clutch stuff

i just started working on a clutch car.i know what base and counter are.what i dont know is when do you put one or the other or exactly what it does.if you change one do you need to change the other?how much is a bunch?its a bb chev with a screw and 10in crower three disc.

 

yes you can change one without changing the other
bas is what you have on the starting line when you let the clutch out
the counter weight is how and where the clutch locks up
if your new to the clutch game you dont want it to loose and burn up disc and floaters example : 10"crower 3 disc i have three turns of base (900lbs)and 90grams total weight (15grams on each finger )it will vary from clutch on how the set up as fingers, and spring pressure crower can give you a base line are who ever the manufacture is good luck

 

Base- Set these all the same number of turns in from contact with the plate. 6 turns in is a bunch. 1 turn is a pretty big change. You probably don't want to start at 6 turns in. The more base you have screwed in to it the less the clutch will slip at the launch and the run.

Counter-if you have weight on one of the fingers you need the same amount on the finger on the opposite side, you do not have to have weight on all the fingers, 40 grams is a bunch and so is 100 grams. The more counter weight you put on, the less the clutch will slip at the launch and mainly at high rpm's, as the Centrifugal force on the counter weight cause the clutch to clamp the plates and disc's tighter together.

You do not need to change one when you change the other.

I hope this helps.

 

New to clutch

Sorry to jump in but 6 turns on what, i have just fitted a 10" crower 3 disc, have .702 to the hat, and turned the other springs downt to feeling pressure and a turn and a half,
we will run a old jp1, 6-71 and 2 spd lenco, in a funny car running sportsman,
do i have a base line setup there
thanks for your help in advance

 

In my TAD dragster, I regularly ran with 6 turns in on each of the base pressure spring adjusters.

You have 6 fingers with a hole in each to put your nut, bolt, washer, weight combo on and 6 adjustable base pressure springs under the towers with allen heads and a lock nut on top. Turn the Allen head in the number of turns you want and tighten the lock nut. This would be set after the clutch is in the car and squared up to your .702 hat to plate.


This one looks like the Allen heads are 1-2 turns in, with 1 aluminum bolt in each finger.

 

there a lot of different ways my 10.7 set up at 702 at the hat my 10" sets up at 785 not sure for the reasoning but it was set up that way when i bought the car and it was set up by john medlin it seems to work wery well killer 60 fts

 

Ok...now im doing somthing different. We have a " glide clutch" in our dragster. Im at 1 1/2 in on blue springs and 55 on the gap. We have 90 grams on .250 fingers. What rpm can we leave at and am i in the ball park un the set up. Brad 526, 1471 ssi at 42 over

 

Heres a hint , the more pack clearance you have the more the clutch is going to lock up, reason, the finger is on a cam, so to speak the more pack clearance the father out the finger is there fore it locks up at lower RPM, no more than .045 in the pack 2.5 turns on dark blue springs, 1 in steel bolt on each finger 1 full nut on each bolt. try it you'll like it. dont rev motor on starting line its not a pedal clutch bring r up just to move into lights.

 

thanks for the input. looks like i had been going the wrong way..... will try it next weekend.

 

Will, or other clutch guys,

I understand the way a clutch works but have never worked on one at the track, what are the general rules for when to use more base/static vs counter?

It would seem (when I listen to the voices in my head ) like if the wheelspeed at launch was good but the slippage was too much downtrack then you would want to increase counter while slightly reducing the static to compensate for the added counter, while if it was going into tirespin and was ok down track you would want less static and to compensate for reducing the static by slightly decreasing the counter?


Or do I have this stuff all wrong, just trying to get some ideas as it seems like there would be a world of variables.

Thanks in advance,

Richard G

 

Richard, you've got the basics there right. The way I normally look at it is like Will explained Molinari's description.. When tuning I look at the counterweight like the stall on a convertor, where do I want the clutch to start tugging at the motor? Its different on every car and every motor. Roots cars tend to keep the clutch right with the motor, screw cars you can have a little more fun with. Anyway, with tugging at the motor in mind, I'm a huge fan of static pressure because it is a constant. I usually adjust the launch with static and RPM and use the counter as more of a tool for getting through the top of low gear shake. If you 60 foot good and grab the motor too quick and dip it to shake, you usually have too much counter. If the 60 foot is slow and it shakes, you are more than likely short on static. Motor is able to rev free and counter weight comes in like a hammer.

A lot of people think you have to get the clutch 1:1, but remember, your motor makes the most power between certain RPM, so the best thing you can do to go fast is keep your motor in that range and don't knock the wind out of it with too much clutch.

 

Justinace,

Thanks for the explanation, that really makes a lot of sense on how base and counter interact on tire shake.

 

Shift and launch rpm's make a big difference as well.a bbc @8500 is way different than a hemi @10500

 

Yep, size of the clutch plays a lot into the tuning window as well..