Zed Head

Another 510. Looks pretty clean, only one license plate (see the blue 510 above). I'm going to say it get's within $1000 of 40K. Very original, minor mods. https://bringatrailer.com/listing/1972-datsun-510-48/

You should do a youtube account for us "anti-joiners". Too many things to sign up for. Not a fan of instagram.

I'll throw a wild guess out - check your grounds. Distributor to block, block to battery, etc. Might be that when people are messing around with the distributor that they disturb a bad ground and it gets better for a short while just from the movement. Good spark is all about a good circuit, good current flow, through the coil, and that goes through the ignition module or points. Since it ran well once, and the good stuff happens after somebody messes with the distributor, and others have focused on it, that seems possible. That's why Nissan adds a separate dedicated ground wire to the distributor body, even though it's already bolted to the block (actually the timing cover). Grounds are the secret cause of many problems.

Seems like you have your solution, that's a lot of years, especially in a rainy humid part of the planet. Might as well jam the brake pedal a few times to go ahead and blow the seals in the master cylinder. Do the clutch too.

I'd try to add your post about the whistling and clicking at the intake manifold but multi-post quotes on this site are difficult. Your symptoms still sound like the "lean problem", just for carbs. Don't know if it's your throttle blade shafts or intake manifold gaskets but it seems to fit. The SU's might be even more susceptible to vacuum leaks because of the way they use vacuum to raise the pistons. Anyway, everything else looks pretty good. Don't know if your oil pump shaft is off or not but you said that ignition timing was correct.

Oops.

Are you sure the fuel is good? Your cold start valve should also be supplying fuel for starting. This won't solve any problems. Good luck.

Funny how the less defined the question is the more discussion it generates. "wondered thoughts on "best" head" >>>> go!

The owner values it. It didn't sell.

I would do this first. Sounds like you have the lean AFM problem. Don't adjust the AFM, adjust the temperature circuit. It's easy and cheap. https://www.atlanticz.ca/zclub/techtips/tempsensorpot/index.html

Seems like your injectors are opening as they should. They need 36 psi behind them though in order to squirt. I don't see any fuel pressure information.

@Derek built his own head, among other things. https://forums.hybridz.org/topic/119641-twin-cam-head-for-the-l6-from-derek-at-datsunworks/ http://datsunworks.com/

Something I found. Has some cross-references. Seems to be based on paint chips. http://paintref.com/cgi-bin/colorcodedisplay.cgi?ditzler=60636&rows=50&syear=1970&smanuf=Nissan&smodel=Datsun&sname=Orange And another link, with more links inside. Looks like Wick Humble's book writes about it. https://www.zcar.com/threads/where-to-find-datsun-orange-paint.74424/

Just to be sure, you said you can't move the shift lever. Did you try rotating the input or output shaft? If it's in two gears at the same time the shafts won't move either. Everything gets locked up. So I'd use the "one gear" method to put the front case on, then rotate the shafts to make sure everything's okay. Then put the tail shaft housing on.

You need to put it in one gear before putting the front case on to the adapter plate. Otherwise the case will push both shift rods as the rods slide through the holes and it ends up in two gears at the same time. Common problem. Pick a gear that already has one of the rods pushed backward in the adapter plate, then the detents won't allow the other to move.

1978 Silvia auction ends today. I had a carb'ed 1978 B210 Coupe. Wish I had still had it. https://bringatrailer.com/listing/1978-nissan-silvia/

And, recent hot topic - is this 918? 71 with a 289Z 5 speed. Looks nice, but, is it just me, or have the quarters seen some work? They seem bulbous. Might be a new record for pictures - 316, not counting the videos and the first few. https://bringatrailer.com/listing/1971-datsun-240z-165/

Rat roddish 510 with power. I bet it goes Reserve Not Met. https://bringatrailer.com/listing/1971-datsun-510-4-door-sedan-7/

More Datsuns. A 1978 Black Pearl, very shiny, with good bumper rubber. But, they forgot to ask for the 5 speed. https://bringatrailer.com/listing/1978-datsun-280z-88/

I only see Wednesday 3/31, then today, Friday, 4/2. 4/1 was yesterday, Thursday but there's no posts. Looks like the "100" was a typo or maybe a modification. One question I'd have is who decides that these numbers are "918"? Could be a computer analysis on a faded 918 chip that somebody put in the "system". Who decides that it's "official"? Dupont is not involved they just supply the materials.

That shoe has been chewed. The chain might be riding on the metal piston. This is probably what BarefootDan's looked like before the chain jumped the sprocket and let his valves meet the pistons.