Mark Maras

Beautiful parts. The craftsmanship shows. Have you considered a garage business manufacturing and selling proper fitting parts? Black Dragon won't be an option in the future.

That first spring looks more like a thread insert from the side view.

That's what I would do. I think it will have the greatest impact on the problem. Let us know how well it works if you go that route.

Development of the Datsun 240Z. Hitoshi Uemura says that after the initial heat resistance tests at 104`F, "The ambient temperature in the engine room did not become a major problem. All the temperatures for the battery fluid, the electrical, and the rubber parts were within the normal ranges. The fuel temperature was also normal and we saw no hesitation during sudden acceleration. However, the NEXT MODEL, to which the more stringent emission control in North America was applied, would cause a problem in this area later."

So, It's looking like (at least to me) the three line set-up might be the place to look first to cure heat soak problems. @Jeff G 78, Did you ever try a two line set-up with the manifold water blocked? @jalexquijano, Refresh my memory about your set-up. Number of fuel lines by the valve cover? Carbs-3 or 4 screw and are they heated? Anyone else have an opinion about the two line versus three line set-up and heat soak?

Jeff G 78, What year were your round tops? I'm trying to figure out which changes Datsun made in 73(?) that caused the problem. Heated carbs certainly added to it. Considering fuel lines, I have a couple of sets of the factory engine bay fuel lines. One set is two lines the other is three lines. I think the three line set-up is newer. Is it possible the three line set-up was part of the problem? I don't remember any heat soak problems on my 71 which had two lines and the early 4 screw round tops.

I found a lot of holes in that story too. No percolation or rich mixture issues mentioned?, heat shields added later on? I'm with Patcon about the rapid turning under EXTREME heat conditions although I've never heard of it. I'm surprised they didn't find the problem before going to that extreme. I get the feeling that Nissan never considered it that big of a problem and just tinkered with it rather than an all out attempt to fix it. To cure the problem, one may need to refit the engine with early carbs. and intake components (didn't seem to be a problem early on) or move the fuel line from the wrap-around stock fuel lines to a line that comes from behind the engine to the carbs. Probably a little easier if you don't run a mechanical pump. @Bruce Palmer, got any thoughts about this subject?

Nice, Thanks

Executive Director Nakagawa, chief of the engine department, trivialized the problem, in the beginning by saying that, at least the car wouldn't fall out of the sky, like a plane, if the engine died. He then offed the problem onto the body department. They may have waited until 77 to vent the hood because they were waiting to see how effective the engine mods would be. Little to no success in the engine department led to vents in the hood being tried and kept but ultimately they had to resort to a fan.

What is the measurement from the center of the string to the bumper?

Just received my copy of "Datsun 240Z, Engineering Development. The Journey from Concept to Reality" by Hitoshi Uemura. In chapter six he this to say about vapor lock issues. Nice to know that the hot start issue ended with fuel injection. "After the 73 model year started to be sold, Nissan Motor Corporation, U.S.A. reported complaints that when the steering wheel was turned rapidly after driving in extremely hot regions, engine problems developed, and, at worst, the engine would just stop. They also reported that once the engine stopped, the customer had to wait in the car, without air conditioning and under the blazing sun, for at least 30 minutes until the engine cooled and could be restarted, which naturally increased complaints. We hurriedly conducted a test on the chassis dynamometer to reproduce the symptoms. After the vehicle had been run at 62 mph (100 km) continuously in 104`f (40C) temperature, it was taken out to the test course and the wheel turned rapidly. This confirmed that the engine problem occurred and at worst the engine stalled. The cause of the problem was vapor lock, in which gasoline vaporizes in the fuel lines and carburetor because of the high temperature in the engine bay. Lacking liquid fuel, the engine stops running. Executive Director Ryoichi Nakagawa, the chief of the engine departments, gave us a pep talk, saying, "In a car, the worst case that can happen with this defect is the engine stalling, but if this happens on a plane, it crashes." Although the engine design departments also tackled countermeasures, satisfactory results were not obtained, and the manager Harada of the Third Design Department asked us to cooperate in coming up with countermeasures for the vehicle itself. As a temporary measure, a heat shield plate was placed between the exhaust system and the carburater, glass fiber was wrapped around the fuel system pipe, and louvers were cut in the engine hood to vent heat. But this was not enough. Then, as a last resort, a powerful sirocco fan, which began to turn when the temperature in the engine room rose above a given temperature, was installed in the engine room to pump out the heat. This almost solved the problem, but it was never perfect, because the fan would turn for a while or sometimes started turning suddenly even after the engine was turned off, surprising drivers. Assistant Department Manager Shidei, who was the chief engineer at this time, visited America to persuade Nissan Motor Corporation U.S.A. to deal with the problem using this tentative measure for a while until a proper countermeasure could be taken. I can't imagine that would have been an easy task for him. One year later, we solved the problem properly by abolishing the carburetor and adopting the L28 engine with electronic fuel injection."

Good idea. I love prototypes that work the first time.

I remember the vibes around that place. Now another dies in the same area. Hmmmm. It might be a Datsun black hole. A Z death zone that I felt. WARNING! Don't go near it with your Z. It could go Zombie on you. Then, you'll be asking the "boy with the banjo" for help.

A crumpled wad of aluminum foil works well for removing crud from chrome. It's softer than steel wool and less likely to scratch the chrome.

If the engine temp. remains normal in traffic, there's no need to alter the fan. Change the fuel line location. That's where the heat problem is located. According to the info supplied by Zed, the percolation problem is forward of the mechanical pump, Concentrate on that section of the lines.

The Lambo's and Ferrari's are nice but I'm Jones'n on the E Type.

The outer springs will work fine. You just need enough pressure to scuff the bluing, Sharpie pen, etc.

I had pictured a lot of beer and the thought, I got no money but I do have parts. If I have to replace the rear end and replace the frame rails, as long as I'm in here, I might as well,,,, OR, a Red Green Scarab.

OHHH, THE TEMPTATION!!! and the return of THE VOICE!!! SchiZophrenia is back. That one appears to only need a few hours of labor to put it back on the road unlike everything I already have. A real bargain for someone with a little knowledge and time. I hope it goes to a good home. My place would be better but I'll settle for good. I've got to finish at least one of my projects before I dare buy another. BTW, Getting old is a steep price to pay for maturity.

Good to hear from you. Is Lilith still running good with the SUs?

Grinding going into reverse (when not moving) is usually caused by a clutch that's not fully releasing or (rarely) the pilot bushing in the end of the crankshaft.

Zed, Thanks. The Nissan bulletin is great reading. A great description of the difference between vapor lock and percolation. It does sound like percolation is the problem.

All the plugs were fouled? I fail to see how fuel starvation (vapor lock) can foul plugs. If the definition of fouled is oily, black, sooty, etc.

Zed, Interesting idea. Kind of a cross between Myth Busters and Red Green. It's possible that stretchy motor mounts are part of the problem.