Mark Maras

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.

A close-out sale on parts?

The sheet metal and rivets could be bearing cages. How do the gears look? Was the sheared off piece still in the release bearing? Inspect the gears, shafts and check the clearances. It was likely popping out and not going into gears because of bad synchros.

Ditto, My kids can't understand how I get along without one.

You might try warming the panel with a hair dryer. You should gain additional flexibility.

Ditto. It would be great to be able to increase the assist in parking lots.

Pulling the trans isn't too difficult. If you do, be sure the car is high enough to clear the bell-housing when you slide the trans out from under the car. If you have an early 4-speed, the bell-housing can be unbolted from the trans. under the car.

I can't imagine what they could be but speakers. Stunning craftsmanship.

Odd, I don't recall any more noise from my flex-fan than the orig. clutch fan. Different styles or manufacturers possibly?

Oh Yeah. There's no doubt that a flex fan would amputate a finger(s), but even with my track record, I have never injured myself with one. Same goes with a chain saw. I have a lot of respect for both. It's not the obvious things that bite me. Out of curiosity I calculated the square inches of blade on my 70s era five blade flex fan, app 87.5 sq. in. (My orig. steel seven blade fan is hiding from me.) The eight bladed plastic fan on the 260 is 120 sq. in. I think the slipping clutch requires more surface area (mass) of fan blade to pull the same amount of air as a non clutched fan and might negate Cliff's theory of the pizza pan flex-fan. Sorry Cliff.

Keep in mind reduced drag means the fan is pulling less air. Especially when the car is not moving, which is when it's needed the most. Most of the road racers "back in the day" didn't use a fan. No need for one if the car is always moving. Take the fan off when the car goes on the track and just turn off the engine when the car isn't moving.

I wouldn't run the flex fan with the clutch. I think the reduction in the number of blades would require the flex fan turning at full engine speed, especially at idle. I'm not a big fan of clutches. Everyone I've turned by hand has different resistance than the others. I measured my old flex-fan assy. The spacer is 2" and the fan is 3/4" from the 3 row radiator.