Keeping a quartermaster clutch alive

sburkett

sburkett

Well-known member
My car came with a trashed Quartermaster 5.5" double disc clutch (the older enclosed "pro series" type). I cleaned up the flywheel, pressure plate and floater on the big belt sander and they look great, perfectly flat and parallel.

But... after sanding, the floater measures .175 and the pressure plate measures .525. The minimum spec published by Quartermaster are .177 and .528, respectively.

Now given that I am running a EP RX-7 while the clutch is rated at something ridiculous like 800 lb-ft of torque, I am tempted to just buy some clutch disks and give it a go.

Alternately, I could take .005 off the housing which I think would theoretically restore clamping force to spec.

Anyone run these things down thin and got away with it? Thoughts?

Thanks!
Steven
 
Have you called QuarterMaster? They gave me some very straight answers to my questions.

-Kyle
 
Removing just .005 will get you to the low end of the spec, but not optimal. We have ground these many times and take the proper amount off to get back to the new preload. See what the spec is for new plate and floater and take off the difference. Mark the outside of the clutch with -.XXX so you do not forget and overload it in the future. Usually .025 or less to get back to new.
 
How strong is your scatter shield? The clutch contains some of the most powerful kinetic engery in your car. I think you have hand grenade in your right hand and the pin in your left hand. Don't release the handle, and quickly replace the pin.

I have used QM for over 20 years, with engines that had 700+ pounds of torque. The QM clutches are rock solid and durable. But when worn they will have developed cracks and weaknesses in the components, from heat and stress. You may have marginally acceptable dimensions on your parts, but they are structurally defective metal parts. The danger is not in the torque they transmit, but, the RPM they operate at. What is your shifting point, 8,500 RPM?

Call Quarter Master, and order new parts.
 
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