Dennis: 7/20/2000 - 7:42:02 PM
Flywheels?
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With a late 4' Merc crank in a 59A, which flywheel should I use? Does the use of the 49-53 flywheel pose any problem with starter alignment? Does an aluminum after market flywheel offer a notable performance difference? I am new to flatheads so I would appreciate the voice of experience. Thank You

Fordholic: 7/20/2000 - 9:05:59 PM
RE: Flywheels?
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Dennis, I used 4' Merc cranks in two of my 59A's, with 59A flywheels. One was chopped to 22lbs. and one was stock weight. Both worked fine, but the chopped flywheel seems quicker.

rumble seat: 7/20/2000 - 9:27:22 PM
RE: Flywheels?
Accessories
The lighter the flywheel the quicker the acceleration. We used to say.... on acceleration, every pound of flywheel weight is the same as 100 lbs of weight in the trunk. But they idle rougher and they take some rpms to get under way. But they do sound REALLY NEAT with their quick wrap and back to idle. Absolutely love 'em. Aluminum wheels don't last long on the street especially if the car is heavy. They made some with bronze or steel faces that seem to work well. My self, I use a stock Ford lip type flywheel for a 9 inch clutch and lighten to 20 lbs and rebalance. If you go much lighter, they're gettting pretty skinny and I sweat exploding them. Just my opinions.....

Trader: 7/20/2000 - 10:31:25 PM
RE: Flywheels?
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Dennis, The later flywheel will fit in the 59A well. There is no problem with the starter. I prefer these to the early unit's because of weight, but mainly because you can use a bigger disk and pressure plate. However there is one drawback. You have to install the disk and pressure plate, before you put the oil pan on. Second problem is that with 35' and early trans, the clutch housing is smaller, and you will have a clearance problem. The 37' and later housing (trans) has more room, but you may have to grind some to clear the clutch cover (pressure plate) or area around the accutuating lever stantions (sp) where they come in contact with trans housing. It is well worth the effort in my opinion. On the subject, always use the proper fasteners, and torque to spec's. Use only shouldered bolts and lock washers to fasten the pressure plate to the flywheel. In my business, I find that if you resurface or lighten the flywheel, it does affect the balance. A great deal of the time the pressure plate is in worse balance, than the crank, or flywheel. Have them balanced as a unit, and mark them, so they assemble as they were balanced. I would shy away from the aluminum for street use. To add to Rumbleseats comment on weight... for every pound of material, you can reduce, at 3 1/2 inches off the crank centerline, will generate 10 horse power. It takes 1 HP to pull 10 pounds. So in retrospect, if you lighten your car by 100 lbs, you free up 10 HP at the flywheel...

JWL: 7/20/2000 - 10:50:11 PM
RE: Flywheels?
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Aluminum flywheels do well in light cars but can be a little annoying to drive on the street with a heavy car. Steel inserted aluminum wheels are trouble-free. Whether or not any performance difference would be noticed depends on your combination. Any increase is very slight.

Addendum 3/15/2001

GasHouse: 3/13/2001 - 1/1/1900 11:54:51 AM
rodnut/lighten the flywheel
Performance
If one were to lighten the stock flywheel, how much do you mill off and where? As an engineer who never uses his Dynamics, would we start in the center to keep up the moment of inertia or move it to the perimeter? If you take some off should I balance the flywheel? Since `friction/resistance` is so great against the flywheel does the moment even come into account? What are you attending thoughts on an aluminum drive shaft?

JWL: 3/13/2001 - 1/1/1900 2:07:43 PM
RE: rodnut/lighten the flywheel
Performance
I`m not rodnut, but I`ll give you something to chew on. If the purpose of the project is to lighten the car, remove weight from any convenient location. If you are trying to improve acceleration, remove the weight from the largest diameters possible. 5 lbs. off at 6 inches won`t do much. 5 lbs. off at 12 inches is noticable. You can waste alot of time removing material from the area between the pilot bearing and the clutch contact face. Don`t necessarily be impressed by weight figures, as they don`t mean much unless the weight is removed from the right places.

JWL: 3/13/2001 - 1/1/1900 2:12:07 PM
RE: rodnut/lighten the flywheel
Performance
OOPs, forgot to mention: Yes, you need to rebalance after machining the flywheel. For acceleration, an aluminum driveshaft would be almost as good as a stock Ford driveshaft in a torque tube.

Bill M: 3/13/2001 - 1/1/1900 10:31:08 PM
fly wheel
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JWL.. on a 49 ford fly wheel how much weight should you remove? what is the best finished weight for a mild street rod engine? lets say a 3/4 race engine, also what is the most you can remove?

JWL: 3/13/2001 - 1/1/1900 11:01:33 PM
RE: fly wheel
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There are no absolute answers to your questions. The amount of weight which SHOULD be removed and the best finished weight for a mild street engine can be different for each combination, because the vehicle, and rearend ratio play a important role. In a heavy car without OD just a few pounds from the area above the pressure plate bolt circle is enough. In a really light car you can remove the max. I don`t know what the maximum amount is that can be removed. It depends on what the clutch size is. The lightest I have made were cut on both sides in the lathe and also profile milled around the pressure plate outline. Pretty light, but not a match for aluminum. Also very time consuming.

hotrod: 3/14/2001 - 1/1/1900 7:27:50 AM
RE: fly wheel
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How about drilling holes in it also? Equal distance and then balance. You couldn`t go overboard But it would lighten it up and maybe cool better. Also might help keep disc clean. All you`d be giveing up is surface area and with a 10` clutch and a light car I`d think it would hold. What do you think people? Am I nuts? hotrod