drivinhard

Finally (sigh) getting around to installing my 5.5" dia, clutch switch




Thanks so far to Danny Popp and Mike E. for helping me with some questions.

For you guys running an LS automatic flexplate as your starter ring, are you beefing up any of the welds on the ring gear or are these things suited to run as is, at ~7k rpm in a road race application?

RAFTRACER

I haven't had any issues with stock GM flexplate to this point up to 8K..

Are you just getting that thing installed ?????

stairman

I used an aftermarket billet piece, sorry I cant help with that one, but I know James and Danny are spinning the snot out of their's.

Did the control arm find you. Thanks again.

wmckeenster

wonder where my QM clutch is?

Danny please advise

Bink

Love the pic! It's not quite a switch...but close to one.

davidfarmer

I was urged by GM Racing engineers to spot-tig the OEM flexplate, since it is only friction welded together. However, the last one I got from Rock Auto was fully welded, so I'll go with them from now on.

photos here http://www.davidfarmerstuff.com/quartermaster-C5.pdf this is the older one that I had to have welded. GM told me the teeth could fly off above 7000rpm

I have 5.5" 3-disc clutches for years, and never had any trouble modulating them in WC standing starts, and usually even drove it into my trailer. Not ideal, but never caused any problems.

0Randy@DRM

We had one come flying apart. It wasn't pretty at all, out the bellhousing, out the drysump tank, out both sides of the chassis, and finally out the body work.

The newer flexplates have more weld on them.

Randy

sperkins

I had just the balance weight fly off of one in one of my older cars. It destroyed the bellhousing and went through the floor pan.

If you weld it up beefy like, won't you have to have it rebalanced?

WBHighwind

que pasa?

davidfarmer

My guy TIG welds if symmetrically, and balance was never an issue for me. Flexplate, unlike a flywheel, has very little mass.

Going to this setup and an aluminum damper saved around 40lbs of reciprocating mass!

Jason

Not to self, do not spend all day running next to Mark.

drivinhard

I'm slower than an underwater fart

2 kids, 3rd on the way, working full time, starting a business, and every time I turn around it's another NASA weekend.

Jason the point of this is to help keep you behind me, not beside me

drivinhard

I ended up having it TIG'd on the backside in 6 spots and had it balanced.

I only had 2" bolts in the kit for the cover, I needed 2 1/4" so I had to go source those locally.

Hope to test it tonight

btw what's the bore size of the C5 clutch master cylinder?

gmccreary

Don't forget. You need to work on my car too.

sperkins

One of the guys at TICK told me the stock m/c has a 3/4" bore vs theirs of 7/8".
I can believe it too. The difference is hue-edge.

davidfarmer

the OEM master works fine, although you want to make sure you only press the pedal just far enough to disengage the clutch. If you overfill the throw-out bearing, it can esplode! However, I've run them in several cars and not had to adjust the pedal stops at all.

drivinhard

I've got a 1.75 bearing/piston, and I got a bearing clearance of .100" when I measured the outside of the bellhousing to the fingers, and the bearing to bottom of torque tube flange (the 2 subtracted).

Unless I was reading all the charts wrong, I think I am in within their specs.

John Shiels

:smiliedr ool:

drivinhard

I've got a .100 clearance and a .150 release spec for the 5.5". So basically I need .250 of bearing travel for full release.

the quartermaster chart assumes 1" of stroke travel for the MC, and I think is something in the .350 range.

can the plate tolerate an additional .100" of travel? may have to see how it works and see if I need a pedal stop

my bleeder extension is leaking. sigh. I think I have given up on vendors and will be making my own lines from now on.

davidfarmer

I never put an extra stop in, but I'm pretty easy on the clutch pedal. If you really like to hammer the clutch (like a student I recently had), you should push it until is disengages, then see if there is much play left. With all you have left to do, I'd just get it together for now.

As I've posted somewhere, I just had an OEM-to-AN adapter made locally, and used the standard lines that came with the bearing.