Vibration

[James Rogers]

Just thought I would start a thread to get opinions from barners about what might be the source of vibrations in a Model A engine. I have never run a totally original motor so, I don't have any experience as to that type of smoothness but, I have run several that were real shakers and one that was as smooth as a modern V8. I have some opinions of my own and will express those as this post progresses and others give theirs. I have found some places that I believe will cause vibrations that I have never been warned of expressly. Hope to hear lots of opinions so I can get verification of my findings and maybe help others calm their engines down some.

[Jim Huseby]

This will be interesting when all answers are in. I'll just name one: front motor mount center stud nut wound down tight.

[James Rogers]

Originally Posted by Jim Huseby

This will be interesting when all answers are in. I'll just name one: front motor mount center stud nut wound down tight.

Good one and probably attributes to lots of engine vibrations. More?

[Brentwood Bob]

wrong plunger spring in timing gear cover. Same dameter, but short, so very weak pressure on the cam. Bob

[Gerard]

A totally wrong grounded camshaft combined with a wrong dialled position of the camshaft gear. ( to just name a few )

[newshirt]

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Wobbly fan blade.

[BRENT in 10-uh-C]

...in addition to ones mentioned above;

Worn Distributor Cam

Unbalanced Flywheel

Unshimmed/Improperly shimmed Flywheel Housing

Bent Connecting Rod

Crank Pulley

Improperly ground Crankshaft

Reciprocating assy not balanced after rebuild (i.e.: thick babbitt on rod)

.

[Mike V. Florida]

how about the pictures we saw of different connecting rods? I would think there are engines that have mismatched pistons and connecting rods.

Low compression in one cylinder.

[pat in Santa Cruz]

bent crankshaft, crank ground off center, rod pins not indexed when crank ground, unbalanced fan, unbalanced pistons and/or rods, uneven compression due to combustion chambers not having equal volumes, cylinders bored off center, main bearings not align bored correctly, flywheel not seated properly on crank shaft. Also, often mis diagnosed as engine: bad U joint, bent drive shaft,

[Fred]

1928 style front motor mount bolts loose/missing..

[ford1]

the biggest reason is the crank shaft is not counter balanced, you will hear guys say that is not the reason, i say if not why did ford start counter balancing them in 32?

[Keith True]

I have an early 31 Tudor that vibrates some from about 30-40 MPH.It really should vibrate a lot more.When I got it,I got it running after a 25+year sit.The head gasket blew within a week.It was a steel clad gasket,simply rotted.What I found was a surprise though.No two pistons protrude from the top of the block the same amount.The car shouldn't run that smooth.The windshield setting material had dried up,and between 30-40 MPH the windshield buzzes in the frame.In high school I worked for a man that patched up A's for people that used them to run to work in the mills.Most lived within a mile or two of the mills,and some owned those cars for 30+years.That guy did things to an A that he would never do for somebody that actually wanted an A for a driver.If you scored a cylinder wall,he would bore one,and put in a used oversize piston for you.He showed me one car that had four different size pistons in it.He only did this for people that drove 2-5 miles a day,and 30 MPH was as fast as they ever would get up to.Some of those would start to vibrate at 30 and just get worse from there.Mill pay ranged from $1.80-$2.25 per hour,so doing it 'right' wasn't in the cards.I remember somebody showing up with a JC Whitney rebuilt for him to install.He said we'd better look in it first.The owner said,why?it's a rebuilt.Two different sized pistons,different protrusions above the block,two regular connecting rods and two X rods(I still have them),three rod journals at .020 and one at .040.And,every time you turned the crank around,it would bind up on the cam gear in one spot so tight you could see the cam gear trying to bend upward.

[George Miller]

Originally Posted by James Rogers

Just thought I would start a thread to get opinions from barners about what might be the source of vibrations in a Model A engine. I have never run a totally original motor so, I don't have any experience as to that type of smoothness but, I have run several that were real shakers and one that was as smooth as a modern V8. I have some opinions of my own and will express those as this post progresses and others give theirs. I have found some places that I believe will cause vibrations that I have never been warned of expressly. Hope to hear lots of opinions so I can get verification of my findings and maybe help others calm their engines down some.

One thing I found on my 28 engine is that the cylinders were bored off location. They are not in the right location. Some one must of located from the worn spots in the cylinders. They were so far off the piston rubbed the rod at the wrist pin. Not sure that would make it vibrate, but not good.

[MikeK]

Volume inequality between combustion chambers. As-cast chambers can vary 10cc or more.

[James Rogers]

Well, this is not really going where I figured it would. I figured someone would mention the flywheel housing which, I think, is the source of most vibrations in the Model A drive-train. Many don't check it or don't know it needs adjusting because I find so many motors that don't have any shims under the throttle assembly mounts. I checked one last week and found the run out was in an unusual place. The flange was out .005 and the flywheel was out .003 at the outer diameter but, the housing was out .020. The unusual part was it was out at the motor mounts. There is no adjustment for this run out and most would not expect cast iron to flex and warp that much but, this did. I figure it was because of being run for years without shims in the top mounts and the frame bent. I don't know about this but it sounds as good as any explanation. I had the housing resurfaced and it was warped .016 from one mount to the other. This would throw the engine to transmission out of line a couple of inches from crank pulley to the universal joint. This, IMHO, would be a cause of vibration if all other sources are in spec. Might pay to check this on the next removal.

[Smitty]

So what then is normal vibration? I have 3:54 gears in my rear end and I am finding that from about 45mph and above I get some vibration. Also if you let off the gas at 45 and above the car is loud and slows quickly as if it were in a low gear.

Steve

[James Rogers]

Originally Posted by Smitty

So what then is normal vibration? I have 3:54 gears in my rear end and I am finding that from about 45mph and above I get some vibration. Also if you let off the gas at 45 and above the car is loud and slows quickly as if it were in a low gear.

Steve

I don't know what would be normal, I guess it depends on the person. I drove a Phaeton at Brent's shop that was the smoothest motor I have ever started. This motor is as smooth as a modern small block.

[Smitty]

My coupe has plenty of power and I am considering an overdrive only to reduce vibration and quiet the car. A smooth motor would be nice alternative if such a thing is possible.

[MikeK]

Originally Posted by James Rogers

Well, this is not really going where I figured it would. I figured someone would mention the flywheel housing which, I think, is the source of most vibrations in the Model A drive-train. Many don't check it or don't know it needs adjusting because I find so many motors that don't have any shims under the throttle assembly mounts. . .

Well, you really lost me on this one. Your original post was about vibration in the ENGINE, not drive-train. Now the subject changes? So, if you knew what you were looking for rather than having any interest in open suggestions, what was the purpose of your initiating this thread? To get on a soapbox and preach about what somebody else didn't do and you do? I get enough of that on Sunday. I'm not impressed.

[newshirt]

Originally Posted by James Rogers

Well, this is not really going where I figured it would. I figured someone would mention the flywheel housing which, I think, is the source of most vibrations in the Model A drive-train.

Flywheel housing was mentioned in Post #7. (Brent)

I'm new to this, so I'd like to understand how an improperly shimmed flywheel housing can cause vibration. I believe it can, but don't understand why. Can anyone explain it?

[Fred]

I agee, DRIVE TRAIN ?? rear end, cross members, motor mounts ?? U joints !!

[Milton]

"I'd like to understand how an improperly shimmed flywheel housing can cause vibration."

Because the shims go on the top two bolts and prevent the flywheel housing from being pulled out of alignment (bending) when the throttle is installed. If it is out of alignment then the transmission will not line up with the crankshaft. Eventually bearings in hard to get to locations die.

[Milton]

If the engine has modifications to increase power, the scrawny crank will allow rotational vibration. Bad news after a while but, can be remedied with a harmonic damper.

[Smitty]

I know that without the shims it is likely to develop cracks in the flywheel housing.

[30Tudor]

Good Thread. What is the run-out on the flywheel housing supposed to be?

[James Rogers]

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Originally Posted by MikeK

Well, you really lost me on this one. Your original post was about vibration in the ENGINE, not drive-train. Now the subject changes? So, if you knew what you were looking for rather than having any interest in open suggestions, what was the purpose of your initiating this thread? To get on a soapbox and preach about what somebody else didn't do and you do? I get enough of that on Sunday. I'm not impressed.

I am posting about the ENGINE. The vibrations caused by this are evident without moving the car and only the engine running. I stated in the FIRST post I had found some vibrations I had never heard explained by the problems I had found. I am not on a soapbox, I just found this and had never considered it before. Just a heads up for those who care. I certainly was not trying to impress YOU! If you don't like my post or have some personal problem with me, don't read them. As for Sunday, maybe you need to listen a bit closer.

[James Rogers]

Originally Posted by 30Tudor

Good Thread. What is the run-out on the flywheel housing supposed to be?

I believe .003 is the max run-out for the flywheel housing.

[roddyb34]

I am interested to read any information i can on Vibrations ,Fordbarn has informed me so much so far ,,i didnt know about the flywheel housing shimming ,as i am about to embark on an engine rebuild and refitting to the chassis i am keen to read everything ,,,thanks guys,,,

[James Rogers]

Originally Posted by roddyb34

I am interested to read any information i can on Vibrations ,Fordbarn has informed me so much so far ,,i didnt know about the flywheel housing shimming ,as i am about to embark on an engine rebuild and refitting to the chassis i am keen to read everything ,,,thanks guys,,,

Not knowing is only part of the problem. There is no good way to shim the housing in the horizontal plane. This means the housing needs to be checked and re-surfaced to make it flat.

[Rowdy]

James, while your idea has alot of merrit and I agree with it in a running vehicle I am not fully convinced that is the full reason. Case and point: a recently rebuilt engine ran on the stand with no transmission vibrated pretty good. The flywheel housing/ transmission alignement was not in the equation. This engine had been well balanced at the machine shop that built it. Had a well known and trusted person poor the bearings. Alot of attention to the details with this build.

Another engine in my shop put together on a budget has little to no vibration at all. Used crank that was just polished as it was round and was the riht size for the bearings as they were. NORS rods balaced the best I could. Ran on the same stand with no transmission

I have no idea why the one balanced by a pro vibrates, and the one pieced together doesn't. Rod

[Kurt in NJ]

On page 218 of Service bulletins it gives the specs for flywheel housing runout---
"If either the inner or counterbored face of the housing are out more than .006" insert a shim----"

This checking of runout can also be carried out to the trans case bores ---that is where checking of flywheel housing runout is intended to provide a straight line for the transmission shafts, the idea being that the centerline of the trans is the same as the engine.
With all that our cars have been through in the last 80 years perhaps the flywheel housing itself may need to have a non spec alignment to have a true alignment of the trans shafts.

[Richard Lorenz]

For Rowdy: If the balancing of the parts of the rebuilt engine were done separately only, this might explain the vibration. If the regrind of the crankshaft was not exactly on the original centerline, balancing of the flywheel while on the crankshaft would be needed.

[Rowdy]

Richard I discussed those issues with him when he called me before he started on it and I am sure he went the extra mile on it. I also discussed the issue of making sure the cyl bores were back where they are supposed to be. Knowing him for 30 plus years I am sure he checked all of this and did it properly. Engine is pretty snappy, just has the bad vibe. Rod

[BRENT in 10-uh-C]

Originally Posted by Rowdy

James, while your idea has alot of merrit and I agree with it in a running vehicle I am not fully convinced that is the full reason. Case and point: a recently rebuilt engine ran on the stand with no transmission vibrated pretty good. The flywheel housing/ transmission alignement was not in the equation. This engine had been well balanced at the machine shop that built it. Had a well known and trusted person poor the bearings. Alot of attention to the details with this build.

Another engine in my shop put together on a budget has little to no vibration at all. Used crank that was just polished as it was round and was the riht size for the bearings as they were. NORS rods balaced the best I could. Ran on the same stand with no transmission

I have no idea why the one balanced by a pro vibrates, and the one pieced together doesn't. Rod

Rod, what James is saying does have some merit IMHO but what are you thinking is the cause? James & I are finding that it is not uncommon to find flywheel housings that are .10+ out horizontally, --which means the shims really don't do a lot for correcting that issue.

Now two theories I have with this;
I know some people here are proponents of the Float-a-Motor mounting system but when you think about a Model A design, the rear wheels/tires are pushing the driveline forward to move the vehicle. The place that everything ties together is the rear engine blocks that attach the flywheel housing to the frame. When one of those blocks (mounts) becomes damaged/cracked, it only leaves one block to push the vehicle by. I am of the opinion that over time, the constant pushing/pulling force will "tweak" the flywheel housing enough for it to become out of specs. That is why I think the housing needs to be indexed off of the Clutch Housing (bell housing) mating surface and then flycut to ensure both surfaces are parallel.

With regard to your 'pro-built' vibration scenario, I think it is entirely possible the flywheel housing could still be warped and when you indicated the flywheel in while on the stand, it gave you a false reading. If you did not indicate the flywheel, I would start by using an indicator on the crank flange and see what you have. Then measure the flywheel using the back of the block as the base for your indicator. Once the flywheel is within specs, mount a bracket on the flywheel and indicate the Clutch Housing mating surface and see what it is. I'd bet something is not gonna be to your liking.


.

[Rowdy]

Since the engine is now in the car it is not likely the owner is going to pull it out to let me check, but it would not suprise me to see something. There was a slight issue with the cam timing gear when it was first installed, but that was corrected. I have an idea as to what the main cause is, but without some engine failure for me to investigate I will not get that chance. This is the same owner that has many body alignment issues with his coupe, but refuses to let me pull the body back off and fix the real problem which is the frame. Guesse he is one of those that is just content to say it is together, so it must be done. Rod

[MurphyJ]

Thanks James Rogers for posting this thread as I have been searching for a vibration in my "A" now for over a year. Any clues, suggestions, ideas or others are greatly appreciated as Ford Barn members have a vast amount of knowledge and experience.

[Louis]

Originally Posted by James Rogers

Good one and probably attributes to lots of engine vibrations. More?

.

Im kinda new to the model A, I also have a eng. vib. that I think is to much.
I looked under the car to look at the frt. eng. mount to see if it was to loose, But the frt. eng. mount looks nothing like the one on page 1-151 in Les Andrews hand book, instead of a spring this one has a large rubber cushion, Is this Pic. the correct frt. motor mount?
Should i leave it alone, or get one like the hand book shows ?
Thanks for any advice.

[marc hildebrant]

Interesting note.

I have vibration that starts around 40 MPH. One version is that they "all do it".

However, in the past I taked to a Model A owner of an original motor setup, who claimed that he would cruise at 55 mph with no vibration !

Sure would like to know if I should work on the vibration or not.

Marc

[Louis]

Marc,
My 31 coupe runs smooth at 35 and the vibration starts about 37-38 but then smooths out around 40-42. Seems like it run's better in a slight up hill then a slight down hill. Mine was rebuilt in 1972 and sat untill i bought it last year. But i don't have another A model to compair it to. I keep hearing about some that say they can drive there stock A model about 50-55 mph, I don't know .

[Barry B./ Ma.]

They seem to like it at 42-45 and beyond that get buzzy. My coupe has an overdrive and the comfort range goes up to 50-55. No two A's are the same so keep that in mind (one of mine is smoother than the other).

[30Tudor]

When we rebuilt my engine, we checked through three flywheel housings to find one that would work within the specified tolerance. I think the best I could do at the time was 0.004. Les Andrews recommends 0.006 maximum. I don't have any vibrations.....so far. Intersting that one of the flywheel housings that won't work for my engine worked fine with another engine.

I also think if you are going to use the float-a-motor setup that you should use the rear mount (the one that bolts to the universal housing and transfers load to the center frame cross member). I think the rear float-a-motor mount helps to carry some of the additional loads from the radius rods that Brent is talking about.

[pat in Santa Cruz]

Louis,
most aftermarket front mounts have been found to increase vibration. The one you have restricts the floating that a stock Ford mount would have, and probably transmits more vibration to the cross member. I think Henry's original design is best.

Originally Posted by Louis

.

Im kinda new to the model A, I also have a eng. vib. that I think is to much.
I looked under the car to look at the frt. eng. mount to see if it was to loose, But the frt. eng. mount looks nothing like the one on page 1-151 in Les Andrews hand book, instead of a spring this one has a large rubber cushion, Is this Pic. the correct frt. motor mount?
Should i leave it alone, or get one like the hand book shows ?
Thanks for any advice.

[James Rogers]

OK, today I picked a random flywheel housing out of a pild and checked it. The results were, horizontally it is dead flat and measures .000 on the exact same place side to side. It measures being out .020 in the vertical plane which can be shimmed out. This housing has some wear in places I wouldn't expect it to but this didn't affect the test. I say check the flywheel housing mounting flange and if it is out, have it re-surfaced.

[Louis]

Pat in Santa Cruz,
I think you are right, orig. design on order. I will let you know. Thanks for your helpfull advice.

[Steinar]

When it comes to adding shims between flywheel housing and engine, both for understanding why, and how, I will recommend the booklet 'How to restore your model A, Volume 4'. I picked up this one, and a few shims, before I started to bolt my flywheel housing up to my rebuilt engine. The book is published by 'Model A Ford Club of America' and refers to a Ford Service Bulletine of February 1928, where the importance of adding those shims are described. But in their own writings they also add a lot of drawings and photos which makes everything easy to understand.
As James Rogers says, I'm sure this is an important step to build a vibration free engine setup!

[James Rogers]

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Originally Posted by Steinar

When it comes to adding shims between flywheel housing and engine, both for understanding why, and how, I will recommend the booklet 'How to restore your model A, Volume 4'. I picked up this one, and a few shims, before I started to bolt my flywheel housing up to my rebuilt engine. The book is published by 'Model A Ford Club of America' and refers to a Ford Service Bulletine of February 1928, where the importance of adding those shims are described. But in their own writings they also add a lot of drawings and photos which makes everything easy to understand.
As James Rogers says, I'm sure this is an important step to build a vibration free engine setup!

I agree this is a very important step and not to be overlooked but, if after all the adjustments are done and the alignment is still out, check the horizontal plane of the flywheel housing. Resurfacing it just might solve the problem.

[James Rogers]

Originally Posted by fordgarage

I am wondering how the housing mounting flange can be 'out' and needing re-surfacing?
It is the datum surface for both location and perpendicularity to the virtual centerline of crankshaft, as defined by the back of block and the block dowel pins.
If cannot be out, in my view.

Practically everything else could be 'out', but the flange surface is a small footprint and is the interface datum to the back of block, and is 'good' by definition.

The flywheel housing mounting flange would be the very last surface on the casting I would ever tamper with.

It is also interesting that this entire thread has sidestepped discussion of how the pan rail surface is related to driveline vibration. That is as big a source as warped flywheel housings in my view.

I don't know how it got out but it is or was. The one I checked today has worn spots where the bottom of the block has worn into the housing. After 80 years you might find anything.

If you have insight as to the pan rails influence on vibration, don't let someone else bring it up, let's hear your opinion about it.

[tiquer]

My freind and I tore down a Model A moror once that had one con rod that weighd 26gr heavier on the big end and 16 on the small end than all the other rods. Tink it might have had bad vibes

[jrelliott]

Guess I am extremely lucky as everyone who hears my A run says it is the smoothest they have seen. Will idle down to less than 400 rpm when spark and throttle rods all the way up. Fires up in one revolution. Engine rebuilt by Byers in Rochester, MN and bearings poured by fellow Model A'er in Rochester.

[MikeK]

Now that I've been rebuffed (and rightly so!) for an earlier comment I made in this thread, I'll throw in some thought about drivetrain alignment.

Both the flywheel and clutch house castings flex under stress. Not all castings are created equal, their rigidity varies. One may flex only a few thousanths under the load of the drivetrain, another from a different heat of cupola iron may flex a great deal. Is it flexing in a way that is additive or subtractive to the static variance from 'zero'? It may run smooth on a stand and vibrate when installed with everything seemingly "in spec".

There are really two castings, not one that need consideration for the final transmission alignment. BOTH the flywheel casting and the clutch housing casting do warp from stress, heat cycles, and age. Even if both are seemingly within spec, the assembly of tolerances can either be additive or subtractive. That is, if each is 'off' 10 thou, the assembly of tolerances can be anywhere between zero (perfect) and 20 thou off. That would account for the same housing working differently in different builds.

Henry addressed some of this in the 'B' by making the clutch housing an integral part of the trans case.

[Rowdy]

I will add one more intersting note that has been discussed before. Sometime in post production these extra ribs were added. Did this have more to do with flexing or cracking? Rod

[JoeWay]

Lots of discussion about shims in this thread.

Some assemblers/builders, myself included, deliberately delete the shims on occasion. I do a trial fit of the flywheel housing without the gasket or shims, and if it dials in well I use RTV in place of gaskets and shims.

I started doing this after I noted that the gaskets supplied in different sets vary from 0.008" to 0.022" in thickness. This means that OE type 0.010" shims are only rarely the correct size. Using RTV to seal the camshaft, with a matching application at the housing ears, eliminates the difficulty of trying to match random gasket thicknesses.

I've since read and heard of other people doing the same. Don't be too quick to assume a problem if there are no shims in your assembly.

Joe

[eystein]

Originally Posted by James Rogers

Well, this is not really going where I figured it would. I figured someone would mention the flywheel housing which, I think, is the source of most vibrations in the Model A drive-train. Many don't check it or don't know it needs adjusting because I find so many motors that don't have any shims under the throttle assembly mounts. I checked one last week and found the run out was in an unusual place. The flange was out .005 and the flywheel was out .003 at the outer diameter but, the housing was out .020. The unusual part was it was out at the motor mounts. There is no adjustment for this run out and most would not expect cast iron to flex and warp that much but, this did. I figure it was because of being run for years without shims in the top mounts and the frame bent. I don't know about this but it sounds as good as any explanation. I had the housing resurfaced and it was warped .016 from one mount to the other. This would throw the engine to transmission out of line a couple of inches from crank pulley to the universal joint. This, IMHO, would be a cause of vibration if all other sources are in spec. Might pay to check this on the next removal.

Unusual ?

Is that really so, that it is unusual for the flywheel housing to be out at the engine mounts ?

Of the two housings that I tried for my engine, both the one that I discarded, and the one that I used was out at the engine mounts.

Had to use an uneven number of shims L-R, which of course makes the adjustment more complex.

[James Rogers]

Originally Posted by eystein

Unusual ?

Is that really so, that it is unusual for the flywheel housing to be out at the engine mounts ?

Of the two housings that I tried for my engine, both the one that I discarded, and the one that I used was out at the engine mounts.

Had to use an uneven number of shims L-R, which of course makes the adjustment more complex.

And it is probably still out. There is no way to shim the housing in the horizontal plane. If it is out there, it has to be surfaced to correct the problem.

[James Rogers]

Originally Posted by James Rogers

Well, this is not really going where I figured it would. I figured someone would mention the flywheel housing which, I think, is the source of most vibrations in the Model A drive-train. Many don't check it or don't know it needs adjusting because I find so many motors that don't have any shims under the throttle assembly mounts. I checked one last week and found the run out was in an unusual place. The flange was out .0005 and the flywheel was out .003 at the outer diameter but, the housing was out .020. The unusual part was it was out at the motor mounts. There is no adjustment for this run out and most would not expect cast iron to flex and warp that much but, this did. I figure it was because of being run for years without shims in the top mounts and the frame bent. I don't know about this but it sounds as good as any explanation. I had the housing resurfaced and it was warped .016 from one mount to the other. This would throw the engine to transmission out of line a couple of inches from crank pulley to the universal joint. This, IMHO, would be a cause of vibration if all other sources are in spec. Might pay to check this on the next removal.

This is how it should read. I found this mistake myself.

[BILL WILLIAMSON]

Originally Posted by 30Tudor

When we rebuilt my engine, we checked through three flywheel housings to find one that would work within the specified tolerance. I think the best I could do at the time was 0.004. Les Andrews recommends 0.006 maximum. I don't have any vibrations.....so far. Intersting that one of the flywheel housings that won't work for my engine worked fine with another engine.

I also think if you are going to use the float-a-motor setup that you should use the rear mount (the one that bolts to the universal housing and transfers load to the center frame cross member). I think the rear float-a-motor mount helps to carry some of the additional loads from the radius rods that Brent is talking about.

Yes, Model A's vibrate, you can't make a purse out of a Model A crank!! Even counter balanced crank engines sometime vibrate. Old Henry, (bless his soul), mounted crap as if he was building a stationary power plant.
My '30 coupe vibrated progressively worse and worse above 45 M.P.H.
I installed Float a Motor rears, complete with rear trans bracket and rubber block, rubber mounted the tail pipe hanger, Installed full Float A Motor front mounts (much like a Model B) The SECRET IS, when you drill the front crossmember bolt holes, enlarge the holes to 1" so the rubber from the lower pads can squeeze through the holes to insulate the long through bolt from crossmember. Otherwise, you have metal to metal contact from the engine mount plate direct to the crossmember, which makes it WORSE than the stock mount.
Mine was like a different car!! Very smooth at all speeds, and yes, it will run a true 80 M.P.H. top speed.
I would like to hear a response from the Float a Motor manufacturer, as they need to revise their installation instructions. Float a Motors are a great product if installed properly.
Conclusion: we probably won't correct engine vibrations, we just find ways to insulate those "power pulses" from the chassis and body in order to make the car more pleasant to drive. REMEMBER, this 80 something year old technology!
By the way, removing the clutch disc springs DOES NOT allow side to side movement of the disc on the splined hub and throw it out of balance. But it would shurely RATTLE AND CLACK!!

[Kohnke Rebabbitting]

Originally Posted by JoeWay

Lots of discussion about shims in this thread.

Some assemblers/builders, myself included, deliberately delete the shims on occasion. I do a trial fit of the flywheel housing without the gasket or shims, and if it dials in well I use RTV in place of gaskets and shims.

I started doing this after I noted that the gaskets supplied in different sets vary from 0.008" to 0.022" in thickness. This means that OE type 0.010" shims are only rarely the correct size. Using RTV to seal the camshaft, with a matching application at the housing ears, eliminates the difficulty of trying to match random gasket thicknesses.

I've since read and heard of other people doing the same. Don't be too quick to assume a problem if there are no shims in your assembly.

Joe

Joe, I would say as you, we have put more A's togather, that did not need shims, then did, and not always even on both bolts, and always leave the housing at least 24 hours, or longer, as when you have got it as close as you can, it most always changes with warpage in that time. Herm.

[MikeK]

Another concern is the spring center of the clutch. If you removed the springs how much radial slop/runout or off-axis side movement is possible between the hub and the friction disk? Any runout would allow clamping engagement under load that flexes the springs to throw the disk off-center from the hub and it will vibrate like mad. Those springs give the false impression that the disk stays true to the hub centerline.

If you took a cutoff wheel and removed the springs, how much off-center can the disk move? Does this vary between manufacturers?

Has anyone ever checked the balance of the clutch disk itself? Every time it engages it seats in a random place.

I once saw a HUGE mistake being made in a local shop. A flywheel/ pressure plate assembly was being balanced with the clutch disk in place. As soon as the clutch is actuated, balance is gone.

[Louis]

Originally Posted by pat in Santa Cruz

Louis,
most aftermarket front mounts have been found to increase vibration. The one you have restricts the floating that a stock Ford mount would have, and probably transmits more vibration to the cross member. I think Henry's original design is best.

Pat in Santa Cruz,
You were right, I removed that rubber donut that had a washer on both sides and was put on so tight that it had compressed the two top springs to where it might as well had been welded to the frame, After removing the hard rubber donut I then put on a spring and the brass support bushing that goes on the underside of the cross member and snuged it down, I could tell when i started it that their was a lot less vib. now 40-45 MPH, very smooth, Thank's for the helpfull advice.
Buy the way, removing that org. frt. motor mount by just jacking up the frt. of the eng. and removing the two bolts from the eng. and the one underside is impossible [for me anyway].

[RHD]

I fitted counterweights to my 30 Phaeton's crankshaft and it was as smooth as silk. The engine, clutch, crankshaft and flywheel were balanced by the engine reconditioner. I installed at the time, new rear engine mounts with fresh live rubber. (A repro set.) A lot of vibration can come through the rear mounts as previously said. Fan blade was a new Al repro. I know some engine reconditioners don't take much care with Model 'A' blocks as they should do, especially when they know it is not going to travel very fast. Many engines could be balanced a lot better with a little more care and consideration by the engine shop. They all charge enough.

[pat in Santa Cruz]

[/QUOTE] ...Buy the way, removing that org. frt. motor mount by just jacking up the frt. of the eng. and removing the two bolts from the eng. and the one underside is impossible [for me anyway]. [/QUOTE]

remove one rear motor mount to flywheel housing bolt from each side, then you can jack the engine high enough to clear the pulley with the front yoke. not removing the two rear bolts can crack the flywheel housing if you lift the front of the engine much.

Unless your car is a fine point Nov 28 thru Jan 29, replacing the brass washer with3/16ths flat washer might improve it a bit more. That's what Henry did.

[RHD]

I have just posted this as below, but it did not appear. Here goes again.

I fitted counterweights to my 30 Phaeton's crankshaft and it was as smooth as silk. The engine, clutch, crankshaft and flywheel were balanced by the engine reconditioner. I installed at the time new rear engine mounts with fresh live rubber. (A repro set.) A lot of vibration can come through the rear mounts as previously said. Fan blade was a new Al repro. I know some engine reconditioners don't take much care with a Model 'A' block as they should do, especially when they know it is not going to travel very fast. Many engines could be balanced a lot better with a little more care and consideration by the engine shop. They all charge enough.

[Louis]

Unless your car is a fine point Nov 28 thru Jan 29, replacing the brass washer with3/16ths flat washer might improve it a bit more. That's what Henry did.[/QUOTE]

Pat,are you saying a 3/16ths flat washer would be better then the brass frt. eng. support bushing ?..Is that because it is thiner and would give you more spring on the top two mount springs ?

[pat in Santa Cruz]

Originally Posted by Louis

Unless your car is a fine point Nov 28 thru Jan 29, replacing the brass washer with3/16ths flat washer might improve it a bit more. That's what Henry did.

Pat,are you saying a 3/16ths flat washer would be better then the brass frt. eng. support bushing ?..Is that because it is thiner and would give you more spring on the top two mount springs ?[/QUOTE]

the bushing fits tight into the cross member hole, somewhat restricting side movement. A flat washer allows that movement without allowing the mount shaft vibrations to be transferred to the cross member through the bushing. I have never tried to compare the two. I just use what Henry did on the appropriate year car. It would be interesting to see if you switch them and find any difference.

[Louis]

the bushing fits tight into the cross member hole, somewhat restricting side movement. A flat washer allows that movement without allowing the mount shaft vibrations to be transferred to the cross member through the bushing. I have never tried to compare the two. I just use what Henry did on the appropriate year car. It would be interesting to see if you switch them and find any difference.[/QUOTE]

I might try that later, but I am so pleased with the lower vib. I think I will drive it for a few days, And then try it.
It seems like if you allow the mount shaft to have side movement that the movement might cut into the shaft it's self over time, I don't know?
Any way right now, Im a happy guy .

[pat in Santa Cruz]

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it does not move sideways enough to cut into the shaft, although I have seen some on warped frames that did that. Henry tried that brass bushing for only 2 months then quit for some reason. I assume it was a good one, but it could just have been costs saving. He was a cheap one.

[James Rogers]

Try the brass bushing but just flip it over so the smooth side is against the frame. A little grease will help.