Zed Head

The super silver is selling today. Doing pretty well. $36,000 and a bidding battle in progress. Edit - didn't sell. That's what happens when you modify. The value is personal. Maybe not objective. https://bringatrailer.com/listing/1973-datsun-240z-153/

How about a shot of the bottom of the cylinder head? You can stand them on end, they'll balance. Seems like somebody over-revved, or had some stuck valves in the past, or didn't get their cam timing right during install. The dings are covered with soot so they're not fresh. Check your cylinder head number too, see if it's an N42, that would have come on a 75 engine.

Sunday might be the best day to end an auction. $42,240 for a 72 that's nice but doesn't seem that nice, plus it has a sunroof (no offense to the buyer. Or the seller). Green is a good color though. The seller apparently had a reserve set higher than the final, but took it off. Must have been close. https://bringatrailer.com/listing/1972-datsun-240z-171/

And another silver car. Crusty 71 4 speed. https://bringatrailer.com/listing/1971-datsun-240z-171/

I posted the link to Bring-a-Trailer so you could see what was happening. The well-done resto-mods and the very original cars seem to get the money. In between, not so much. And yes, it seems like a recent thing. Hence, the spotlight. https://bringatrailer.com/datsun/240z/

There's a person or two on the forum who've said that they wouldn't have done things if they knew that the cars would be worth so much in original form. That's the point. You're not restoring, you're modifying. It's your car, people, I think, just want to be sure you know that your changes might detract from future value. Beyond that you're really just asking opinions about what looks good. That's subjective. Silver, green, red, brown. Favorite colors, as many opinions as there are colors. Good luck with it.

Like madkaw says, vacuum leak probably. You're tuning at idle for the leak, then when you get on the throttle the leak has less impact and your tune is wrong. Motorsport has good advice about the Pertronix and coils. Lose the ballast. https://www.thezstore.com/page/TZS/PROD/classic11g/12-4020 Coil Notes: The only performance coils that should be used with the PerTronix Ignitor, the 40,000 volt Flame-Thrower canister coil's higher voltage allows larger spark plug gaps for added power, smoother response and better fuel economy. They are oil filled for great heat control, and internally resisted. Legal in all 50 states and Canada (C.A.R.B. E.O. #D-57-10). The 3.0 Ohm coil is not for use with the factory (or any other) ballast resistor. If your setup requires you to keep the ballast resistor, please select the 1.5 Ohm coil above (see Related Items below for more information about the 1.5 Ohm PerTronix coils).

Nissan changed the hose routing in 1977. Here's something I've found useful. The cars on BAT all have numerous pictures and usually run like tops. Here's a 78. (Funny though, I see that the guy left the brake fluid reservoir open. Still got a good price.) https://bringatrailer.com/listing/1978-datsun-280z-84/

In short - your symptoms seem to fit an engine that is not pulling through the throttle body. Could be pulling through the PCV system, or the EGR system, or the valves and/or pistons are not generating enough suction. I think that explains the AFM vane not moving. There's no air flowing through it.

Could also be that some valves got bent during head installation. A cylinder pressure measurement will show that.

Who rebuilt and installed the head? Is it the one the car came with? Your PCV hoses look right, I couldn't see that the one in front of the AFM was an elbow. I'm afraid you have the typical internet dilemma of assuring everyone out here that things like cam and ignition timing are "right" and don't need to be verified, yet you can't get the engine to run right. It's hard to get too involved when you don't have verification of those important things. No offense, but the thought that runs through your mind is "why should we believe this guy"? Anyway, two things that come to mind are: 1. a rotten EGR passage, where the blockoff plate doesn't work because the passages themselves are rotten. Somebody had that problem a few years ago and he had all kinds of odd problems with the way the engine ran. I think that he might have found it by measuring intake vacuum. It was much lower than it should have been. You might take an intake vacuum measurement since it is a measure of how the engine is pulling iar through the manifold. It's a clue. 2.

Here's your other thread, in case anyone thinks they've seen this one before. Reptoid is right, there's something off about your PCV system. Looks like the valve cover is open to the atmosphere. That's not good.

How about a description of a normal cold startup, warm up, then the driving experience? It's hard to tell what is really wrong. Make sure you distinguish between tailpipe "backfire" and carburetor popping. Does it just not "go", or does it go with a lot of bucking and back or front firing? A video would be great. You can tell a lot by how an engine sounds.

Which Pertronix do you have? There are two. I don't think that you need the ballast if you're using a 3 ohm coil. With either of them. That's going to give you weak spark probably. https://cdn.shopify.com/s/files/1/0247/6913/4628/files/1741.pdf

If you don't do excellent work on the modifications you'll reduce the value of the car considerably. Early 240Z's with originality are getting good money on the auction sites. Just something to be aware of. https://bringatrailer.com/datsun/240z/ Here's a silver on silver on silver car. https://bringatrailer.com/listing/1973-datsun-240z-153/

Sorry, I don't recognize those. Looks like he has his garage set up as a showroom. Or maybe that's his living room. Dan Tanna style. Just realized that there are other "zedhead"s. Mine has a space between.

The raw version. Thanks gwri8, that was interesting.

Three drummers. WTF. Look at those guys...Shaver's Live Forever.

If air flow drops low enough the fuel pump will shut off. That's what it is supposed to do. Yes, the idle screw on the throttle body. If idle speed doesn't increase that's not right. If the engine dies when it's closed that's a sign that there is no vacuum leak. The backfire makes me think of incorrect timing. Any chance that there is a hole in the tube between the AFM and the throttle body? If the engine is pulling air the AFM vane should move. The tube between the AFM and throttle body needs to be sealed. Last thought - has the AFM spring been messed with? If somebody tightened it it might not move fast enough to let the engine rev. When you open it by hand you're telling the ECU to give more fuel.

Your 77 would have the AFM fuel pump switch. You might try turning up the idle speed to see if it will stay running once it warms up. More iar keeping the vane off of the switch. If it keeps running after warmup with a higher idle speed it will be a clue. Not really sure what this means either. Kind of sounds like a blockage in the intake system. Mouse nest, rag, etc. It should rev just fine even when cold. So the advice above might be irrelevant.

The AFM vane should move free and easy, in concert with the throttle blade. When you "redid" the engine and components did you modify anything? PCV tubes, maybe? All air must pass through the AFM. The PCV system is connected to the intake system.

Looks good to me too. I had KYB's and liked them a lot. CO's comment about urethane on the T/C rod is good, it will steady the steering on hard braking but he'll never notice otherwise. You might go with urethane on the steering rack also, it will tighten the steering up a little bit.

I'm not 100% because my brain doesn't mesh with whatever Nissan means with their newer-former-superceded interchange lingo but I think that they're saying "Yes". Not really sure though. They left some boxes unchecked I think. http://www.carpartsmanual.com/datsun/Z-1969-1978/steering/steering-gear/2