Stick car, too much clutch?
I have 2 stick cars, my 85 Mustang Stocker, and a 78 Fairmont with a FE Ford engine, back halved ladder bar bracket car. Both have Jerico 4 speeds and McLeod Soft Lok clutches (10" on the Mustang, 10 1/2" in the Fairmont). I`ve been running both cars ( as sticks)for over 10 years each, and thought that I had a fairly decent handle on the clutch setup, as I normally get 2 years out of a disc, and have minimal breakage. Neither car is high RPM, and the clutch is set low enough that a drive up the return road in 3rd gear, at about 25 MPH, will result in considerable slippage if I lean into the throttle much.
However, a local track photographer recently made a DVD of a few of my runs in the Fairmont, and I gotta admit I was suprised to hear the tires barking on the gear changes. It is quite noticable in the recording. I had always assumed that with this style of clutch, there would have been enough "cushion" to prevent the clutch from hitting so hard. Is this normal, or am I way off on my clutch setup? I know that Mr Gullett and Mr. Lee will be saying to get a Youngblood clutch, but a pair of dual 7"ers are not in the budget anytime soon. |
Re: Stick car, too much clutch?
Red@ Mcleod told me years ago to keep backing pressure plate down until it slips in high gear have to make 1/4 mi passes,my car always starts bouncing front end like you are letting off and on throttle when I get to point where it is slipping in high gear,then raise press back up 1/2-1 turn.
I say if you are chirping tires you are too agressive or have too much air gap .050'' max too much air gap will cause to hit tires too hard Mike Taylor 3601 |
Re: Stick car, too much clutch?
Hi Rory,
What do you have for levers, and CW? I had a heck of a time with my original Ram 10.5" Hyatt setup. No CW levers, and then I switched to his billet CW levers. It should not be hitting that hard on gear changes. With the original setup, I had to adjust base to be a compromise between the launch and high gear. Sean |
Re: Stick car, too much clutch?
You really have not provided any info that anybody could comment on other than you are chirping your tires.
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Re: Stick car, too much clutch?
Where do you leave and shift at? Are you running counterweight? If I had to guess if your running to much counter weight and its locked up tight at your shift points. That is just a shot in the dark.
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You have too much clamp load at your shift point, whether base or counterweight induced. Peak torque is at lower rpm where counterweights are less effective. If the base is quite low and you make up for it with counterweight to get enough clamp load at peak torque, it is easy to then have too much at the higher shift rpm.
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Re: Stick car, too much clutch?
For the last time you don't need a Youngblood clutch to go fast. PM me and I will direct you to some very fast cars in ND in the records section not running that clutch.
As others have stated give your base,cw if any and rpm shift points. That will help. Good luck. |
Re: Stick car, too much clutch?
The pressure plate has a 280 lb base, I started at 5 turns out, and backed it down until it flared on the 3-4 shift, and added 1/2 turn. I normally leave it like that until it flares again, however many runs that takes. I don`t really play with counterweight, as I can not remove the bellhousing in the car, engine has to come out. For counterweight, I have the short steel bolt and nut, I believe that is about 6 grams per lever. I launch at 6000-6200, and shift about the same.
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Re: Stick car, too much clutch?
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Now if you have a problem with Advanced Clutches, whether you can't afford one or you think they don't work, take it elsewhere. |
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although I can only suggest what could be going on as I only have 25 passes on my combo ,the one thing I can tell you is if you get a data logger you can see what is happening during the run ,,,when you make changes to the clutch you will be able to see it on the graph and compare several runs together,,,i have a rpm data logger 10 channel with the basic engine rpm,drive shaft rpm ... it also gives you a R.A.T number witch is the slippage between the engine and input shaft ,with that system you can add other sensors,o2's, it takes the guess work out of runs that went bad(loosing traction down track,bad starting line or slipping the clutch) its not priced bad and its made in America and they always will return the phone call if you have a question, I have learned a lot and still learning gmonde
http://rpmperf.com/ |
Re: Stick car, too much clutch?
Rory, do you need that CW? Have you ran without it?
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I made a mistake one time I thought mine was flaring up on 3-4 shift so raised base 1 turn and it got worse, put a new set of tires on because car had became inconsistent also,tires fixed it, I would have swore it was slipping clutch on 3-4 shift when it was actaully spinning the tires and this is only 7.8 1/8 car.
I'm not saying that's what is happening just a suggestion,sometimes what you think you feel is different than you think. As someone suggested I would try to get set w/out counterweight ,personally I'm not a big fan of counterweight when shifting w/clutch Mike Taylor 3601 |
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I also would look at the CW's but you really need some way of seeing some data. I used an Autometer 2 channel tach for the last 10 years and it worked great. Some times to good as it shows you just how bad of a driver you really are lol. Are you shifting with the pedal?
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Rory's Fairmont video
[ame="http://www.youtube.com/watch?v=VGTtrnq31So"]FE Fairmont - YouTube[/ame]
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Re: Stick car, too much clutch?
It looks like you already have a 2 channel tach. That should tell you right there. But in my opinion you do have way to much clutch for my liking on both the starting line and at the gear changes. Its bogging the motor down on the starting line and the one pass I heard it bark 4th LOL. But if its consistent and its not breaking anything yet run it. I know that if I was running that much clutch in my car it would be breaking stuff.
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Re: Stick car, too much clutch?
Well, it is pretty consistent, and in 12 years, the only real breakage has been knocking a few teeth off 3rd gear a few years ago. I need to pull the trans to fix an oil leak, so I guess I will remove the counterweight at that time. I never really used any counterweight before this clutch freshen up. My tach is a playback model, but it has no provisions for driveshaft RPM. I`d really be suprised if I have "way too much" clutch static though, as when I do encounter flare up on the 3-4, or noticable slippage in 4th, I can normally cure the slippage with 1/2 turn increase of static. And as I mentioned in the first post, rolling on the throttle on the return road at 2500-3000RPM will result in noticable slipping. I do normally shift it clutchless. One other thing I should add, don`t know if its really relevent or not, but Hyatt did the last clutch rebuild, and instead of the normal .280" disc McLeod supplies, Tim uses a .380" thick disc, and I have the pressure plate shimmed up .100" to compensate for the added thickness. And lastly Kris, since you also run a FE, have you had any issues with the pilot bearing "falling out" of the crankshaft? I use the ball bearing pilot, and it kinda sticks out of the crank a ways, and is not a very tight press fit, and has been found just sitting on the input shaft a couple of times . I last installed the pilot bearing with red Loctite, I`ll take a look when I pull the trans out in the near future.
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Re: Stick car, too much clutch?
From what I just read, if you remove the counter and don't add a few turns of base you will drive through the clutch in high gear.
One affects the other. You can mostlikely, take some more base adjustment out and it will soften the clutch durring the shifts. The CW no CW debate is very split. When you run counter, the base adjustment should be run on the soft side. When running enough counter, you will have a hard time driving through the clutch. When set up like this, you should lower the starting line RPM to soften the launch. Leaving where you shift at will produce the " Sledge Hammer Effect " because of the counter producing more clamp pressure on the disc. In the end you have to figure out what clutch management theory you subscribe to and go out and test. Be sure you take a lot of notes durring testing. When you get some data from your results , you will be able to tailor your clutch to your needs and desires. That is the fun of this game. Quote:
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Re: Stick car, too much clutch?
Put just enough base in it to launch the car , and throw in a little c'weight. Thats alI do.........I dont play around with c'weight , dont mess with base much either. Watching a playback tach can sometimes tell you if you need more weight as the needle will bounce around. With my Nash 5 speed , 23 degree 355 , at 3000 lbs Ive run 9.60s at 138 n change.........must not be that far off........but the bottom line is this , without a data logger and historical logs you're going to work yourself to death playing with that clutch.
I also want to add , my advice is for clutch assisted stuff.........and breakage? Rarely |
Re: Stick car, too much clutch?
Spend your money on a data logger you can tie into the input and life will be much easier. We used to tune our cars by feel and using a video camera but that's just frustrating with all the affordable technology out there now.
Soft Loks are great but if you're looking to upgrade and don't wan't to spend the coin on the Advanced stuff hit up the Comp Eliminator guys for some of their used stuff. Shocks are critical on our small tire cars on leaf springs and may help you also depending on what you have but a ladder bar car isn't as violent. |
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We have used a sealed bearing in the end of the crank on our Chevys. You need to either cut a snapring groove to hold it or machine a ring that has enough crush to hold it. We did that in our modified engines as well and have never had a failure. One other pilot bearing that I tried is the kevlar one. I put one in a 327 and have had no issues with it in two seasons of running. Put green loctite on it and it stayed. I noticed many diesel trucks had a kevlar pilot bearing so they must be spec to severe use. Anyway, I think ram and others make them. We bought ours at the carshopinc.
For what it is worth, there are some great options on clutches out there. Yes a data logger is really needed or you will have a harder time really getting exactly what you want. I have run all kinds of clutches and have found that lighter is quicker, but only if you can figure out how to slip it enough to keep it from bogging and still not drive through the clutch down track. I can't tell you how many times we had pullednthe light stuff out and would put the heavier clutch back in becausenit was quicker. Only until we stuck with it and made ouselves figure it out did we finally discover what it needed to be right. Only testing on your specific car can lead you to discover that. Even the best clutch person can only advise you enough to get you close. You will have to do some good testing. I will say that to me, the advanced stuff is the easiest to tune counterweight with. It just seems to do what I think it will do. I know many slam Jeff because he comes off like he is a sales manager for youngblood, but it is an easy clutch to work with. I have said this before, I have never bought a new one from him either. An advanced clutch set on kill will eat some disc. When we are not interested in the quickest run, but are just set fornthe eliminator and don't want to worry about slipping too much, we leave counterweight alone and just put some more base in. It bogs a bit, but is very consistant. Another thing hou might consider if you feel that you are hitting it too hard, is to try a smaller disc. You tuning window might be smaller, but you could try this for the cost of a custom size disc. |
Re: Stick car, too much clutch?
For pilot or any other bearing, if you need an odd size, check into IBT or someone similar. The bearing manufacturers have many sizes to chose from, that may fix the issues with not being a snug fit. If you have a spare input shaft, I would recommend taking it with you. They may also have a repair sleeve for the OD. Or you could take shim stock and make your own sleeve.
Sean |
Re: Stick car, too much clutch?
I already use a sealed ball bearing for a pilot. (after learning very early on that a stock bronze one gets chewed up really quickly!)m The problem with the FE Ford is that the pilot bearing fits into a recess at the end of the crank, and sticks out 1/4-3/8" of an inch, so no way to cut for a snap ring retainer. Kris, I think that the Loctite would be a better attempt than RTV silicone. I have used the Loctite in the past, with OK results (so far), but I don`t leave the trans in for 2 full seasons anymore either. If I get a semi warm day this weekend, I`ll pull the trans and take a look to see if the bearing is still in place.
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Re: Stick car, too much clutch?
Any clutch will work. You just have to be honest about what your goals are. You also have to be honest about your abilities & limitations. Speed cost money; how fast do you want to go? That hasn't changed since the first drag race. Speed costs time also. If your not willing to pull the bell housing off to try something new, then your just spittin' in the wind.
Any clutch can be made to perform better. Or more consistent. Or longer lasting. If you can obtain 2 out of 3, your doing good. Seldom will you see 3 out of 3. But there is no magic pill or magic tune. What works on one car is not going to work on another. May be close, but it wont be 100%. If a guy wants a stick for fun and bracket race super consistency is paramount, buy the cheaper parts that require less maintenance and less tuning. Throw in a single or dual disk diaphragm and be done with it. But even when I ran a McLeod Mag-Force Dual 8", I still had the bell housing off all the time shimming it up for more slip. When I ran the McLeod Soft-Lock, I still had some pretty fast times, still pulling the bell housing off countless times. And if I had to say one thing along the learning curve that was the biggest loser, it was the no CW theory. My McLeod became really fast with zero turns in it, some CW and a lot more RPM off the line. It also became more consistent. But since this is Class Racing ~ Stock & Super Stock Tech, I'm the type that believes that Class car owners should strive for the very best performance; not "good enough". I've been down the clutch road and my money & performance are hooked with the A team (so I don't look like a promoter & upset the admin). I use the formula 1320 / MPH and it tells me who really knows what they are talking about when they brag about their ET & MPH and how well they think they have the clutch dialed in. And yes, those that meet or beat the formula do not always have an Advanced unit. But a lot of them surely do. And here's another tip. There are a lot of racers that have an A unit and are doing well. But if you ask them what they have, they may steer you in another direction. But that's the nature of any competitive sport. |
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Well, this is my bracket car, and I normally go to 12-14 races a year, every year, so consistancy and reliability are at least as important as absolute lowest ET possible. That said, Jeff, using your 1320 formula, my car seems to pretty much hit its potential pretty well dead on, even with my "less than ideal" clutch setup. Actually. if you watch that last pass on the video, it even ran a bit quicker than the formula shows. As I mentioned earlier, with the stock floor and trans tunnel, removing the bellhousing requires pulling the engine, and frankly, I`m just too lazy to do that on a regular basis. If running too much clutch can continue to give me a couple of years on a disc, maybe I`ll sacrifice that 5 hundreths or so.
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Re: Stick car, too much clutch?
My 2 cents,
If you have a big-tired car, chances are you don't need counterweight on your clutch. Counterweight is great for a small tired, high hp car with limited traction. Low base pressure gets you off the starting line, counterweight locks it up at the gear change. If you use the clutch at the gear change, you'll need more pressure to lock the clutch back up, and that usually means the tires will chirp at each gear change. I usually start with all fresh pieces and turn up the static around 1000lb. Make a run and start backing down the pressure until it slips, then add 1/2 turn. Watch the tack on the starting line. When you let the clutch out, the rpms should not drop then rise. they should load the engine and then rise. Should shift smoothly at each gear change. If it slips into high gear, add counterweight. On a cool day you may need slightly more pressure. Hot days, it may be too aggresive. This is where you need to know your car. The clutch makes or breaks these cars... If you have a bearing problem, I suggest checking the bellhousing alignment. If its right, you should have no problem. _____________________________________ Andy Stone 1102 A/S 1112 SS/C |
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I pull out some base in the interest of better 60fts or preventing breakage.......I offset that with c'weight. What exactly are you saying? |
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Rob Youngblood has a big tire and he uses CW. And so do the SS/AH cars that run (very fast) with his clutches. The CW is there to adjust the slippage on the shift.
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Not trying to steal the thread, but this has come up a few times here. To align the bell housing properly, get the browel tool, (which I now have), or, a simple method I used to keep pilot shaft bearings in that worked for me goes like this, put your clutch and flywheel in,( not in that order, Ha), set your bellhousing on, with dowels removed, start a few bolts, get a pilot shaft out of the transmission you use, slip a spare collar over it, slide it in through the clutch, let the collar go into the housing, wiggle it a little to make sure it's in the bushing, look at where your dowels go, and you will see what offset dowel you need, leaving it like that, drive the dowels in, make sure you can still slide the shaft, and collar in and out freely, start to tighten bolts, and wala, it works good. Beats the hell out of a dial indicator for me.
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It all depends on the stagg rpm...lol :cool:
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Re: Stick car, too much clutch?
For those of you wondering, heres a link written by fellow stocker racer Jerrry MacNeish.
http://www.camaros.org/bellhousings.shtml Jerry |
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