McLeod 500 series clutch disc. Organic/Ceramic...Anyone using one?

[biomedtechguy]

I am about to install a HitMaster launch control system in my 440 6bbl 70 Roadrunner. I currently have a 2,950 pound clamping pressure McLeod diaphragm style pressure plate, and the organic clutch disc. 18 spline, 10.5" diameter disc.
I spoke with McLeod and they basically said either you put wear on the disc, or wear on the flywheel and pressure plate.
They said the 100 series clutch disc I have is worth a try, and won't cost anything since I already have it. The 500 series clutch disc is the next step up to try, and it has organic material on the pp side, and ceramic on the flywheel side. My flywheel is "like new" and a billet steel unit I bought from Brewers.
So my thought is to try what I have and see if it can "take the heat" that the HitMaster will impart during the 1½ appx seconds delay to full clamping pressure.
My question is have any of you used the 500 series clutch disc (organic/ceramic) under track conditions where you are aggressively launching around 3,000 RPMs and how well did the disc, pp, and flywheel surfaces hold up, any scorching? How long did they last before you had to have any of those parts replaced or rebuilt?
Any alternatives to this setup that may work better?
Any other comments?
I am absolutely going to get the HitMaster launch control system, so that is not part of the discussion of options.
I would be interested in any personal experience with the "Soft-Lock" series by McLeod. That would actually replace the HitMaster as that disc material and pressure plate is designed to fully grab once heated, that heat being imparted in fractions of a second. The initial cold surface slips by design, and the heat that initial slip produces then causes the disc to grab.
Thanks!

 

[68 HEMI GTS]

A normal soft lock won’t live on the street. You will need a custom built one with a sintered iron disc. Even then it’ll require being loosened up for the track and tightened back up for the street. That’s what I had in my dart last go around. It was built by Hyatt racing clutch. Not sure they are still in business as Tim died. There are other clutch builders out there though.

 

[68 HEMI GTS]

Now that I think about it, one like mine with the hitmaster may work well. You wouldn’t need to adjust it and the slipping wouldn’t bother it.

 

[biomedtechguy]

A normal soft lock won’t live on the street. You will need a custom built one with a sintered iron disc. Even then it’ll require being loosened up for the track and tightened back up for the street.

McLeod is the company that told me about it. I take what you just posted as 100% correct, so I have a couple of questions, and I want to say that the HitMaster is NOT compatible with a soft lock clutch, and I am ordering the HitMaster, and I believe that it is going to work VERY well.
Still, I'm curious: How do you "adjust" the hit, in other words how do you loosen and tighten it, and can that be done without sliding the transmission back out of the bellhousing? If it can't be adjusted as it sits, through the removal of the access panel at the bottom of the bellhousing, that is out of the question.
I saw some McLeod discs with sintered iron material, but I'd like to know something about that please.
Thanks a lot!

 

[biomedtechguy]

Now that I think about it, one like mine with the hitmaster may work well. You wouldn’t need to adjust it and the slipping wouldn’t bother it.

Once again, you may be right, but McLeod said it would not be compatible.
Maybe if you can tell me about the characteristics of sintered iron discs, that would make sense to me.

 

[68 HEMI GTS]

Once again, you may be right, but McLeod said it would not be compatible.
Maybe if you can tell me about the characteristics of sintered iron discs, that would make sense to me.

Tim used the sintered iron disc so it could be used on the street. The disc that comes with a soft lock (if you bought it from mccleod) is not street compatible. I just had to change the base between street and track. I’m thinking with the hitmaster you could just leave the base tight and let the hitmaster slip it. You will need to call a custom clutch builder to get it right though.

http://hyattracingservices.com/

 

[biomedtechguy]

Tim used the sintered iron disc so it could be used on the street. The disc that comes with a soft lock (if you bought it from mccleod) is not street compatible. I just had to change the base between street and track. I’m thinking with the hitmaster you could just leave the base tight and let the hitmaster slip it. You will need to call a custom clutch builder to get it right though.

http://hyattracingservices.com/

Thanks a lot!
I've bookmarked their website.
I'll give them a call.
My takeaway from the conversation with McLeod was even if I get a clutch disc that handles the brief but intense heat and other harsh effects of the appx 1½ seconds of slipping imparted by the HitMaster, that "tougher" disc will transfer the wear to the pp and flywheel. Also, I asked about a dual disc setup and would that spread the load and the wear, but he said no, and that is a common misconception.
Eventually I'm sure I will have to upgrade clutch components when I install the 540 cu in 6XX-7XX HP and torque stroker motor, but for now, I want to work with what I have, including my warmed over 440 6bbl.
Thanks for your thorough and thoughtful advice, as always.

 

[biomedtechguy]

Well, I had to change out my clutch disk and pressure plate for an unrelated reason, and spent time with McLeod tech support. I've ordered the RXT dual disk clutch and pressure plate setup. Ceramic/Metallic 1,000HP
The plan is for this to work with the heat of the HitMaster and my future stroker motor too. 10% off at LMP made it $843
I sure hope it works great, because that's a lot of money.
https://www.lmperformance.com/709553/6923-05-mcleod-mopar-rxt-twin-disc-clutch-kit-18-spline.html

 

[747mopar]

Well, I had to change out my clutch disk and pressure plate for an unrelated reason, and spent time with McLeod tech support. I've ordered the RXT dual disk clutch and pressure plate setup. Ceramic/Metallic 1,000HP
The plan is for this to work with the heat of the HitMaster and my future stroker motor too. 10% off at LMP made it $843
I sure hope it works great, because that's a lot of money.

Good call, I'm running one like you described in your original post, a Mcleod with ceramic on one side and organic on the other.. think it was rated for 500 hp?? It works well after breaking it in but I have smoked it a couple times grabbing 2nd in a burnout but no slippage other than that lol. Mine was the McLeod Racing 75225 - McLeod Super StreetPro Clutch Kits.

 

[biomedtechguy]

Good call, I'm running one like you described in your original post, a Mcleod with ceramic on one side and organic on the other.. think it was rated for 500 hp?? It works well after breaking it in but I have smoked it a couple times grabbing 2nd in a burnout but no slippage other than that lol. Mine was the McLeod Racing 75225 - McLeod Super StreetPro Clutch Kits.

Yes, 550 HP. Looks like organic on one side ceramic/metallic on the other?
There were too many things pointing me to the dual disc series for me to deny that looks like my best solution.
Easier pedal effort by design should alleviate the firewall flexing issue, which has also had a chain and turnbuckle added to it to resolve this problem until the engine comes out for the 541 stroker swap, and at that point I'll have reinforcement plates installed permanently, if I still want or need that. I'm also swapping OUT a 2,950 pound pressure plate, so I think the twin disc will be a LOT less pedal effort. The reason for the RXT instead of the 800HP RST is the material on the discs. Apparently organic just can't take the kind of heat anticipated.
Better safe than sorry. Once and done, until wear makes it necessary to change the worn part(s).

 

[747mopar]

Yes, 550 HP. Looks like organic on one side ceramic/metallic on the other?
There were too many things pointing me to the dual disc series for me to deny that looks like my best solution.
Easier pedal effort by design should alleviate the firewall flexing issue, which has also had a chain and turnbuckle added to it to resolve this problem until the engine comes out for the 541 stroker swap, and at that point I'll have reinforcement plates installed permanently, if I still want or need that. I'm also swapping OUT a 2,950 pound pressure plate, so I think the twin disc will be a LOT less pedal effort. The reason for the RXT instead of the 800HP RST is the material on the discs. Apparently organic just can't take the kind of heat anticipated.
Better safe than sorry. Once and done, until wear makes it necessary to change the worn part(s).

In my case with the T56 and it's hydraulic clutch setup, pedal effort is pretty minimal but for what your doing I'd buy the twin as well. If I've smoked mine a few times going into second with a mildly built 451 you'll definitely do the same at the track eventually.

 

[biomedtechguy]

I find it encouraging, in a mystical way, that the only review for this Mopar big block specific clutch is...
A built up 440 6bbl!
From Summit:
My built up (full roller,high compression, aluminum headed) 440-6 was slipping at high RPM's and I didn't catch it. After only 2,000 miles I check the old clutch and flywheel. What a mess. Appeared the steel flywheel and pressureplate got so hot it smeared the metal! No way that's going to happen with this new clutch! Don't screw around with a lesser clutch upgrade to one that will handle your engine!