clutch size questions

[BattlestarGalactic]

This disc was made 20 yrs ago.  That might have something to do with it.  I used to run that disc for years, until 2006 when I met Tim Hyatt and converted it to a slipper for 2007.

I had a nice tune up for quite a few years, then suddenly, in 2006, I couldn't keep it working for a whole race.  I was pulling it every other race and surfacing things.  I finally got ahold of Mike at RAM and he told me that they changed the material slightly(or something like that) and did not want to tell anyone I guess?  I gave up their stuff and went to Tim.

The disc was from my early toploader days and that is why I threw it in the black car(it has a Dan W big input wide ratio box).  I had it, why not use it.  I hated driving it, but just never wanted to tear it apart.  It finally wore out and that is when I replaced it with a new adj PP I put together and a dual friction disc.

My '69 F100 still runs a CF DF from the mid 90's.  I raced the motor/trans in the wagon for first couple seasons, then put everything back in pickup and still there.  I only turn it 6K so the clutch works fine.

[cjshaker]

The Ram HD kit that I put in my Mach has been working flawlessly for 5 years now (purchased from Brent). It's been through several FE Reunions, 2 Drag Weeks and quite a few street miles. Obviously quite a few street miles just during the Drag Weeks. It's been great on the street, never a hint of chatter, but getting the right amount of slip on a drag strip start was tricky to say the least. I wouldn't describe it as a light switch on a hard launch, but there's very little wiggle room. There's maybe 1 inch of travel from disengaged to full engagement; not a problem in normal driving, but nearly impossible to do when the car is lurching forward on a launch. At first I worried about slipping the clutch while launching from 4-5000 rpm, I've burnt up a couple of street clutches that way, but so far it has taken it without complaint. Pedal effort is actually less than my '09 Mustang GT's stock clutch.

I'm sure sprung hubs have real value in taking some shock load off of gears on a normal street application, but I can't imagine those springs doing any good on a hard launch. I would imagine it being about the same as your clutch slipping for a 1/2 inch on the flywheel.

[BattlestarGalactic]

Those early clutches I ran in the wagon(908 disc) were sprung hub.  I would get a full season out of them wear wise, but the hubs themselves would be tweaked and the springs would be very loose. If I would try to use them into a second year, it would grenade.  I used to remember the number passes it would last, but been too long ago now.

Yes, for street use the sprung hub is fine.  In a full time drag car, useless and a ticking time bomb.

[6667fan]

Talked with Mike today at Ram. Going to send him a Ram 11” long style cover plate that I have kicking around here. He says he will rebuild it to the 98988HD specs with counter weighted arms. It will be paired with a 911 metallic disc which is bronze/iron. He said the clamping force would be 2500-2600 lbs. That does not sound like a butter soft pedal.
Brent, do you know what type of pedal pressure you usually get with the HD kits?

Thanks,
JB

[blykins]

About 2500 lbs.  You won’t have any issue with it.  A lot of diaphragm pressure plates are higher than that.

[JamesonRacing]

I was on the horn with McLeod earlier today. They in theory have an 11” long style cover plate that has a  counter weighted arm. I say in theory because a year ago when I was  looking for one they did not have any and STILL do not have any. That was what pushed me to the 12” I ran last year.  The part number is in the big supply houses catalogs but you can’t get one and Billy at McLeod can’t say when they will be available. The 11” ceramic 600 series disc is available and so is an 11” diaphragm but the clutch pedal may not leave the floor after 6500 rpm.
I know Brent likes the Ram stuff so might start looking there.

John, thanks for the info on The Tamer.

As part of this continuing expensive grand experiment David Kee just received my TL so it can get rebuilt with some face plated gears.

Thanks much for the perspective Larry. 

JB

I'm using a McLeod aluminum wheel and diaphragm plate in my street Fairlane.  I'm using a TKO600 behind the 465FE.  Launches are just a matter of feeling the clutch to find the sweet spot on RPM and speed of release.  Car has run a best of 11.40 at 122 on old 275 drag radials.

[6667fan]

Been working with Pat at Ram. He will be hooking me up with a 438CW cover plate and a 911 disc. The used, long cover plate I sent them is not up to being converted.
I'm liking the South Carolina customer service better so far than the Southern Cal experience.