Float a Motor

[Art Bjornestad]

Planning on putting a Float a Motor in my A. I get a lot of vibration and hope that this will help. My question is that there seem to be two styles, a cast iron kit and an aluminum one. Is there a difference beyond the $17.00 price? The cast iron set up is cheaper.

[Jim Parker Toronto]

Why not put that money into fixing that vibration instead of just covering it up? Eventually, you will have to fix anyway, and in the meantime might cost you the motor! Jim

[Dennis L Oberer]

I truly believe that the A as built had MINIMAL vibration. I think ANY vibration you get in an A is a problem and the FAM units just are band aids.

IMHO

Dennis L Oberer
Green Bay WI

[CWPASADENA]

Originally Posted by Jim Parker Toronto

Why not put that money into fixing that vibration instead of just covering it up? Eventually, you will have to fix anyway, and in the meantime might cost you the motor! Jim

As I am sure you already know, stock "A"s do not have a countered weighted crank and they vibrated. If the engine is original, a Float -a -Motor Kit may help. These have been used for many years.

Short of building a engine with a counter weighted crank and having everything balanced, I am not sure ther is an easy fix.

Please understand, this is just my opinion.

Chris.

[pat in Santa Cruz]

Originally Posted by Jim Parker Toronto

Why not put that money into fixing that vibration instead of just covering it up? Eventually, you will have to fix anyway, and in the meantime might cost you the motor! Jim

I agree with Jim, Excess vibration is a result of internal imbalance in the engine or drive line. Counterweights do not balance the vibration as much as they inhibit crank shaft flexing at high RPMS. Excessive engine vibration is from gross internal imbalance or poorly indexed crankshafts. Its normal for all 4 bangers to have some vibration as it is inherent in the engine design unless there are 2 counter rotating shafts internally, as in toyotas.

F.A.M's contribute to frame sag, as they weaken the "cross member" effect of the original mount system. I have first hand experience with them that resulted in a sagging and twisted frame at the mount area. They did reduce vibration, but at the price of a mis-aligned hood and doors.

Regarding iron or aluminum, I doubt there's much difference. I have had both and they performed similarly.

[Logan]

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Everything said here is true. Yes they help out with vibrations, especially in the Steering when letting off the gas.(that's where I have felt the biggest difference). But they also contribute to frame sag some times. Just whatever you do, don't put the front engine mount replacement one in. It makes the engine fixed in one position, and eventually will make the crank in the engine become unalighned. You can always just freshin up the original motor mounts, and put some new rubber in between the frame and mounts. Hope this was of help.

[Logan]

Originally Posted by Jim Parker Toronto

Why not put that money into fixing that vibration instead of just covering it up? Eventually, you will have to fix anyway, and in the meantime might cost you the motor! Jim

I don't understand what changing motor mounts has to do with blowing up a motor. All model A's rattle in one way or another. If your doesn't, can I please have a ride.

[Kevin - Illinois]

I love how people post things like "use the money instead to fix the problem" and don't give details on how they did and how much time and money they spent. Like you are going to "fix the problem" for $59.00 or something.
I agree with staying away from the front FAM's though as they seem to really bind the engine to the front crossmember. I put the rear mount on my coupe and it did help the vibration problem. A also installed a new original style front mount as mine was shot. Check to see if you have a good rubber pad in the steering column clamp also. This helped me also.

[Ron Engen]

Another concern for the F A M ---I have been told they could let your motor shift forward and the fan could kiss the radiater. I agree that the loss of the cross member effect or the original was enough concern for me . In fact I have a brand new F A M for sale $ 40. Ron Engen [email protected]

[Mike V. Florida]

The rear motor mounts have a rubber pad. Depending on the age of yours, they could be hard as a rock now. I would try new rubber in the rear mounts from Brattons as his are made to fit the mount as others need to be trimmed.

[Kevin in NJ]

Some basic facts about the A engine, not opinion.

From the factory it did not vibrate much. The engine was built to what most consider race car standards today. Sure there would have been the engine that was right on and the engine that was a little out, but nothing like you see today.

The rods were constructed to +- 1 gram weight on each end. Pistons were added and the unit re-weighed and put in batches. The moving weight was within 4 grams total.
The crank was statically and dynamically balanced as was the flywheel. The flywheel was located to less than .001" of the crank center line.

This is based on Ford prints and the book "Know Your Model A Ford".
These details have also been confirmed by various people that have had the luxury of working with Model A production era NOS parts. You have to be careful as post Model A era Ford production NOS parts were not held to as tight a standard. You also have to consider that any NOS parts sitting on the shelf at a dealer may have been the part the factory rejected and sent out as a service part. The dealer mechanics found the part did not work so it was put on the shelf in the corner and forgotten till it was bought as a prize NOS part years later.

Very low mileage original cars prove out the fact the original engine did not vibrate hardly at all. A while ago someone posted about one that was at a meet. They were all amazed at the engines lack of vibration.

We only hear about vibration because relatively few engines are built with the same level of detail as the engine would have had during production. So to most of use a vibrating car that is not comfortable over 45 MPH is considered normal.

Fixing the problem is not cheap.
Odds are real good the crank was ground off the centers. Because of how the crank wears and how grinders grind cranks the rear flange is likely to be out of plane. The crank gets bent a little when the mains are tightened as the center main is probably a few thou off the center of the front and rear main. The flywheel is out of the center line. The rods, if you are lucky, are within 5 grams total weight. So the bottoms could be spinning with significant difference in weight. The pistons could be off my as much as 30 grams in a set- Yes I have measured a set of pistons off by that much. Then throw in a used cam and a little loose distributor and you have lots of places for an engine to vibrate.

It is not cheap to return the Model A mechanicals back to factory specs.

[jhowes]

You say "crank and flywheel balanced" How? Are weights added or metel removed by drilling? I have never seen a crank with the tell tale holes where metel was removed.

[MrTube]

Our crank has holes drilled in it for balancing.

Note far left near front main.

[brokenspoke]

Would someone explain to me what a F A M is? thanks

[MrTube]

Originally Posted by brokenspoke

Would someone explain to me what a F A M is? thanks

Float A Motor

[Kevin in NJ]

Here are factory pictures of the crankshaft balancing machines. Marco had posted them at one time.

[IrishHills]

Originally Posted by brokenspoke

Would someone explain to me what a F A M is? thanks

Float A Motor?

edit: opps to late

[John LaVoy]

An interesting thread. Having driven an early 28 Model A with the motor bolted to the cross member with no "float" or spring and putting over 60,000 miles on the engine there was no problem so using the float a motor set up on the front should work out OK. I have not been a fan on the float a motors on the rear mount for the reason mentioned about the cross member effect and the new rubber being made for the original mounts is very good. We also showed how incorrect installation of the float a motors can lead to front end shimmy by changing the front end geometry.

Much of the vibrations in a Model A can be attributed to the indexing of the crank when it is turned. Most machine shops make the journals round but do not index the crank so it is no longer properly aligned and tends to vibrate. It you have the opportunity to see and hear an original un-restored Model A run you can see how little vibration the original engines had with out the use of counter balanced weights etc.

As to the original question..Cast iron was what the mounts were made of when introduced during the Model A production, but aluminum is lighter in weight and will work every bit as well.

[BILL WILLIAMSON]

Originally Posted by Kevin - Illinois

I love how people post things like "use the money instead to fix the problem" and don't give details on how they did and how much time and money they spent. Like you are going to "fix the problem" for $59.00 or something.
I agree with staying away from the front FAM's though as they seem to really bind the engine to the front crossmember. I put the rear mount on my coupe and it did help the vibration problem. A also installed a new original style front mount as mine was shot. Check to see if you have a good rubber pad in the steering column clamp also. This helped me also.

When installing my front Float-A-Motors, I drilled the crossmember hole to 1 1/4 inches so the rubber pads could be squeezed into the hole to insulate the bolt from making metal to metal contact to the crossmember. otherwise, the bolt makes metal to metal contact from engine plate to the crossmember, making it worse than stock mounting.
"THE ASSISTANT GURU OF STUFF"

[Kevin in NJ]

Just to throw another tid bit out.

Ford first had a floating rear mount on the A. It was quickly replaced with the solid mounts we see today. Not sure of the time line with relation to the solid front mounts.