11/16 Inch Or 17 Mm Bore Clutch Master Cylinders?

[Chris Wilson]

Stock R33 GTS-t clutch master cylinder is 5/8 inch bore, does Nissan make a similar style (offset bolt holes, short body) master cylinder in 11/16 inch bore or 17 mm ? Thanks.

[The Dan]

What are you trying to achieve?

That would possibly push the pushrod out of the slave cylinder

[Swiper the Fox]

What are you trying to achieve?

That would possibly push the pushrod out of the slave cylinder

i think he may mean slave cylinder anyway Dan. The 'offset bolt holes' bit did it for me.

Edited October 29, 2009 by DiRTgarage

[Chris Wilson]

I have a Tractive sequential gearbox that I have fitted with a concentric push type clutch release bearing assembly. Whilst the stock 5/8 bore clutch MC releases it you need ALL available pedal travel. An 11/16 cylinder would give more bearing travel, and I can run a pedal stop if required. The pedal is currently light enough to press with your index finger against a Giken triple plate clutch, so a bit more pedal effort won't matter By offset holes in the MC I meant they aren't vertical or horizontal, but displaced to about 45 degrees from the vertical. I could probably use an AP or Tilton short cylinder, but was wondering if Nissan did a different bore in the stock casting. Thanks for the reply.

If you are interested the gearbox and release stuff is here: http://www.skylinesaustralia.com/forums/Tr...amp;hl=tractive

[Swiper the Fox]

I have a Tractive sequential gearbox that I have fitted with a concentric push type clutch release bearing assembly. Whilst the stock 5/8 bore clutch MC releases it you need ALL available pedal travel. An 11/16 cylinder would give more bearing travel, and I can run a pedal stop if required. The pedal is currently light enough to press with your index finger against a Giken triple plate clutch, so a bit more pedal effort won't matter By offset holes in the MC I meant they aren't vertical or horizontal, but displaced to about 45 degrees from the vertical. I could probably use an AP or Tilton short cylinder, but was wondering if Nissan did a different bore in the stock casting. Thanks for the reply.

If you are interested the gearbox and release stuff is here: http://www.skylinesaustralia.com/forums/Tr...amp;hl=tractive

ahh yes i have benn following this on the uk site. Id take it to a specialised brake manufacturer and have it bored with a larger piston fitted. A friend of mine did this when he was using a Nismo slave cylinder.

[Chris Wilson]

Just found this, I'll grab the drawings off AP tomorrow and see if it'll fit easily. Will be cheaper than boring and honing mine, and finding a suitable piston assembly I think. Cheers. http://www.apracing.com/info/products.asp?...+Type_2390_2389

[wlspn]

Id take it to a specialised brake manufacturer and have it bored with a larger piston fitted. A friend of mine did this when he was using a Nismo slave cylinder.

Sorry, bit off topic but I have fitted an OS Giken triple in an RB25 box with Nismo slave & a smaller (than standard Nissan) thrust & have a really wierd pedal feel. There is a thread on here somewhere about it... Pedal is soft as until just before hitting the floor & then gets quite firm. Hard to explain but not nicest pedal feel... Is this the sort of reason your mate fitted a larger bore master cylinder? Basically after a standard(ish) pedal feel with the triple plate. Thought Nismo slave & this thrust would do it but apparently not...

[Chris Wilson]

Sorry, bit off topic but I have fitted an OS Giken triple in an RB25 box with Nismo slave & a smaller (than standard Nissan) thrust & have a really wierd pedal feel. There is a thread on here somewhere about it... Pedal is soft as until just before hitting the floor & then gets quite firm. Hard to explain but not nicest pedal feel... Is this the sort of reason your mate fitted a larger bore master cylinder? Basically after a standard(ish) pedal feel with the triple plate. Thought Nismo slave & this thrust would do it but apparently not...

I work on single seater and sport prototype race cars for a living and this problem sounds absolutely typical of a release bearing of either the wrong diameter, or the wrong nose shape. If the bearing presses on the incorrect part of the diaphragm fingers the geo goes all to pot, and a very strange over centre action occurs. It gives a funny pedal feel, and can even damage the diaphragm itself. The bearing should be contacting the fingers within 1/6 inch of their tips, and be round nosed, not flat. I'd pull the box and have a look. Did Giken supply the bearing?

[T04GTR]

i would of thought youd have a pedal box setup by now... that would solve alot of things.

from the sound of it, youd need a 3/4" one. going up only 1 size will make a differance but not alot.