74_5.0L_Z

Really like the cage. My main hoop attaches to the floor with a similar but smaller box where the seat belts mount. I assume the you car is going to be an automatic, because it looks like the tube going to the front strut tower would interfere with the clutch master cylinder. Also, I agree with johnc about the bar that goes across between the main hoop legs. You could really strengthen that by adding bars that go from the center (top of drive shaft tunnel) to the plates on the rear strut towers. As stated by others, I am not criticizing. I like the fact that every cage that I've seen posted by this group is unique. Please post more pictures as your progress continues.

I am using most of the factory datsun wiring, although I have simplified it where ever I could. I am also using the Ford engine harness and computer. I got rid of the Ford alternator and went to a Powermaster 1- wire alternator (no external regulator). There is very little overlap of the Ford and Datsun wiring. The computer really only needs power, ground, and wiring from the fuel pump relay to the fuel pump. I also added a relay in the ignition circuit to protect the Datsun switch as I believe the TFI ignition draws more current than the stock Datsun set-up. From my 260Z service manual, the Black/Blue wire BL goes from the ignition switch to the C-5 connector (green) to middle terminal of the ballast resistor for the ignition coil. This wire is hot only when the key is in the start position. The Black/White BW wire from the ignition switch is powered while the switch is in the on position, and while in the start position. This wire branches several times and powers instruments, and the interlock relay as well as other things. This wire I cut from the connector at the inter-lock relay and redirected to power the TFI ignition (pin 30 of the ford computer). The Black/Yellow (BY) wire goes from the ignition switch to the C-5 connector to the interlock relay and to the emergency switch. I assume that you will delete both the interlock relay and emergency switch. I would take the black /yellow wire or the Black/Blue wire and redirect it to the tang on the starter solenoid. All of the above is from looking at my Datsun 260 factory service manual, and from Charles Probst's Ford EFI book. I would double check my observations before connecting anything. Good Luck, Dan McGrath

I am using the factory mini starter, and yes the positive cable hooks directly to the large lug on the solenoid. I also have the main power leads for the engine and chassi nelectical systems attached to the large lug on the solenoid on the starter. The only wire that goes to the small tang on the solenoid is the start wire from the switch.

I have been running on 2.5 year old Kumho Victoracer V700 tires, and they are hard and worn out. I feel like my driving skills at the autocross have finally progressed to the point where I can use a better tire, so I just ordered a new set of these: Hoosier A3S04 245/45/16 Now maybe I can give those national level AP Z06 vettes a thrashing. Anyone else using these yet? What camber, tire pressure, etc... are you using?

I have accomplished what you desire with the exception of cutting the steering shaft. Cutting the steering shaft, however should not intimidate you. It was one of the easiest parts of the project. My engine is mounted as far back and as far down as I could mount it without without removing the stock hood latch. My harmonic balancer sits ~ 1 inch above the steering rack, the engine is centered from side to side, and is tilted back 2.5 degrees relative to the frame. The stock hood clears the intake (EFI). I use dynomax blockhugger headers and have full dual 2.5" exhaust. The headers just barely cleared the stock T/C brackets. With the 5.0L and T5 mounted as I have it, the car has 53.6 percent of the weight on the back tires (full of fuel with me in the car). I have built the car twice. The first time, the car had all the stock body and the engine was mounted using the ford rubber mounts and plates the sandwiched between the frame and front crossmember. The second build of the car (after a nearly head on collision with a '71 GMC) has the motor mounted using a front plate mid-plate arrangement. In both cases the motor was mounted in the same location. If you or anyone else is interested, I will soon be selling the exhaust system (headers to mufflers), and the modified steering shaft. My next project is going to be the construction of custom 180 degree long tube headers that dump into side pipes.

I found a picture showing the passenger side of the rear half-cage.

Zero, With my rollbar installed, the passenger seat can go all the way back, but not recline in that position. The passenger side of these cars has tons of leg room. I am 6'1" tall and with the seat all the way back on the passenger side, I cannot touch the curved portion of the floor where it meets the firewall.

2126, I believe that the cage you are referring to belongs to 260DET. He did some very nice work, and my only concern with his design is that is has too many bends (scca only allows 4 for a total of 180 +/- 10 degrees), and that his driveshaft tunnel diagonals don't allow either seat to recline. With my design, I can fully recline the driver's seat, but not the passenger seat. I am not speaking badly about his work (It's beautiful, and I like the mounting tabs), but I just chose differently. If I had mine to do again, I would make some improvements. In fact Branden's cage will see some of those improvements.

The door bars are going to be tied into the floor pan and also vertically onto the rocker panel. I plan to make the joints where the bars are removable such that buckling will tend to be outward. The joints will satisfy Figure 3 or Figure 4 on page GCR-156 or Figure 9 of page GCR-169.

Door bar will be removable. I consulted 2004 National Solo rules: For Solo II Paragraph 3.3.2 states that rollbars or cages must satisfy the criteria of Appendix C or section 18 of the GCR. Here is my interpretation without quoting the rules (copyright), For our cars, 1.5 x 0.120 or 1.625 x 0.095 DOM steel. At least 2 braces to control fore and aft motion of the roll bar. I interpreted this to mean 2 minimum. Correct me if I'm wrong. Suggested transverse brace (diagonal) For SoloI, I consulted Appendix J Said essentially the same thing but allowed provisions for Alloy Steel 1.750 x 0.120 for mild steel 1.625 x 0.095 for Alloy steel I am in the process of making this roll bar, and I want it to be as light, as tight fitting, and as functional as possible. Any critique will be graciously accepted. The intended function of this bar is to provide safety and additional chassis support for the SoloI, SoloII and track day competitor. This is a bar not a cage, and does not satisfy the requirements of SCCA club racing or NHRA cars running quicker than 10.99.

If you are talking about my cage, then maybe I can help you out. I am currently making a bolt-in / weld in version of my cage for one of the other members on HybridZ. Depending on how well it goes, I may try to make it available to others. Specs: 1 5/8" x 0.120 wall chromoly tubing (TIG welded) Connections at outboard seatbelt mounts (will allow use of stock belts or race harness) and top of strut tower. Diagonal in main hoop Bars from top of hoop to top of strut tower. Bars from side of hoop to top of strut tower Bar between strut towers. Swing out/removable door bars. The best part is that it will be almost fully assembled (no or little welding required). NHRA and SCCA approved. I'll have Branden's done soon, then I'll have a better idea what to charge. Here is a picture of my cage installed in my car. Branden's cage will be based on mine except it will be removable.

This same thought occurred to me a couple of months ago when I was converting to the CV joint rear axles. The CV joints are more tolerant of misalignment, and can operate at higher angles. The CV joint the off-roaders use is called a double-cardan joint. I believe that this would work well for a driveshaft, but it would also increase the rotating mass of the shaft. What I have never seen is the ball and cage type CV joint (like the 300ZXT axles) used in a driveshaft application. Is there an operating speed limitation that makes them unsuitable for driveshafts? Anyone have any insights on this?

I am in the process of putting the Koni 8610 stuts up front. My ride height is about 6" at the bottom of the rocker panel. Will I have enough droop travel if I section the struts 2" as suggested by johnc? The write-up in this thread is well written. Can we make it sticky, or include its content in the FAQ?

I haven't posted any pictures of my car lately because my space on HybridZ is full. Thrillz (Thomas Scott) was nice enough to host some pictures of my car. As you can see, I still haven't repainted the car since the accident.

Ok guys, Based on the above discussion(and the fact that one of my front cartridges has died), I have decided to get some new struts. I have been looking at Koni 8610-1149 single adjustable struts. Has anyone gotten a Koni 8611 double adjustable to work in a Z? What other struts would you suggest for 250 - 300 lb/in springs?

One other silly suggestion. Verify that the bleeder screws on your new calipers are mounted so that the bleeder is point up (not down). I have heard of people putting the calipers on the wrong side and getting the orientation of the bleeders incorrect. You can bleed them as many times as you like and not get the air out if the bleeder is not on top.

You need to bleed the master cylinder. Until you get all of the air out of the master cylinder you will not get any pedal pressure, and you will not be able to bleed the rest of the system. Get a bleeding kit from an autoparts store that comes with the plastic cup and some clear tubing. Fill the reservoirs. Attach the clear plastic tube to the rear bleeder on the side of the master cylinder, and put the open end into the rear reservoir. SLOWLY, stroke the piston of the master cylinder through its entire range (its usually better to do this on the bench where you can verify full stroke). Repeat until no air bubbles appear in the tube. Close the rear bleeder and repeat the procedure for the front. After the master cylinder is fully bled, bleed the res of the system starting at farthest wheel and working towards the closest. Have fun

Here are three more pictures of my chassis. These pictures are about 1 year old, and I need to add some more on the web. Unfortunately, I am out of space on HybridZ.

I don't think you're nuts If you look close here, you can see the clevis and the head of the shoulder bolt. I have since added gussets between the clevis and frame (this picture is over a year old).

When at all possible I design my connections as double shear. If you look at my front tension compression arms, they consist of a rod end (loaded correctly), a threaded tube, and a large clevis welded to the frame. The rod end fits into the clevis and is through bolted (double shear). I too had proper engineering practice beat into my thick head, and have read all of Carroll Smith's work.

Arizonazcar's control arms are toe adjustable on the car because the adjuster is captured by and free to rotate in the forward tube. To adjust, you just loosen the lock-nut, rotate the adjuster, and retighten the lock-nut. When I was brainstorming the design of mine, I considered doing something similar. Unfortunately, I couldn't find an internally threaded fitting like his adjuster. I could get a long hex coupler and get most of the hex machined down.... In the end, I decided it wasn't woth the hassle. As far as the rod ends in bending, I had to struggle with that one. In the end, I settled for using rod ends that were WAY stronger than necessary. The rod ends I use are Aurora XAM-10T 3 piece heat treated chromoly units with a 5/8" hole and 3/4" shank. Aurora's literature lists the axial strength of these as 41,000+ lb, and suggests 4,100 lbs if the rod end has transverse forces applied. The way my arms (and Arizonazcar's) are designed, the load is always shared between the two rod ends. If anything fails on my design, it won't be the rod ends.

Rick, I've been wondering how your project is coming. I haven't seen any new pictures lately. I am planning to run an autocroos up your way soon. I'd like to come check out the progress while I'm there. iskone, Yes, I have considered building an upper/lower control arm front end. If I do, I think I'll build new (longer) lower control arms and a custom front crossmember.

Dave, I don't dispute that you make some sweet control arms, and I am not trying to go retail with mine. I am just a person who likes to make things for myself (As many of the people on this site are). I used to think that the prices of your control arms were way out there, but (after making a set of my own) now realize the cost and labor involved. My control arms cost me about $330.00 in materials/welding, and about 20 hours of my own time. Most of my labor went into the construction of the fixture. I could make subsequent sets in about 4 hours. Even at that, the profit would not be worth the liability or headache. My control arms were designed with my own needs in mind (light, strong). I looked into making an adjuster very similar to yours, and decided that the added weight wasn't worth the extra convenience. I have to disconnect the control arm from the strut to make adjustments. I have had the rear alignment set, and it was far easier than trying to align the rear with the aluminum/delrin bushings. I am glad that you have decided to join us here at HybridZ. I always wondered why you weren't an active member here since you have been playing with these cars for so long. Hopefully, you will make this site a home, and not just use it as a storefront. Cheers, Dan McGrath

I did a complete tubular front end on my 1974 260Z after I went head-on wth a pick-up truck. I cut the front end off at the firewall, installed a 2.5" square tubing frame to the rear subframe, and built 1.625" chromoly tube shock towers. I designed mine to use the factory suspension parts (I already had coil-over, sway bars, Koni's, big brakes). Here are pictures showing the completed front end: When building the front end, I had the car on a fixture that held the car in a fixed, level position. The fixture also allowed me reference my measurements to the factory frame alignment drawings ( The back of the fixture was aligned with point C) I have been driving it since September.

Guys, I am a mechanical engineer and also did a little homework before designing and building the control arms. AISI 4130 steel is known for its weldability and toughness when welded properly. Weldability of steel is dependant on several variables, but the most important that I've been able to determine is carbon content. Low carbon steels have good weldability. 4130 is a low carbon steel (0.30%). From steel textbooks, and welding-advisers. com: "The concept of Carbon Equivalent was developed in an effort to reduce to a single number the influence of the contribution of the various alloying elements on the difficulties encountered in Welding-alloy-steel, therefore making the problem more tractable. One of the accepted empiric formulas equates the carbon equivalent to the sum of the percentage of each element divided by a certain factor as follows: Carbon Equivalent CE = %C + %Mn/6 + %Ni/15 + %Cr/5 + %Mo/4 + %V/5. The usage of this formula is intended to provide a rule of thumb for deciding if and what special provisions should be implemented for Welding-alloy-steel: for CE equal to or less than 0.40, no provisions are required. For CE more than 0.40 but less than 0.60 some preheating should be provided before welding. For CE more than 0.60 both preheating and postheating should be applied. " The chemical compositions for some common alloy steels are given below: C Mn Ni Cr Mo Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. 4130 0.28 0.33 0.40 0.60 - - 0.80 1.10 0.15 0.25 4140 0.38 0.43 0.75 1.00 - 0.18 0.80 1.10 0.15 0.25 5046 0.43 0.48 0.75 1.00 - - 0.20 0.35 - - Therefore, the carbon equivalent of 4130 is given by: CE = 0.30 + 0.50/6 + 0/15 + 0.90/5 + 0.20/4 + 0/5 =0.66 Based on this, I anticipated a need to preheat and post treat the welds. So I researched preheat and postheat requirements and found that preheat and post-heat requirements are dependent upon material thickness and the type of filler rod used. For 4130 material less than 16mm thick the metal should be warmer than 50 F before welding, and for thicknesses greater than 40mm the preheat temperature should be 300 F. The preheating is performed to slow the rate at which the weldment cools after welding is complete (this applies to large weldments that may not be thoroughly heated during the welding process). Cool sections of the weldment act as a heat sink that causes rapid cooling of the HAZ (heat affected zone). The following article summarized much of the information on welding technique and rod selection that I applied towards the construction of my control arms: http://www.project-ch701.net/ch701_misc/FAQ4130N.pdf The tubing was cleaned, meticulously fitted, and welded using ER70S-2 filler rod in still air. The ambient temperature was ~85 F(the tubing was hotter than 100F as it sat in the sun prior to welding), and the whole piece was brought up to temperature and allowed to air cool. It also didn't hurt that the man doing the welding is an aircraft certified welder with 30 years experience including welding on the space shuttle and space station components. I didn't want to get on a soapbox. I was only offering these control arms as possibility, and expected a bit of a warmer response. By the way, don't try to weld tool steel. It has too high a carbon content and get very brittle