Hello

I have been searching and still confuse if my problem can be call CLutch Lock Out.

PLease I need help and input how to solve the problem from the members here or vendors who rev their engine to more than 8000 rpm.

When I rev to 8000 - 8500, the clutch wont let me shift to higher gear (but the clutch was not sliping). But when I shift at around 7000 it can shift smoothly without any problem

My clutch is ATS Twin Plate Carbon Push type with 1300kg Pressure Plate and the car is Evo 8 MR JDM version.

This is the step when it happened (for example from 2nd gear to 3rd gear):
- Rev to 8000 rpm or more (I have built stroked engine)
- Depress Clutch
- Clutch pedal become Light or lighter .. like empty no pressure
- Move the stick shift from 2nd gear to 3rd gear but stuck at neutral position can not push the shifter into 3rd gear.

Note:
- Once again, when I shift at around 7000 rpm the gear change went smoothly without any problem.
- There was no clutch slipping when in gear and rev it to 8500rpm
- This problem happened when I was using 6 speed and also the current 5 speed gearbox.

Questions:
- Is it call clutch lock out?
- How to solve it? adjust the clutch engagement?
- Any other solution to fix the shift problem if clutch adjustment wont work?

Thanks in Advance.

 

http://www.jackstransmissions.com/pa...kills-synchros

clutch adjustment video (good watch)
http://www.jackstransmissions.com/pa...-tech-articles

http://www.teamrip.com/faq.htm

 

I am going to guess you have a hydro TOB? If so I am going to say your issue is air in the lines. That would explain you pedal feel. Clutch adjustment is never a bad idea either. Should have been done at time of install, but better late than never.

 

Thanks to Mike and Evo Dream for the inputs ... please keep the information coming so I can have more potential solution to my problem.

To Evo Dream ... just like to discuss, If some air trapped in the line, the empty or light feels on the clutch pedal suppose to happen at all rpm range right?
This problem only happen when I shift at close to 8000 rpm or more. When I shift at about 7000 rpm, the clutch pedal weighted like it suppose to be, some heavy feels, and I can shift normally, relax shift or hard shift all works fine.

What do you think about it?

 

Have you changed both lower and upper clutch lines? Not sure, but the lines might bulge more at higher RPM. Also I know the carbon clutches like more heat, could it be possible that he needs to get it hot before shifting at 8000rpm+? Were you using carbon clutch with both transmissions? None of this might not make any sense, just trying to help, I love the sound of the 4G63 over 8k RPM.

 

Hi Casper, Thanks for the response.

Let me check with workshop mechanic about the clutch lines.

About the heat, Even when I have already did some warm up on the clutch still the same result. Cannot shift into the next gear if shift at around 8000 rpm or more and the clutch pedal went very light (much lighter to push compare when I shift at around 7000 rpm).

Yes I am using this ATS twin plate carbon on both 5 speed and 6 speed (was).

This problem really give me a headache...

Btw just checked the master cylinder clutch are fine both the upper and the bottom.

Please keep the input coming. I really need it... Thanks

 

Carbon clutches have been known to drag. We tried an RPS prototype and pulled it out in less than a week because it was doing the same thing. I have heard it has since been remedied but we arent using anything other than triples in most of our cars.

You are describing something that sounds like either a clutch that needs bled or a master cylinder that needs replaced.

 

To John Bradley

Thanks for your input,
The Master Clutch Cylinders are fine.

Finally Today the workshop started to adjust the clutch engagement. It seems heading into the right direction to fix the cant shift at 8000rpm or more.
The clutch pedal adjusted higher from the floor. The clutch pedal position become higher than the brake pedal. Now I can shift at 8000rpm. Still need some adjustment.

When this problem completely solved, I will update this so maybe this can help other people in the future.

Thanks