johnc

Even with a smaller welder, you can weld thicker material. Preparation requries a proper 60 degree bevel with a perpendicular root and you use multiple pass welding.

All the suggestions above are good but be careful about removing anything structural. The stiffer the chassis the more consistent you can be with launches and 60' times.

"Pay no attention to the man behind the curtain..." RX8 is over with Jeff at Mazda Power getting the engine built. My work is done (for now).

The aluminum "fittings" on top of the injectors appear to be machined square blocks that are part of the plate that's bolted down, holding the injectors in place. The blocks probably have a hole on the bottom the fits over the top of the o-ring injectors and AN fittings project out of the top of the plate. I used something similar from Pro-Jay when putting a turbo 13B engine into an RX8. BTW... Keith at KG Parts is a good person to work with.

Looking at the picture above it looks like I'm using seamed tubing. The line you see on the tubes are orientation lines I draw to make sure: 1. I'm bending the tubes in the right direction. 2. The notches are oriented correctly. 3. All the bends are in the same plane (it sucks to end up with a main hoop that has a twist).

Yes, what you've surmised is correct. The tubing is also notched to get about 50% of it on top of the rocker and the rest tapered to the side of the rocker. You can also build a box or shelf like I've done here: Ideally the main tube should be closer to the rocker in my picture above but my customer wanted to be able to easily re-install the interior parts, so I moved the legs in about 3". There are a couple ideas behind building a box: 1. Tie the rocker, the floor pan, and the rear bulkhead together beyond the existing OEM structure. 2. Create a horizontal (or near horizontal) area so compressive loads in the main hoop legs are more normal to the tube's vertical orientation. 3. Its really easy to get the main legs positioned correctly. A box takes up more space (can interfere with moving the seat back), adds weight, is more complex to build, and you have to get the welding right or the box will come a part in an impact Z (or the main hoop leg will punch through).

Uuuuh, no. Unless you also shorten the strut tube the same 1" the bump stop will still be hitting the gland nut in the exact same place. You will have just reduced droop by 1". Shocks should ALWAYS be positioned in the strut at the very top of the tube - that's why the spacer is there on your Konis.

Dan, Olderthanme, put your top hats down, take your hands off your tools, and walk away from the car...

This is a question you need to answer yourself. Search the site for all the info about each swap, but ultimately you need to decide.

And I agree with Mike. A person's choice of engine for a Hybrid swap is primarily an emotional choice (unless rules get in the way). Each of us has an affinity for a certain type of engine based on how the engine sounds, how it delivers power, what we fell in love with as kids, or some other emotional reason. After the decision is made, ALL of us go through some rationalization process to come up with objective reasons for our decision. That's normal and is a result of our upbringing (emotion bad, reason good). This site exists for all of us to say "I'm building myself a toy and MY toy has to have this engine because it makes me feel all tingly inside when I put the gas pedal to the floor!" without fear of someone trying to use reason to argue against our emotional decision. I can't make a blanket statement that a NA L6 is a better engine in a 240Z then to anyone else on this site. I can say that I prefer a NA L6 in the 240Zs that I build for myself because it makes me all tingly when I hear them at 7,000 rpm.

Oh boy, here we go... Ultimately the answer comes down to how much you want to spend. If its thousands of dollars, head choice doesn't really matter because whichever head you choose will be modified so much that it really isn't what it was to begin with. If you have hundreds of dollars then you're probably better cleaning up and mildly preping what you have while also giving it a good full radius (Serdi) valve job. But, that advice is too simple...

The diagonal brace in the plane of the main hoop and/or the X brace between the rear braces are there to keep the main hoop from racking in a roll over. Without the braces a hard impact on one of the top corners of the main hoop will most likely cause to the main hoop to bend over to one side like a carboard box does when you open up both ends.

That's "generally" true for a fully dressed 260Z vs. a fully dressed 240Z. But in the example I cited the big weight difference items (doors and bumpers) were modified/removed on the 260Z so they were somewhat comparable (actually the bumpers were lighter) to the 240Z. There is a weight difference in the bare shells between a series 1 240Z and all subsequent ones. Its obvious around the firewall/cowl sides and how the front top frame boxes meet the firewall. I don't know what that difference is but my guess is about 35 lbs. of extra sheet metal. Again, the example above is not a perfect comparison. I posted it to show that, at least for highly modified eary Zs, engine choice has little affect on the total weight and weight distribution.

Uummm, I'm not picking a fight with anyone. Did you folks miss the smiley at the end of my sentence above? It was meant as a joke, humor, a quick reparte', just a funny comment... There a lot of chips on people's shoulder's here. Let's brush them off. From what I've seen on scales a 280Z is typically in the high 2,600s with normal stuff on board. I've seen some heavier and some lighter but 2,675 would be a typical number. SCCA requires an ITS 280Z to weight 2,760 (this is from memory) with drive aboard and SCCA figures the typical driver is 180 lbs. so they calculated that a 280Z in IT trim should weigh 2,580 lbs (stripped interior, 14" rims, roll cage, fuel cell). Pulling the bumpers AND the bumper supports saves about 100 lbs. A SR20DET swap can save an additional 100lbs (or more) depending on what's involved in the swap beyond the basic engine and intercooler plumbing. Unfortunately, a lot of the extras that are "while I'm at it" items add weight and tend to negate the SR weight savings. The closest comparison that I know of between a NA L6 and a SR20DET swap is the Rusty Old Datsun and Amir's SR260Z. Even that isn't perfect. I'll lay out the comparison information here and you guys make up your own minds: I guess the above list shows that, at least for heavily modified early Zs, similar weights and weight distributions can be achieved independent of engine choice. I did the chassis and suspension builds on both cars above and I know I could achieve similar results with a V8 engine. I have started on a 1973 240Z using a L28ET and I will most likely hit basically the same weights and weight distributions as above. Despite all the hype, engine choice is not a big issue when it comes to building a great handling, fast early Z. Sorry to disappoint.

Removing the bumpers off a 280Z probably saved you more weight then the SR swap. Did your car really weigh 2,875 or is that the number off the data plate on the door jamb?

An aspect of load transfer that I forget from time to time:

If the damage is from an accident, the repair you've done will be fine. One trick on crack repair is to drill the very end of the crack (the root) with a 1/8" bit to spread out the concentration of force where the crack is continuing to grow. Then weld from that point back to the start of the crack.

I've never seen a frame crack in that spot before. Must be from an accident as you said. Usually the frame rails crack lower down at the firewall junction.

The newer inverter TIG machines play havoc with a lot of the lower cost auto darkening helmets. I use a Speedglas 9002X and it stays very steady even when welding .049" stainless tube at 40 amps.

Yes it is, but not the orange one. He had a '73 shell that we're using and he plans on swapping the engine/trans out of the orange car when I get the chassis done.

That's pipe. Use tube.

I have no idea what a Johnny Joint is, but it will need to rotate and articulate to properly follow the steering of the front wheels and accomodate the angle change between the strut tower and the strut itself during bump and rebound travel.

Search...

Time, money, and a car trailer. Right now I'm booked through June. I'm just starting (today) on a SCCA Solo2 SM2 class 240Z. Have to strip the chassis and send it out to media blast by the end of the week.

Yes, the TB is a ProJay along with the intake manifold and plenum. I started to build a custom intake but the price would have been stupid because of the positioning of each fuel injector. I would have to make or purchase individual fuel rail/injector mounts and then plumb them from a fuel block. Going with the ProJay parts saved the customer $1,000.