High gear clutch slippage

[Mark Madison]

Originally Posted by Jeff Lee

Besides the mechanical issue of changing gears due to ratio, the clutch will slip more or less dependent upon the time spent between gears. A racer that uses the clutch to shift, no matter how blindingly fast he may think he is, requires a completely different clutch tune that a racer that does not use a clutch to shift. On top of that, the transmission (clutch or clutch assisted by design) choice affects slippage even if the clutch is not used to shift gears.
All of these issues can be tuned with the proper clutch. That includes not only the basics like base pressure and counterweight, but also lever design and friction materials used. The Sportsman Single 10" I have used in the past and the Sportsman Dual 7" I am going to use in the very near future has heat shields made from specific alloys not found on competitors components. The clutch disks employed on these, while not a trade secrete by design (like the heat shields), are specific to the application by material and density.
Finally, a racer that has had his clutch friction materials "rebuilt" by resurfacing instead of having friction materials replaced with new components will not see the same results by rebuilding vs. replacement parts. The reason is rebuilding by cutting surfaces lessens the thickness of the materials and their ability to absorb heat and as a result the clutches friction materials service life can be severely shortened. The thinner the parts, the quicker they will warp. The quicker they warp, the quicker you reduce the plate loads to unacceptable levels. This causes the racer to run excessive base and / or counterweight in an attempt to overcome the slippage. In the end, this is just a band-aide and performance (and more importantly; consistency) is impacted greatly.
So Stewart, there are many factors to consider. Hope this helps.

So replacement of heat sheilds is normal with a $900.00 clutch rebuild. mark Madison

[Stewart Way]

Had a PM from a regular poster on here and he hit on a point not yet mentioned. Power strikes on the crank. As Jeff pointed out the drop is less on the 3-4 shift than the 2-3 shift. So the initial rpm after the gear change is higher resulting in more power strikes for the same time period and at a higher HP (RPM)level so more force is applied at the 3-4 shift than any other shift.
Jeff
When is the "very near furure"? Don't think I'll be out this year in my car. I went against the trend and made a couple realtors happy. Bought a house on 4 acres with a 3000' shop.
Still own the other house and equiping the shop so not much spending on the Cuda. Putting the old house on the market in a couple weeks. Will take a beating but got a deal on the new one so we don't care. You selling anything out there?

[Rory McNeil]

Originally Posted by Mark Madison

So replacement of heat sheilds is normal with a $900.00 clutch rebuild. mark Madison

Yes, I`ve had several McLeod Soft Loks rebuilt by both McLeod as well as Tim Hyatt, and each time new heat shields were installed on the flywheels and pressure rings. Usually by the time the clutch needs a rebuild, the heat shields are getting blue hot spots, irregular surfaces, and the outer edges that don`t see disc contact are curling up.I would have to think that any money saved by grinding the old heat shields would be offset by a very rapid re-occurance of warpage. New heat shields are a must.

[Jeff Lee]

When Rob rebuilds a clutch for about $900 it's new heat shields & disk. I hear others saying that's too much so they go elsewhere and somebody takes a grinder to the surfaces and sometimes to the disk or possibly a cast off from a fuel team or maybe even a new disk. Ask, don't assume.

Use this common gear spread:
3.19
1.95
1.40
1.00

Shift all gears at 7,000 RPM
1-2 shift = 38.87 % drop = 2,721 drop = 4,280 RPM
2-3 shift = 28.21% drop = 1,975 drop = 5,025 RPM
3-4 shift = 28.57% drop = 2,000 drop = 5,000 RPM

Not sure if that helps...

I had one of my best years ever last year and I'm already ahead of 1st quarter of last year. Since I made the decision to go back in Stock, i've been pushing all parties involved. Just found out the other day the wheels I had made are not right so Monday I'm having another pair made, it will be 2 weeks. Hopefully my new custom bell housing will be done this week. Cam just received last week. Heads are done except final cut to CC spec. Short block just needs rings & bearings to assemble.
My goal is engine dyno within 3 weeks. New floors in car & fix chassis issues within 1 weeks after that. Garrett Monde is building me a new set of headers. I want everything within 90% of track readiness by end of April.
I'm changing all fuel lines, a data logger and a few other things that need to get done. Test / tune summer (aargh!), NHRA event in the fall.

[Dinsdale]

"When Rob rebuilds a clutch for about $900 it's new heat shields & disk. I hear others saying that's too much so they go elsewhere and somebody takes a grinder to the surfaces and sometimes to the disk or possibly a cast off from a fuel team or maybe even a new disk. Ask, don't assume."

Just got my Soft-Lok back from McLeod. They replaced both heat shields, 3 levers and pivot hardware, supplied a new disc, cleaned, repainted, re-certified and set it up for me. New studs in the flywheel and supplied a plastic aliignment tool. It looks like new and the cost was $550.00. Same as a buddy of mine had done a couple months back. I was very suprised at the work and price.

[Mark Madison]

Originally Posted by Jeff Lee

When Rob rebuilds a clutch for about $900 it's new heat shields & disk. I hear others saying that's too much so they go elsewhere and somebody takes a grinder to the surfaces and sometimes to the disk or possibly a cast off from a fuel team or maybe even a new disk. Ask, don't assume.

Use this common gear spread:
3.19
1.95
1.40
1.00

Shift all gears at 7,000 RPM
1-2 shift = 38.87 % drop = 2,721 drop = 4,280 RPM
2-3 shift = 28.21% drop = 1,975 drop = 5,025 RPM
3-4 shift = 28.57% drop = 2,000 drop = 5,000 RPM

Not sure if that helps...

I had one of my best years ever last year and I'm already ahead of 1st quarter of last year. Since I made the decision to go back in Stock, i've been pushing all parties involved. Just found out the other day the wheels I had made are not right so Monday I'm having another pair made, it will be 2 weeks. Hopefully my new custom bell housing will be done this week. Cam just received last week. Heads are done except final cut to CC spec. Short block just needs rings & bearings to assemble.
My goal is engine dyno within 3 weeks. New floors in car & fix chassis issues within 1 weeks after that. Garrett Monde is building me a new set of headers. I want everything within 90% of track readiness by end of April.
I'm changing all fuel lines, a data logger and a few other things that need to get done. Test / tune summer (aargh!), NHRA event in the fall.

Then why did my dual 7 came back without this being done? I had to complain to Rob to get this done ,After paying the $900.00 to rebuild the clutch . I paid to have it fixed the first time and didn't question the price. I just wanted it fixed. . No song and dance just fix it. Rob did as I asked and replaced the heat sheilds, the second time around. But, there should have not been a second time around.

Any body want to buy a Jerico and Advanced 7 and a clutch program from Mike Sullivan for the Dual 7? E mail me at mark_madison @sbcglobal.net And I will provide all prices and product info.

Mark Madison