RebekahsZ Posted August 27, 2014 Author Share Posted August 27, 2014 You are a god! I will want to talk more. Quote Link to comment Share on other sites More sharing options...
rsicard Posted August 27, 2014 Share Posted August 27, 2014 I have a 72 521 truck, LZ 2.3 /stick, I bracket race. (13.60's @ 94mph) I cant run a 2 step in my class, so I had to find a way to leave on the high chip (7k) without it coming apart. This is what worked for me. Plumb a line lock between the clutch master and slave. (39.95 Summit). On each side of the line lock, put a T running to a one way adjustable valve. (28.00 McMaster Carr) Wire the line lock to a switch on the shifter so it is only activated when pushed in 1st gear. It diverts the fluid through the valve so you can control the flow and reduce the shock. Once you get it set you can lock it down with a locknut. Three years of abuse without a failure. Push the shifter forward, mat the pedal and let it go. Sorry for the thread jack. Just trying to help. My V8Z digested the stock halfshafts last week (auto) so I feel your pain. Thanks for this post as it is extremely valuable. Could you please share the McMaster Carr part number for the bypass valve. Thanks. Quote Link to comment Share on other sites More sharing options...
Eric JB Posted August 27, 2014 Share Posted August 27, 2014 I might still have the receipt in the shop. I will try to find it. Quote Link to comment Share on other sites More sharing options...
Eric JB Posted August 27, 2014 Share Posted August 27, 2014 # is 7824K21. Needle valve, 1/8 nptf female. Quote Link to comment Share on other sites More sharing options...
rsicard Posted August 27, 2014 Share Posted August 27, 2014 Eric JB: You have spurred a lot of thought from your post. Thanks much for the part number. Already have one on order. Please post an explanation of the sequence of using the system at the drag strip. Start at neutral on the transmission. Push in to disengage the clutch. Select first gear, which toggles the switch to engage the electric shutoff valve in the hydraulic clutch line. " Push the shifter forward (first gear), mat (mash) the (gas) pedal and let it go (of what? the clutch pedal?)". Don't know what is next in the sequence nor what is exactly happening or supposed to happen. Quote Link to comment Share on other sites More sharing options...
Eric JB Posted August 27, 2014 Share Posted August 27, 2014 After I do my burnout, I roll up and turn the top bulb on.(prestage) Then I LIGHTLY hit the brake pedal and press the line lock button. Not enough to lock the front tires, just enough to give resistance. Bump it in with the clutch, til the 2nd bulb flickers on. As shallow as possible so I know where I am every time. Push the shifter forward to activate the clutch line lock. I have mine set so it has to be pushed, not just in gear. 1st amber, mash the gas pedal to the wood and let it bounce off the rev limiter. 3rd amber dump the clutch as hard as you want since the flow is slowed down. Since it is a one way valve, you can put the pedal back in normally for the 1-2 shift, and when you let it back out the line lock will be open. I have my valve set pretty open. I just dont hear the BANG when I dump it. Same clutch/ trans/driveshaft/ Datsun truck diff. (488's) Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 27, 2014 Author Share Posted August 27, 2014 I'm loving this! How has it effected your reaction times and 60'? How consistent are your times during an evening at the track? Bringing home any priize money? I have given thought to putting a line lock on my clutch line, but I was worried about the release being too digital. I currently have clutch pedal actuated switches for line lock release (at the bottom of pedal travel) and 2-step (at top of pedal travel), but I'd love to launch off a button instead of my foot. I'm already so busy at the lights that it is pretty hectic. Before the 2-step and line lock setup i was trying to feather my clutch myself and I warped that puppy-how's your clutch handling being squeezed off at 7 grand? I started dropping (not sliding off) the pedal to keep my clutch healthy. But that has cost me three driveshafts and an axle. Quote Link to comment Share on other sites More sharing options...
rsicard Posted August 27, 2014 Share Posted August 27, 2014 Eric JB: Thanks very much for your response. I am trying to visualize in my head what is happening to the clutch fluid along with the sequence of clutch pedal all the way in, all the way out, the one-way valve and its orientation in regard to the master and slave cylinders also with regard to the line lock valve etc etc. Trying to understand the mechanics, hydraulics and sequence of events in usage of the system. Quote Link to comment Share on other sites More sharing options...
rsicard Posted August 27, 2014 Share Posted August 27, 2014 Eric JB: Just guessing, once the clutch pedal is let up on launch, is the clutch line lock switch held engaged and the fluid from the slave flows through the bleed clutch engage softening adjustable valve back to the clutch master cylinder in the allowable one way direction. The adjustable valve will not allow flow from clutch master cylinder to the slave but will in the other direction with the clutch line lock engaged blocking flow through the line lock? Maybe I have figured it out?? Once out of first gear, let the clutch line lock switch relax to the not-engaged position. I talk it that switch is momentary action type push to close and actuate line lock? Quote Link to comment Share on other sites More sharing options...
weedburner Posted August 28, 2014 Share Posted August 28, 2014 I went about this clutch slipping in a little bit different way. I use an inexpensive screen door hyd cylinder to do basically the same thing. It's adjustable for the amount of "initial hit" that the clutch has, as well as the amount of "secondary delay" for final engagement. Also adjustable from the driver's seat. Here's a link to the DIY details, including PN# for the cylinder that you can get from the local Home Depot... http://grannys.tripod.com/hillbillyclutchslipper2.html Here's what happened without it... Hi Eric JB, i'm the guy from Concrete with the V8 RX-7 Quote Link to comment Share on other sites More sharing options...
Eric JB Posted August 28, 2014 Share Posted August 28, 2014 Hey weedburner, I thought I saw you not long ago rolling down Hwy 20. Car looks baddass. RebekahsZ As far as 60ft ( 1.70 ) and consistency goes, It repeats pretty well. It is VERY sensitive to tire pressure. I run Hoosier 26x8 slicks @ 13psi. 12 dead hooks (and usually redlight) and 14 spins too much ( and is late) When I tore it down 2 years ago, the clutch was smelly, and a very slight discoloration on the flywheel and PP. I run a stock lightened 240mm flywheel and a stock Z PP. I don't even notice a slip, Just enough to not break shit. I have been in the money twice in 3yrs. Just getting back into it after a 20yr lapse. Once in the truck, once in the Z. I thought about putting switches on the pedal too. I just went with the steering wheel. Rsicard, The valve is free flowing in the engaging of the clutch. So whether the line lock is activated or not, it is not restricted, Just the release is restricted (adjustable), and only when the shifter is pushed. Quote Link to comment Share on other sites More sharing options...
rsicard Posted September 6, 2014 Share Posted September 6, 2014 Eric JB: It appears that some of the posts were LOST when Hybridz.org went DOWN. Perhaps I did not see it before, but your statement stuck out: "...I just went with the steering wheel". That came as an unknown to me as to what THAT switch is for. With the clutch line lock engaged and the clutch pedal pushed in, it seems that the clutch pedal needs to be released, to launch, and to cause the clutch hydraulic line pressure to bleed through the valve and somewhat soften clutch engage. Once that has happened, the clutch line-lock switch can be released for shifting into the next gear. Does that sound like what is happening? Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 16, 2014 Author Share Posted September 16, 2014 My properly set up CV axles did 12 1/2-mile passes coming out of the hole easy but shifting hard on 275/60/15 drag radials woth 35 psi on unprepped concrete this weekend with no issues. Quote Link to comment Share on other sites More sharing options...
Zfan1 Posted September 16, 2014 Share Posted September 16, 2014 You put a 275/60-15 in the back, how did they fit? I run a 255/60-15 and it is tight. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 16, 2014 Author Share Posted September 16, 2014 I cut the hell out of my fenders, that's how! They fit great with over an inch of clearance to the modified dogleg and 3" to the to of the fender arch. I keep the rear of the car high just to be sure I don't rub. If you want pics, send me a text to 256-366-4685 and I will send you some pics from my cell phone-too much work to post pictures with my low-technology computer skills. The big tires let me leave the unprepped surface pretty hard, whereas, with my 9" wide 26" slicks I was spinning like crazy. I really like the drag radials for landspeed launches and the slicks for launches on VHT. I'm going 28" tall rear tires all the way because with a 3.54 gear, it just works out nicely. I might want a 26" tire for 1/4-mile, but I rarely do the 1/4-mile. Quote Link to comment Share on other sites More sharing options...
Zfan1 Posted September 17, 2014 Share Posted September 17, 2014 I see, how do your 60. ft's compare. I am running a 27" drag radial with 3.70 rear gears and get 1.55 on motor and 1.40 on some juice. I got a best of 6.83 at 101 on motor in 90 degree weather. Cannot wait for fall/winter weather, maybe 6.70's on motor. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 17, 2014 Author Share Posted September 17, 2014 I have only had the 28" tires on VHT one night. It was when they were 28X10.5 on the stickiest track on the planet. I dead hooked, so my 60' probably sucked, and on the third pass I broke that axle, so I haven't even looked at the timeslips. Since then I have bought some 28X9s, so perhaps I won't deadhook. I'm setting up for roadracing now, so I won't have a 60' time with the 28s to report for a while-maybe in November. I may 60' worse, I dunno, but to be able to finish the distance in the desired gear is super nice. There's two ends of a track, you know? Quote Link to comment Share on other sites More sharing options...
dreco Posted September 19, 2014 Share Posted September 19, 2014 fyi, i have a set of Z31t axles that I may not need. I dont have the matching parts to use them yet and still undecided about which way to go. I was considering Wolf Creek axles and using a set of 280Z stub axles. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 19, 2014 Author Share Posted September 19, 2014 Send me some pics and a price and maybe we can work something out. I can get them for free from a buddy who has a field full of Z31s, but I don't like spiders and snakes, so if they look good, I might trade you some axles for some dollars. Quote Link to comment Share on other sites More sharing options...
dreco Posted September 25, 2014 Share Posted September 25, 2014 Send me some pics and a price and maybe we can work something out. I can get them for free from a buddy who has a field full of Z31s, but I don't like spiders and snakes, so if they look good, I might trade you some axles for some dollars. i'll do that tonight when i get home Quote Link to comment Share on other sites More sharing options...
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