Twin Disc users, how long are yours lasting?

[sbiggi]

So for you 500+whp twin disc users.

How many passes at the drag strip are you getting out of your twin disc?
and who makes yours?

I seem to kill mine super fast. The first time I got something like 12 passes out of mine.
I was preloading on the launches and it did not like the heat. Wore the discs down, warped the PP surface.

So I stopped preloading.

Except last race I had to do a round robin final round. I dont think the cluch much appreciated that. Pedal movement feels the same, release fork has full movement, but the clutch drags and grinds gears now 18 passes on this one with no street driving.

-Seth

 

[Slippi84]

So for you 500+whp twin disc users.

How many passes at the drag strip are you getting out of your twin disc?
and who makes yours?

I seem to kill mine super fast. The first time I got something like 12 passes out of mine.
I was preloading on the launches and it did not like the heat. Wore the discs down, warped the PP surface.

So I stopped preloading.

Except last race I had to do a round robin final round. I dont think the cluch much appreciated that. Pedal movement feels the same, release fork has full movement, but the clutch drags and grinds gears now 18 passes on this one with no street driving.

-Seth

Couple things to help solve your problem. One which clutch are you using? Two which disks(some company's have ceramic and metalic). Three and even more important how did you install it because most premature twin disk failure is due to improper install

 

[sbiggi]

Couple things to help solve your problem. One which clutch are you using? Two which disks(some company's have ceramic and metalic). Three and even more important how did you install it because most premature twin disk failure is due to improper install

I have a PTT unit with the high torque plate and metalic discs.

Not sure what you mean, how did I install it? It only goes on one way. The discs are marked engine side and transmission side. PP bolts torques to their spec.

Pretty sure it was not hyper extended. They didnt say it was the first time I sent it in.
The clutch was adjusted so that it would release fully when the pedal was at the floor. IE, car in gear and off, wouldnt roll till the pedal hit the floor.

 

[Slippi84]

How it was adjusted is what I meant. You don't usually want the engagement point to be all the way up or down. Usually you aim for just over 3/4 pedal travel for full engagement.

 

[sbiggi]

How it was adjusted is what I meant. You don't usually want the engagement point to be all the way up or down. Usually you aim for just over 3/4 pedal travel for full engagement.

My understanding on a twindisc is; no more pedal travel then is required for full release. Otherwise you will overextend the pressure plate fingers.

If I wanted a higher pedal I'd have to make a pedal stop, which seems pointless if it only makes for a shorter total pedal stroke due to more preload.

Mine fully releases on the floor, but full friction point is maybe a inch and half to 2 inches off the floor. I'd have to measure for sure. The full friction point right now when it is grinding, is the same height as it was when it seemed to be working fine.

 

[Slippi84]

My understanding on a twindisc is; no more pedal travel then is required for full release. Otherwise you will overextend the pressure plate fingers.

If I wanted a higher pedal I'd have to make a pedal stop, which seems pointless if it only makes for a shorter total pedal stroke due to more preload.

Mine fully releases on the floor, but full friction point is maybe a inch and half to 2 inches off the floor. I'd have to measure for sure. The full friction point right now when it is grinding, is the same height as it was when it seemed to be working fine.

Yeah that's what your suposed to do make a pedal stop. By making it so it has to be all the way on the floor you may not fully engage when trying to shift fast or what not and cause premature failure. WHen you say your preloading the drivetrain are you using the e-brake or a staging brake? What rpm and how long are you holding it at when staging?

 

[sbiggi]

Yeah that's what your suposed to do make a pedal stop. By making it so it has to be all the way on the floor you may not fully engage when trying to shift fast or what not and cause premature failure. WHen you say your preloading the drivetrain are you using the e-brake or a staging brake? What rpm and how long are you holding it at when staging?

I stopped preloading.

When I did, I would use the ebrake to hold the car. 6000rpm launch with the 2step.

Now I just do 6000rpm launch with no ebrake or anything, so no preloading.

I can make a pedal stop and adjust it up higher, thats pretty easy.

My last run I only had 7 minutes in between the passes. I hope the disc wear is better this time and maybe only warped the PP surface. I still would like to know how long others are lasting.

 

[Savage Talon]

My disc's wore down fast but I was weekend driving it. I would say less then 5K miles and 1 trip to the strip and the disc's were gone. The disc for my PTT are .200 new and need to be changed at .180. I wore mine down to .170 and barely made it home it was slipping so bad.

 

[Slippi84]

My disc's wore down fast but I was weekend driving it. I would say less then 5K miles and 1 trip to the strip and the disc's were gone. The disc for my PTT are .200 new and need to be changed at .180. I wore mine down to .170 and barely made it home it was slipping so bad.

You have a stroker I know that's not helping longevity for a WW car but that's still WAY too soon to be swapping disk. How long has the second set lasted?

 

[Savage Talon]

They are still in the car, so no telling. Right now it is just sitting because I stripped the teeth off the intermediate shaft on the dyno. Thats the second time in 6 months Ive shredded 3rd and the I-shaft. One thing I did notice right after I installed new disc's, was the clutch slipped in 3rd gear after preloading for a few seconds on the line. So these clutches do not like preloading at all, to much heat.

 

[twicks69]

The PTT disks are going to be much more succeptable to preloading/slipping overheating and premature wear due to the thinner disk friction surface and lower heat capacity when being compared to the QuarterMaster counterpart.

Savage -- check your flywheel friction surface for flatness. You might be having uneven disk wear due to a bowled surface or using new disks with reused floaters. I am sorry to hear about the transmissions -- This is what I have been dealing with for years now due to the amount of torque and the load generated by the car being strapped to a dyno.

 

[kawboy]

How much does a QM replacement disc/floater setup run?

 

[twicks69]

How much does a QM replacement disc/floater setup run?

I am not sure offhand -- contact QuarterMaster and find out. Their prices are supposed to be fixed-price across their registered vendors for fair pricing. If I need something from them, I just contact them directly for assistance.

:: Quarter Master :: Home

 

[sbiggi]

I called Quarter Masters up.

Their disc are the same thickness, wont last any longer then a PTT because of that.
They will handle heater better because of their material.

I asked them about pedal adjustment.
He said to adjust it a 1/4" past where it fully releases.

Anyone have the part number for the quarter masters .200 thick replacement clutch pack?

 

[twicks69]

I called Quarter Masters up.

Their disc are the same thickness, wont last any longer then a PTT because of that.
They will handle heater better because of their material.

I asked them about pedal adjustment.
He said to adjust it a 1/4" past where it fully releases.

Anyone have the part number for the quarter masters .200 thick replacement clutch pack?

Actually, you are incorrect, the clutch disks for our application are 0.250" thick and are for the RALLY 7.25" V-drive Twin Disk Clutch -- not just the standard V-drive. The floaters are the same thickness, but the clutch cover is taller and the disks are thicker than the standard 0.200" V-drive clutch assembly or PTT clutch assembly.

I called my contacts at Quarter Master and confirmed the information.

As well, the disk assembly they sell for the 7/8"x20-spline application are ONLY available with the hardened heat-treated hubs now. This was an upgraded version from last year as there were cases of really high HP cars shredding the splines off the disks (as I did on the dyno last July). They heat treated the hubs to increase their strength and reduce surface fatigue that would cause spline failure prematurely.

The part number is 226041RYS
The list price is $320.37
The material thickness for the Rally disks used for our application are 0.250" Thick.

 

[outlawdsm]

I have over 15k on my Devo/QM twin. Lots of abuse, preloading, 9k shifting, launches...ect and it looks awesome last time i had it out (not that long ago) no pedal stop, just adjusted so it doesn't over extend.

 

[Hal]

Seth,

I'll look when I get home.

I have a new pair of the thinner Q/M discs waiting to go in the car.

I'm sure the part number is in the box.

Part number should be: 226041RY3P

 

[sbiggi]

Actually, you are incorrect, the clutch disks for our application are 0.250" thick and are for the RALLY 7.25" V-drive Twin Disk Clutch -- not just the standard V-drive. The floaters are the same thickness, but the clutch cover is taller and the disks are thicker than the standard 0.200" V-drive clutch assembly or PTT clutch assembly.

I called my contacts at Quarter Master and confirmed the information.

As well, the disk assembly they sell for the 7/8"x20-spline application are ONLY available with the hardened heat-treated hubs now. This was an upgraded version from last year as there were cases of really high HP cars shredding the splines off the disks (as I did on the dyno last July). They heat treated the hubs to increase their strength and reduce surface fatigue that would cause spline failure prematurely.

The part number is 226041RYS
The list price is $320.37
The material thickness for the Rally disks used for our application are 0.250" Thick.

Hmm, I asked the guy this morning, he said they were the same thickness...
.
so QM uses .250 and PTT uses .200

To use the .250 discs I'd need the QM basket right?

 

[sbiggi]

Well I pulled it apart. the discs are good both are .196" thick.

Going to have the Pressure Plate and Floater checked for flatness.

 

[twicks69]

Seth, it sounds like you are having an issue with complete engagement of the clutch/floater/flywheel surfaces. I would look into getting the clutch cover rebuilt with the proper high-capacity spring, and check the fulcrum plate and floater plate for overall flatness and measure for thickness variations or surface bowling. As well, check that flywheel for surface flatness with a proper steel bar. You should be able to see engagement variation also in the clutch disk friction surface by uneven wear characteristics.

If I remember correctly, the PTT 0.200"-thick disks are at their maximum service life around 0.185". As well, I would always recommend replacing your floater and fulcrum plate when you replace the friction disks, along with a flywheel resurface to ensure proper engagement of all surfaces for optimal clutch engagement and reduced premature wear issues.

As for the QM Rally 7.25" V-Drive disks, the part number I have given above is for their only stocked version of the 20-spline 7/8" hub for the Rally twin-disk setup. It is the revised version with the heat-treated hubs, hence the increased cost. This information was directly from Dave (I forgot his last name) and Jeff Wiegert.

I ran the original version of the clutch disks (the standard hub) for 2+ years and over 30K miles with well over 250 dyno pulls, and well over 100 track passes at 650-760AWHP / 560-700TQ the entire time and when I replaced them -- due to shearing the splines off the clutch disks and twisting the input shaft splines simultaneously with exploding a transmission -- they were at an overall thickness of 0.244", and the floater and fulcrum plates were well within spec.

I then went to a new set of disks with the hardened hub (the part number listed above), and a new fulcrum plate and floater plate, along with new hardware, clutch fork, TOB. I only had 500 miles or less on them when I pulled them from the car (due to other issues...turbo exploding, and pulled the engine for rebuild). Upon inspection, they were at 0.2491"-0.2489" for both friction disks, but were unevenly wearing due to the main bearings being shot from a bent crank, causing uneven wear from excessive chatter and a bowled flywheel surface which required a later resurfacing in preparation for the new prototype clutch disk design I am currently installing for the 2009 season.

The new clutch disk design is a gear-drive design of the rally 0.250" friction disks with a refurbished clutch cover/new spring, new floater and fulcrum plates and a resurfaced flywheel.

http://www.dsmtuners.com/forums/dri...ch-sneek-peek-prototype-design-twin-disk.html

Finally....yes, if you are going to use the QM rally disks with your setup, you will need the Rally 7.25" V-drive twin-disk clutch cover to fit the disks. The floater and fulcrum plates are identical to the PTT. You will likely require a bit of grinding of your clutch fork to clear the clutch cover.

 

[sbiggi]

Seth, it sounds like you are having an issue with complete engagement of the clutch/floater/flywheel surfaces. I would look into getting the clutch cover rebuilt with the proper high-capacity spring, and check the fulcrum plate and floater plate for overall flatness and measure for thickness variations or surface bowling. As well, check that flywheel for surface flatness with a proper steel bar. You should be able to see engagement variation also in the clutch disk friction surface by uneven wear characteristics.

When I rebuilt it before I sent everything but the flywheel in.

PTT replaced the Pressure Plate diaphram, PP surface (fulcrum plate) and the discs. They said the floater was fine. I didnt check the flywheel though.

So I'll be rechecking everything.

 

[twicks69]

Always worth doing!

 

[94awdcoupe]

the .250 will not last longer than the .200 discs. The .250 will handle more heat, the .200 will shift faster due to less rotating mass. both clutches start slipping at about .050- .070 worn off both discs combined. . The pressure plate looses its leverage more and more as material is worn off..your pedal feel gets stiffer as well. that stiffer pedal is the lost torque the PP has on the discs.

The last clutch I serviced had ..040 worn off the discs and it went back in the car for more service.

 

[Team Addiction]

Old thread I know...............

Daily driven my QM twin lasted 2500 miles at 3-350hp. With no launching whatsoever! But I will admit to some jacka$$ driving here and there. Yeah more clutch than I needed I know original plan was to break it in on the 16g then move on to my T67. While preparing to swap in the 67 I pulled the tranny and lo and behold warped floater and cracked discs?! These things are a little pricey for that kind of mileage .

 

[twicks69]

Actually, you are incorrect, the clutch disks for our application are 0.250" thick and are for the RALLY 7.25" V-drive Twin Disk Clutch -- not just the standard V-drive. The floaters are the same thickness, but the clutch cover is taller and the disks are thicker than the standard 0.200" V-drive clutch assembly or PTT clutch assembly.

I called my contacts at Quarter Master and confirmed the information.

As well, the disk assembly they sell for the 7/8"x20-spline application are ONLY available with the hardened heat-treated hubs now. This was an upgraded version from last year as there were cases of really high HP cars shredding the splines off the disks (as I did on the dyno last July). They heat treated the hubs to increase their strength and reduce surface fatigue that would cause spline failure prematurely.

The part number is 226041RYS
The list price is $320.37
The material thickness for the Rally disks used for our application are 0.250" Thick.

Thought I should update this information, as I am now a Quarter Master dealer....

I have special pricing on the old version disks (heat-treated hubs), and on the new upgraded Gear-Drive Heavy-Duty clutch disk pack located on my website.

TMZ Performance


These disks are able to be used on Quarter Master and PTT clutch assemblies and are 0.250" thick.

To use the new version gear-drive HD disks on a Quarter Master 7.25" V-Drive Rally twin-disk setup, you will require a new set of clutch disks only. It is still recommended to replace the pressure plate and floater plate with new ones if they measure out of spec or have alot of hot-spots.

To use the new version gear-drive HD disks on a PTT 7.25" twin-disk setup that normally uses the 0.200"-thick disks, you will require a new Quarter Master 7.25" V-drive Rally twin-disk clutch cover, new clutch cover hardware, and the clutch disks. It is still recommended to replace the pressure plate and floater plate with new ones if they measure out of spec or have alot of hot-spots.

The Mitsubishi OEM throwout bearing or the PTT throwout bearing are recommended for this setup, and the OEM Mitsubishi slave cylinder for your application is recommended. A clutch pedal stop is not required; just proper clutch pedal adjustment for proper disengagement properties is required.

The OEM Mitsubishi clutch fork requires a bit of grinding for usage in any Quarter Master 7.25" rally twin-disk clutch setup to clear the clutch cover hardware. This is also required for all PTT users that are doing the clutch disk and clutch cover conversion.


I also still recommend using a Fluidampr crank harmonic damper pulley to further reduce 4th Order harmonics, and torsional harmonics. This will substantially decrease the clutch harmonics and decelleration chatter commonly associated with multi-disk clutch assemblies.

The 4G63 DSM application is:
6-3/8" Mitsubishi 4G63/T DSM
Part #: 630701

The 4G63 EVO 8/9 application is:
6-1/8" Mitsubishi EVO 8 & 9
Part #: 610701

Thought that you guys would enjoy having this information!