Light clutch pedal

Eng1

Member
If the master cylinder piston was square and 1 inch and you applied 30 pound force , you get 30psi on the piston , if it was 1/2 inch you now get 60 psi .
The fluid acts like a solid bar as it won’t compress and transmits the pressure to the slave cylinder .
Any restriction in the pipe , dent or buckle or restriction in the flexi pipe will cause a problem creating a back pressure .
The slave piston moves depending on the amount of fluid provide by the master .
The load is purely mechanical , the clutch spring load and bearing load , but the forks both at the pedal and the clutch add mechanical advantage due to their length and pivot .
You cannot multiply the hydraulic force other than piston size .
Maybe the flexi is blocked ,maybe the slave has a problem sticking (rust) it’s strange someone changed the rod ,why?
maybe it’s the wrong clutch? For another car , it’s happened before with suppliers or maybe the wrong bolts fitted restricting the cover .
I think a ball park of how hard it is to push would help or what if the slave is removed ,does it shoot out without load .
Has the clutch always been heavy or after replacement only
 

andy_tt

Member
It's working but there's not enough travel. With a smaller bore master there's is less fluid moved so the slave will not travel far enough to disengage the clutch. It's a new clutch line from master to the slave. It looks clean inside the slave behind the boot and if you push it in, it comes back out on its own. It has always been heavy since I bought the car but I got used to it but after a stroke could barely drive it. So I had to buy a new daily.
I think I'm going to go back to original and refit the servo I had before. It's a pain as it was temperamental. But it made it useable
 

Eng1

Member
Ok , I understand, I have got a super rare jap auto car I am selling shortly ,that would tick a
Lot of boxes if going from a GTIR , that might suit you and like all the JDM cars going up and up in price (if you can find one !)
 

andy_tt

Member
Is it a gt4? i've just got it off. No so bad only took half hour measured the travel and the original is 30mm approx and the new is about 32mm. So maybe I would need closer to 40mm to make it work?
 

Eng1

Member
No a late model soarer , the VVTI single turbo .
Yes you would need around 40 mm or so to move the same fluid or reduce the size of the slave piston so it moves further
 

andy_tt

Member
But if I reduce the size of the slave surely were getting back to where we started. Never hear of or seen one. Googled in and it's not really my cup of tea mate.
 

Cathode

Active Member
Ahhhh... The GT4. I had one for nearly 10 years. Great cars. Good memories. Those late soarers are awesome cars!
 

Eng1

Member
The VVTI are super awesome and very rare now , I’ve only ever seen 11 in the Uk , and only 1 for sale in the last 3 years .
They are about 25 times more reliable than a pulsar , rust is a rare thing on them - I’ve got three of them now , 350-650 hp ,best car never sold in UK !
The drifters have slowly depleted them and the supras keep taking the engines !
 

Cathode

Active Member
I hear you Andy. Chasing rust is not a fun factor of owning a much older car. I say this owning a 30yr old pulsar, but the coolness of it outweighs the rust.
 

Cathode

Active Member
Yes, the VVTI engines are very good and a little underrated. Same goes for the 3S-GTE. None interference too!
 

Eng1

Member
The 1jz is underrated due to the internet and a lack of knowledge , the 2jz was put on a pedestal and anything smaller can’t be as good .....
They share the same block , the rods are slightly shorter and a different crank throw , but material spec is the same , this means the 1jz can be revved higher and is stronger ( shorter rods =less stress)
800 hp on stock bottom end not a real problem .
The 1jz came out first and the 2jz was based on the 1jz , it was made a bigger capacity to increase torque for a road car - but if racing you want the higher revving engine , the 1jz
I have both and prefer the 1 vs 2 , due it’s ability to rev freely
The drifters got hold of them as they were seen as a “cheap” alternative to the 2jz , they love revvy cars .
It is in my opinion an equal as a minimum and a giant amongst engines .
That’s why I bought 3 !!! Back when everyone said it’s not a 2jz ,oh how I laughed
 
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