11 1/2" clutch wear

[Michael C Henry]

I have the McLeod set up, an alluminum flywheel ,machined and setup for up tp 12" clutch, 11 1/2" clutch and pressure plate. I allready failed to keep up with the clutch wear and resulting loss of free play a few years ago and the trowout bearing froze up and tore up the pressure plate fingers. My problem is trying to navigate city stereets around here the speed limit is mostly 30mph, stop and go, and school areas. I have the tunnelwedge intake a long duration cam and not much low end, at least from idle. I end up slipping the clutch to get things rolling and before you know it clutch throw out bearing free play is almost gone . I have a hydraulic slave cylinder on the frame a 3/8 dia push rod threaded at one end and a 5/8" hex ( bullet) about 1 3/8' long wtih 1" of internal threads to actually push on the throw out arm. I figure I have about a 1/2" to 5/8" adjustment range. I had to dismount the slave cylinder and remove the spring to remove the pushrod assembly. I bottomed tapped the internal threads in the bullet and removed about 1/8" of taperd threads on the 3/8" pushrod. I have free play now but no where to go after this clearence disssapears. I plan on making another bullet, this new one would be about 2 1/2" long . I'll grind one end to a taper with a rounded tip as original bullet. I plan on 2" of usable internal threads in the new bullet. I'll a make a new pushrod out of 3/8" drill rod, just a bit shorter than the original.
Any thoughts or reccamendations or warnings?

[RICK LAKE]

Mike If you do alot of starting and stopping with a motor that needs 1,000 rpm to idle, you may want to look a trans change or rearend gear change to low speed driving. If you keep slipping the clutch to get the car moving, you are going to keep going through clutches. Do you know what the ratio is in the trans for 1st gear? You may need to look at something in the 3.15-3.25 range. Get a wide range trans with over drive. This way you can crawl along at a low speed and have the motor not lugging and hicupping trying to run. It will also make it easier to engage and disengage from 1st gear. This will cut the slipping down. I have a 3.15 in a race trans and never use it. My street trans has a 3.25 first with overdrive and again don't use it at the track. When I need to putz along a 1-3 mph this works great. Parade speed. The other idea is to put a smaller camshaft in the motor to move the power band lower and increase the torque band off idle. You will still have almost the same power, just at a lower range. Talk to Ernie, (Excaliper) aout his motor change or look at the old threads on his motor build. Hie gas mpg doubled, drivability improve big time, power was still there, and the car was only .5 slower in a 1/4 run. Rick L

[FUNFER2]

Rick-slipping the clutch to get going, is this situation caused by using a aluminum flywheel ?

[jwd]

Originally Posted by FUNFER2

Rick-slipping the clutch to get going, is this situation caused by using a aluminum flywheel ?

Yes. That's why I don't like aluminum flywheels in a street driven car. Been there, done that, didn't like it. Billet steel is the way to go on the street.

Jim

[Michael C Henry]

I would have made other descions, but it is what it is. A little less cam next time is a certain. This is the first alluminum flywheel I ever had. The intake and dual fours are another part of the problem. I think I can get a better stste of tune also.

[FUNFER2]

I've heard from both sides of the alum. flywheel for starting from a stop.
What's the weight difference from the alum. and the billet steel ?

[Tim Brewer]

I really don't see how an aluminum flywheel makes any difference with your clutch slipping or not. It works steel to steel same as a billit flywheel. I hope nobody thinks that there is contact with aluminum with an aluminum flywheel.

[jwd]

Originally Posted by Tim Brewer

I really don't see how an aluminum flywheel makes any difference with your clutch slipping or not. It works steel to steel same as a billit flywheel. I hope nobody thinks that there is contact with aluminum with an aluminum flywheel.

Tim, It has to do with rotating mass and stored energy. An aluminum flywheel will rev quicker but you have to use higher revs., and slip the clutch when taking off from a stop, especially on hills. Think of it as using your hands to try to stop a spinning basketball or a spinning bowling ball. To require the same effort, the basketball would have to be spinning much faster. Letting out the clutch is basically trying to stop the flywheel from spinning but instead of stopping it , the car moves. I've run both and for the street, it's steel billet for me everytime.

Jim

[RICK LAKE]

FUNFER2 Kevin what the flywheel is made of doesn't matter unless you are looking at a certain application. As stated, a 40# flywheel has more stored energy that a #20 flywheel. This is great to get 3,500 lbs car or trucks moving. With 2,500lb cobras, DEPENDING on the motor torque and power range, you don't need this. Some of the guys on here are running complete multi disc setups that weight 22 lbs. like Nascar. High HP low torque production motors. This is why nascar guys leaving the pits do burnouts all the time to clean the new tires and also saves the clutch from glazing.
Mike didn't say what his trans ratios are or the rearend ratio. The problem if the clutch disc and the air gap getting smaller are the riding of the clutch pedal. Clutches like to be either fully engaged or fully released. Riding glazes both plate and flywheel surface. Over time will warp and give hot spots on the flywheel surface. It sound like he has a motor with a large camshaft and a rough idle. His motor makes it's power higher up on the rpm scale. The size or how many carbs are on the motor is not as important as the low end torque numbers. IMO Mike needs to either change the power bands in the motor( lower with a camshaft change ) or get a taller trans mission ratios in the 1st and 2nd gear. This way the motor will be able to run better ( in the rpm range it needs ) and he wouldn't have to ride the clutch pedal in and out to make the car move at low speed.
Aluminum flywheels do have inserts that are steel or iron. They are also rebuildable on some units. If you build a torque motor, using a #20 flywheel will kill some of the low end power in a lite car. This helps to get off the line without blowing the tires away. A high rpm motor also use lite flywheels with there 6,000 rpm launches. It's about matching parts to work togeather and get the best over all performance, drivibility, mpg, and enjoyment.

[FUNFER2]

Yes, alum. flywheels have a replacement disk.
Yes, any type of flywheel can be torched, blued and heat cracked by any idiot driver like my brother-in-law.

I see some people at a stop light riding the clutch to stay where they are, rather than the BRAKE !
That drives me nuts and I want to slap them !

I am concerned about the lack, of enursha with a light weight alum. flywheel and having to ride the clutch a bit to get going. Some say to release the clutch fairly fast, and you won't have a problem but, what about stop and go traffic ?

[patrickt]

Originally Posted by FUNFER2

I am concerned about the lack, of enursha with a light weight alum. flywheel and having to ride the clutch a bit to get going. Some say to release the clutch fairly fast, and you won't have a problem but, what about stop and go traffic ?

I have a Centerforce aluminum flywheel along with the Centerforce DF clutch. My rear ratio is 3.54 and I have a TKO-600. In stop and go traffic it drives the same way a Toyota does. You do not need an iron or steel flywheel in a 2500 pound car -- c'mon, you can push these cars by yourself. An aluminum flywheel lets you rev up faster, rev down faster, and you're slightly less likely to bust your rear loose on a fast hi-rev shift. I am 100% satisfied with my aluminum flywheel -- I wouldn't think of changing it.

[Michael C Henry]

I initially had a problem with my clutch master cylinder (7/8") didn't have enough volume. I had to run verry little clutch freeplay to still get adaquet clutch release. I ended going to a larger 15/16" clutch master cylinder. I gave up some leverage (it takes a little more foot presure now). I didn't keep up with adjustments ,let the freeplay disappear and the throwout bearing froze up and took out the fingers in the pressure plate. I went to a larger diameter master cylinder to have more volume. I now have generous freeplay and full clutch release. I can actually see the freeplay and notice when it's reduced. I try to keep the idle as low as possible and if I think it's going to be while before moving I put the transmission in neutral and release the clutch to keep throwout bearing wear and tear to a minimum. The engine idle is about 600rpm (much less and it starts limping doward) but If I try to engauge the clutch at that rpm it'll cause the engine to start dieing , so now I have to try and save it and still leave the lite in a reasonable time. Better low end throttle response would help. A better state of tune and some practice will help.

[patrickt]

Originally Posted by Michael C Henry

...but If I try to engage the clutch at that rpm it'll cause the engine to start dying , so now I have to try and save it and still leave the lite in a reasonable time. Better low end throttle response would help. A better state of tune and some practice will help.

You have to give a little throttle at the same time you ease out our clutch ... that's just the way it is. I bet if you upped your idle to 750RPM, slightly richened your idle and, if you have a solid lifter cam, loosen up the lash a little bit, then you'll find your take offs will be a good bit easier.

[jwd]

Originally Posted by Michael C Henry

I initially had a problem with my clutch master cylinder (7/8") didn't have enough volume. I had to run verry little clutch freeplay to still get adaquet clutch release. I ended going to a larger 15/16" clutch master cylinder.

J


Just curious, what slave cyl. are you using? Wilwood and CNC all require a 3/4" MS in order to have full movement of the slave. Anything larger actually moves the slave too much and you can blow the seal out of them.

Jim

[maurice19]

I don`t have to slip my my clutch with my setup of TKO 600 and 342 rear.

I also have the tunnel wedge with 2 660`s on a 511 cubic inch Shelby.

I think Rick has the right idea about changing to a lower trans or rear gear.

Maurice

[Michael C Henry]

I'm using three Tilton master cylinders, one 15/16" for clutch and two 3/4" for brakes. The thing the throttle is touchy, some times it stumbles when gassing and other times it revs just fine. I have plans on getting together with a friend that has some testing equipment to get some of the bugs worked out. The car has a 3.56 Jag rear end and a Ford 4sp toploader trans with big 1 3/8" input shaft. It like most high performance doesn't do slow well and ramps in crowded parking garages are a pain then steep hill with stop go traffic and then a plugged up freeway. I once had a really bad problem getting it up on a car trailer under it's own power.
It originally had a 7/8" clutch master cylinder. I bought a 1" master cylinder but was warned of over traveling the slave cylinder so I just sat on that and ordered another Tilton master cylinder kit in 15/16" dia.

[patrickt]

Michael, I didn't see your rear end ratio in any of the postings (or your 1st gear ratio). What sort of rear are you running?

[blykins]

Look up in the previous post....3.56 rear with a Toploader.

My Cobra had a big cammed 428 with an aluminum flywheel, a TKO 500, and a 3.70 rear gear. I didn't have nearly as much trouble.

What cam are you running Michael?

Also, on master cylinders, they behave in reverse to how you described. With a larger master cylinder, it takes more pedal effort to actuate the system, but the travel is less. With a small master cylinder, the pedal effort is a lot easier, but you have to push the pedal further to get the same results.

[patrickt]

Originally Posted by blykins

....3.56 rear with a Toploader.

Then that's very close to my set up. There must be another problem.