Stanley

Some great roads around Eureka and points North for a sports car, as long as you don't get behind the logger trucks.

You can plug it or hook up the heater. On the 240Z there's a Wye hose barb fitting screwed to the right side of the block that the return heater hose, the intake manifold heater hose, and the hose that returns coolant to the water inlet all attach to. Don't know if the 280 is the same. What I did was put tapered rubber plugs in the hose barbs and clamp silicon caps over them. But if I lived in PA I'd want the heater hooked up.

yeah, I had to work it for a half hour to get the wire all the way through. I want to pour some Gumout in full strength from the engine bay and let it sit for a while. Scared it will hurt the hoses at the tank though.

Here's a BSPT plug for the outlet on the head. McMaster-Carr

Simple and effective. BTW once one float is set where you want it, you can move the tube in front of the nozzle and make marks (or just eyeball both sightglasses) at that fuel height just below the mouth of both carbs. Then adjust the other float so fuel level is same height at both nozzles. Eliminates the difference in bowl levels due to engine tilt or rake, and lessens the chance of human error.

Suggest wait for the guy with the "fine shop" if he said he can fix your Z. Sounds like the guy that worked on my dual carb 73 VW in the eighties. He was from Germany, his shop was so clean you could eat off the floor, and he got my Type 3 running perfect the first time. Even better for a Z if he was from japan.

Filter manufacturers say use only 100 micron filter on suction side for carbs. I have a new one ready to install by the tank outlet. OK to eliminate the one by the mechanical F.P.? I've also got a new high-flow 40 micron that was going there, but might not need it (and I wouldn't be following the instructions). Concerned about particles in the 40 year old hardline. I did run some braided wire attached to a drill through it couple years ago, and last week put some Gumout fuel injector cleaner in the tank, hope it got most of whatever was left in the hardline. The electric fuel pump by the tank is removed.

The air galley, the metal tube running horizontally near the top of the photo, looks rusted out. If it's not leaking exhaust fumes yet, it probably will soon unless it's not as bad as it looks. A new one may be available if you want to keep it stock. Many have removed them and welded or plugged the holes in the exhaust manifold.

Starting to think most of the air is getting into the system from leaks. The glass filter for example, has 6 places that can leak: the O-rings at each end of the glass, the threaded plastic hose barbs, and the hose to hose barb connections. If it was under pressure you could see a gas leak, but it's suction. Thinking I'll use threaded fittings where possible, double clamps on the hose barbs where I can't, and keep the hoses short and situated so there's no high spots where big bubbles can develop.

Got my 5/16" clear yellow Tygon today (way better than the clear colorless Tygon, btw, it's thicker and has a much smaller bend radius, and it's rated "A" for gasoline). So hooked up the clear fuel filter between the hard line and the fuel pump with about 2 foot of clear tube on each side. Seems like the filter is making all the bubbles, somehow. With the filter located horizontally, about the height of the outlet on the hard line, it sends out a steady stream of bubbles, though there are little or no bubbles coming out of the hard line (except at start-up). With the filter lower but horizontal, there's somewhat fewer bubbles. With the filter low (resting on the oil filter), inclined about 30 to 45 degrees from horizontal, with the outlet down, the filter stayed full at idle, and there were no bubbles going into the fuel pump. Ran full for ten minutes. Perfect? Then I reached over and revved it up; the glass started to get empty and a big bubble started up the outlet line and grew until it got sucked up. And the check valve I got doesn't work with suction on the outlet side. Maybe with the electric pump by the tank.

Maybe post a picture of the water hoses, so we'll know exactly how it's hooked up. At least it ran 30 miles, wow.

Tried a few little experiments today. Got a 2 ft. piece of 5/16" hose and a 2 ft. piece of 1/4" Tygon clear tubing. Hooked the hose from the metal fuel line to the clear filter, and hooked the Tygon from the filter to the mechanical fuel pump inlet. So I had a flexible setup to try the filter in different positions. About 1/4 tank of gas. With the filter slanted outlet up, a steady stream of small bubbles came out and collected at high point in the Tygon tube. Raising the filter up made more bubbles than at lower position. Only a little gas at the bottom (inlet side) of the filter. The bubble at the high point got bigger and bigger and the suction pulled it toward the pump until it all got sucked in. With filter outlet slanted down, it quickly filled 1/2 full. A bubble started in the Tygon right under the outlet, and began to grow. It got bigger and finally got sucked to the high point in the Tygon, until it got sucked into the pump. The gas level in the filter went down towards the bottom (outlet). Horizontal, the bubbles seemed to develop faster when positioned higher. But same thing, they grow, find the high point, and get sucked in the pump. So some empirical evidence of something or other. I got nothing. Bought a check valve today, wonder if it will do anything. If not, I wasted $22. On Monday I should get some clear 5/16" tube, so I'll be able to see bubbles on there way toward the filter if they're there. When I took of the Tygon and put it back together for the road, and tested it, there was more gas in the filter, 3/4 full instead of 1/8. Maybe I fixed it?

My new in-line fuel filters got here today. There's a 100 micron pre-filter going near the tank outlet, and a 40 micron filter that will be in the engine bay before the mechanical fuel pump. For now, the electric fuel pump is removed, the mechanical one seems to have plenty of pressure. The glass filter that's in front of the mech fuel pump seems to have almost no gas in it when it's idling. My float bowls are set a little higher than stock, but it's still running lean at 3.5 turns down, so I'm not eliminating any suspects yet. I read in a tech article that any air bubbles that get into the fuel pump will emulsify into the fuel and cause a lean condition. Yeah, I know most stuff I've read online says air in the filter is normal - just paint the glass filter black so you don't see the bubbles. Supposedly there are a number of possible sources of that "air": 1. leaky hose connection between tank and filter, or crack in fuel pick-up tube in the tank. 2. Cavitation at restriction causes air bubbles (probably not enough flow in my setup for that.) 3. Sloshing in tank causes air-entrainment that results in bubbles hanging at high point in line, the filter. 4. Suction in line plus heat causes reduced boiling point in fuel, so it's fuel vapor not gas. 5. When float valve shuts down, there is no flow, and gravity siphons gas back toward the tank leaving air bubble. Anyway, I want to set up my filters to reduce air in the system if possible. One suggestion, from a filter manufacturer is to place the pre-filter as low as possible, so it will be gravity-filled from the tank. Another suggestion, from a pro drag racer, is to install the (front) filter vertically with the outlet facing down. Another suggestion is to put a check valve inline. (I guess it would have to be after the pre-filter or the gravity-fill idea wouldn't work, since it takes some pressure to open.) Any ideas? what would be specs for the check valve? The one for F.I. Z's probably wouldn't work since I'm only getting 3.9 psi with the mechanical pump.

Drove the Datsun down to Costa Mesa, got there a little late, missed the awards so don't know which cars won. Saw plenty anyway. Best part for me was when two Datsun Roadsters with turbo'd twin cam engines left the parking lot. They sounded great. Nice drive back on Highway 1. Will post a few photos here in the next day or two after I reduce them.

Thanks for the links about the Shift kits. I'm interested, of course, especially since it doesn't sound very expensive.

Car and Driver ran a favorable review of the Z with AT. It's not gutless if you shift it like a stick. You can also downshift, but it's not recommended over 70mph or so according to the owner's manual, so not good for a road race where you need to downshift for a 90mph curve. Can't burn rubber unless the tires are crappy. With a 2 1/4" exhaust you can get very close to the 1/4 mile time that C&D got with the stick (launching at 6000 rpm with the borrowed car). 119mph top speed compared to 124mph with stick. Read somewhere it's good for autocross where you leave it in first and just drive. I like it for the quick 60 to 90 mph which is handy on the freeway. Worth it to swap, I don't know.

I can't believe very much fumes are going to make it out of the evap tank, down the long 1/4" tube, and out into the engine bay, especially since air is supposed to be going the other way when you're driving. Nice idea, but I doubt if it does very much except vent the tank, which is necessary. If it turns out you have the tube (shown clearly in the post above) but no flow valve, you could just leave it as is. If the tube is disconnected at the evap tank, maybe put some emission hose on it and let it go down under the car, to keep any fumes out of the cabin. Anybody with a flow valve, give that thing a good blast of carb cleaner so it actually works.

After setting floats, removed the rear banjo bolt to get the hose barb at a better angle. Afterward it leaked. Leaned on the wrench until it was only a tiny leak, it didn't drip but it felt slightly damp. So today, finally fixed the leak I think. Used two composition washers from the carb tune-up kit from MSA, don't know if that's what they're for but they fit. Also used the aluminum washers that were on there, on the outer ends. It still leaked until I sanded both sides of the inner aluminum washer. Still had to use what seems like too much torque (but not as much as I used last time) to get it to stop leaking. Something's wrong there. Are there some other washers I should be using? Would be OK to put some sealant on the washers? Not much surface there. Seem to remember a post about this but couldn't find it.

According to fig. EF-40 in the engine manual, at 4500 ft. baseline setting at 86F is about 1.5 turns down. 68F: 2 turns, 50F: 2.5, 32F: 2.75. Depending on float setting, condition of needles and nozzles, and where you want A/F ratio (fine tune for gas mileage or performance). So from wherever it runs best for summer, maybe a full turn down for winter.

Euro D606-52 mechanical advance comes on quicker and has less vacuum advance. US type D612-53 is for emissions. A lot more detail is on this site. The timing procedure for dual point is omitted from my '72 engine manual, but described in a Nissan revision posted here recently.

Concerned about running the bowls dry at WOT, and on advice from members, I've been trying to raise the fuel levels without much success until yesterday. I've heard the 19mm down from bottom of lid/top of bowl, so that's what I was going for. More precisely, for 3-screws, 18.5mm for the rear and 21mm for the front, the 2mm difference due to slope of the engine, fudged a little because my car is raked slightly higher in front, to result in equal fuel height at both nozzles. Last week, finally got the rear one set, but the highest I could get the front one without overflowing was 24mm down. Yesterday decided the float was hitting the side of the bowl and sanded the back edge, where the vertical part meets the sloped part, with 400 grit sandpaper. Just slightly. It worked, it's at 20.5mm down now, measured with sight glass. Maybe there was a defect in the float. Hope sanding it doesn't damage the fuel resistance of the float. Noticed that the fuel level goes up and down a little while the engine's running, so the decimal place in the numbers doesn't mean much. The fuel level goes up slightly when the engine is shut down, wonder why?

Regarding switching the dual point AT distributor, you can also drop in a new (if available) or rebuilt stock single point distributor, preferably Euro/JDM type. I did, quick fix for poor starting and better acceleration. Only drawback: missing out on the fun of the insanely complicated FSM procedure for setting the timing with dual points.

Factory competition cross-flow head re-emerging after all these years? Or something else?

See John Coffey's response to the thread Blue posted today for an overheating issue on cylinders 5 & 6. This was also discussed previously. Other than using the now-rare competition head, hooking the head outlet to the thermostat was discussed as a fix; there was a question about which way the water would flow unless it was introduced at a tee between the thermostat and the radiator. I bought the silicone hose to do an experiment to check that, however it's not clear enough to see which way the coolant is flowing. This only relates to racing anyway, I think, a non-issue otherwise. I want to get my heater working again, if only to defog the windshield. Hope I can get the horribly corroded valve out.