Background: The project car is a 29 roadster. The body and frame started out in great shape and my goal has been to do as little cutting on original parts as possible. I love the symmetry of flatties with the generator/alternator centered over the intake. An off-center generator was not what I wanted. I mounted the engine to just clear the firewall, no cutting, and wanted to run a mechanical fan rather than electric. The truck fan mount runs from the front crank pulley. The double pulley will fit, but the belt can not be changed due to how close the pulley is to the cross member. Besides that, the truck fan is too large for a model A radiator and would have to be cut down. A generator mount car fan is too high for the model A grill/radiator. Here is the chassis in question. The 3<SUP>rd</SUP> photo shows the firewall clearance with the fuel pump re-clocked. I'll continue with another post.
So, I decided to take a truck fan mount, an Offenhauser alternator fan mount, a car fan, a couple bearings and a double groove alternator pulley to mount the fan centered on the radiator and belt drive from above rather than below. Like most things, this has probably been done before. Here is my go at it. I chose to use tapered roller bearings, although the axial forces are low so ball bearings would probably work fine. But, ball bearings with the ¾ inch bore required to fit the truck mount shaft would have too large of an OD for the Offenhauser fan hub. You could machine a smaller diameter shaft to fit the mounting casting and use smaller bearings, but much smaller than ¾ seems too small. The tapered roller bearings have limited speed ratings, so choose carefully. The front bore in the fan hub is too large for the race, so a sleeve was pressed in and machined for a press fit of the race.
The bore for the rear bearing was machined to size, and the center through hole was opened up to leave a shoulder for the races with the edge of the race exposed enough to get behind it to push out should it ever need to be replaced like a wheel hub. (excuse the chatter marks it is a small lathe!)
The hub is not deep enough to have room for a press-in seal behind the rear bearing. A spacer is required between the truck mount casting and the rear bearing, so an exterior wiper seal was added to the spacer. The spacer has set screws to keep it from spinning on the shaft from the wiper drag. The truck mount shaft was shortened. A shaft collar is used to retain the hub on the shaft. The car fan covers the shaft collar and bearing, so no seal is used on the front, although I may use a gasket between the fan and hub to keep any grease from leaking out or water leaking in over time. Here is the assembly apart, and together.
Although I made it as compact as possible, the radiator had to be moved forward 1 inch to clear the fan. Also, the radiator needed to be a little lower to have a straight shot to the water pump inlets. I added inset shelves to the cross member to re-locate the radiator. The front pulley was cut off the crank pulley assembly so the main belt could be changed without having to lift the engine (or modify the cross member).
Thanks! It is a standard pulley, but standard to what I don't know. It happened to work out good. I found the same one as I used on e-bay: http://www.ebay.com/itm/Double-Groo...Parts_Accessories&hash=item35d2a2fe74&vxp=mtr I hope this helps, Don
I like your headlight-shock mount.I have F1 shock mounts and a model A headlight bar that I have been trying to visualize cut and welded. Good picture. John
Very nicely done. Did you know that a Merc car fan looks like your fan setup? The trucks used the bulky fan clutch but the cars did not. Ford cars were narrow belt and Merc cars were wide belt. I think Y blocks also were wide belt. The double wide alternator pulley must be new as I was not able to find one not too long ago. Thanks for the info on that. I would be interested in a shot of the alternator pulley from the front to see how far back from the face the nut sits.
I did not know that the Mercury fan was car sized and wide belt. Not the first time I re-invented something. I'll keep a look out for one, but I imagine they are hard to come by. The alternator is on the car and too close to the radiator to get a photo quickly. But I'll attach a view from a previous photo - upper right is Powergen, lower right is 2 groove, and lower left is Offy. All have about the same alternator shaft bore length. The 2 groove is deeply counter bored and provides the same amount of thread engagement for the nut as the other 2. John - I was hesitant to shorten the F1 mounts since they are originals. This pushed the headlights up higher than I was thinking I wanted. I'm going to see if it grows on me. If not, I'll take a few inches out. Don
Update I did find a Mercury fan (I was told it is a 49-50). Unfortunately it will not work without modification with the off-the-shelf 2 groove alternator pulley. The alternator grooves are about 1/4 too close together. In other words, the crank pulley grooves must have been 1/4 farther apart. There might be enough room between the Mercury fan hub and mount to move the hub rearward enough if the shaft is modified, or possibly take 1/8" off each mounting surface. The Mercury fan assembly depth is about 6.5 inches (mounting surface to radiator minimum). The Offy roller bearing hub version is about 5.75 deep.
Hmm. The Merc fan shaft has two grooves where the bolts go so could easily modify to slide the shaft rearward about 1/4 inch. So close.
Exactly I plan on milling the clamp bolt clearance scallops on the shaft forward 1/4 and cutting the flats back flush with the back of the fan mount where the shaft engages the alternator mount slot. I think there is just enough room between the back of the fan hub and the mount bracket. If not, Ill shave a little off the bracket. I like the fact the Mercury fan is more period correct. But, I also like that the roller bearing hub eliminates the oil bath lubrication. Not sure which Ill settle on in the end. Thanks for the lesson learned it was a fun project making the hub, but I would have been time ahead if Id have jumped on here and asked a few questions first!
Very cool, pretty much the exact setup I am building for my Mercury C1BA into my '33 truck. Good tech, thanks for posting it up.
Nice. I know what you mean I too have built stuff only to toss it aside trying to get a certain look.
Interesting and well done adaptation! It also illustrates some of the tradeoffs on stuffing a flathead into an early chassis. If you had gone to an early ignition and pump set, the generator would have moved aft a bit and not fit on any manifold without an extreme setback or riser setup But with early stuff engine in total could have been built substantially shorter making other areas of fit easier...if you look at rightmost pic in post # 4, the blue area on water pump approximates space you would save with early pumps, which set back pulleys as far as they can go and still have a belt. So you choose your battles... Somewhere, I have an old post on here with dimensional info. There are a bunch of long and short pulley setups around from different age flatheads.
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