Skrill

I was at the track today and it was danmed hot (Willow Springs about 90F ambient -- who knows what on the track).

Anyway, I was running hard and found that that as I got into my sessions my clutch pedal would get real soft, and drop to the floor as I upshifted and not come back up. This was at the top of 4th going down the front straight at well over 100 mph.

Anyway -- I would calmly pull the pedal up with my foot and proceed through the session but as the temps built up it would start happening at other areas of the track. Once I came into the pits and let thinks cool off -- it was fine. I had no issue shifting and the clutch would disengage (i.e., I had power) -- but it was extremely unnerving. Once everything was cool -- the issue went away completely. When I started out the next session -- everything would be fine, until stuff started getting hot again (about 10-15 minutes into the 25 minute session). Then the problem would come back and get progressively worse.

I remember Doug Crawford telling me that some people w/ Crawford Headers who drove their Z's really hard (like at the track) would boild their clutch fluid. I have never experienced boiled clutch fluid -- but I imagine that is what I did given that the problem when away when I cooled everything down.

I have stock clutch, flywheel and clutch fluid (which is just the stock DOT 3 brake fluid). I had no issues with slipping of the clutch at all, and no issues shifting. I had no other issues with overheating (I also have a Koyo rad, Nismo P/S cooler, and Nissan Motorsport Oil Cooler).

Engine mods as follows --

Nismo CAI
ProFlow Bored ThrottleBody
Crawford Cast Plenum
Crawford Headers
Crawford Cats
Nismo Exhaust
Technosquare Tuning

I put a call into Doug, and left a voicemail. Previously he said that people with this issue replaced the stock fluid with a higher temp fluid (like Ate SuperBlue DOT4 or Motol RBF 600) - and it solved the problem.

Any help would be appreciated.

Edit: This was the first time I tracked the car since putting on the headers. And they are coated with JetHot 2000.

Z BOY

iTrader: (41)

the same thing has happened to me with my jethot-coated crawford headers, and doug told me the same thing. i tried to get away with the valvoline higher temp brake fluid, but i still get the same symptoms after driving awhile. i bot some motul and steel mesh clutch and brake lines but haven't installed them yet.

Skrill

Steel clutch lines??? Who sells those?

Z BOY

iTrader: (41)

here: http://www.intensepower.com/agpobrclli35.html

Redfoot

iTrader: (25)

No, however I did flush out the stock stuff & replace it with Motul RBF600 this spring due to previous discussions of this happening with others. Better to be proactive than reactive.

Skrill

Do you have a write up on how to do it? I don't know where the bleed valve is.

Also, any issues with the RBF600?

Morris

iTrader: (1)

I had the same problem. The Crawford headers sit very close to the clutch line on the drivers side. I did two things. One, I has a heat shield installed between the clutch line and header. The guy charged me $50 to make it and install it. Second, I switch to SuperBlue Dot4 fluid.

I haven't been to the track yet with this setup, but I did not have any problems at the Dragon this time. The first time at the Dragon, the clutch would go to the floor and stay there.

Skrill

So there is space in there for heatshield? What did it look like? How was it mounted? Did you also put one on the passenger side for any reason?

Thanks for the help!!!

Morris

iTrader: (1)

He used a heat shield off a cat converter he had laying around. Not sure how he attached. I don't know of any reason to put one on the other side.

The heat shield may not be necessary. I know others that have just gone to the high temp fluid and not had a problem on the Dragon or the track. I was having some other work done and the tech suggested it. For $50, I thought I might as well.

Good luck....

mcduck

Had this problem at Tail of the Dragon last year. Flush clutch fluid and replaced with the Motul. Have had zero clutch problems since and that includes a weekend of running the car very hard at VIR.

MIAPLAYA

iTrader: (3)

Greg V at Mossy sells an SS clutch line for just this reason. I thinks its like $40 or $50. Made by Crown lines... call him at 1-866-55-MOSSY. You can also try and run some Motul with it...

MIAPLAYA

iTrader: (3)

Looks like they are $40...link http://www.mossyperformance.com/product/?id=3270

350Zteve

iTrader: (6)

Besides upgrading the line and the fluid, I would wrap the line with some thermotec heat tape to reflect the heat away.

Skrill

Well -- just to follow up. Here is my solution.

I just purchased this Stainless/Kevlar clutch line from Mossy:

http://www.mossyperformance.com/product/?id=3270

And will wrap it with this product from Thermotec:



And use Motul RBF 600 fluid. That should prevent the problem from occuring again.

MIAPLAYA

iTrader: (3)

If that doesn't fix it nothing will...

VandyZ

iTrader: (2)

Everyone is on the right track.

In most cases changing the fluid solves the problem.

Z CRUZN

Changing my clutch line (Mossy) & fluid out this Thur. to 600 temp. while my shop does a warranty replacement of a leaking rear seal on my tranny (where driveshaft connects).

Leo14

How many ounces do you need to replace the clutch fluid? I'm thinking of getting Wilwood Hi-Temp 570 degree Racing Brake Fluid.

Thanks