Clutch, master- and slave cylinders...

[Bowtie]

Huston, I have a clutch problem...

I have a Chevy 350 with a 4-speed manual. I have mounted a 3/4” slave cylinder and a pushrod to the trough out fork. The slave cylinder needs to travel ~25mm to disengage the clutch and the full possible stroke is ~35mm (the clutch is then fully disengaged and has well passed the pivoting point where the pressure needed to keep the clutch disengaged is lighter).

I connected a 5/8” master cylinder (from a Toyota) to test the setup but the slave cylinder moved just some disappointing 20mm. One reason is probably the short stroke of the master cylinder (less than 30mm). I am now planning to buy a real master cylinder for the clutch but what size would be best? I am leaning towards a 3/4” from Girling or Wilwood (35mm stroke). I guess that it would fully disengage the clutch but it would require heavier pressure on the clutch pedal compared to a smaller master cylinder.

AK is using a 3/4” master and a 7/8” slave from Girling. The ratio it pretty close to a 5/8” master with a 3/4” slave but I don’t dare to take a chance with a 5/8 master. Some 5mm extra stroke will simply not be enough for me.

I would therefore like to know about your experiences. What sizes and ratios between master and slave are you using? What is the required travel needed for disengage and full through on your clutches and trough out forks?

Thanks in advance / Bowtie

[Miket]

Hi Bowyie

I have a 3/4 master and a 7/8 slave, both Girling, fitted to my 355 Chevy with BMW Getrag box.

The pedal pressure is reasonably light and it all works a treat.