I just put an alternator on the 39 standard. . The radiator fan is mounted to the alternator pulley. Everything works great except for the noise from the fan now. It sounds like a prop job on take off. I realize the fan is spinning faster due to the smaller pulley but the noise is awful. If you take the fan off it is quiet like normal even at half throttle. Could there be some kind of turbulence or something between the radiator fan and alternator fan fins ? It's too noisy to drive. It's a 4 blade 16 inch original fan. I want to leave the alternator on and I'm looking for suggestions. Thanks for looking.
What difference would it make if the fan was mounted to a generator or an alternator??? You already tested it withe fan off and it was quiet. How close or far away is the fan from the radiator. Should around an inch. Maybe you need a larger pulley on the Alternator to slow down the fan.
Mounted on the generator it was quiet. Fan is about an inch from the radiator just like when it was on the generator.. The only difference is the smaller alternator pulley thus giving the fan a lot more speed. I'm having a hard time believing that the extra fan speed with the smaller pulley would make so much noise but anything is possible.
if its a fan mounted on a delco, it will get quiet after the fan goes thru the hood. the ford generator had better bearings for the fan load
You just might want to go back and study the Alternator parts drive end and commutator end bearing charts For both Ford and Delco in the years that would be applicable https://www.rockauto.com/en/catalog...alternator+/+generator+drive+end+bearing,2484 https://www.rockauto.com/en/catalog...alternator+/+generator+drive+end+bearing,2484 203 bearing on the front of both Ford and Delco standard size alternators and the needler bearing on the back of both is close enough. You can believe all the BS you want but they have the same bearings.
How about removing the alternator fan? With the engine fan mounted there, the alternator should run cool anyhow. Sent from my SM-T350 using The H.A.M.B. mobile app
I think the alternator front bearing is not set up for a load pulling it forward. When the fan spins fast it is pulling air from front to back, causing the alternator pulley to pull forward against the bearing. I think you need a stock fan with pulley in the center, and the alternator mounted on the side.
I don’t have a clue about the bearings, but do some math on the pulley sizes and rpm at the fan. Having had a clutch fan fail and lock up at 2500 rpm, it’s hard to believe the noise they make. Smaller fan, less pitch, IDN?
One simple thing to check is the tracking of the blades. If one blade got bent (out of track) during the change, the fan could make more noise.
All of the early Ford generators, up through 1938, AND 1939 Standard Fords, had the cooling fan mounted to the generator pulley. Every one of them used a Timken tapered roller bearing on the fan end of the armature.....not a ball bearing. And you can’t just swap in the tapered bearing for the ball bearing. This is the problem everyone faces when trying build a hot rod. Up through 1937 the Ford generators were the 3 brush 6 volt type, which used the simple cut-out (mounted on top of the generator) to control the charging. Certain 1938 and Standard 1939 cars with the factory radio were equipped with the 2 brush generators, made for use with the firewall mounted voltage regulator. Because those types were on vehicles with generator mounted fans, they still got the tapered roller bearing......good hot rod candidates, but very hard to find these days. Seems that the only real choices in today’s builds is to stay traditional 6 volt with the 3 brush stock generator.......or mount an electric fan and use a modern 12 volt alternator......or convert a typical 1940-48 flathead 6 volt (2 brush type) generator to 12 volt and use an electric fan. Hiding the fan in front of the radiator eliminates the “ugly non-traditional” look, wherever it’s possible. It’s not such an easy thing to do with a Model A grill. Your choice of early or late flathead V8 engine always limits what you can do as well.
Van pelt. What about the '39 standard & trucks with a two brush generator & a fan mount pulley. Are there different bearings ?
Guess I didn’t make it clear ...... those 39 Standards (and the pickups) with the 2 brush generators, still had to have the Timken tapered roller bearing at the front of the generator because they still had the generator pulley mounted fan.
Thanks everyone for your replies. I may go with an electric fan set up and do away with the stock howler.
How much slower would the alternator spin with the pulley from the generator (or a pulley of the same size)? Too slow, or fast enough to keep up?
I believe it would be too slow to charge at an idle that was the reason for the small pulley. it charges now real good at idle with the headlights on. i'm going with the electric but thanks for the reply.
Another option would be to go to a early to late 50’s 12 volt generator. Simply cut the mounting tabs off the housing and the length and diameter is the same as the originals.
I think the problem with using the later generator is the same as using an alternator. Not having the tapered roller bearing at the front of the case. My question is when things let go what's more likely to be damaged the radiator, or the hood? -Dave
I think it will be safer all the way around with electric. I had a fan blade break on me one time and it wasn't pretty. Another reason too is that fan is 80 years old and has made a lot of revolutions .
I'm hoping a 16 inch puller fan will do the trick. The stock fan is 16 inch so here's hoping plus I can put it a little bit lower on the radiator instead of up at the top.
My question if the bearing is a issue whats the power generator using in there set up. The 39 ford came with the fan mounted generator and many of them still running around stockers. I have to ask why not go with a powergen type setup? And have seen them in stock applications. I understand your going with a electric fan but would love to figure out whats going on and solve the problem and may help others in the future...
I believe the Powergen suffers with the same lack of the tapered roller beraring up front. I've no personal experience with the unit, but I've heard this from a few sources. -Dave
My biggest complaint was the noise from the fan with that smaller alternator pulley. I don't think you would get the charging rate at idle or low or mid throttle with the standard pulley, I'm not sure. At idle the fan noise is very loud and at 2 to 3 thousand rpm's I could only imagine. I looked into a power gen and if I remember right they have a smaller pulley too.
Give it a go. Hey twostick maybe a fan with a fluid action that will only spin X amount of RPMs can be used . ???
I think i'm just going with the electric for now and if that doesn't work out i'll try something else then I don't have to worry about the front bearing and the noise.