Hi Tim,
Everything you say about the clutch master cylinder is correct. The trade
off between the different piston size is force vs. motion. The 0.7 inch
cylinder produces less motion at the SC but requires less force at the MC.
Force and motion curves are plotted in a Clutch Calculation note on the
Technical page at http://www.buckeyetriumphs.org/ .
I have 0.7 inch MC in my '76 TR6 and a 0.75 in my TR250. To be honest with
you, I really don't see much difference. Both have an inch or two spare
pedal. Some folks have replaced 0.7 inch MCs with 0.75 inch ones because
they had insufficient pedal. Many reported that it worked for a short while
and then they were out of pedal again. Some of the other clutch notes on
the BT website gives some suggestions on getting more pedal.
It has been reported that some women refuse or are unable to operate the
stiff TR6 clutch. Some men consider that an advantage (unless the woman
decide to drive the car without using the clutch). The significant other
may be the determining factor of which MC to install.
Nelson Riedel
Granville Ohio
'68TR250, '70TR6, '76TR6
Subject: Clutch master cylinder
| Since there is both a .70 and a .75 inch diameter clutch master
| cylinder available, am I right in thinking that the .75 is the better
| way to go? Seems like the .75 would be better, because it would
| displace more fluid, therefore giving more clutch throw. Right? That
| seems to make sense. Stroke would obviously be the same, so if bore is
| greater, then displaced fluid should be greater, therefore the slave
| cylinder would move further and you'd get more clutch throw. But why
| is it that Triumph switched from the .75 to the .70?
|
| Tim Holbrook
| 1971 TR6 (cousin has bought a TR6, needs advice on replacing clutch
| hydraulics)
|