NewZed

Maybe you're developing a speed tolerance.

A big C clamp, or a big screw type wood clamp (the long ones for gluing boards together like in high school wood shop), and some fixturing. A gear puller and some fixturing. A long bolt run through the middle and pull it in with some fixturing. Fixtures could be big sockets, pieces of wood or metal with holes drilled in them, bars of metal placed along side the bushing, etc., stuff like that. Set it all up right and all you have to do is turn the screws.

One possibility - the nuts and studs are bottoming out before generating full clamping force. If you have aftermarket studs they might have wider unthreaded portion in the middle, wider than the combined flange and gasket thickness. A thick washer (with ID bigger than OD of unthreaded portion of stud) can fix it or add insurance.

Sorry about the bad info on swapping cams. Pretty sure I've seen accounts where people have done it and survived but apparently the odds are against it. I took a look at some other sources, the FSM and Monroe's rebuild book, and if you put all of the advice together, the safest route is to just get another head complete with untouched cam, rocker arms, lash pads and cam towers (never unbolted - misalignment) and install it as a complete assembly. Apparently, the cost of new or reground rocker arms is the big killer if you want to do a cam swap the right way. Seriously, you could probably find a used engine for the cost of a spray bar assembly. Used car economics don't make a lot of sense sometimes. Here's one for $50 with a few extra parts, but a little far away - http://forums.hybridz.org/index.php/topic/105590-for-sale-280z-l28-engine-transmission-50/

My mistake on the shafts. 280ZXT in to a 280Z is what the OP is doing, same body styles. Dave Irwin was using 280ZXT shafts in a 240Z, correct? But using the MM adapters. Odd that that wouldn't slide in, since the MM adapter package is made from 280Z parts, I believe. Still trying to get all of the mix and match stuff right, myself.

Don't you want to refer him to JMortensen and CHEQUERED FLAG JOE's stuff? Might be happier in the long run. hint.

Just happen to be browsing the FSMs. Here's the illustrations for 72 and 76. I'm not sure exactly what the sealing mechanism was designed to be, but I think that metal rings are supposed to do the work. The rest is just carrier and alignment material. If the rings don't have a flat good sealing surface on both sides, it will leak. Have you checked the center rings of a used gasket to see what's getting crushed (good) and what's not (bad)? Good luck with it.

Maybe it's the injectors or an exhaust leak. Maybe the lash was too tight before and now that it's right, you're hearing normal noise. They are noisy, in general.

The 280Zs and ZXs I've seen (my 76 and a 78 I had and various wrecking yard cars) have the shorter siamesed pipes, the 240Zs I've seen have the longer separated pipes. BlueStag, have you taken a good look at the manifold side? It may be too corroded to seal correctly. The head interface on my manifold was so corroded that even after a resurfacing it was a narrow sealing surface. The cast steel will corrode over time. You might be replacing the wrong part. And, assuming that your engine creates a little bit of carbon in the exhaust, where are the carbon trails at the flange and manifold surface? That will tell you where exactly the leak is happening. You might find that you have a mismatched sealing surface, and some simple re-centering would fix it. There is a some play around the bolts at that interface, that will allow the surfaces to get offset. You could put some sort of witness material on the surfaces and bolt it together to see if it's an alignment issue or a surface flatness issue. How about some pictures?

Look in Engine Fuel of the FSM for a description of how the thermotime switch works, what it's for and how to test it. It's only purpose is for easier starting.

Get a used one. That might be a point of discussion though, a mismatch between cam and rocker arms. Not sure, but I don't think the rocker arms are as sensitive as the lash pads. I think that I've read accounts of swapping cam only, with no issues. But, your whole thread is mainly about peace of mind anyway. In the end, you're probably looking at about the same cost and effort to fix the spray bar and reinstall it on a cam that might already be damaged and dying, versus installing a used cam that might not like the rocker arms, and die. Those spray bars are difficult to find, but a local wrecking yard might have one. They're used up to late 77 on all of the L6s, 240 through 280. Edit - here's what will probably happen - you'll find an old Z car or engine, take the valve cover off and there will either be a usable spray bar or a usable internally oiled cam. That's when you'll have to decide.

I just re-hosed 6 injectors using 5/16" (7.9 mm) Gates 225 psi (that was the rating, I don't know where it would ever be seen) FI hose from Baxter Auto. They're installed, with about 100 miles of running on them, no signs of leakage or weepage, not even the smell of gasoline with my nose right over the fitting. No clamps on the injector side, just the barb and ferrule (if that's the proper name). They went on nice and tight, with a good bulge at the barbs. 1/4" (6.3 mm) seems a little tight, that puts more strain on the hose, which could lead to earlier cracking with age, but would probably be fine with good quality hose, if you can get it jammed on to the barbs. I've seen 7.5 mm printed on what looked like factory hose. That's probably the ideal, design size, since these are metric devices. A little too tight or a little too loose, or search around and probably pay more money for 7.5 mm hose.

Couldn't the OP just get an internally oiled cam, block the spray bar holes and live happily ever after? Less chance of ground up cam debris in the oil. Seems odd, but the L24 and the L28 used the same cam, according to the atlanticz info. I think that the internal oiling came around in late 77 with the N47 head.

Thanks for taking away the feeling of security I used to have, riding around on E, knowing that there was still 4-5 gallons in the tank.

http://atlanticz.ca/zclub/techtips/cam/index.htm If you find that it's a stock cam, you can download the FSM and look in Engine Mechanical for the valve lash specs. Your cam lobes will most likely die if you don't fix the spray bar.

You've probably seen them, and I don't know if he has design specs in them, but if you search "throttle bodies" under the username Derek you'll get three threads that might help.

I think that laser is used to help set the pinion shaft parallel with the transmission output shaft. You may have got lucky and your pinion shaft and output shaft are on the same center line, or you might be able to get better results with a little more adjusting. If you can put the laser on the center of the transmission output shaft and it points back at the center of the pinion shaft, then they're on the same center. Otherwise, you want to adjust until you get the same offset pointing backward as frontward. Point the laser backward and measure offset from the pinion shaft center to the laser line, move the laser to the back and point it forward and measure offset from the output shaft center to the laser line. Adjust until the offsets are the same, both up and down and side to side. That will give equal and offsetting movement of the front and back u-joints, nullifying the vibrations. That's my understanding.

11 - 12 gallons is typical for a fill on my 76 if I let the gauge get down close to E. The capacity is only 17 1/8 gallons. The fuel pickup starts sucking air on hard left turns when the gauge reads ~1/4 full so I get about 12 gallons on every fill, filling up with ~4- 5 gallons still in the tank. The needle tops out above F after a fill. The needle also drops fairly normally to 1/2, sits there for a long time, then drops rapidly. Needle position doesn't really tell much about how much gas is left in the tank. Why do you say that the gauge works perfectly? You could check how much you really have after a fill by siphoning and draining the tank dry if you wanted to know for sure.

http://atlanticz.ca/zclub/techtips/electrical.htm http://xenons30.com/reference.html Buy a volt/ohm meter. Even a cheap Harbor Freight unit will be better than guessing.

The 79 ZXs had the older 5 speed, with the 3.321 first gear. Probably why they came with the 3.364 or the 3.7 rear, but not the 3.9. Just to confuse things even more.

By "long stop" do you mean coasting to a stop? Is it your foot on the brake pedal when the high idle happens? Does the idle drop when you take your foot off the brake, and does it go back up when you press the brake again? Could be the brake booster. But more details would help the diagnosis.

Should have mentioned also, that the 5 speed the 3.9 came with had a 3.062 first gear ratio in the ZXs. The 4 and 5 speeds that the 280Z with a 3.54 came with had a 3.321 first gear. So it also matters which 5 speed that you have. Lots of possible combinations out there.

If you're talking about the blob or orangy colored stuff on the end of the can, that's just the factory seal of the adjustment hole. It's stock. The thermotime has two wires to a two wire EV1 plug, and looks jsut like the water temperature sensor plug. Don't get them mixed up. The temperature sensor for the gauge is one wire, maybe that's what you're looking at. Unplug it and see what the temperature gauges does. The resistor in line with the water temperature sensor circuit is a fairly common old time way to richen the mixture. It makes the engine temp look colder to the ECU, which then adds gas. It seems to pop up a lot on 78s for some reason. I have a 76, that seems to run on the rich side, but the ECU, AFM, block and head are all essentially identical to the 78, so the whole thing is kind of unclear to me. But several people have found them on their 78 cars. Maybe there was a rogue mechanic out there in the past, installing resistors on every Z he worked on.

Whether you have a 4 or a 5 speed matters also. The 3.9 typically came with the 5 speeds, the 3.54 typically had a 4 speed or automatic.

I was just pointing out the recommendations a for stock Nissan engine. Hence the trailing "For whatever it's worth". The PO said he's doing a stock rebuild. Since Nissan wrote the Owner's Manual for the domestic market, I assume that they meant whatever standard was used in the USA in the 70s, but were probably erring on the side of caution, like they did with their timing specs. From what I've gathered, fuel quality is so variable around the country that the PO won't really know until he drives it. So he'll just have to gather as many facts as he can and make an educated guess on what might work and how much risk he wants to take. Don't forget to factor in 15% ethanol if you're in Oregon.