Zed Head

Different colors probably go on at different thicknesses due to their ability to cover. The Green Monster video was pretty good but that guy kind of just walked around and took a bunch of measurements but didn't say much about why some cars had different thicknesses, besides assuming that a repaint would be thicker than original paint. He assumes that a second paint job is always thicker, like a painter doesn't strip and sand areas to make them smooth, before painting. It would be better to have 20 or so specific locations to measure at, and measurements at those points from a whole set of cars, as a database. The old beat-up $5000 Z's probably have plenty of untouched paint to measure. That would mean more, I think, than these random measurements. Good idea, questionable execution.

Quality and/or calibration? Method? Training? https://www.measurementshop.co.uk/blog/guides/all-you-need-to-know-about-thickness-gauges Or the red car has a second coat of paint? We need microscopy on a paint chip cross section.

What's funny is that in the 70's I think that they still had a guy with a spray gun painting parts as they came down the assembly line. I think they even masked off and repainted parts if there was a ding from a clumsy assembler. Probably tons of variation in these old cars. Today it's all robotics and dip tanks. Paint thickness readings seem like a strange new criterion for originality. What if they measure a rust spot before it bubbles?

Use a meter and measure voltage at the battery terminals while it's running. The dying could be a separate problem.

One of these articles might help. https://www.classiczcars.com/articles/body-paint/

The Flukes have a $15 fuse inside to teach you to pay attention to your leads and settings. You get about 8 fries to breakeven point.

This one ended like they thought the other one would. But the end result is the same. People have high opinions on the value of their 240Z's.

Six minutes! A different 1970 240Z! https://bringatrailer.com/listing/1970-datsun-240z-63/?utm_source=dm&utm_medium=email&utm_campaign=2020-10-21

Sounds like what you're asking about is whether you should temporarily brace things before you remove the old body reinforcements, AKA "frame rails". The body is a unibody, or monocoque, chassis, basically just a steel box with strategically placed reinforcement, like the frame rails. If you want to get a better feel for it, just do a Google on unibody or monocoque and you'll find a bunch. There are several "boxed" sections around the body that are important, mostly on the edges, like the rocker panels and the door and windshield openings. The frame rails are kind of secondary to the major boxed sections, like the rocker panels. The Body chapter shows cross sections of all of the boxed areas. I wrote all of that stuff because you used the word frame. There's no frame. Anyway, I've read that removing the floors in order to put new ones in can lead to flexing. The floors are a critical part of the steel box. So just think of it as a steel box and support areas so that the box can't twist. Probably just well-placed jack stands are enough.

I meant diameter. I learned a while ago that the first number is the sidewall width (I thought it was tread width), which is important. But the second is the ratio of width to height. So you need the calculator to know the final dimension. 205's seem to work well as far as rubbing goes, although some brands do rub. I had 205/70-14's and one brand rubbed slightly on hard corners and the other didn't. the car was lowered about an inch. Low profile tires will give a rougher ride. So, it all depends on what you're trying to achieve. Looks, performance, comfort, or a combination. I don't think I've seen anyone talk about a 55 series on their car. Don't forget offset also, that needs to be right or you'll get rubbing. You can also roll or cut the wheelwell edges to get an extra 1/4 inch.

How does the size compare to stock? There are calculators. That would be a good starting point.

Not a lot to do in Richland. Close to Hanford. Pretty dry out there. I used to tell people that there was desert in Washington and they had a hard time believing. It's not all rain. https://en.wikipedia.org/wiki/SSC_North_America

I think it's only the insulator length that is changed. Your drawings show a longer threaded portion but I don't think that's right. Here's NGK's stuff. Look at the porcelain. Threads are the same though. https://www.ngk.com.au/technical_info/heat-range/

Food for thought, if you would rather avoid removing the head. That area should be an unpressurized area, it only sees oil that drips down from the valve and timing chain sprocket area. So, you could probably reseal it from the outside without removing anything. Clean it up well, maybe dig out the old gasket, spray it with some cleaner. Then put some RTV on the gap and work it in to create a new gasket. Just a thought. There should be a bunch on the site about head removal and replacement. Try words like "shaved head", engine rebuild, rocker arms, cam replacement, etc. Can't really guess on "while you're there" stuff unless the condition of the engine is known. Timing chain, for example, might be worth doing. Valve guides, why not? Once you get the head off you'll want to measure flatness. Might need a skim. Then maybe some head saver shims. You'll probably break a head bolt, of course. Might as well resurface the exhaust manifold, it probably needs it. And you'll probably break an exhaust manifold bolt or two. But it'll all be fun.

Shouldn't need a hammer for the drums. But, as you can see, none of the kits seem to be very well put together. There's no way to pick a "best". There is one advantage to the discs in that the pedal height varies less. With drums, the pedal will drop a bit until the next click on the self-adjuster. The Zstore kits look like they'll al give the same performance on the street. They just do more work on getting the parts for you. The more parts, the more expensive. Performance about the same, except for maybe if you race, with the Stage 2 kit. You could probably get their basic kit and do some Rockauto shopping and be done, for the best price.

I screwed up and posted a link to Hybridz about a different kit. Not the ZStore kit. Looks Like Joseph at the ZStore never replied to my notification anyway. Still, they should be able to send you the instructions before you buy. But, as people are saying - why?

Recheck the plug first.

I've read that detonation can cause the plug gap to close. Detonation does a lot of damage, it can look foreign object damage on the piston top. All it takes is a hot day, some low octane fuel, maybe having the timing off a bit. I like Mark's suggestion. Try a new plug and see how it does. Everything else looks pretty good, the pressure numbers and the other plugs. The pressure numbers are on the high end though, which might mean a high CR, which might be a reason for detonation. If you do hear knocking you can just dial the timing back a few degrees and should be safe.

Derek over on Hybridz is a really capable guy. He has designed, cast, and built his own cylinder for the L6's, among many other things. He is a member here also. He had some comments about the ZCD kit. https://forums.hybridz.org/topic/131360-rear-disk-kit-from-zcar-depot-anyone-using-it/

Go back to something that worked before.

They're black. See if either is grounded. Meter time.

Greggers13 bid $110,000, up from $105,000 by dfwelite, and both let themselves get outbid by $1,000. I think the comments started to stick. The funny thing now is that, even though it was presented as an untouched survivor, it probably needs to be touched now. It needs the refresh that people were saying it has already had.

Should people feel bad? Seems like the car was not presented properly. Shouldn't have been so many questions to be asked.

The reserve was above $111,000, apparently.

Thanks for sharing this AK. Sorry that your father, and your family, have been caught up in this mess. Better days are ahead, I hope. The work to find solutions is continuing despite all of the chaos.