So, really, in a well tuned Model A, how much vibration is 'normal'?

[P.S.]

I have an unrestored Fordor that used to have the original motor in it, no balanced crank or anything, and it was pretty smooth. Got the motor rebuilt and it vibrates a bit more than it used to.

Also have a restored (fine point level) Tudor with a rebuilt motor that has all the fancy doo-dads like insert bearings, balanced crank, lightened flywheel, etc. and it vibrates the steering wheel right out of your fingers at certain RPMs! The body doesn't vibrate much, but you can sure feel it in the steerng wheel (all vibration is from the motor, not steering or road vibration)

So... How much Model A vibration is 'normal'? Is there any reason why the fully balanced motor should not be smoother than the unbalanced motor?

I'm not talking about Model As in bad shape, I'm talking about the Model As you guys poured your full effort into that you can reliably drive anywhere, anytime.

[mshmodela]

I cannot speak from a lot of experience but mine is smooth until the higher level rpm ~ 43mph... My engine has not been rebuilt with your above mentioned "doo-dads". I suppose
the only real way is to get some real life Model A's near you can get some LIVE opinions....

[Tom K.]

My stock 29 Tudor is smooth up to around 47 mph.

[BRENT in 10-uh-C]

Originally Posted by P.S.

I have an unrestored Fordor that used to have the original motor in it, no balanced crank or anything, and it was pretty smooth. Got the motor rebuilt and it vibrates a bit more than it used to.

Also have a restored (fine point level) Tudor with a rebuilt motor that has all the fancy doo-dads like insert bearings, balanced crank, lightened flywheel, etc. and it vibrates the steering wheel right out of your fingers at certain RPMs! The body doesn't vibrate much, but you can sure feel it in the steerng wheel (all vibration is from the motor, not steering or road vibration)

So... How much Model A vibration is 'normal'? Is there any reason why the fully balanced motor should not be smoother than the unbalanced motor?

I'm not talking about Model As in bad shape, I'm talking about the Model As you guys poured your full effort into that you can reliably drive anywhere, anytime.

Paul, one of the very issues with rebuilding an engine with parts today is the variance from original specified weights. When a crankshaft journal is machined undersized, then Babbitt fills the void in the rod. Now the big end of the rod is heavier. Next, a larger diameter piston is used which is heavier, ...and adding to that, the wrist pins are quite a bit heavier over the original pins weight. The bottom line is lighten the replacement parts to O.E specs, and you will likely find the smoothness returns.

[Pete]

Originally Posted by P.S.

I have an unrestored Fordor that used to have the original motor in it, no balanced crank or anything, and it was pretty smooth. Got the motor rebuilt and it vibrates a bit more than it used to.

Also have a restored (fine point level) Tudor with a rebuilt motor that has all the fancy doo-dads like insert bearings, balanced crank, lightened flywheel, etc. and it vibrates the steering wheel right out of your fingers at certain RPMs! The body doesn't vibrate much, but you can sure feel it in the steerng wheel (all vibration is from the motor, not steering or road vibration)

So... How much Model A vibration is 'normal'? Is there any reason why the fully balanced motor should not be smoother than the unbalanced motor?

I'm not talking about Model As in bad shape, I'm talking about the Model As you guys poured your full effort into that you can reliably drive anywhere, anytime.

Here is something that has been posted here several times before that may help.

The degree of balance in any rotating part is directly proportional to the rigidity of the mounting.
A 4 cylinder engine with a single plane crank cannot be be so called "completely balanced".
It has the same problem as a single cylinder engine.
You can only balance it for a narrow rpm range.
This is why you still feel a model A engine shake at certain rpm ranges even after being balanced.
You can change the rpm it shakes at but you can't eliminate the shake.
Certain types of industrial and racing 4 cylinder engines have achieved something close to ideal balance by using "balance" shafts. This is a counterweighted shaft that is mounted on the opposite side of the engine from the camshaft with the weights synchronized to counteract the vibration of the crank.
In a model A/B engine, the ideal situation would be to have the harmonic damper the same weight as the clutch/flywheel assembly to reduce harmonic vibration. This however will not eliminate the felt vibration.
It will prolong the life of the engine though.
We have achieved something about as close to this as is possible in the real world by using a 11 lb. aluminum flywheel with an aluminum clutch and a damper from a big block Chev. The only drawback to this as far as the car is concerned is you have to trim some off the back side of the front cross member to clear the damper. This damper weighs about 13 lb.
Reducing flywheel weight has an added advantage in making shifting easier and faster.
All of this modification will eliminate much of the TORSIONAL vibration but will not eliminate total engine vibration. You do not normally feel torsional vibration in the seat of your pants.
Crankshaft counterweights help reduce overall vibration by adding rotating mass and hence damping the felt vibration. There is not enough room in the "A" crankcase to add enough counterweight to achieve a comfortable "seat of the pants" vibration level. 60% is about all the weight that can be squeezed in without redesigning the whole engine.

[P.S.]

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Thank you Mike, Tom, Brent, and Pete.

Mike and Tom- Mine is too, but not perfectly smooth. It feels smoothest at about 52 MPH.

Brent- Yes, agreed. When I had the motor in the fordor rebuilt, it got reamed and sleeved, then original size pistons installed. No oversize or undersize anything. All exactly the same as stock (with exception of the valves). The original motor was silky smooth, almost unreal smooth. The motor having been rebuilt is not as smooth, but still much smoother than the Tudor's motor with oversize pistons, balanced crank, lightened flywheel, etc. Just wondering if that is normal.

Pete- Very well explained. OK, so this may almost sorta answer my question. So, the Tudor's super-touring rebuild isn't smooth, but the motor will last longer. Hmm... the rest of the car gets vibrated to heck, but the motor is happy. Sounds like I may have made a newbie mistake when I ordered the touring motor. I thought it was going to be smoother running. It sure runs strong though.

All- I don't want to rekindle the stock flywheel vs. lightened flywheel debate. I would like to point out that having put several thousand miles on both, I really prefer the stock weight flywheel driving experience.

[burner31]

It all depends on how smooth the road you are driving on is.

[Fred K-OR]

Originally Posted by BRENT in 10-uh-C

Paul, one of the very issues with rebuilding an engine with parts today is the variance from original specified weights. When a crankshaft journal is machined undersized, then Babbitt fills the void in the rod. Now the big end of the rod is heavier. Next, a larger diameter piston is used which is heavier, ...and adding to that, the wrist pins are quite a bit heavier over the original pins weight. The bottom line is lighten the replacement parts to O.E specs, and you will likely find the smoothness returns.

This thread is very informative for a person like me that knows little about the subject of "hopping" up an engine when rebuilding.

When I had my huckster engine rebuilt I was the "cheap" guy and ask my rebuilder to re-use everything that he could and only replace parts that needed to be replaced. From what is being said here on this thread, I may have made a reasonable decision in the area of having an engine that has little vibration but on the other hand is not the ideal touring engine. I feel I made the correct decision in that I only use it for a "driver" around my local area. Anyway I thought I would mention this for someone that may be considering doing all the things mentioned above and may not enjoy them after getting their engine back.

Brent and all, am I thinking correctly or am I giving out incorrect info? If so please correct me. And thanks for the informative info.

[Tom Wesenberg]

As far as too much vibration, I worry that the crank grinder may not get the flywheel mounting flange EXACTLY centered on the rear main journal. Or, I should say the rear main journal centered to the flywheel flanged, since the flange doesn't get ground.

[Mike V. Florida]

Originally Posted by P.S.

I have an unrestored Fordor that used to have the original motor in it, no balanced crank or anything, and it was pretty smooth. Got the motor rebuilt and it vibrates a bit more than it used to.

Also have a restored (fine point level) Tudor with a rebuilt motor that has all the fancy doo-dads like insert bearings, balanced crank, lightened flywheel, etc. and it vibrates the steering wheel right out of your fingers at certain RPMs! The body doesn't vibrate much, but you can sure feel it in the steerng wheel (all vibration is from the motor, not steering or road vibration)

So... How much Model A vibration is 'normal'? Is there any reason why the fully balanced motor should not be smoother than the unbalanced motor?

I'm not talking about Model As in bad shape, I'm talking about the Model As you guys poured your full effort into that you can reliably drive anywhere, anytime.

The answer is very little and for sure if it really "vibrates the steering wheel right out of your fingers" you have something wrong with the engine and or mounts.

[SSsssteamer]

From experiences: Our '29 Tudor had only 55,000 miles on it when we first purchased it in 1968. It was smooth all the way to 70 mph, until one day that number three rod lost its rod babbit. Replaced the rod with a used one that seemed to fit correctly. It vibrated there after. Eventually replace the original engine with a model B engine and still used the A flywheel. It has been smooth as silk to 70 mph. No vibration in the mirror or anywhere. Our 30 Phaeton has a touring motor by H & H. All the bells and whistles added including a lightened flywheel. Anything above 45 mph vibrates terribly. I will put the stock flywheel back on to the motor the next time that I have it apart. The moral of the story here is: original engine parts that came together from the factory are the best balance. After that, a full weighted flywheel over a lightened one will give a smoother running engine.

[mike657894]

mine is very smooth suprisingly so for a solid mounted engine. i haven't got it going more than 40 though i dont think. my speedo is broken, full stock

[H. L. Chauvin]

Hi P.S.,

Model A engines were designed to run smoothly.

One (1) shared experience:

Several years ago after calling him & speaking to him, I mailed my crank and flywheel to Mr. Ron Kelley, RK Designs in Royse City, Texas; (972) 771-1911.

He provided counterweights, lightened my flywheel, added a new clutch plate, and balanced all three (3) items and marked bolt hole positions for each. He also provided a new flywheel ring gear and Dan McEachern crankshaft gear.

I bought a new digital Gram scale, and bought four (4) new 0.125" oversized pistons & new rings from Rainmaker Ron at Standard Auto in Illinois, and found all four (4) sets of pistons and rings weighed the exact same number of grams.

Bought connecting rod castle nuts and washers from different Model A Supplier sources, and also bought same locally to interchange to achieve exact same number of grams on the Babbitt ends of connecting rods.

After some time, finally all four (4) pistons, rings, and connecting rod assemblies weighed exactly the same when weighed on opposite ends or individually as a whole.

Always takes just a little more time to do anything correctly and once.

Engine idles and runs smoothly at all RPMs; however, I never exceeded 55mph & have no idea of top speed.

If you call Mr. Kelley to inquire about remedies for Model A engine vibrations, I think you will be glad you did.

Just hope this helps.

[Synchro909]

The Ford crank with the additional side weights were one piece and shrink fitted on AFTER grinding the crank. The side portions are not removable. Some guys bolt on the additional section to facilitate crank service at a later date.

Here is a first-class job and picture posted by Bill Stipe in a previous related thread on the same subject. It appears that you started that other thread on 11/19/2014! Of note in Stipe's work, the attachment is through collars on the added side pieces. The side weights present no sheer load to the fasteners.
The above was posted by Mike K in a previous thread about crank shaft counterweights along with a picture of a crank shaft in Bill Stipe's workshop showing extra weights added to the side of the usual add on weights. Does anybody know how well this works. If Bill has been doing it, I expect it will be a good thing. The reason for my asking is that I am about to do the same thing to a new Burlington shaft so long as it works.
The way I see it, counterweights obviously work or Henry wouldn't have gone to the trouble, let alone the expense.

[Tom Wesenberg]

I'll try to find that picture of Bill Stipe's counterweights, but Mike V. is much better at searching than I am.

Bill's crankshaft is the one I'd like to use in my engine, and I was thinking of making some weights like it. I don't have the equipment though, so I bought the heavy weights that Dan Price sells, which are like the ones Ford installed.

[Kevin in NJ]

What is typically missing is the full understanding of what it takes to balance the A engine.

First you start with the crank. Few crank grinders are going to get even close to the required precision to make the crank right. They can not even get the modern cranks close to right and they are not going to spend the time to get your little simple 4 cylinder crank right. So expect a normal crank grinder to not get the radius right, grind the mains off centers, get the throws off in distance, and not get the flywheel close to center.
Keep in mind a NOS Ford crank (from early 30's production) will be spot on in all dimensions. Of course the big thing is getting that flywheel to something close to less then .001" from center.

Then there is the whole balance thing. The crank needs to be accurately balanced. That is not too hard to do since the machines today practically do the job for you. The rods are a different story. Ford made them to +-1 gram at each end. Rods today are done to 5 grams total weight, not good enough. Then the pistons, which were kept to a couple grams each, were added on and the units weighed and put in a bin. So on the line any 4 units taken from a bin would be within 4 grams of each other.

So you can see Ford did some precision race car type building on the engines. I do not think you get that with all the builders. I know in some discussions some flat out do not believe what I tell them even though I am reading what the print says and is backed up with parts that have been measured.

Then you have other areas the affect vibrations. Put in a worn cam or even a regrind and you introduce some variance in how each cylinder fires. You also need to consider the metal of the valves and the diameter of the head of the tappet. They all have a factor.

Oh and what about the play on the upper dist plate allowing the point gap to change a few thou each time you change the left lever?

A lot of little things add up to some odd behaviours in the engines. In fact, I believe many of the vapor lock issues are really just something not done right with the valve train coupled with other slightly out of wack parts.

To rebuild the A properly you have to pay attention to every detail if you want it to run right. It is not cheap, fast or easy to do it right.

[George Miller]

My experience is the crank is ground off the center line. Rods and pistons not weight balanced. Flywheel and clutch not balanced.

If the crank is ground off the center line, you will have 60 lbs of flywheel plus clutch and pressure plate jumping up and down. When ever thing is right, you will not feel bad vibration while driving your A. But A inline 4 cylinder does have some at certain speeds.

[ericr]

my question might be, are we to believe that when the engines were rebuilt by dealers when the cars were relatively new, that all of these finepoints were observed? I would find it hard to believe that they were, given how replete the Service Bulletins were with castigations about mechanics doing dumb things.

[BRENT in 10-uh-C]

Originally Posted by Kevin in NJ

Few crank grinders are going to get even close to the required precision to make the crank right. They can not even get the modern cranks close to right and they are not going to spend the time to get your little simple 4 cylinder crank right. So expect a normal crank grinder to not get the radius right, grind the mains off centers, get the throws off in distance, and not get the flywheel close to center.

Kevin, I am not disputing what you are saying but am questioning a few comments based on my personal experiences. I do not know if you own a crankshaft grinder but when I purchased mine (a Storm-Vulcan 15), I had a huge concern based on comments I had read by others. What I came to learn after experimenting with my machine and paying for tutoring is much of these concerns were really just fabricated hype by someone. In other words, it really isn't that hard to center or grind a crank correctly if you have a machine within spec, -and an operator who pays attention to what they are doing. My machine uses centers to hold the crankshaft which most knowledgable folks tell me that is more than adequate providing the machine is within specs. With a dial indicator, I can tell within a few moments whether the crank is running true with the machine. If it isn't, I can make it true in less than a couple minutes. If I can do it, I'm sure others more experienced than I can do the same!

What I have found is, every once in awhile I will encounter a crankshaft that is twisted or bent where there is major run-out in the center journal. This is a quick fix in a crank press. So, doesn't it really boil down to whether someone has a conscience machinist? Most quality shops (which I think are more predominant than we sometimes give credit for) have the equipment and the craftsmanship to be able to turn out a quality machine job.

The only downside to crankshaft work is the time involved. For me, I have about 3 hours in doing a quality job. Until recently, it seems the going rate was about $120 for a machined crank, ....which is about the same price shops were charging back in the 1980's. With the cost of good equipment and labor, it is unprofitable at that price.

[larrys40]

Brent, I agree with your aaseent as like mine now there are plenty of opinions with less experience than with more experience . I haven't ground cranks but have watched it done and the straightening process . It's incredible how easy a model a crank bends... In fact it's a wonder it stays good when running .
I believe most machinest who are still at shops doig this type if work are capable competent machinest, the just need to understand the crank and frailness of it compared to other cranks.
In my opinion the biggest vibration factor aside from the other simple factors of stuff like engine mounts etc is rods . The new inserted AER rods as a set straight and balanced will greatly run smoother than serviced originals that have been through the mill

Just my quick 2 cents worth . I've driven plenty if A's that were silk smooth as older babbited engines without counterbalance and other mods. Just goes to show you it can be so
Larry Shepard

[P.S.]

Wow! So much information. Thank you, guys.

It appears that I have to decide how much vibration is acceptable and find a machine shop.

[Mitch//pa]

Call rich at AER and pick his brain

[ericr]

I think since this in such an important subject to us owners, it would be appropriate for members to relay who rebuilt their engine and got a smooth-running result, which is not to exclude other rebuilders, just relaying a personal positive result.

[George Miller]

I use to grind cranks in my Dads garage many years a go. Also ground them in the car if they lost one rod, not the best way but back then that is what people wanted.

Model A crank is very flexible. If you grind the center main you have to be very car full that you do not push the crank off the center line. It is a balancing act between the grinding wheel and the steady rest that supports the center main when you are grinding. You also need to be very care full that you get the crank on true center line.

The ones I see today that have been ground, have run out at the center main. Run out at the flywheel flange. Plus they do not have enough radius at the rod journals. This is also important because that is the weak point that will break first.

[tennsmith]

Where does one find the rod big end and little end weights, wrist pin weights, piston weights, etc.

thanks

[Al 29Tudor]

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Originally Posted by ericr

I think since this in such an important subject to us owners, it would be appropriate for members to relay who rebuilt their engine and got a smooth-running result, which is not to exclude other rebuilders, just relaying a personal positive result.

I agree!
It's such important information it would be nice if folks would share it.
Al

[Mitch//pa]

Originally Posted by ericr

I think since this in such an important subject to us owners, it would be appropriate for members to relay who rebuilt their engine and got a smooth-running result, which is not to exclude other rebuilders, just relaying a personal positive result.

Your going to get mixed reviews without a definitive answer. There are to many variables and causes for vibrations.

[H. L. Chauvin]

Very Precise Results ??????

Lots of time precision work comes from the guy who doesn't talk much, never brags, but can out perform any task handed to him in working with wood, steel, plaster, masonry, electronics, sheet metal, or whatever.

Just one (1) example:

Grab 1,000 guys in any town and hand them a fiddle after offering a $3,000,000.00 prize as to who can best play "Mary Had a Little Lamb" after practicing for one (1) year.

Come back in one (1) year to witness who has developed the hand and eye coordination and the precise timing and dexterity to operate a fretless instrument with one hand and a bow with the other.

Could be the loud mouth alcoholic who smokes cigars, could be the corner lawn mower repairman, the guy delivering the mail, or the chicken plucker who rides his bike to work every day.

One thing is certain ....... there will be an enormous difference between the talented and gifted winner and the loser.

In the end, after hours and days of discussion during the one (1) year trial period, one never really knows the final results until one hands them a fiddle ....... appears it is not much different with Model A engine rebuilding.

[BRENT in 10-uh-C]

Originally Posted by ericr

I think since this in such an important subject to us owners, it would be appropriate for members to relay who rebuilt their engine and got a smooth-running result, which is not to exclude other rebuilders, just relaying a personal positive result.

While I suppose that would have merit, doesn't it really boil down to what the customer is requesting his machinist to do? A more brutal way to say it is that often it boils down to what the machinist is being paid to do.

For example, if a customer walks into any experienced Model-A shop and asks specifically for them to match reciprocating parts and to balance them to factory specs., doesn't the logic say that each shop will likely build an equal-smooth running engine? For every hobbyist out there who will spend the extra funds to have a 'blueprinted' engine, there are likely three other hobbyists who will not spend the extra money necessary to have that 'blueprinted' engine. IMHO, it is those hobbyists that give most Model-A engine builders as a whole a bad rep.

Originally Posted by tennsmith

Where does one find the rod big end and little end weights, wrist pin weights, piston weights, etc.

thanks

I have collected most of my info from studying the factory blueprints which I obtained from the Bensen Library.

[Chris in WNC]

extremely subjective from car to car. some anecdotal examples:

our Town Sedan had a counterbalanced crank and was smooth as silk even at 60MPH.

our low mileage unrestored Coupe NEVER ran smoothly even after a counterbalanced crank was added.

our unrestored Tudor ran very smoothly with no modifications to the factory engine.

your results may vary.......

[ericr]

Originally Posted by BRENT in 10-uh-C

While I suppose that would have merit, doesn't it really boil down to what the customer is requesting his machinist to do? A more brutal way to say it is that often it boils down to what the machinist is being paid to do.

For example, if a customer walks into any experienced Model-A shop and asks specifically for them to match reciprocating parts and to balance them to factory specs., doesn't the logic say that each shop will likely build an equal-smooth running engine? For every hobbyist out there who will spend the extra funds to have a 'blueprinted' engine, there are likely three other hobbyists who will not spend the extra money necessary to have that 'blueprinted' engine. IMHO, it is those hobbyists that give most Model-A engine builders as a whole a bad rep.








I have collected most of my info from studying the factory blueprints which I obtained from the Bensen Library.

I am not sure the customer always has the expertise to know what to ask for.

[hardtimes]

Hey P.S.,
Lots to digest here !
Sorry to hear of you feeling the strong vibrations...through the steering wheel...with an expensive engine rebuild. IMO as an neophyte builder, there is a great variety of 'things' that can and do make an engine shake. Lots of those reasons discussed here so far. I had a B engine built , up north calif, about 12 yrs ago.
NOS B block, brand new full B crank drilled, NOS B cam and set of new Crower rods.
I think that you know the guy who was responsible for my B build. I mention all these NEW parts, because they were double checked and installed into a NOS block.
This engine runs strong , fast and SMOOTH ! Just saying that what a guy puts into any engine is indicative of what will come out. Like when Ford put in all new balanced parts and we all loved what he did then !

[ericr]

there can be more than one way to look at this:

https://youtu.be/Eab_beh07HU

[hardtimes]

Hey ericr,
You are spot on with this statement , IMO and experience ! Most guys do not build engines. Nor do we have the expensive equipment and extensive knowledge necessary to use such. These are reasons why we have to pay such ridiculously high $ to have , what we hope/pray, is high quality end product. Alas, it doesn't exactly work that way, because as customers we put limits on what time the builder spends in time/parts/work. To the ethical builder, time is money also. If you pay enough , you should get what you want (perfection?) but does THAT builder have the skills/ethics to deliver. I just know ONE guy who did deliver for me. However, to your point, I didn't know all that I should have, then, to get what I ultimately wanted....which would have cost more $. Getting experience is expensive . If I'd only known then , what I know now...would I have spent the extra $

[BRENT in 10-uh-C]

Originally Posted by ericr

I am not sure the customer always has the expertise to know what to ask for.

Very true Sir, ....however I can also share with you that many customers (in all type of businesses) already have their mind made up when they go shopping.

More specifically to prove my point, look at how many hobbyists here on this forum have their minds already made up on what is the "best" when a topic is discussed. Often times, these folks are not really interested in what the experienced person's advice is. I tend to believe that prudent shopper will always get several opinions from people with actual verifiable experience. As we know, often times a cheap price interferes with what is best. If the customer does not have the expertise in what they need to be asking, then who is at fault? Surely not the machinist's fault who likely was only following the direction given to him by the customer.

[ericr]

Originally Posted by BRENT in 10-uh-C

Very true Sir, ....however I can also share with you that many customers (in all type of businesses) already have their mind made up when they go shopping.

More specifically to prove my point, look at how many hobbyists here on this forum have their minds already made up on what is the "best" when a topic is discussed. Often times, these folks are not really interested in what the experienced person's advice is. I tend to believe that prudent shopper will always get several opinions from people with actual verifiable experience. As we know, often times a cheap price interferes with what is best. If the customer does not have the expertise in what they need to be asking, then who is at fault? Surely not the machinist's fault who likely was only following the direction given to him by the customer.

I think you are 110% correct: people have their firmest opinions, about which they know the least.

[H. L. Chauvin]

Excellent advice given thus far about certain customers.

Keen insurance representatives who insure businesses and/or professions carefully repeat this same scenario often where:

A sure way to get in trouble and quickly obtain a bad reputation is to try to "help" someone by doing "half" of a project and allow some other "unknown" person to "try" to finish the other half.

After failure, the one who performed the first half correctly usually witnesses "finger pointing" for the rest of his life for something done later that he never even touched.

Finger pointing ?????

Most elections are won this way ...... appears the majority never caught on ..... yet.

In reply no. 29 above, the Chicken Plucker's wife, (who wasn't mentioned), won the fiddle contest ...... just thought you wanted to know.

[Pilotdave]

After reading all of this thread (whew!), it seems that the most helpful information would be a summary that educates us non-engine builders as to what we should ask for to get a particular "smoothness result". I'm thinking that this information is embedded in some of the posts above, but wouldn't it be helpful to know what to ask the rebuilder for? Often I think these topics boil down to understanding the terminology and how to ask for what we want...I suspect that the ethical rebuilders would explain options and make the choices clear to the novice, but an educated consumer is a powerful tool.

To this point.....please see Brent's last post (#35)!

[CarlG]

Originally Posted by BRENT in 10-uh-C

... often times a cheap price interferes with what is best...

To get "the best" many times one has to "pay the price" as well as wait in line, sometimes for an extended period of time.

[Mike V. Florida]

With what was stated here one should ask the builder, "what do you do to get a smooth running engine". Listen to his answer. Does he state weight, balance whole assemblies and so on? Yes, most likely good to go. If you get something like, "we have been doing this for XX years and we know what we are doing", go elsewhere.

If one were to do a search of the builders here on the forum you will find out that they all have mentioned step by step what they do when the build customers engines. Some have also contributed to this thread.

[DougVieyra]

I set a dime on edge at the top of the front left fender. With engine running and transmission in neutral, If the dime remains 'standing' during all phases of the quadrants, I am happy with the vibration level of my Model A.

[colin1928]

Another area that needs to be addressed is the flywheel housing alignment
I have seen a miss aligned/cracked/broken flywheel housing cause the same amount of vibration as talked about in the OP

[P.S.]

Follow-up:

SO, I knew the motor was rebuilt properly (a "touring motor" from a very popular Model A motor shop that has a reputation for very good work), the problem had to be me. It was.

When I had the motor rebuilt, I requested the "touring motor" package and got it. Toward the end of the time he had the motor, he called and asked me to bring the clutch pressure plate over so he could have it balanced along with the flywheel. I was away on business and could not get it to him in the timeframe he requested. Since the pressure plate came off my other motor and was "balanced", I didn't think it would be a big deal. The rebuilder had the motor running on a stand when I picked it up, and it was smooth. I took it home, installed it, and it ran STRONG, but vibrated as mentioned in the OP. Not teeth-shaking vibration, but enough to make the rear view mirrors 'blurry' at certain RPMs. I just assumed that was normal.

OK, now fast forward.

I got another flywheel from a friend (adopted dad) that was stock weight. I took it and another original pressure plate to a machine shop and had them balanced. He first balanced the flywheel alone, then he mounted the pressure plate to it and balanced it. He marked where they mated on the balancing machine, so I could reassemble the same way. Last weekend, I swapped the flywheel and pressure plate in the tudor.

Using suggestions from fellow barners, I removed the rear end and tranny so I could run the motor with the flywheel and P-P combinations as an experiment. With the old flywheel and P-P, the motor vibrated. Removed the P-P and clutch disk, ran it again. Less vibration. Swapped the flywheel to the new full weight flywheel. MUCH smoother and quieter. Installed new P-P and clutch disk- Still smooth and quieter. Verified they were running true, reassembled the car and drove it.

First impression - It is MUCH smoother and quieter! Not quite as smooth and quiet as the 99.9% original fordor, but pretty close. Keep in mind, I am now running a counterbalanced crank AND a full weight flywheel (I'm sure I will get flamed for this). It will idle down to 200 RPM, and keep running. Sound level inside the car while driving at highway speed is about half of what it was before.

Gear shifting- No difference. Shifts exactly the same as before.

Hill climbing - This is where I notice a major difference. Going home, there is one road that is a steep climb for a little over 1/2 mile, and almost all straight. With the previous flywheel in place, I could make it maybe 1/3 of the way up that road, then would have to downshift to 2nd for the rest of the climb. Having changed nothing else except the flywheel and P-P, I can now take the whole hill in 3rd gear, no sweat. It is as if I added 10 HP that is only noticeable when climbing hills. On the flat and level or on a downhill, there is no difference from the lightened flywheel. Only notice this when climbing steep hills.

Even on the gentle rolling hills on the highway below, you sorta notice it there too. I don't have to give it as much gas to make the hills now. Yes, when revving the motor, it takes a fraction longer to spool up. It is barely noticeable though.

I am no motor builder and no machinist, I'm an electrical engineer. So, I am not prepared to argue the engineering for a lightened flywheel. However, as a Model A owner, I am convinced that the flywheel weight Henry Ford chose is much better than the lighter flywheels popular now.

[mshmodela]

P.S.

Thanks for the detailed report... as a former EE myself (do programming etc. now) I recall that one can make "moment of inertia" of a flywheel greater with more mass from the center --or by removing mass from the center.. e.g. pulleys that that are not solid, e.g.



I would guess a lightened flywheel is similar to some degree --maybe.

[Mitch//pa]

Paul I am glad the ideas seemed to work out and your vibration is basically resolved

[Barry B./ Ma.]

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They are all different, I've had smooth ones and have had rough ones. Probably matched weights and assembly are different also some have balanced crankshafts. My present coupe is smooth right up to top speed and doesn't have a balanced crank.
P.S.
When I originally bought the coupe back in the early eighties the original engine vibrated so much the rear inside mirror shook. That engine ended up in another car and it vibrated there too, had it rebuilt and it still vibrated.

[RonC]

Originally Posted by P.S.

I have an unrestored Fordor that used to have the original motor in it, no balanced crank or anything, and it was pretty smooth. Got the motor rebuilt and it vibrates a bit more than it used to.

Also have a restored (fine point level) Tudor with a rebuilt motor that has all the fancy doo-dads like insert bearings, balanced crank, lightened flywheel, etc. and it vibrates the steering wheel right out of your fingers at certain RPMs! The body doesn't vibrate much, but you can sure feel it in the steerng wheel (all vibration is from the motor, not steering or road vibration)

So... How much Model A vibration is 'normal'? Is there any reason why the fully balanced motor should not be smoother than the unbalanced motor?

I'm not talking about Model As in bad shape, I'm talking about the Model As you guys poured your full effort into that you can reliably drive anywhere, anytime.

P.S before you blame the engine one source of vibration is misalignment of the drivetrain. From the factory Ford set the engines so that you could draw a straight line from the crank pully to the back transmission spline centers. There are two adjustments. One where the flywheel cover attaches to the engine and one at the front motor mount. See the service bulletins for the adjustments. Who is installing your engines?

[P.S.]

Originally Posted by RonC

P.S before you blame the engine one source of vibration is misalignment of the drivetrain. From the factory Ford set the engines so that you could draw a straight line from the crank pully to the back transmission spline centers. There are two adjustments. One where the flywheel cover attaches to the engine and one at the front motor mount. See the service bulletins for the adjustments. Who is installing your engines?

Thank you for bringing this up. I am aware of the drivetrain alignment issues. To answer your question- I installed my own motor each time.

As mentioned in my post from yesterday, the vibration could be felt any time the motor was running, even with the entire drivetrain removed from the car and the flywheel exposed.

Thank you to Mitch, Marco, Brent, and many others for helping in this thread, by PM, email, etc. I learned a LOT!