BarrettB

So I’m doing a track day at Putnam Park on Friday and having a great time with the Nismo. After the second session, I noticed that the clutch didn’t feel quite right. During the third session, I consciously tried not to abuse or ride the clutch. After this third session, the clutch would not release fully. I was able to adjust the pedal and drive it back to my shop. Back at the shop, I flushed and bled the clutch and used Motul 600 in it. The pedal came back and all seems to be OK now. So it appears that the original clutch fluid simply boiled and caused the problem.

My question is; How or why can this fluid boil at all? I don’t understand why there would be that much heat in that area. The slave cylinder does appear to be an internal unit. Does that mean I overheated the gear box? Was I riding the clutch and still didn’t know it? Or was the OEM fluid really that crummy? Or “D” all of the above? Ay input would be appreciated.

Trapu

iTrader: (2)

The best way to keep a good pedal clutch is to put a stainless steel line with a reflective wrap on it to prevent from heat.

The gear box should be ok as long as the clutch can fully press on the clutch disc. But no stress for a overheating gearbox.

Good luck,

Martin

ROCA Z

iTrader: (1)

+1, also if running an oem master clutch cylinder, might want to upgrade there....

this is how i did mine after i had similar problem.... u used zip to hold in place, bc its easy... and then i used metal wire to secure

SE5spd

iTrader: (17)

stock cats, HFC, or test pipes?

BarrettB

Thanks for the input.

I’m glad to hear someone else has had that issue as well. The exhaust is totally stock, however it is the nismo. The original heat wrap was in place on the original hose. It made me think I fried the clutch at first, which was quite alarming. This would be a good item for a track day checklist. I will change that line out later and insulate it real good. Heading back to the track today even though there is rain coming...

Thanks again

SE5spd

iTrader: (17)

I'm not sure if its true for 350z but with 370z having stock cats makes you boil fluid because the car is so close to the clutch lines and the cat gets so hot it makes you boil your fluid. People get test pipes for this reason (from what I've been told)

Don't know if its the same for Z33 but I've never boiled my clutch fluid.

laze1

iTrader: (17)

Wrap all the clutch fluid pipes/hoses that you can. Also wrap the exhaust on that side as well. I wrap both Test pipes and the fuel lines on the passenger side on my race car...

betamotorsports

iTrader: (1)

Uuuhhh, guys, if the plastic tie wraps in the photo above are not melting, then heat isn't the issue. Remember, good brake/clutch fluid boils at +500F. Those tie wraps will melt at 400F. So if those generic tie wraps are not melted, there's not enough heat to affect the brake/clutch fluid.

BarrettB

I finished another day at the track and didn’t have any more issues with the clutch fluid boiling. I’m reasonably certain that it had DOT 3 in it originally. DOT 3 has a wet boiling point of just 283°f. I presume this figure is with new fluid and may continue to absorb moisture over time and make an even lower wet boiling point, don’t know. I could easily understand how that slave cylinder between the engine and trans could reach 283°f or something close to that after 3 sessions on the track. That clutch line wrapping around just in front of an exhaust pipe is definitely venerable.

Removing the cat’s and wrapping / fire-sleeving all those lines would be a great safety improvement. Looks like safety wire would be a better choice than tie-wraps.

There was a guy there with a Porsche Space Ship 1 and proceeded to crash it on his 3rd or 4th lap. He just bumped into a tree, not hard, but it ruptured a cooler or a hose and immediately caught fire. No injuries, but made a real mess out of the car.

N80

There is a recall on the clutch slave cylinder (which is inside the bell housing!!!) for some year models. I have a 2007 and had this problem at the track. Took it in and they replaced the slave cylinder for free. No porblems since then.

Of course, I have no idea if this was a slave cylinder issue or just old fluid, either way, no problems now.

Buster-here

I had this too on my first track day. HR motor so internal clutch slave cylinder, and about 10,000 km on the clock. Original fluid. Lost the clutch towards the end of the day, and the brakes about the same time - oops.

Let it cool and was able to drive the 200km home.

Took it in to Nissan and they bled the clutch for me (warranty), however I decided to put some high temp fluid in there later at home. Hasn't been a problem since - track days or otherwise.

I upgraded brake lines, pads, and fluid at the same time.

pez1111

iTrader: (2)

This is a common prob in OZ during summers. The fix is as said is Higher boiling point brake fluid, S/S lines and the fixer , instead of using the flimsy heat shield wrap go for Earls Flame proof Hose