Jim_PA

iTrader: (9)

Here's my setup:

Wilwood 7/8" master cylinder, GM F-body slave cylinder, all the proper plumbing, etc...

I'll be drilling a hole in my stock clutch pedal, and fitting a heim joint, shoulder bolt, and some threaded stock to make the connection to the master cylinder push rod.

Will the stock F-body slave cylinder take all of my 1.12" with the 7/8" bore?

How do you figure out how much travel you need in your master cylinder so the slave doesn't blow out?

Jim_PA

iTrader: (9)

(stock) 3/4" bore X 1" stroke = 1.77 cubic inches of fluid pushed to the slave at full travel

(Wilwood) 7/8" bore X (what stroke??) = 1.77 cubic inches of fluid to the slave at full travel? Answer is: ~.75"

So... If I set up my pedal (and a positive stop) to push in my master cylinder a full inch, then, I can just shim it out at the firewall by .25", this will give me the .75" stroke needed to match the volume of the stock master cylinder.

I'm thinking this will be a good starting point anyway, and should keep me in the safe operating range of the limits of what the stock slave cylinder will take...

Your thoughts?

Jim_PA

iTrader: (9)

Seems to be very little information known about master/slave cylinders around here

Jonathan@Tick

iTrader: (5)

What are you installing this in? Our kits are based off of a Tilton 7/8 bore cylinder with a 1.1" stroke. If I recall correctly, a stock f-body slave has almost .900" of travel on the tob from fully seated to fully extended. If you give yourself 3/16" of "clearance" between the tob and the base of the slave as measured with everything assembled then your slave would have a travel of about .712". I have crudely measured the amount the tob is actuated on the slave with one of our tilton cylinders and with the full volume of the cylinder being actuated the tob only moved roughly just a bit over 1/2".

That would make it pretty unlikely that you would over extend your slave using the master in question. We've sold a couple thousand of these kits to f-body, c5 vette, and GTO guys and to my knowledge only a couple of guys have claimed they damaged their slave. Based on the testing and results we've had here at the shop I would have to believe that their slave failures were un-related to our master cylinder kit.

The whole basis behind our kits and using this master with a greater volume is that it offers an adjustable displacement in order to push more fluid if necessary for a full clutch release even at high rpms. If you're worried about it, why not just install a 3/4" bore wilwood cylinder instead? The 7/8 bore will add some effort to the pedal as well.

Jim_PA

iTrader: (9)

It's a '68 c10 pickup.

I want some extra volume available if needed but being that I didn't know the limitations the slave, I wanted to mimic the stock volume, and adjust it higher if I had problems flat shifting at higher rpm's.

Your data makes me feel better about starting at an inch or so with the larger bore MC. Thanks!