So I have this Motor. It came to me in a running and driving 40 Ford truck. It was a very low mile rebuild with a confusing vibration. The owner/builder had given up and hired me to do a 302/auto and 9" change over. While removing the motor I uncovered the cause of the vibration and showed him what was going on. He stuck to his decision to make the change and I ended up with this motor. Fast forward several years and it's now sitting in my 30 roadster. The vibration issue was caused by the Crankshaft and Fan pulley combination. This motor is a 24 stud block. I've been told the motor is most likely a 37. The end of the Crankshaft is only a 1/2" past the front cover plate and measures 1.185 o.d. A normal 40 crankshaft (I'm told) is almost 2" exposed past the front cover and 1.310 o.d. Where I'm going with this is I want to run my 2 carb intake and being my Roadster is channeled I need the fan to be in about the center of the motor top to bottom. This requires a double grove bottom pulley. To date I have not been able to find a stock 2 belt pulley for this crankshaft. A Billet pulley nor an electric fan are even close to an option. So,, What to do? Can I just change to a later crankshaft? I've been told 37 motors still had full floating rod bearings. Would that require a new set of rods to go with the crank? To add to the issues I'd like to stay with the early 2 cap dist and not change to a crab cap style. Remember, this is a running motor, re inventing it was, and is, not on my list of things to do. How can just adding a fan in the so called standard place become such an Issue? There's always something isn't there? What to do? The Wizzard
I am sure Bruce will be along in the A.M. to give you the perfect solution. (It's like 1:A.M. on his side of the continent.)
Wow, I bring nothing to the table on this one except for the fact that I can relate with you on being stuck on what should be the easiest part of the build. I've never done anything with one of those motors, but if you did find a billet pulley that worked, could you just paint it black? I'm just throwing it out there.
For what I know, 37 engines were 21 stud, with the water neck in the middle of the head, and Ford flatheads had full floating rod bearings through '48. Swapping crankshafts with those FF bearings can be an expensive ordeal, along with a hassle. The problem is the bearings I have seen are not round, and getting the proper clearance on the inside and out is really tough. Good luck.
If you use the 59A style fan you will need the shorter crab or '46 style distributor. Just won't fit with a helmet style distributor. Also, I'd bet good money that no 59A style pulleys were ever made for the short-snout crank. How about you find a super-rare double generator pulley and drive the fan from the top? Will probably require a custom fan bracket/spindle, but could be do-able, right? Then you could keep all the belts and brackets up above the helmet distributor.
alchemy; I was thinking about driving from top pulley somehow. It looks like I'll be mounting the Gen on the Passenger side head and will need an ideler at the center manifold mount point. As of yet have not found a way to do that either. Your correct about the belt/dist issue unless there is sufficent space between the 2 groves. The Wizzard
Both double groove gen pulleys and double pulley water pumps (which are a bit different internally, but interchange with passenger pumps and have that first sheave in right place) are fairly available and would allow an alternate drive in a couple of different ways. Easier than messing with crank nose. Center idler would be made from a generator cut down to very short case with front and rear plates remaining...if you go to truck double pulleys on pumps and gen, there might be useful simplification in the separate drives... maybe idler and pumps run by stock belt, then generator and fan run off of one of the forward sheaves and adjusted at the gen...? 1938 24 stud crank is same as 1937-38 21 stud and 1936 LB. It uses floaters like all through 1948 and of course virtually all race flatheads. Swapping cranks has been done to get 4" crank into these but is fairly major grinding operation reducing journals to suit and I think slightly lengthening a main in there somewhere. Big job, but if you go to '49 Merc you can use the needed grinding for the good rods to go to 4 1/8 stroke and have a big 221 suddenly...but as a practical thing, not worth doing if motor is running well now. The ways above allow running extra stuff without messing with crank. To use crank double pulley, there WAS a double sheave pulley for your crank used on bigger trucks. It has surface where the crank nut tightens set back in to the right place. Early (1938 and back) crank just barely protruded from front cover, '39-53 is maybe an inch longer and was introduced specifically for the fan problem you started with! I have a device somewhere I have never fully figgered out; I bought a junky 1942-8 pulley that had an obstruction in it. I hammered that out, and it proved to be a crank extender, I think! It was a round slug just about an inch long. It had the keyway, and a protruding stud on back to allow it to screw onto a crank...how those square up I don't know, as it would be pretty lucky to have the key end up in right place with the stud tightened. Maybe that's actually something longer and free that's broken off...I haven't cleaned the thing. What exactly it was made for and how meant to be used, I have not figgered. Would be simple to do something like that...maybe.
Thanks Bruce; I was just on a page with many photos of Flathead pulleys but no I.D. info. I had thought of making an extention and using a threaded stud with a long key in the slot but was looking for another way first. I didn't know about the truck double grove lower for that crank. Think I'll try to come up with one of them first. Spacing is the key for anything to work out. My real issue is mounting a fan down about center. Using a Gen mount fan blade puts the fan tips above the Rad. tank. I will change to a crab cap dist if necessary. I have all that stuff. If you have a small I.D. double lower for sale I'd be your guy. The Wizzard
There is a pair of double groove water pumps listed in the classifieds, not mine. http://www.jalopyjournal.com/forum/threads/flat-head-ford-double-groove-water-pumps.985382/
Correct me if I'm wrong but a Truck 38 double grove pulley would also be correct for my Helmet style dist. The Wizzard
Sure it would, cause they didn't have any other distributors in 1938. But it's not saying they used that pulley with a fan bracket like a 59A. Spacing front-to-back on the second sheave is the key to making it work. How's your clearance between the pulley and your front crossmember?
That's interesting Marty, thanks for posting that. So the currently available full floater inserts are crap (why am I surprised by this). As a general rule, I'd rather run the full floaters, but if you cant get round bearings anymore, that's kind of a game changer.
Lot's of room. Long story. Short version see photo. I wish I knew where I could put my hands on one for test fit.
Lower one looks more like what I need. Can you get me the I.D. of the crank hole as well as the space center to center of the two belt groves? I was just on the Ford Barn and see there is quite a bit of chatter around this very issue. The Wizzard
I jacked the pictures off the inter-webs so I don't know the I.D. Both are not uncommon and be can found on Ebay or the classifieds here and the barn. Another option is So-Cal makes a spreader that mounts off the block down low to clear the belts from the dizzy. It doesn't look modern and would go along with an old school look. There's alot of ways to skin a cat.
Pictures up there...the red one is1942-48 with wide spaced sheaves, uses '42-8 separtae fan, late crank. The iron one is for double shaeve truck, which uses dual identical belts and double pulleys on pumps and generator. Normally, I'd say you'd have to look at the depth of the place where it tightens with the crank nut, but here's a part number...looks like 51 is the prefix! That would make it for th short crank engine. Early crank length is listed as 24/47, late is 26.03...that extra length should all be in the front snout.
I think I see a way to tell early from late lower pulleys. I have 2 single grove small I.D. units. They both only have a notch in the end to index on the timing gear key. No full length key way grove in them. My 40 lower large I.D. pulley has both a notch for gear key index and a full length key grove. This may help identify the pulley I need. The Wizzard
Wizzard...I've never mixed the early and late ones because I've had complete assemblies and no need to swap... I can pretty well spot the difference by how far back the nut surface is on the earlies, late has a sort of protrudig tube to match up to crank nose...on the passenger double shown above (red primer) that is capped by the extra sheave, on '40 type by fan flange, on the rare late single and on late truck double it is just a brare protrusion. Earlies have flange way back in there. How do ID's of the shanks compare? Outside must be same, to fit seal
http://www.fordbarn.com/forum/showthread.php?t=32674 Marty, may I hear your thoughts on the approach described on this thread on the ford barn? Is it a matter of the bearings being squashed in shipping, or are the shells themselves an inconsistent thickness?
Solidaxle. what I'm looking for is the ID of '32-38 pulleys vs ID of '39-53 ones. I know what directly swaps and what is different on the length of hub, and OD of shank must be the same since all run in the same seal up there. I don't have much early stuff where I can get at it, all '39 up in engine department and in the pulleys. If ID is the same, the lenth problem can be finessed pretty easily to get whatever sheave arrangement.
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