Model A flywheeel lightened
 

How much needs to machined off an A flywheel for a B engine?
Thanks

Re: Model A flywheeel lightened
 

What transmission are you using? Seems like unrelated question but the Model A transmission interferes with the Model B transmission case.

Charlie Stephens

Re: Model A flywheeel lightened
 

If using the A bell housing and trans, nothing needs to be trimmed. If using the B bell housing and trans, just a little off the outer, rear edge. B Bell housings must be used with the B trans and an A bell with the A trans, they are not interchangeable. To use an A bell on a B engine, the rear section of the B pan must be removed. If you want more info contact me at [email protected]

Re: Model A flywheeel lightened
 

I installed a model B engine into my 1929 Tudor. I used the full weighted model A flywheel on the B crankshaft and it all went together very nicely. My big bonus was with using the A flywheel, the B engine really runs vibration free. There never has been a vibration seen in the Tudor's mirrors at any speed. On our 1930 A Touring, using a lightened flywheel and the crankshaft having added counterweights, I have never driven such a terrible vibrating model A before. It was professionally built up as a "Touring motor". During the rebuild, the touring's engine/ crankshaft, and flywheel were all balanced by the well know engine re-builder too. Very disappointing. If you like a smoother running engine, I advise against using a lightened flywheel.

Re: Model A flywheeel lightened
 

That is disappointing, especially since I just bought a rebuilt engine with a lightened flywheel and fully counterweighted crankshaft (everything fully balanced all the way back to the Ford V-8 clutch), amongst other goodies, at a cost of almost $10,000. I have not yet installed the "new" motor. Who was the engine re-builder and did you complain to him? If so, what did he say?

Re: Model A flywheeel lightened
 

I beg to differ..... I bought my Town Sedan, over 13 years ago, with a newly rebuilt motor, but no counter balanced crankshaft. After I took delivery, I had the flywheel lightened, and also added the V-8 clutch and pressure plate. I was warned by some that the lightened flywheel would ruin the Model A....it would never run right, wouldn’t idle properly, etc. After 14,000 miles I can report that mine runs very smooth, without any undue vibration, at any normal speed, including over 60 mph on the freeway. And I can still pull away in 2nd gear, although I see no reason to do so.

Re: Model A flywheeel lightened
 

ssssstemer I have a A with b engine and lightened flywheel with V8 clutch that I will trade you.

Re: Model A flywheeel lightened
 

About 10 pounds, but as said above, the machining of an A flywheel to mimic a B flywheel will be more money than buying a B flywheel. FWIW, several years ago I started a topic on how much is too light. I think it is worth a read.


As for the engine above that has a vibration. My instrict is that can be cured by rebalancing the flywheel, then adding the pressure plate and rebalancing.

Re: Model A flywheeel lightened
 

I actually just did this to my flywheel this fit into my B flywheel housing with a B transmission. I took it to get balanced and the flywheel was within a gram. But when he bolted the pressure plate on it took a lot of weight added to it to get it balanced within a gram as well. I did take a lot of weight off as well as machined it for a 9” v8 pressure plate. The complete assembly with pressure plate, disk, pilot bearing weights about 46lbs. So about 20lbs. off by my estimate from stock. I followed the flywheel lightning dimensions that they have as a cad drawing over on the HAMB.

Re: Model A flywheeel lightened
 

Reading Brent's post makes me think of of my own efforts to lighten an A flywheel. I believe in a bunch of "Slight" modifications. I don't like radical changes to anything. The Mod. A flywheel weighs 63 pounds, there is plenty of weight that can be removed without substantially changing the weight to engine power ratio. How much more power is drawn off by turning a 63 lbs wheel compared to say a 53 lb wheel? Moreover, the weight that is removed is mostly at the farthest part of the wheel from center where it has the most effect. We lighten pistons and rods to harness more power from the explosions above. Why shouldn't we lighten the the heaviest link in that chain?
There is one more consideration. The weight on the rear main bearing. While most would agree that rear main is pretty substantial and can stand up to the weight of the flywheel. Most would probably agree that 10 or 12 lbs less on it would be a good thing. But I believe that the flywheel should be accurately balanced and that's with out the clutch. Ok if you balance the whole spinning mass and then you replace part of that mass (replace the clutch) is the flywheel still balanced?
Terry

Re: Model A flywheeel lightened
 

I had mine balanced separately. I also made a witness mark between the flywheel and pressure plate so I made sure the pressure plate went back in the same position it was balanced in. So I guess when I get a new pressure plate it may be good to have it checked again.

Re: Model A flywheeel lightened
 

I am running a 28# flywheel in my '31 slant window sedan with counter weighted crankshaft, V-8 pressure plate, 6-1 HC head, large intake valves, B carburetor and a 36% OD with 3.78 rear end. Great combination, love the way it drives. Drove from San Diego to Reno this summer. Drive it nearly everyday to Model A Garage in Ramona about 18 miles on hilly HWY 67. Yes I do have to shift out of OD on the 6% grade hill but no big deal, just shift back into OD at the top of the hill and back to 55mph speed limit. Just my thoughts and opinion. Arlyn Bieber San Diego

Re: Model A flywheeel lightened
 

I bot model B lightened flywheel from Stipes $250 June 2018...I ran engine on stand and seemed to run good,oil pressure was low so I'm going to pull pan and replace..will know more after i drive 32 PU.also I bot Stipes model B cam not cheap..34 engine with bal crank..Spencer

Re: Model A flywheeel lightened
 

Model A flywheel about 63 lbs Model B flywheel about 50 lbs.
You should not have a vibration problem with a light flywheel, some one messed up.
Most of the engines that I have done had light flywheels,never had a problem.

Re: Model A flywheeel lightened
 

This guy should know something about balanced cranks.

https://fordbarn.com/forum/showpost....4&postcount=64

Re: Model A flywheeel lightened
 

Daren, I recently sold my phaeton with engine balance problem. I still have the Tudor with the B engine and the A flywheel combination and it runs super smooth. I am very happy with the Tudor and I will keep it like that for long as I have it. Thank you for asking.

Re: Model A flywheeel lightened
 

Something else occurred to me after I finished the signing and sealing of my last post. It could roughly be called torquing or twisting the crank upon stopping the engine. I see this old iron as living on borrowed time (85 + years) How long before the twisting action of a heavy flywheel is going to twist off a crankshaft. They're already flexing plenty at stopping when the energy in the flywheel wants to keep turning. We may have to make a larger diameter and heavier harmonic
balancer to equalize and minimize this twisting action. Just some random thoughts on the subject.
Terry

Re: Model A flywheeel lightened
 

I have had two failures of the Burlington crankshafts. I don't have positive vibes about those cranks nor of either of the owners. It cost me a lot of money to correct their malfunctions. Not sure how this applies to this thread though.

Re: Model A flywheeel lightened
 

His suggestion is 30 to 36 pounds. I don't think he would have suggested it if it created vibration.
Failures are probably to do with manufacturing.

Re: Model A flywheeel lightened
 

Does the weight really matter with regard to vibration? If the weight of the flywheel is 30 lbs, 40 lbs, 60 lbs, or 100 lbs, if it is correctly balanced, why would there be a vibration?