Tilton 5/8 master cylinder
Thread Starter
Burning Brakes
Joined: Oct 1999
Posts: 1,236
Likes: 91
From: Pittsburgh,PA
Tilton 5/8 master cylinder
I recently installed a Tilton ST-246 twin disk clutch, I've had a Tilton 7/8" master cylinder installed for years it worked great with all the other single disk clutches I've used over the years. But with the twin disk the 7/8" bore was way to big it literally was just an on off switch. After talking to Tilton they tell me they usually recommend using there 3/4" bore master. I installed the 3/4" and It's definitely better but It's still a bit of an on off switch. I was wondering if any one ever used one of there 5/8" bore master cylinders?
Thread Starter
Burning Brakes
Joined: Oct 1999
Posts: 1,236
Likes: 91
From: Pittsburgh,PA
Not that any one cares but I talked to Tilton yesterday they said the 5/8" master as well as the 7/10" master would be to small they would not have enough fluid volume to release the twin disk clutch.
Melting Slicks
Joined: Dec 2018
Posts: 2,677
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From: Orange County, CA
Whether or not I care, I'm intrigued by the discussion topic.
Don't know if you're interested, but since you have the ability to adjust MC push rod length I have an idea for determining if the smaller MCs would push enough fluid for your clutch to disengage.
Don't know if you're interested, but since you have the ability to adjust MC push rod length I have an idea for determining if the smaller MCs would push enough fluid for your clutch to disengage.
- Drop midpipe (assuming no long tubes) and clutch inspection cover.
- Adjust your 3/4" bore MC's push rod to fully out (longest length) where the pedal still engages the lower clutch switch, and adjust out your upper clutch switch if needed.
- Measure the stroke length of the push rod at the back of the MC, from pedal not pushed to pedal fully depressed.
- Tilton specs a stroke length of 1.1" so this is the number you should be able to measure.
- Note from below how loose/free the clutch disks are with the pedal fully depressed (this will take a 2nd person pressing the clutch pedal).
- With the push rod stroke length measurement, reduce the length of the push rod with the numbers below. i.e. with Tilton's 1.1" stroke length spec, if you are aiming for 20% shorter stroke length then reduce push rod length by 1.1" x 0.20 = 0.22"
- 7/10" bore is 13% less fluid, reduce stroke length by 13%
- 5/8" bore is 30.5% less fluid, reduce stroke length by 30.5%
- For each of the reduced push rod lengths, see from below how loose/free the clutch disks are with the clutch pedal fully depressed.
- This will give you an idea of either of the smaller MCs will still adequately disengage your clutch.
Thread Starter
Burning Brakes
Joined: Oct 1999
Posts: 1,236
Likes: 91
From: Pittsburgh,PA
I'm fairly certain that the 7/10" master and probably the 5/8" as well would work. I should have added that I have the rod most of the way out now the clutch pedal is even the brake pedal. I only have to depress the pedal 3 1/4" to disengage the clutch, if I go much more than that I would over stress the clutch fingers. I also have a pedal stop installed as well as an extension to make contact with the clutch switch.
Thread Starter
Burning Brakes
Joined: Oct 1999
Posts: 1,236
Likes: 91
From: Pittsburgh,PA
Update I'm getting somewhat used to the clutch there's only 3.2" of pedal travel from full engage to full disengage , I don't drive this car on the street except for an occasional test run. I would not recommend this clutch (with the Solid Hub Cerametallic disk) for the street. Tilton even tells you It's not for the street the Sprung-Hub Organic discs should be ok for the street. I did order a 7/10" Tilton master but did not receive it yet. I'll post when I get it installed.
