Fan blades are BREAKING

F

forte

Junior Member
Less than fifty miles between the two radiator fan blades breaking off two seperate fans. Before I replace a thrid time common sense tells me there is something causing this. My luck is not all bad. Motor = 1940 V8 85. all orig. Info that may help = Both times it happened in second gear. Since ownership of the car last Sept. it has a hard rumble accerlating from 0 to 45. Replacing the exhaust system including manifolds it does not hurt between my ears anymore, but it is still there. Purrs 50 to 60mph. And the rumble is gone after 45. Might hear a bit going up a hill but nothing like it use to be. Can this be connected to my baldes breaking?
 

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Hi there, just for a quick try remove the fan belt and drive it (briefly) and see if the noise is gone. This will narrow down your search. Regards, Kevin.
 
So how do I get a url from my picture folder to be able to post one. Even my 14 yr old son is shaking his head on that one. Can't cut and paste, cant select drag and drop.
 
Chuck the next fan up in a lathe and check it for balance after closely inspecting it for cracks. Are you talking about genuine Ford parts or one of these modern plastic replacements?
 
Click on the picture icon above on the message bar. Looks like a mountain with a postage stamp. Then paste your url in the popup box.

Or If you have pictures on your computer that you want to upload, you can click "go advanced". Scroll down and you will see "manage attachments" click that and upload pictures straight to the site.

Heres a link to how to post pictures with a better explanation then what I quickly did...

http://www.fordbarn.com/forum/showthread.php?t=183568&highlight=uploading+pictures
or
http://www.fordbarn.com/are-ya-lost/posting-images/




.
 
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forte said:
Less than fifty miles between the two radiator fan blades breaking off two seperate fans. Before I replace a thrid time common sense tells me there is something causing this. My luck is not all bad. Motor = 1940 V8 85. all orig. Info that may help = Both times it happened in second gear. Since ownership of the car last Sept. it has a hard rumble accerlating from 0 to 45. Replacing the exhaust system including manifolds it does not hurt between my ears anymore, but it is still there. Purrs 50 to 60mph. And the rumble is gone after 45. Might hear a bit going up a hill but nothing like it use to be. Can this be connected to my baldes breaking?
Click to expand...
I wonder if someone has been turning the engine over by the fan blades and then straightening them when they were bent? As unusual as it is for a fan blade to break if you broke two there must be something else going on. How about pictures?

Charlie Stephens
 
Both blades are metal. both were exactly like original. Now truth be told the first breake I blamed on myself as I did try to move the motor by hand and I DID feel like i bent a blade. But this second one I did no such thing. So I checked the pully there is no budging it one bit. It spins true while motor runs. Still working on the photo advice.
On the note of driving the car w/ out the fan on. Any damage to motor doing so. I need to get it up to 25 mph . Breifly means five minutes or less???
 
Yes. Just checked my engine mounts and by tightening one up front I now snapped the water pump mount.
 
Yes, I'm just spitballing here but this reminds me of of a guy who had a totally different modern modified engine that kept loosening the bolt and shearing the key of his front pulley over and over again. Finally, he pulled the trans and found the flywheel bolts were loose with elongated holes. The vibration was transmitting through the crank and wiping out the front pulley as the only symptom.

Lonnie
 
And I will do that kind of work too see, and if its not then I want to understand that nothing else can be checked beforehand and then I pull the engine and check the crankshaft. But it makes sense that it could be something like that. I will find a machine shop that can test # 3 fan for balance.
 
Without having the fracture point analyzed, searching for and blaming some mysterious rumble or vibration for the failure is probably a moot point.
The as manufactured sheared and formed parts with jagged edges such as this are a perfect breeding ground for cracks to start.
I suspect that without stripping to bare metal and properly inspecting the area, the failure point existed before installation.
Having seen this failure if I had such a fan I would immediately strip the area and radius/polish the jagged edges.
 

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40 fans mount direct to the crank pulley and are not run by a belt. It is possible that the mounting flange on your pulley might be bent. Also check for interference from the fan hitting something. I doubt that turning the motor over with the fan blade caused this. It does appear from your comments that something between the pressure plate and fan tips is loose or out of balance and I would believe that a flywheel related problem could cause a harmonic balance thing that could cause a fan problem.
 
I had a cat engine that was shaking the fan mounts loose and also breaking some of the mount bolts, It had the wrong pressure plate in it , the thing causing the problem was causing Harmonics at a very high frequency, the average person couldn't detect the vibe, myself included, after a couple of failures, I had my tech. pull everything off the rear of the crankshaft and inspected all the parts, There was evidence of the bell adapter alignment pins being elongated due to the vibe. causing misalignment contributing to the problem, I had to replace all the parts and realign the flywheel, problem solved.
 
Correct pully is mounted as part of the hand crank shaft.
I am trying to remove the pully. Using a 1 1/8" 6 point socket, transmission in reverse, parking brake on, this is not coming off. I am actually moving the car w/ every turn of the ratchet. The socket is not hitting the handcrank teeth. How do it stop the motor from rotating to enable the pully to be removed for inspection? I will start to soak the area w/ Gibbs in the meantime. The book states an impact wrench is used. But only a right angle one will fit behind the radiator. Please advise if this is the only way before I start asking to borrow one.
ASLO not sure if this helps: ever since I drained the super thick 4oz. of transmission fluid and replaced w/ 80W90 gear oil to correct level and drained and redid after 10 miles AND adjusted the clutch pedal to have the speced 1.5 to 1.75" of free travel it has been tough to shift from 1st to 2nd. Meaning I can feel it thru the column shifter. Not the teeth but its like it rubs. 2nd to 3rd is great. I'm thinking to set clutch pedal back to very little free play.
 
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Not convenient with a running engine, but I put vice grips on the ring gear thru the starter hole. It really secures the engine from turning.
 
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