Adjustable or Non-adjustable Clutch Advise Needed

After seeing the "Soft Lok Thread", I didn't want to hijack so started a new one.
I keep breaking the 18 spline A833, blow all the teeth off third gear on the cluster. Broke 3 in the last 8 years only going to the track about 5 times a year. Car is a 68 Plymouth b body, A833 with a centerforce clutch, 420HP to the rear tires with a 4.10 Dana that I don't drive on the street?
Is an adjustable clutch my answer? What other adjustable clutches like a McLeod Soft Lok are available? The "clutchtamer"
http://clutchtamer.com/
sounds interesting, anyone run one?
I'm wondering what I should do?? Different disc? get away from the cenerforce and go with a regular Ram or Mcleod? switch to an adjustable clutch? or maybe try a clutchtamer with it the centerforce??? The more I research it the more confused I'm getting, HELP?

I run an adjustable. When I started with a sintered iron disc I couldn't get an adjustable pressure plate.

Would you want a carb you couldn't tune? Clutch is the same. I'd rather have an adjustable clutch.

I'm glad you asked this because I'm feeling the same way. I am about to convert my Duster back to 4 speed and would like to be able to run both street and strip.

I have a '68 Roadrunner with a stock (except slick shifted)18 spline tranny. I also run a Center force. I have NEVER broken a tranny part. I run several races a year(around 7-10). Engine makes around 600+ hp and I also run a Dana but with 4.56 gears. Car weighs in around 3926 with me in it. My car is mostly street driven. I do run slicks when racing.??????????

Plus. How do you shift (granny shift or power shift)? Granny shifting is very hard on gears.

Can you please explain how you granny shift and how you power shift? I always thought power shifting was harder on gears..but maybe I'm doing something wrong...by the way the most recent casualty was a Liberty Pro shift

These are "old" terms. Granny shifting is very hard on gears because you "unload" and "load" the gears by lifting off the gas between shifts. Power shifting is done by keeping the gas pedal on the floor between shifts. No loading and unloading of the gears..

I ran a 600hp 440 in my Cuda weighing close to 3,000 pounds with 32x14 slicks. Used a Hemi box with Liberty lugs. I ran it with a Ram B&B plate, and metallic disc. Never had any issues running as fast as 9.90. I know some guys running heavy pressure plates are using a rag disc to soften the hit. That might be an option for you. If you are tearing up Hemi boxes on a regular basis, you will probably hurt a Nash tranny also. A Long style clutch might help. They are available preset, non adjustable. The problem is using an adjustable clutch in a stock body. To adjust the pressure plate, you have to remove the trans and bellhousing. And it is a constant maintenance item. Clutchtamer might be the answer, although I have always been skeptical on higher hp engines and how fast it would eat up a clutch.

Lakewood and evidently Hyatt will put a window in your bell housing. Then you don't have to pull all that stuff out.

Interesting. Dan Brewer told me to not power shift 3rd or there would be damage. Apparently 1st and 2nd are fine, just not 3rd.

are you using the clutch? fully? or just tapping?

Third is where the main shaft and imput mesh, slop-flex with those needle bearings. I've thought of using a bushing there instead.

Did that. Didn't help.

Do you think the flex is from the main shaft or the input shaft since its riding on a ball bearing?

Fully. Can't tap with stock tranny.

power shifting is way easier on gears and drivetrain. what gear do you do burnout in? 2nd or 3rd? the soft loc clutch is best set up. you adjust the base from the back side. where trans bolts up. on mopar trans , I used upper right bolt hole to get to adjusters. on a jerico, requires a hole drilled in back of housing, you can do that in a drill press. power shifting into 3rd doesn't hurt it. comes down to release of clutch and shifter adjustment. I've ran stick cars for last 50 years, they were stockers.

Liberty gears told me the same thing. I hadn't have a problem until I upgraded my engine to 600 hp. Yep, 3rd gear blew out on the 3rd pass. Completely rebuilt the 833 with new bearings and replaced the broken gears . Tried that one more time . The rebuilt trans after 2 runs sounds like a bunch of bolts being shaken in a metal bucket. The power pushes the input and output shaft away from the 3rd gear = BOOM!!!!!!

What gear ratio is in the trans you keep breaking is it a 2:65 or a 2:44

I've broken the 2.65, 2.44 and a 3.09 boxes. All this crap about flex and not power shifting third is just that. Crap.

If you are breaking the gearbox your clutch is doing it. Most guys can run LESS than a 1000 pounds of static and tune with some counter weight and never break 3rd gear.

I agree. I have learned clutching is every thing, I just hear that the 2:44 ratio is harder on parts, My self I've never damaged the 4 speed in my car but from what I have learned on the forum I will spend the money on an adjustable clutch and have the bell windowed for access.

I was told the same thing. So, I prepped a 2.44 box and broke it. I'm as hard headed as an army mule, so I broke 8-9 boxes before I got sick of it and bought a clutch.

Damn I'm dumb. And a slow learner.

ok have a question for you guys. what gear do you do burnout in??

3rd gear. 5,000 rpm.

I use second. I was told to start in third and shift it to fourth but my box isn't clutch less or even face plated. So I just use second and call it good.

I was using 2nd also for so long because i grenaded so many 3rd gears in the tko600 boxes, i became paranoid about that gear. Its amazing i didnt just race using 1-2-4. Then i put in a jerico and now do burnouts in 3rd and shift gears not even worrying about it.

I try to stay away from burnouts with my A833...I guess 2nd gear would be it for me. If I were, I would at least turn my PP back to the 200lb base and go from there.

I am not a hard core racer, and I just like going down the track anyway.

Mark

Yep, the clutch is the problem. I always like the RPM's to go up when I power shift instead of dropping. Really helps lower you ET . And also, the smell of the burning clutch disc is such a wonderful aroma. And for you guy's that are going to have a hole cut in your scatter shield, don't forget to do the floor also as that's how you get at the pressure plate at the top of the transmission.

ok, the 3rd gear is the weakest gear. that's why you can break it!!! 2nd gear is the best gear to use. unless you have a clutchless trans, you don't shift gears in water box!! herb mccandless said never use 3rd gear for burnout! I ran 833 for 32 years, did burnouts on every pass, now I have a jerico. still use 2nd gear.I did break a few gears in 833, but trans was raced a lot!! I can count on one hand , times broke the 833.

From the pics posted it looks like the window is cut in the bottom of the bell housing not the top.

Yes, that is mine, and I have a lift, so that is how I adjust it.

I am not a hardcore racer, so for me it works out just fine. Chris at Hyatt Racing can make the cut out, however for it to be certified, the window has its size limitations.


Mark

Window installed by Chris at Hyatt, but not Certified...

Has any one been nicked at the track for a steel blowproof that has no certification???

So, if I use the slipping clutch, I can use a 23 spline behind my Hemi?
Still haven't been told how to adjust these clutches. I can see where one turns the bolt-screw, but there must be some type of guage used, not done by feel I hope?
If starting from scratch, what size would you use 10-1/2 or 11" ?

The instructions from Mcleod says adjust by feel, See attached.

https://www.mcleodracing.com/content/tech-center/tips-instructions/instruction-sheets/

The Manual that Tim Hyatt produced for me was turned all the way out CCW was 200 lbs with a certain number of shims between the PP and flywheel attachment bolts. I will need to look that up for you.

Turned all the way in CW is 1200 lbs of base on the McLeod Softloc...

My Ram Long Style with weighted fingers is 1800 base, and adjustable to 800 lbs. Ram sells a number of Long Style 11” under truck pulling PP’s.

Ram and McLeod are exactly the same, just a different color, and the Ram is 11” and McLeod is 10.5” PP.

McLeod sells both the 10.5” and 11” sintered Iron Discs for a great price. Ram and McLeod used the Same supplier for the disc’s. I can’t tell the difference.

Seems Ram is more interested in working with the end user, and McLeod wants you to work with a racing clutch shop.

BR, Mark

Pic of the Tim Hyatt McLeod Softlok and a Pic of the Ram and Bell in my A833 car. Sorry, I did not take a pic of the Ram clutch, but they look and adjust the same, just a different color and size.

BTW, I am not an expert at this, and I am learning as I go...

Next question, do you have to buy flywheel-clutch and disc as a unit? Aluminum or steel flywheel? Pros and cons. Street- strip car, 70% street.

Why do you think that Ma Chrysler put an 18 spline behind a 440 or a Hemi back in the day? The 23 spline has a lower HP and torque rating than an 18 spline by over 100+hp/torque..... Just look at the difference in the gears between the two.

Here is the correct pic of the Ram Clutch install with the A833

Mark

the base pressure is set by, turning the adjusting screws in the pressure plate with allen wrench.we have a hole cut in back of bellhousing for this . we use a long allen wrench to reach in and adjust clutch. you can turn it 1/4 , 1/2 3/4 or full turn to raise or lower pressure. no shims are required. we use a speedhandle, rotate to hands on a clock, 3 clock, 6 clock 9 clock or 12 clock, very easy and simple!!! on the mopar trans, the upper right side bolt hole lines up to adjuster. you do have to index the balancer to find the spot. on jerico, had to drill a hole, 1" in back of housing. it's not complicated. BTW, you use a aluminum flywheel, it disapates heat out if the clutch.

In a heavy car use the Steel Flywheel, I tried an Aluminum Flywheel on the street, and it was very bad!

In a race only, then I guess it will still depend how heavy the car is...

Mark

All the info so far is great, Thanks, But Back to the original question, Car is a 4000lb 68 Plymouth b body, 18 Spline A833 with a Centerforce II Pressure Plates CFT361800 with an original steel flywheel and a 384071 Clutch Disc, 420HP to the rear tires(slicks) with a 4.10 Dana that I don't drive on the street? From the info so far I'm thinking I need to get away from the Centerforce and a different Disc.
Sounds like I need a clutch that's going to slip some to not shock the car so bad. Do I NEED an adjustable clutch or is there a NON adjustable clutch that would be good for my above application? What Disc to use? What Flywheel to use? Thanks again

ADJUSTABLE CLUTCH.
SINTERED IRON DISC.
ALUMINUM FLYWHEEL.

You can call Hyatt, the guy in Idaho whose name I can't think of right now, McLeod, Black Magic Clutches just to name a few can hook you up.

You need to be able to adjust the clutch.

Also, it's not so much that the clutch slips. It's more correctly termed engagement. You need to control how fast the disc catches up to speed with the flywheel and pressure plate. Slipping the clutch is a bad way to describe it.

That would be Rob Youngblood, owner of Advanced Clutches.

http://www.advancedclutches.com/metalcoverclutches.htm

NOTE: There is a similar named company at advancedclutch.com that sells ricer stuff. Don't go there. You might catch some exotic asian disease.

Yup. Rob Youngblood. Do know why I couldn't think of that.

the softloc, will slip enough to let you use aluminum flywheel , even on street! a rag disc and more pressure does not!! mcloed flat said, aluminum flywheel only, the cluch gets hot and will grab so hard and be very jerky. there's a reason why they want you to use their setup. less problems and comebacks. all my cars have had aluminum flywheel on the street, had no problems driving them. even had one behind a 265 chev in 55 chev. with a 3000# clutch!! very old school back then , 1965. like anything else, you learn how to make it work correctly.

A SoftLoc style clutch isn't likely to be any easier on your 3rd gear than the Centerforce. The basic problem with both is that they hit their hardest after a WOT shift. That's just a function of them using centrifugal assist as a part of their overall clamp load. The SoftLoc's iron disc makes it even worse as it grabs harder as it gains temperature. If your 833 still has synchros, forget about hi rpm powershifts with that heavy full face iron disc.

Another thing to keep in mind is that going to a lighter flywheel doesn't affect how HARD a clutch hits, it only affects how LONG it can maintain that hard hit.

No need to buy an expensive lightweight clutch. You'll get better results at your power level with a simple ClutchTamer softening the hit of a RAM Powergrip HD. Far less maintenance, no need for a hole in the bellhousing, and more efficient than a SoftLoc style adjustable clutch. I doubt there's a more cost effective way to improve your 60' while softening the hit on your drivetrain at the same time.

The 833's I'm running do not have synchros. One is a "slick shift" and one is a "Liberty pro shift"
What is the best way to be shifting? WOT? Pressing clutch? Tapping clutch? No Clutch?

Weird that you blew up the trans before the centerforce clutch blew up.... I blew my center force before the trans let go, it use to just smere the clothe side, 550 whp.. I always ran an alum flywheel but had to lauch it fairly high... like 6000+ rpm. car has stock 833 23 spline. I would def try an alum flywheel or else just order a soft lock from chris hyatt. IF your interested I have his number you can PM me.

*from my experience, I would guess that an alum flywheel and a centerforce clutch would prob solve the issue but I could be wrong....

only way to shift a proshift trans is at WOT. if driving around slowly, then double clutch to up shift and down shift. trans will not grind. the ratio of Z bar will dictate how you use the clutch. I could tap mine, but my Z bar ratio was changed to do that. you do have to use the clutch. BTW, the softloc does slip on gear change, which softens the hit, that's way it was designed to operate. the pressure is less at lower rpm. I know it's not as hard as a 1600# clutch with rag disc hits. also, I don't have C/W on my softloc. also, as mcloed guy said, it fools the engine, has a convertor behind it. the RPM drop is less, because the clutch does slip some, as RPM comes up , it locks up.

I still can't see why you are breaking 18 spline transmissions with your horsepower. Doing a burnout in first, second or third has nothing to do with breaking third gear. Clutch types only affect the launch. Once you get moving and into second gear, all clutches are grabbing hard. Very little slippage, if any at all. If you're breaking third gear with a 400+ hp engine, you got something else going on and it ain't the clutch.
I run a slick shifted 18 spline with syncro's. You need to use the clutch to shift. I power shift it at 6000 with no issues. I have shifted it as high as 6500. Seeing no difference in time slips, I went back to the 6000 rpm shift points. I ran a pro shifted 18 spline for a time. Didn't like it much on the street. It also needed to be shifted with a clutch. My car is very simular in weight to yours, but with a 600+hp stroker 440.
I run an 11" Centerforce DFX with an aluminum flywheel. I don't break my tranny's????????? Like I've said before, I must be just lucky after 50 years of driving my car..

Hey bud, you break last time out? I don't think you're going to do much better switching to McLeod or Ram non-adjustable. They're all pretty similar coefficient of friction/static pressure to hold similar power. My Ram Powergrip HD is like a dump truck clutch.

I think if you go adjustable with an aluminum flywheel you at least have a chance to improve your 60 ft too. Coming out at 5 grand will be easier on your trans. You can switch to a Ram adjustable setup pretty cheap, and if its a stock flywheel I would change the flywheel to a billet one anyway. That thing is taking a beating for a 50 year old cast piece, don't want that coming apart even with the scattershield.

Do you still have the over-center spring on the clutch pedal?

NO

Adjustables typically play on the difference between shift rpm and fallback rpm. At shift rpm they are at maximum clamp pressure, but as the clutch pulls engine rpm down they reach a point where they lose enough centrifugal assist that the clutch begins to slip a significant amount. This raises the fallback rpm some, which adds a little hp.

The actual hit after a wot shift with a SoftLoc is not softened at all.

On 10.5" Long PP geometry, the stock cw levers alone still add about 500-600lbs of centrifugal clamp @ 6k even without any added counterweight...



Bump that shift rpm up to 8k with your right foot flat on the floor, those stock cw levers, without any extra weight added, still add over 1000lbs to the base clamp load.

Thanks for responses, interesting graph, amazing how the clamping load increases so much from 6000 to 8000 but I am running a rev limiter set at 6200 and shift at 5600 and never hit the limiter during shifts.
We only heard from a few different guys so far, like to hear more from others that aren't breaking of what clutches they are running?????and if they were happy or not with their setup?

My last clutch when I was racing the car was an old Hays MK12 adjustable and they weren't very easy on the drive train. I had it set at 1200 for the track and 2000 for street driving. I used a RAM bronze disc and that probably saved the transmission because once it glazed over they slipped pretty good. I never ran bigger than a 9" tire with 833's or a Richmond 5-speed with face-plate gears.
Now I don't race it much anymore so I am running a CF2 with a Mcleod 500 series dual friction clutch disc.
If I race it again I probably will only use DOT street slicks so it doesn't hook so hard

Gus

Do many people run an adjustable pressure plate without a sintered iron disc?

Does anyone think something like the 6 puck Rametallic with a lighter pressure plate might work for the OP? Anyone know what kind of static load you're supposed to run with those?

Here's some very general calculated torque capacities per 1000lbs of clamp pressure for typical "10.5" clutch discs (actually around 10.375" dia od friction material)...

organic- 180ftlbs
dual friction- 276ftlbs
ceramic- 293ftlbs
iron- 289ftlbs

From those numbers if a 440 made 600ftlbs, here's the minimum amount of clamp required to hold the torque for various friction materials...

organic- 3334 lbs
dual friction- 2175 lbs
ceramic- 2048 lbs
iron- 2076 lbs

With the typical adjustable you are trying to slip as much as you can off the line without slipping too much in high gear. An organic disc is going to limit what you can do as it loses cof as it gains temperature. Ceramic is a pretty much the same compound as a ceramic brake pad, heat doesn't really change cof much. Iron does exactly what you want as it gains cof as you work thru the gears, which widens your tuning window.

From the above you can also see why ceramic has such a bad reputation for being like an "off/on switch". They are typically paired with a pressure plate suited to hold an organic disc, when they should be paired with a pressure more like that for an iron disc.

X2 on trans shouldn't be breaking

ok, so if I would do all clutch slipping with the pedal the "ideal" clutch setup would be a pressure plate that has just enough base pressure to not slip at idle and added counterweight pressure that follows the torque curve throughout the rpm range.
Well, since the added counterweight pressure usually can't follow the torque curve perfectly (centrifugal pressure increases exponentially whereas the torque curve usually has more of a logarithmic shape) you start with a higher base pressure and add less centrifugal pressure, correct?

In my case I have a McLeod B&B/Long PP (360951) with 2400lbs base pressure and counterweights. If I would use an organic disc I need roughly 1000 lbs of centrifugal pressure at the rpm I hit 600 ft/lbs of torque (let's say at 4000rpm) for the clutch not to slip (2400 base + 1000 = 3400 pressure). At 6000rpm the centrifugal pressure is more than double that at 4000rpm which is not really necessary as the torque increase between both points is only a few ft/lbs.
Would I be better off if I lower the base pressure and centrifugal assist (less or no counterweights) and run a disc with a higher friction coefficient than an organic disc?

This only takes into account going through the rpm range without shifting (where you don't want your clutch to slip).
When shifting you want some slippage though - otherwise shifts are too violent (at least for a street car). So is a dual friction disc the solution in a street car? It would have some slippage when shifting but a much higher cof (less base and centrifugal pressure needed).

Using base/counterweights is actually a pretty crude way to dial in a clutch.

The calculated pressure to hold a certain torque doesn't include the additional pressure necessary to cause rpm fallback after a wot shift. Fallback is the indicator of inertia energy being released from the rotating assy, which adds torque to the input shaft. The amount of additional clamp pressure over that required to hold the engine's torque is what determines the rate of inertia energy release from the rotating assy during fallback. Not enough additional clamp, rpm won't fallback fast enough and the clutch will slip too long and burn up. Too much additional clamp and it will fallback too fast, creating a much more concentrated release of inertia energy from the rotating assy which shows up as a huge torque spike to the input shaft.

Here's some shortcomings of using counterweights to control clutch slip-

...Staging rpm is limited, as too much rpm causes the counterweight in the clutch to hit the tires too hard. This reduces the amount of energy you can effectively store in the rotating assy on the starting line.

...While counterweight can allow for some slip after shifts, which effectively raises fallback rpm to increase net hp, it wastes more of that fallback energy release than it needs to. Just look at a graph of a base/counterweight run to see the evidence. First you will see the rpm trace fall straight down after the shift, which indicates a quick/intense release of inertia energy from the rotating assy...so intense that it shows up as a wheelspeed spike on the driveshaft rpm trace. When rpm gets pulled down far enough, the fallback part of the engine rpm trace begins to transition into a backwards "J" shape. This lower curved part of the backwards "J" is where the effective clutch slip occurs that actually raises hp. The upper vertical part of the backwards "J" was the clutch not slipping enough, causing fallback energy to be wasted in a blip of tire spin.

Theoretically the rotating assy is just an energy storage device- it soaks up energy when accelerated, then gives that same energy back as it slows down. If that give/take were actually averaging out, there shouldn't be much difference overall in a heavy vs lite flywheel/clutch comparison. But there is a difference that I believe shows up on the time slip for two basic reasons...

1- lower launch rpm compared to the trap rpm. Basically if you were to launch a car at 6000 and trap at 8000, the engine will be burdened with creating enough additional energy during the run to make up that overall 2000rpm difference. Keep in mind the exponential effect that comes with rpm, it takes 16x more energy to accelerate that rotating assy from 6000 to 8000 as it did to accelerate it from 0 to 2000. In this case a lighter rotating assy is an advantage because it will absorb less energy while making up that 2000rpm difference between launch and trap.

2- less energy wasted in the post shift wheelspeed spike. The problem is the return of energy after the typical adjustable clutch shift is so intense that it instantly knocks the tires loose, instead of being applied over time to usefully accelerate the entire car. Then the engine has to make up that wasted energy as it accelerates the rotating assy back up to the next shift point. Because a lighter rotating assy releases less energy as it loses rpm, that also reduces the amount of energy wasted as wheelspin after the shift.

Because the ClutchTamer is time based and does not rely on counterweight to manage clutch slip, it gives you the ability to launch at 8k without killing the tires, which effectively makes it possible to pack more energy into the rotating assy prior to launch. The softer hit after a clutched shift then converts fallback energy that would otherwise be wasted in a wheelspeed spike into productive energy. These two things work to restore a more balanced give/take relationship of energy stored in the rotating assy, greatly reducing or eliminating the advantage of a lightweight clutch/flywheel assy. This allows using a heavier clutch assy with more thermal mass with little penalty, which in turn allows one to further exploit clutch slip to effectively raise the engine's average rpm and increase horsepower production even further.

Stock, Super Stock, Comp and Pro Stock must be ignorant.

They all use CW and lever ratios to tune their clutches. Except for a few classes which are mandated to run an OE clutch.


You should probably slide by the Elite Motorsports trailer this weekend and let them know your way of clutch tuning is better. And cheaper. And more tune able.

Make a sweep thru the nhra stock, super stock, and comp records for stick cars, let me know how they stack up against the 1320/mph=et efficiency formula. You will find that they have around the same reletive efficiency as the Coyote Stock guys. Some come in a little under the formula, some come in a little above, my point is that even the trick clutches and clutchless transmissions that are used in Super Stock are no more efficient at converting mph to et than the single disc diaphragm and clutch assist setup the Coyote Stock guys use.

Pro Stock pretty much has to use centrifugal assist, pretty tough to get enough clamp without it.

Well you talked me into doing as you say since I already have a new diaphragm plate and a disc that has different material on either side. My nephew worked at perfection clutch in SC and set this up for me. He said they made all the clutches for the hipo company's.

Is there a site that would have the clamping force numbers of various clutches?? or where could I find that info?

Used to be a chart on blackmagicclutches.com