clutch setup

I have searched high and low with no luck on pulling clutch information.

So my questions are to do with best setup and clearances as it would be nice to be able to check our clutch throughout the season without the onerous task of removing the driveline and clutch to bench set it

Now I know with any manufacturer there are "setup" procedures on the bench - but none of them give what I would call definitive type measurements for the released discs, or plate fingers to throw out bearing in the vehicle.

I think they assume that so long as you are running a stock hydraulic setup that you will have what's needed for clearances, throw etc etc.

However that is rarely true due to manufacturing sloppiness in tolerances. bell housings are never bang on for centre or runout, , pivot balls vary in length, throw out bearings are not all exactly the same length, throwout forks vary, etc.

All of these together can and do cause engagement and disengagement issues when in competition if not just driving around the pits

If I was drag racing - and ran a dual disc or slipper style clutch one would have a bell housing window and one could measure clutch disc clearances with a feeler gauge and you could readily tell in the vehicle if your setup was going away by the measured clearances. These clearances being supplied by the manufacturer. But apparently not by any pulling clutch suppliers.

There is also minimum and maximum throw out bearing clearances to the fingers and depth/throw distance for just about any other type of performance clutch, but none seem to be found for pulling?

or have I missed something

my nv4500 bell has a top window plate that would allow for measuring throw out bearing stuff, , and I am sure I could put a 1" hole in the bell for disc clearance measuring purposes.

Does anyone out there with good clutch knowledge have some baseline figures for say the Valair, or the South Bend, or the Haisley Comp?

You talk to the Clutch manufacturer for their specs

phone

had zero luck with that - sales people have no ideas, other than to say setup on the bench - ergo this thread, asking if anyone knows from experience

I have had great luck getting specs and tolerances from valair, sb and Kennys. Guess it comes down to who happens to answer the phone

phone

They won't have specs like that because look at what those clutches are. The 10.5" dual or triple sintered iron disk clutches are the same thing as what was in stock pickup trucks in the 60's or 70's but with more spring pressure and a weighted arm in it. Those were designed by trial and error most likely.

I would start measuring and taking notes and begin compiling notes of info to see when you need to start adjusting. Would probably only take a year of notes to get a good idea of what's needed.

To get that info from someone else that has done it will probably not happen.

Alright. valair gave us in truck tolerances and adjustments to make while in truck. Every adjustment we made following there number were correct.

phone

Also had recommendations for where and How Big to drill a hole in the housing for adjustment

phone

I believe Kenny's will do the same thing

We do not use factory type pressure plates, factory ones had a nut you could adjust on top the pressure plate to move the lever up or down, but proved unreliable for extreme pressures. Our weighted triple disc pressure plate utilizes a fixed lever, with billet eyebolts ,adjustable only by adding or removing shims that are on the stands below the pressure plate.

The levers on our unit set .565" from the top of the cover (over the springs) to the top of the lever where the bearing makes contact. As the clutch wears the lever rises, loosing free travel in the fork. Our clutches require 1/2" of travel on the lever for a full release, this is approximately 0.040-0.050" between pressure plate and disc.

You do need clearance between the bearing and levers, usually in the 3/8-1/2" range, but would depend on your particular set up.

Valair1 - what is the minimum clearance in the discs when the clutch is released ie .060 .075 .125 etc?
thanks

You need .055" clearance with disc closest to flywheel to properly release as this is the critical one. Then that or more with the other disc.

Peter

Kenny has helped me too. And I bought one of his clutches used. They can be a little hard to get ahold of though.

thanks to the clutch guys - awesome info and thank you for taking the time to answer