Stanley

That sounds easy.

Thanks Steve, we might need to do that. It doesn't matter which wire is connected to which end of the ballast resistor as long as they are the correct two wires, correct ? I think there's supposed to be a green wire with a white stripe, and a black wire with a white stripe on the ballast resistor, a black wire with a white stripe to the coil +, and a black wire from the coil - to the distributor. It was easy to tell what went where before the harness was un-taped. The length of the wires should provide a good clue. Yes, Site, I've seen those two photos. Unless StinkyCheeze confused the + and - terminals on the coil, which seems unlikely, he's got the black wire with the white stripe on the wrong terminal of the coil. This is from Friday - totally wrong:

I take pictures of everything - except the stock wires to my coil and ballast resistor. I think the mechanic got confused by all the extra wires (for the long-ago deleted dual-point distributor). He un-taped the harness to get rid of the crappy-looking extra wires. I Googled it but no good-enough picture. Main trouble seems to be that there are two B/W wires. One goes to the coil +, and one goes to the ballast resistor. Sometimes it's better to not know anything. Then you're careful.

Engine was running but no lights, tach, etc. There's some confusion about what wire goes where. There's a green/white wire, some others, colors faded so not sure. Don't have a good photo of how it was. It's the harness for the coil, ballast resistor and distributor. There's also some wires for deleted smog stuff. We've got the schematic but it would be a big help to have a good photo of stock wires. It's a '73 but I think '72 was the same.

Thought your car would be exempt by now. F.I. right ? Mine has SU's, that stuff is beyond me. It's B.S. that you can't modify it. Rebuild the engine, install a Cat and a modern EFI, get emissions way down from what you're allowed with the stock engine, and it's still illegal. Makes no sense.

Asked the builder, he said about 12.5 to 13.5 for this stage II engine with stock ignition. 13.0 AFR at 3000 rpm.

There was an issue, but Bob called the builder and he sorted it out. Engine is sounding rather vicious, especially with no muffler and tailpipe, just the headers.

Get some Porterfields. R4S I think. I hate the way they wear out so fast, and the way way they dust up my wheels. Noticeably quicker stopping compared to new stock pads and shoes. I'd guess at least 10% better since I don't think any less would be noticeable. They may have saved my car, my life and lives of the family that failed to yield, pulling out right in front of me from a side street with a stop sign.

Digital gauge or analog ? I was looking at some on YouTube. Digital sort of irritating as the numbers seem to jump around a lot. Zeitronics looked a little better than the others in that respect. But with analog meters (Only saw AEM, autometer and stewart-warner) the needle jumps around a lot. Maybe the needle mechanisms are cheaply made. I like the look of analog better but that's a minor issue.

Will check the floats.

I wasn't there but Bob the mechanic said the engine started and ran well for a few minutes, then made a "ppttt" sound and died. I went over and we tried a few more times. It would try to start, popping through the carbs and dying. I richened the mix a quarter turn but it didn't didn't seem to help. Timing is 30 at 3000 rpm. Any ideas? Engine builder is very well respected. Bob knows his stuff and can probably sort it out.

My road trip playlist is Stones, Hendrix, Parliament, James Brown, and some named above. Mazzy Star for quiet time. But as a guitar picker myself, I can't deny my great love for the Soukous. It's rock n roll to me. Franco & OK Jazz is my favorite Kinshasa band, but check out a little Tabu Ley with Mbilia Bel and shake it down. This from about thirty years ago I think. Original version is in Swahili. This English version by non-English speakers went big all over Africa. No one understands the lyrics but you sort of know what they mean.

Thank you. Once the tune is right I plan to remove the sensor so it doesn't get cooked, and then put it back briefly twice a year when the mix needs adjustment, when the weather turns cold and again in the summer. Not sure I'll really do that but it's the plan. When the car was running rich it was noticeably faster on cold days.

Try for 14.9 or is it dumb to be attached to particular number? Engine is new, mild cam etc.

So yes, the math in post #1 was useless (except at station 1). The smaller the stock needle area at a certain station, compared to nozzle area, the more would need to be be removed from the modded needle to make 1/6 more gas surface area. The graph in post #4 shows this. Eventually the needles get very pointy and getting 1/6 more gas area than stock becomes impossible. There's another problem with the math though. The larger engine makes more vacuum at a steady rpm, raising the piston and putting the needle at a richer station as discussed above. Maybe stock needles would work on a larger modified engine, except for acceleration. Bought a pair of stock SM's and a pair of ZH's (slightly leaner than SM's) today. Also have the modded SM's and N-27's. Don't know if I should stay with the 4 ounce red springs or move up to 8 ounce yellow. Nothing in between. Got to think about fuel economy. Yellow springs might make it a real guzzler.

Saw this today, not much information but something about modifying flat tops for racing. https://www.zdriver.com/forums/240z-280zxt-s30-s130-tech-tips-275/carburetor-differences-20083/

I don't get it either but last summer I tried richening stations 1 & 2 on the SM's thinking it would allow me to raise the mix nuts and have a good idle without going too rich at mid-range. Didn't work, it ran way too rich; don't know why.

Here's part of the needle profile book, just the .100 needles so is easy to print. It's an old book so there might be newer needles that aren't listed. Needle charts pp 47 to 49.pdf I don't think there's a one-size-fits -all SU needle for Z cars. Not that I know very much, but the official SU tuning book page 7 says you need different needles if you change the exhaust or air cleaner for example. Here's a PDF of the whole book, it also has the needle profiles. Tuning_SU_Carburetors.pdf If the needles are too lean they can easily be polished richer. If they're too rich you're stuck, pun intended.

Thanks for the graph. I need to think about it before commenting. Would like to hear from others with L28 daily drivers using SU's (not race cars since they don't have similar idling and low RPM performance requirements). I saw at MSA site if you use early nozzles you need early needles. Called them this morning but didn't get a definite answer about the difference. Called Bruce Palmer, asked if the distinction was bogus, he said yes. He also said the stock Hitachi SU nozzles were 0.100 inside diameter, same as the British SU's that use SM and related needles. So if that's true, then why are SM's and similar British needles, listed as .100 which refers to the nozzles, all listed as 0.099 at station 1, while the N-27's are 0.095 (miked by Captain Obvious and verified by me and my Japanese micrometer ? I expect the other stock Hitachi needles, like N-54's and N-58 (US spec. emissions) are also .095 at station 1. I wonder why the stock non-emissions needles were changed from N-27 to N-54 for '72. I was thinking of getting some oversize nozzles but Bruce says they would be too rich. I remember reading a thread about SU needles on an AU site. Boring out the nozzles to use British needles like SM's was discussed but no one had tried it. The R&R mechanic, a reliable source IMO, says it can't be running rich or the rings won't seat. Plan to wake up the new engine in the next few days.

Station 1 is 0.099 for (British) SM's vs. 0.095 for N-27's etc. (Hitachi). SM's wouldn't work on my L24. Too lean at low end under load. Had to set mix nuts 3 1/2 turns down or it would go lean and stall out leaving a stop sign. Then it would be too rich at mid-range and foul the plugs. Might be OK for L28 though. Maybe OK for L24 with oversize nozzles (if stock needles are too lean).

280 engine will move more air and so need more gas. The question is how much to reduce the needle diameter for stock N-27's. Did some math but wondering how helpful it is. So it would seem like you could just polish the needles down from stock dimensions at each station by one tenth. Not that easy though. When I installed K&N's and a 2 1/4" tailpipe on the stock 240 engine it was flowing more air and had to richen the mix. When I installed a better-breathing skyline Y-70 head it was flowing more air. Had to modify the needles and install stiffer springs to keep from running lean. The new engine is not a wild build but will have a 280zx head and other mods. It will have 3-2 headers but same 2 1/4" pipe. Is my math useless ?

Didn't get a photo but they are cupped on one side.

Thanks, lucked out, MSA had that stuff.

Saw a C.F. bumper at MSA. Doesn't fit '73's. http://www.thezstore.com/page/TZS/PROD/classic02n02/50-1752 They say you can swap 71-72 bumper brackets that fit the bumper but they need modification, without explaining the modification except to say cutting and bending is required. I have some experience with fiberglass and have some carbon fiber cloth so wonder if I could make a CF mounting plate on the CF bumper and use the '73 brackets instead of buying and modding 70-72 bumper brackets. Feel like I brought a spoon to a fork fight.

To install this grill in my '73, with the stock '73 bumper brackets, it's going to need some modification. Also, it's made to fit cars without a bumper. Ben says it will work with early Z brackets but not '73. The mod for the grill is not a big deal but I don't currently have a bumper. Considering a carbon fiber bumper since it's way cheaper considering all the parts and hardware required, and looks OK IMO. Changing the brackets to 71-72 might make it easier for bumper and new grill. Starting new thread about that.