugh that is ugly. I would take it over what happened though.


The radiator got completely trashed. Not salvageable.


No way will I leave the side panel like it is. The rig is too nice to have that awful looking mess! It just wouldn't fit the rest, plus i lean heavily towards OCD. :)
 

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Lee Mitch said:
First time posting on this side of FB as I am a Model A guy.


I picked up this pretty nice stock '39 pickup a little over a year ago and just got it back on the road. Test drive #2 and the metal fan blew apart and really caused some ugly damage. I've heard of this happening in Model A's, so that it why some of us put on those ugly plastic fans.
The previous owner had upgraded to a 12V system and I think that is where the problems began.



I need your help. When switching to a 12V system, is there a conversion kit that includes a fan and spacer that attaches to the new alternator? Is this sold as a complete unit? I don't know where to start on this and could use some ideas, perhaps some vendors and or parts numbers.



Give me your ideas guys! Thank you!
Click to expand...

It looks like the fan in your picture #4 has been modified from its original construction, based on seeing hex head bolts and slotted round head screws holding blades to center hub. The stock construction of these early Ford V-8 fans had rivets holding blades together and blades to hubs.

Question: Was this fan mounted to the front of the crankshaft, or to the pulley on front of alternator?
 
Thanks John. I thought it was modified, but not certain. It was mounted to the front of the alternator on a very small belt pulley. I think that was the problem as it was maybe 2" in diameter, turning the fan much too fast. This is just a guess, as I have never seen what a correct one should look like.
 
Lee Mitch said:
Thanks John. I thought it was modified, but not certain. It was mounted to the front of the alternator on a very small belt pulley. I think that was the problem as it was maybe 2" in diameter, turning the fan much too fast. This is just a guess, as I have never seen what a correct one should look like.
Click to expand...

Actually improperly mounting of fan blades to hub, and the increase in fan speed when mounted the assembly to the smaller diameter alternator pulley, could have both contributed to cause of failure. Also, the front bearing in an alternator was not necessarily designed to carry the additional load of having a fan mounted to its pulley. Some folks get away with doing these types of fan mountings, while others experience unfortunate catastrophic failures. I am very sorry to see what happened to your nice looking '39 pu truck.
 
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Wow thats a real mess alright ,I don't do them now but have done a few alternator into Ford cases and I always used the Ford front bearing the two tapered rollers back to back ,sorry I don't have a fan one to show you ,I don't trust the ones they stick on a stock alt .
 

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JM 35 Sedan said:
Actually improperly mounting of fan blades to hub, and the increase in fan speed when mounted the assembly to the smaller diameter alternator pulley, could have both contributed to cause of failure. Also, the front bearing in an alternator was not necessarily designed to carry the additional load of having a fan mounted to its pulley. Some folks get away with doing these types of fan mountings, while others experience unfortunate catastrophic failures. I am very sorry to see what happened to your nice looking '39 pu truck.
Click to expand...


John's got it right on all counts. For all those thinking how great it would be to have an alternator, Read John's post again.
 
I also agree with John's assessment. There's not much doubt that the blade was weakened by the extra bolt/screw holes and fractured along the axis of those holes. The small pulley and resulting high fan speed could easily have been another factor. Sorry, can't help with regard to changes to the alternator.

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436222
 

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Hate to see that.... brings back bad memories of what happened on my '48.
Fortunately I didn't get any sheet metal destruction though, the jacked up radiator was bad enough.
 

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Yes, it is horrible. It could have been even worse. Imagine leaning over the side panel observing the running engine, revving it up. That fan blade could have gone through your head. I NEVER stand in line with the fan of a running engine. You probably won't now either. You can get another side panel, fix the rest and be back on the road.
You should inspect all other safety items on the truck (steering, brakes) now that you have seen what incidents poor workmanship can create.
Good luck.
 
My very first vehicle was a stock flathead Ford V-8 1950 F-1 panel truck purchased for $25.00 in 1971. The stock fan was 4 blades until the day one blade broke off while the engine was just idling. That fateful day I heard a big bang upon investigating I discovered the now missing blade was sticking out of one of the lower radiator hose! All the coolant hitting the ground was a good indicator of something not right. Dam good thing no one was looking under the hood at the time. That Panel truck is long gone but I still have that 8BA and the used fan i put on her so long ago..
Ronnieroadster
 
This is a text book metal fatigue failure........these fans go through millions of cycles in the 70+ years of operating........they are not precision balanced, nor precision machined and do not have an infinite life and will fail eventually.....the sharp edges, corners and bolt/rivet holes are primary suspects for starting cracks. Good reason to put fan examination on your routine maintenance plan.
 
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