Does anyone know anything about the assembly of the clutch using the method of two large disc's then two small disc's and so on ending with a large one .... if so what are the advantages and or dis advantages..... Thanks Joe .... firstname.lastname@example.org
The advantages would be none.
Disadvantage - the clutch won't work right, and you will have to tear the engine apart to fix it.
The Ford clutch works great if you put it together right, with all parts in good condition. Be sure to use a suitable oil for weather conditions.
I have run this set up for 6 years and 38k miles with no problem, several friends have also done this and seem to have a better neutral. KB
I don't see any advantage. You cut the friction surface in half. Of course you'll have a better neutral. You might as well remove half the disks and add a spacer to fill the gap.
Joe - I have a feeling that you would have to add more spring pressure to make up for the loss of friction surface that Ken Kopsky pointed out. Can't see any advantage to that,....harold
There is no disadvantage I can find as we have plenty of hills here in Tn and I have no trouble with clutch slippage or anything else. Every one is quick to criticize others work having never tried it themselves, I have great respect for other opinions on this forum and try not to be a nay sayer about things I have not done or had experience with. Everyone has a right to their opinion but sometimes we need a basis in fact, which I do have on this subject. That is all I have to say about it. KB
I don't have to try and send a bottle rocket to moon to know it's not going to work. Engineering tells me it won't work.
Removing half the disks, which is what you are doing by doubling up on disk back-to-back, not only reduces the friction surface but also increases slip and heat. The same horsepower must be transferred through half the usual number of the disks. Whether you have problems or not is of no consequence to the facts. You're just lucky you haven't burned your clutch up... yet.
Gee this sounds like the skinny tire has less stopping power debate.
Engineering science tells us definitively that the width of the tires has essentially no effect on traction.
Force of friction is determined by co-efficient of friction multiplied by clamping force (or for tires the weight on the tire). Contact area is not part of the calculation.
Yes wider tires will last longer in high force situations as there is more rubber to wear off.
So Ken your statement is absolutely incorrect.
And so if the clutch is slipping a lot then you will get more wear to the plates. Now I must say that I have not encountered worn out clutch discs in stock T clutches . Maybe others have.
Here's a fact based on experience; You don't need rear axle nuts.
What's lacking is some critical data. Like I only moved the car six feet in the garage. But the fact must be true because I did it and it worked. So can we say that all axle nuts can be left off the cars? I think not but you are free to do as you wish with your car and have a great time with the experiences. You don't have to change anything. But if you're suggesting an engineering change for everyone, you may get a difference of opinions. That's all I'm saying on the matter.
Hardly a relevant comment. But I guess no surprise there either!!
We were typing at the same time and my comment was just a follow up to my previous post. But it's clear you didn't follow anyway and just out for an argument.
Your statement is incorrect.
First off, your using the friction force calculation in the wrong way to prove the tire trick. Second, it applies to dry surfaces. In any case, if your claim was correct, all modern cars would come equipped with bicycle tires and 3" disk brakes. You are assuming "applied load" (not clamping force) remains the same. It does not. The applied load decreases as more disks are added and so does the friction force. Try running just two disks in your clutch and see where you go. Your saying there's no change?
"Yes wider tires will last longer in high force situations as there is more rubber to wear off. "
Dry surface/wet surface; No difference to the calculation. The wet surface has a lower coefficient of friction than the dry surface as a general rule.
Lets see if you can explain the difference between "applied load" and clamping force!!
Lets see now;
We have a stack of discs that "float" in slots in the hubs. So the clamping force anywhere in this stack is identical. Now we all know that problems can occur in clutch release (causing excessive drag) if there are grooves worn in the slots. Ford eventually accepted this as a problem with the '26 model. But I digress.
So lets talk about disc brakes as you seem to need a education there as well. Naw lets not. You are just being silly now!!
I had to go look it up. I was confusing torque braking when I said load decreases but Now you're just being silly. Clamping force is not a term used in the formula but I understand what you mean. The formula states: Friction Force = CoF x Applied Load. Applied load is the force, usually given in mass, applied between two surfaces. And yes, the surface area is not considered. BUT.. There's more than just two surfaces in contact with each other in the clutch pack and each pair have their own friction force. You can't just forget they are there. The sum of the forces is the total friction force. When you remove a pair of surfaces, you lower the total friction force.
If you use the common example of the block pulled across a surface, note that it is for one block (two surfaces). The clutch pack is multiple blocks being pulled across the surface at the same time and each block requires a certain amount of force to overcome friction.
My point remains the same.
Keith you are right on the money !this set up is called the watts clutch I have run it for years I bought it from R V Anderson I to was scheptical -I have built a strong power plant -when properly installed / adjusted it works great.you do have to have smooth lugs in the brake drum,
I hope R V pipes in on this.
In no way am I claiming to be a expert ,as some of these other guy's who have been reading text books for the most part of there lives,I only have a good high school education [THANKS to my MOTHER rip] I have been turning wrenches for 40 plus years.I don't comment on things that i'm not familiar with, but there is one guy on here that is a expert on every thing! and is not open to up grades/modern ideas except if it's concerning his vehicle-as far as I know Henry never painted anything orange the closest was the red oxide primer and i'm not sure that was original.
I think you are both correct, you just don't see it yet
What makes the difference between the two trains of thought is; one clutch plate can work, but at what diameter and at what safety factor for uniform load?
That actual diameter required to transmit may in fact not be all that different than what we have and the rest is for heat dissipation, hope for less cupping warp under heat, etc.
The power transmission engineering rules for clutches ARE linear and ARE based on the number of plates! (Number total minus 1)
So we know the maximum Torque is about 80 ft. lb. @ 1000 RPM on a stock T. All other points are less possible Torque to be transmitted.
So, take Max Torque divided by number of plates (13+12-1)and you get
80*12 / 24 = 40...forty what?
The 40 is the product of the Force developed by the spring AND the coefficient of friction AND this thing called contact average radius the force acts on.
When you take away steel plates- the average contact radius does NOT change and it is based on the little's anyway- the Coefficient of Friction does NOT change because you are still steel on steel in the same environment, and the Spring Force does not change.
Yes, to do what is being discussed results in less TORQUE possibility being passed through the transmission, but suppose the original design only required that "forty what?" and the boys designed for (say) 100?
I have never run the numbers, someone else can that wants to be the engineer's engineer, but we know the suggested spring force at compressed length, we know that the steel coefficient of friction isn't going to change and when clamped is '1', so that thing called "effective radius" CAN actually be back-solved!
The goal in using a number of plates is that it solves two other negatives in design:
1- You can keep the rotating inertia down which robs power
2- It can give you lots more surface area to dissipate heat
As an example (Sorry, I don't know the 'A' numbers)...a '41 C%^&y developed 190 Ft-Lb...it had a single clutch plate...yeah, it had asbestos pads...it used a spring system rated ~1200# under compression...and only needed a 9" OD and 6" ID. Once the plate is locked under compression, the Coefficient of Friction is again '1' anyway!
Rich, I think that he's referring to the original Ford clutch, just talking about installing the disks in a somewhat different order.
I like the math, but the real point is that joe gallagher (weird, no capital letters like most names) has been convinced by someone that there is some sort of advantage to having a half clutch.
This is truly odd, because anyone who has ever figured out how to properly adjust a Ford clutch knows that it cannot be improved upon. I can walk up to one of my cars on the coldest day, with the car outside overnight, and the clutch will have a perfectly free neutral. You cannot improve on the Ford clutch.
You amuse me Royce, on how you interpret some ones posting, how in gods name can you read into it that Joe has been CONVINCED?
Thank you to all who have contributed to the conversation. First I would like to let Royce know I have not been convinced this is a good idea. That is why I posted the question to begin with.
I found out about this procedure while watching a Model T Club of America (T-Tips) video. A gentleman by the name of Frank Banta from the Central Kansas Chapter was a guest with Fred Houston. The method I described is ONE of the three ways he replaces the clutch plates in his Model T. He learned it from an old timer (neighbor) who worked in a Ford garage and worked on many Model T's. Mr Fred Banta said he was able to take his Model T up to 12,000 foot level without any problems His thought to positioning his plates in this manner, is that this would create a free(er) neutral.
I am still not convinced, are any of you?
So WHY would the Model T Club of America produce a video with this method of clutch assembly if it does not work.... I am just asking....
I said I would say no more, however Joe, I am convinced it works as like I said I have put 38k miles on the 24 with this set up and NO problems. Who else has done this other than Richard? I guess I am being called a lier! Regardless I know this works and is still working, so to the naysayers either put up or shut up! KB
O.K. With the plates arranged as normal, there are more surfaces in contact for a given, unchanging, spring pressure. Also constant is the coefficient of friction. Also, the clutch plate diameter, as George points out as being a factor as well.
Let's say for the sake of argument, that the spring pressure is 100 lbs. With the original set-up that 100 lbs. is divided amongst each of the mating surfaces. So, each disc-to-disc interface has some fraction of 100 lbs. acting on it, at some given coefficient of friction.
Now, with less mating surfaces, (doubled up disc stack), that same 100 lbs. is divided up by only half the amount as before. So, each dis-to-disc interface gets double the force acting upon it, making up for the fact that there are essentially fewer discs.
That's why surface area does not enter into the equation. BUT, the number of discs definitely does!
Here is the formula for the horsepower that can be transmitted by a given clutch, where;
H = Horsepower
u = Coefficient of friction
r = Mean radius of engaging surfaces
F = Axial force in lbs., (i.e. spring pressure)
N = Number of frictional surfaces, (i.e. DISCS) !!!!!!!!!
S = Shaft speed in RPM's
H = [urFNS]/63,000
(You could easily convert the formula to read in ft-lbs. if desired)
Nobody is calling you a "lier". If you crunched the numbers above for your situation you would probably find out that your clutch does not have the torque bearing properties of a stock clutch BUT, it is probably still enough to perform as needed and since you say it works for you, apparently, that's the case.
AND, if we plug in some numbers, (guesses), here's what we get;
u = .10
r = 3"
F = 100 lbs.
N = 24 friction surfaces, (2 per disc)
S = 1800 rpm
H = (.10 x 3 x 100 x 24 x 1800)/63,000 = 20.6 HP
I don't know much about Ford clutches, but I do know something about tires, and do not agree with Les's point about tires... sorry in advance for the thread-drift.
Wider tires do have more available grip than a narrower one, assuming all else is equal (rubber compound, etc). It's true that increasing the lb/in^2 vertical load does also increase the grip, but the increase is neither linear nor directly proportional. As load is increased, grip efficiency is decreased.
If my attempt at an explanation isn't making sense, I'd recommend Herb Adams' book "Chassis Engineering" (Chapter 1: Tire Characteristics and Chapter 2: Weight Distribution & Dynamics) It took him 2 whole chapters with pictures, charts, and formulas to fully describe what I'm trying to say here.
If all the plates are free to move fore and aft, ie, they don't bind as the clutch is engaged then in theory each friction surface sees the full spring force. Of course, the plates have some axial restraint on the shoes and clutch drum depending on wear, etc, so the axial force does diminish somewhat as you move forward thru the clutch stack.
No Keith, you're not being called a liar. My apologies to you if anything I said even hinted to it. If it works for you, that's great. Much depends on the weight of car, number of passengers and gearing. Even the type of oil adds a variable. Where the slip will be most noticeable is start up in low gear with a load or shifting to high without reducing rpm.
I ran some numbers on the stock clutch pack for both dynamic and kinetic friction force. Dynamic would be the break-away force and kinetic would be the start up or shift force on rotating surfaces.
Dynamic - 396lbs at 16.5lbs per surface.
Kinetic - 158lbs at 6.6lbs per surface.
These numbers are by no means substantiated from actual tests. I simply used tabled variables for CoF. They don't include any other variables such as sticktion or added slip caused by the type of oil. I included the per-surface number so that you can see the effect of reducing the number of surfaces.
Take the numbers for what you think they're worth.
I'm with Ted. All discs see the full force of the spring. Do a free body diagram. The first plate sees the spring force on one side. There has to be an equal force on its other side pushing in the opposite direction. That force is the same force that first disc puts on the second and so on and so on. Each disc sees the full force of the spring.
We are all familiar with the F=uN formula where F is the frictional force, u is the coefficient of friction, and N is the normal or 'applied' force. My theory (And it's just that, a theory) is that u will change with temperature. I don't believe the surface area has a DIRECT effect on the friction, but the increased surface area does help with heat dissipation and if heat build up results in a decrease in the coefficient of friction, then the surface area does INDIRECTLY affect the friction.
You should be able to bench test the two powers of the clutch packs either way.
Just a break drum, plates , disk drum and a tail shaft complete.
Assemble and use a press to hold the brake drum, and a very large torque wrench and or a length of bar to go with it. I think it would be interesting to find out.
Keith, can you tell any difference when in neutral, does it release better for a good neutral?
Hal - This discussion has begun to be a bit too "deep" for my old and feeble brain, however, I think the friction Ted was talking about, or, at least this is what I "pictured" by his explanation, is the friction of the little "tabs" (my word) on every other disc that bear against the lugs of the drum. In other words, the first clutch disc "tabs" slide very little if at all on the cast "lugs" (my word) of the drum, but each set of tabs of every other disc in the stack has to slide on the lugs a bit more than the preceding ones. If those cast lugs are rough and worn from use (and they usually are) the tabs would tend to "hang up" somewhat, which is the reason for the stamped metal "shoes" (my word) that were placed over the cast lugs on the "new improved '26/'27's. Anyway, I believe that is the "friction" Ted was talking about.
Having said all that, I'm still thrilled that I learned a new word on the forum today, thanks to Ken Kopsky! "STICKTION"!!! Love it Ken,.....ha,ha,......harold
I don't believe we have conflict
Winter tires have a softer compound that conforms better to the road surface (assuming you are not on "black ice") and so provides a higher CoF
In Engineering Mechanics 401 Dr. George Ford ( I've got trust a guy named Ford) spent a entire lecture on friction.
He was of course prepared and went over it in great detail
One of the things he touched on is the fact that top fuel dragsters can achieve a CoF of more than 1 due to the special rubber compounds actually totally conforming to the track surface.
To get a CoF of more than 1 you need a true surface "bite".
I think Hal sums it up quite well
LOL... Thanks Harold. Actually, I misspelled it. There's no "K" in it. It's heard a lot when talking about machinery and oil. I'm sure there's others but that's where I heard it.
"Stiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact."
You are correct, I was mistaken in my posting above about the spring force per each disc interface being reduced by adding more discs to the stack and, conversely, increased by reducing disc pairs.
It took a while to get my head around it, (and a little reading to jog my fading memory of engineering school).
Sorry to confuse the issue guys. Thanks for keeping me honest Ted!
However, the formula I referenced and the fact that more discs increase torque transmission capacity is still valid.
Sorry for the confusion. My reference to Ted was in that he and I believe that all discs feel the total force of the spring, rather than each disc taking a portion and them all adding up to the total spring force. He was making an exception for the small amount of friction each disc might feel against the lugs, but it would be minimal, and as a matter of fact, the first time you let off the gas and had the car push the engine rather than the other way around, any friction between the lugs and the edge of the discs would go to zero as they left contact with one edge of the lug and made contact with the other.
The friction I was referring to was the actual friction of the clutch plates against one another. In other words, the force that keeps the clutch engaged and not slipping. We usually think of friction as a bad thing, but in the case of clutches and tires against the pavement, it is a good thing. But 'friction' nonetheless.
You stated it even more elegantly, "...all discs feel the total force of the spring, rather than each disc taking a portion and them all adding up to the total spring force."
Ken - Either way you spell it, I like it! Good that my wife doesn't read the forum too often, or else she might use that new word to somewhat alter her usual comment about me "getting my butt out of this recliner" when I've spent too much time in my recliner and on the laptop/forum! Maybe the next time she "reminds me" of errands needing to be done and such, I can blame it on "stiction",....or, "sticktion"! Ha,ha,....harold
Looks like everyone is getting lost in the science. If it was done in the past and found to work, more likely it was someone trying to save money, or a dishonest mechanic leaving out parts to make money. The end result was it still worked. How well and for how long is a lottery.
P.S. Royce, who's cornflakes did you piss in to get so many people upset with you?
The point is, a Ford clutch, properly assembled, gives a completely free neutral that you cannot improve upon. Any thing you do to rearrange the discs simply gives less available driving torque. There's no reason to do this.
"STICKTION", seems to me that's just a new way of saying gription.
All I can say is that the stock Ford clutch can work great when properly adjusted... For the most part.
However, when I pulled the clutch pack from my '24 Touring (which never had a free neutral) I found that every steel plate had warped from age and heat damage to the point that I had no choice but to replace them. They certainly weren't slipping from a weak spring. My original spring measured at about 98 pounds at 2".
I put in a Jack Rabbit clutch from Snyder's, as it was cheaper than putting in a stock clutch. I put it in as per the instructions, and without any further adjustment, I had a free neutral! There's a reason why modern cars run lined plates. They just work better.
However, the engagement is much harsher than a stock Ford clutch so you can't just dump the pedal into high like so many do. You actually have to put it in neutral, reduce the throttle, and then put it into high gear. The stock clutch is more forgiving in this aspect, but if you wind up slipping it too much, the plates will overheat and warp. As many have said, "to each his own."
I would think with as many people who hate the Ford clutch as there are, there would be a pretty good supply of free Ford clutch discs. Maybe not.
I'm pretty happy with my Ford clutch. I see no reason to change.
I LOVE IT!!!
You guys are a riot! In a nice way.
On the race cars that I worked on in my life (many) and NOT T's nor A's. The tire design, width, compound and even the belting ALL make a difference in traction, handling and STOPPING. Let alone tread design. Keeping all other things fixed or GIVEN. You ALL surely KNOW this! Really guys. The main things that changed racing was where to set the roll center, control the jounce, weight distribution, etc. of the chassis.
I know NOTHING about T tires and racing.
Also a word on clutches. Yes the T is VERY different in it's design and function. But on "real" race cars we use to have to have the 11" or 12" dia. jobs and heavy duty B&B pressure plates. Nowadays the clutches are around 6" to 8" dia. and multi-disked (2 or 3). Less mass area. Different compounds and they must be replaced a lot esp. before a real race.
If you are removing just the larger mass plates to get less drag they you will have a weaker clutch assy. on the T. But as everyone else here has said it STILL may be enough to do the needed job. BUT, if you abuse the clutch assy. then it will heat up quicker (slippage) and you had definitely better have a STRONG release spring for tension. That is what takes the place of the pressure plate in newer cars (30's up). If that spring is weak then I do believe that the clutch slippage could definitely have scorching of those plates without the other plates that were removed and replaced with the smaller ones to keep the number of plates the same for their thickness. Scorching = slippage = welded plates and WILL damage the whole assy. including the engine.
What I have learned by you all's discussion is that the original clutch WILL hold up on touring with the T's without any problems. I was NOT sure of this before tonight. Thank you Royce and others. I am definitely thankful for you others who spoke of the version that was mentioned in the club videos as I wasn't sure of that and I did hear that on my set that I purchased 10 years back from the club. I was wondering if I will need to do that if I FINALLY build a driver.
I think I won't have to now.
Just my humble opinion.
I think Joe, the thread originator, maybe was referring to stock plates or maybe a Jack Rabbit setup.
I think Keith is right on with his comments about being respectful when posting on this forum. If you don't like what someone else says or thinks, start a new thread and post your opinions without mentioning anyone's name. That way it doesn't look like your attacking someone, personally.
For the record, I'm using a Watts clutch in a 26 fordor and a stock clutch in a 27 coupe. I'll probably change the stock to another Watts.