74_5.0L_Z

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

Here is one link: http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=12979&highlight=61601

Don't let "master cylinder, slave cylinder problems" scare you. Several of us have solved that issue. I use a Tilton hydraulic throw out bearing, and Tilton clutch master cylinder. If you searh my old posts (circa 2000), you will find a complete parts list of my clutch set-up. Mine is not necessarily the best solution, but is has worked very well for me. Terry Oxendale uses a similar set-up, but I believe he uses a McCleod bearing. Others have had success using the pull type slave cylinders. I haven't used one myself, but they look attractive because they attach external to the transmission. If you search the Ford section of this forum, you will find the needed part number and I believe a drawing of this set-up. Either way, its not that difficult to do. By the way, the Tilton master cylinders are direct bolt in replacements for the nissan clutch master cylinder and only cost ~ $70.00.

I did a little testing of the control arms yesterday. I drove the car ~ 75 miles to the course, and ran an autocross practice day yesterday (got about 30 runs). I am happy to say that the conrol arms are still intact. I did pretty well against most of the competition. The only cars that ran the course quicker than I were some AP ZO6 corvettes that were brought in on trailers and driven by national level drivers, and a factory Five cobra. I feel pretty good about this considering that I was running on 2.5 year old street driven Kumho V700 tires, and the vettes were on new Hoosiers. I need new tires. Only time will tell if there is any fatigue issues. Until then, I guess I'll just drive it like I stole it until the wheels fall off.

Thanks for the responses guys. The car is used for autocross and track days mostly. Its does see occasional street and dragstrip duty. I was thinking about moving the 250#/in springs to the front, and getting 275#/in or 300#/in springs for the rear. I have the old Koni Reds on the car.

I just got back from a local racer's shop where we set the corner weights on my car. My car is a 1974 260Z with a 1989 Mustang 5.0L and T5. The 5.0L has edelbrock aluminum heads, the car has a full tubular front end and an extensive cage. Here are the results with 16 gallons of fuel and me (190LBs) in the car: LF = 648 Lb RF = 607 Lb LR = 751 Lb RR = 710 Lb. Total = 2716 Lb Here are my percentages: (LF + RF)/ Total = (648 + 607)/2716 X 100%= 46.2 percent on the front 53.8 % on the rear. (LF + RF)/ Total = (648 + 751)/2716 X 100% = 51.5 % on left and 48.5% on right. my diagonals are equal ie.. (LF + RR) = (RF + LR) -> (648 + 710) = (607 +751) = 1358. I am pretty happy with these numbers. Here's a question for johnc, Jmorstensen, RossC, et al... What rate springs would you run based on these scale readings, and is it worth adding ballast to the right to try and equalize things left to right? I current am running 250Lb springs in the rear and 200 Lb springs in front. I have a 1" front sway bar and no rear bar.

So laurentz, your a Town and Country resident? I grew up there myself, and graduated from Leto High School back in 1984. I am over in that neck of the woods fairly often. Maybe I can look you up. Do you ever run the West Coast CFR SCCA events at the fairground?

This first set requires that the bolt going through the strut housing be removed to adjust the camber and toe. The next set will be on the car adjustable. The first set was for me, and I wanted to keep it as simple and light as possible. I don't make frequent adjustments to the rear, and I don't expect that many people do once they find a setting they are happy with. As it is, I can adjust the rear fairly easily and quickly. These control arms also don't have provisions for the rear sway bar; I don't use one. If and when I make these available to others, I will make sway bar provisions optional.

The gear ratio is usually stamped into the outer circumference of the ring gear. A 3.36:1 gear is marked with 37:11. A 3.545:1 gear is marked 39:11

I like it better without the grill.

Zero, Rear struts are really not that difficult to replace assuming that you have some basic tools and skills. First, my guess is that the mechanic tried to remove the rear strut assembly by removing the spindle pin (never an easy task). It is far easier to remove the rear strut by removing the rear control arm along with the strut assembly. Here is a web page that does a pretty good job of explaining the task. http://www.biopatent.com/rearstruts.html If you are going to own a car like this, you are going to have to learn to work on it. Otherwise, the mechanic's bills will cost you more than owning a much newer car. These are great cars to learn on. [/url]