As mentioned in the first "What is this?," I came across some neat parts and detail items while organizing my shop the other day. This was a pretty neat find... I knew I had it, but it had been buried in storage over the years. Not something you see all that often!



OK... What is it?

Regards,

Stan Falenski

 

1969 MA6 Dual disc clutch set-up.

 

Very interesting. Stan, can you separate the assembly? What is the difference from the stock clutch set up?

 

Paul,

Close...

Pete,

Yes, will do!

Regards,

Stan

 

Hi Stan,

It looks like a finer spline than the MA6, is that a clutch set up for an LS6?

 

Yes... That's it!

A better photo of the components...



Pressure plate... Slider plate... Two clutch discs. Available from the factory on 1971 LS-6 Corvettes and 1971 Olds 442s (as an option).

In any case, it's a pretty cool part and one that you won't see too often.

Regards,

Stan

 

Thanks for the lesson as usual Stan...

 

The MA-6 option started in 1969.....I worked in an auto parts store that sold speed parts in the 70s Borg Warner also sold this style clutch called a " double coupler " in both fine/coarse spline configurations. The original discs have a aluminum heat shield between the friction material and Marcel springs. One of my customers bought a BW clutch for his 70 SS454 El Camino he used to tow his circle track car.....he was ever thankful to me for many years for finding that bullet proof setup.....they were around $300 back then.....not cheap! I sold a used MA-6 I had for $500 on Flea Bay years ago/with the GM flywheel.....there are several modern equivalents now from McLeod and Centerforce that work well.

 

That's true. The coarse spline setup was available on many cars in the 1969 Chevrolet model line with a solid lifter, big block engine... L-78 Novas, Chevelles, and Camaros, L-72 Biscaynes, Bel Airs, and Impalas, and L-71 Corvettes. It was not available on L-88/ZL-1 Corvettes or any of the COPO Camaros or Chevelles.

The fine spline setup didn't show up until 1971 in production, but as you mentioned, both were certainly available as a service item and turn up from time to time.

They go for a bit more than $500 these days.

Great clutch as you mention... Relatively light pedal pressure (compared to your standard GM clutch) and great clamping power due to the dual friction discs.

Good stuff!

Regards,

Stan

 

Hmmm you learn something new every day. thanks for the lesson.

 

Stan that is very cool to see. I'm assuming the sequence goes flywheel, clutch disc, slider plate, clutch disc, pressure plate. How does the slider plate mount? If my assumption is correct, how is the clutch plate between the flywheel and the slider plate released?

 

Hi Stan,
" I knew I had it, but it had been buried in storage over the years".
Sorta like that shoe box filled with $20s and $50s!!!!!!
Regards,
Alan

 

I didn't know GM had a factory dual-disc setup, thanks for the lesson.

 

Pete,

Yes, that is the sequence.

The slider (or floater) plate rides between the pressure plate and flywheel when installed, sandwiched on either side by a clutch disc. It slides back and forth on the smooth portion of its mounting bolts as pressure is applied and released. When pressure is applied, both clutch discs and the slider are moved toward the flywheel until friction is sufficient for it grab. Similar to a single disc clutch... Just a few more moving parts!

The clutches are smaller than your standard 11" clutch, but there are two of them so the friction surface is greatly increased. In addition, pedal pressure is lower which is also a benefit. There are a couple of drawbacks... The clutch assembly is heavier so it doesn't allow the engine to spin up as quickly (one of the reasons why the L-88s continued to use the smaller 10.4" diameter clutch) and requires greater torque to overcome the inertia (why you only saw it behind solid lifter big block engines). There is also a tendency for it to be a bit noisy when not fully engaged. Still, it is a well engineered design and a neat piece of Chevrolet history.

I should mention that the flywheel is a unique piece to the dual disc clutch assembly as well. I don't have any good photos of that yet, but when I start to restore my LS-6 (soon!) I'll grab some photos.

LOL Alan!

I purchased a lot of parts for cars over the years... Some for cars that I have, some for cars long gone. It's amazing how many neat parts I forgot that I had stashed away.

On an unrelated note, can you give me a call when you get a chance? Not urgent, just want to touch base with you on a couple of items.

Thanks Alan!

Regards,

Stan