Zed Head

Still haven't seen any evidence that you know that the clutch fork is moving and pressing on the springs on the pressure plate. You can actually see the fork and slave cylinder from the engine bay, you don't even need to jack the car up. You might be spinning your wheels (pun intended!) until you know that for sure.

The gouge on your cam looks like it's on the base circle so it won't have any pressure on it, and most likely won't cause further damage. Although, in your pictures it looks like the lash might have been tight on a few lobes. The base circles are shiny like they've had the rocker arms riding tight on them. Just a couple more observations.

The 78 N47 cylinder has exhaust liners in round exhaust ports, but otherwise is essentially identical to the N42 head,with rectangular exhaust ports, on the 76 engine. All of your 76 pieces should bolt n to the 78 engine. There are tricks to working on the valves without removing the head, involving hose or rope jammed in to the spark plug hole or compressed air to keep the valve from falling in to the cylinder. You'll need a valve spring compressor also. I've never done it but apparently it's not super difficult. Are you sure it was the keepers and retainer that you found or was it the lash pad? Without the keepers I believe that the valve would fall in to the cylinder unless it was jammed closed from bending or binding.

It does sound a little bit like an alternator going bad. Or, if you have AC, check the idler pulley. You can start and run the engine for a short while with the belts removed to see if it's a noise from something belt-driven. With the alternator belt off the water pump won't be turning so don't overdo it.

Min came out of either 76 or 78 cars. They have the same number as yours, that cover looks like a typical 76-78 AFM cover number, maybe even 75. I assume that it's possible that someone removed the counter weight, maybe with some misguided idea that it would increase throttle response. Or maybe it just fell off and they ran it anyway. It's main purpose is as a damper for pulses on the vane, if I remember right. Or they took the cover off of the 1978 model and stuck it on a different AFM. The design is a Bosch design and common, you'll see them on BMWs, Audis, Volvos, Alfa Romeos, etc. No idea what you should now. If you could borrow an intact AFM, that might tell you something.

I am pretty sure, based on what I've seen, that the specs are the same as the licensed Nissan injectors. The real question (for me anyway) is if Bosch quality is better than Nissan quality. You can get the Bosch 0280150116 injector from these guys for ~$70 each - http://www.fuelinjector.citymaker.com/catalog/item/7638068/9161583.htm $420 total

Looks like someone has done more than the usual messing around with your AFM, not right for 1978. Looks like your counterweight is completely missing. Was there a number on the cover? Maybe someone installed a ZX or even a BMW, or other brand AFM. Maybe it came with the Bosch injector. You might have the balance right from your calibration, but the potentiometer trace or aerodynamics of the air flow path might be totally wrong for the engine. You have a new puzzle piece. Here's a link to the atlanticz site, probably Blue's work, for a comparison picture - http://atlanticz.ca/zclub/techtips/afm/index.html All of mine (4 so far) have looked like the atlanticz pictures. The injectors look correct for a 280Z, one's a Bosch (the same number that I have on mine, that I've seen on several local Z cars in the salvage yard, no confirmation on the cross-reference though), the other is a stock Nissan or their supplier (I think that's tan color under the black grime).

Do you have the Bosch part number? I have a set on my car, from a wrecking yard car, and they work very well. I've never actually seen a cross-reference of numbers for Bosch to Nissan though.

What color are your injectors and what are the numbers on the side (tiny numbers on the plastic)? The assumption has been that you're working with stock parts, but since you've found that your AFM was leaned out, maybe someone has misguidedly installed turbo injectors for "turbo" performance and leaned out the AFM to try to make them work. Just a guess, but worth confirming that you have the right ones. The stock Nisaan injectors for the 280Zs and ZXs were either tan or green. Turbo injectors are a purplish brown color. There are other injectors that have the same form also, like Bosch injectors.

It's a stock part. There are drawings in the FSM, AC section, of where it mounts. The threaded holes will still be there. You 'll need one of them at least if you want your heater controls to work. That might include the vent, depending on year of car. All they need is a vacuum source and the correct wire hooked up, easy.

I would try driving it (start it in first gear) and getting on and off the throttle, with the clutch pedal down, to shock the clutch free. Same effect, just tapping it free instead of pounding it with a huge sledge. I assume that you've confirmed that the slave cylinder actually moves the fork when the clutch pedal is pressed. New parts have been known to be bad.

Saw your post about your collector pipe on another forum and though for sure that someone would respond that it was not stock. I have three 280Z collector pipes and they all look like the attached picture. I have a portion of a ZX pipe also and it looks similar.

Might be a magnet valve. If so, you have disabled the heater and AC controls. What's the other side look like?

Have you done the testing of the AFM described in the FSM? At least the resistance measurements? You can do those without removing the cover. You might be about to waste a lot of money. When the AFMs fail, the signs are usually poor, "stuttery", jerky acceleration with popping back through the intake manifold. Running rich is not a typical failure mode. I looked back through your thread and it doesn't indicate AFM problems. Replacing the AFM is not a cure-all, even though it seems like a magic piece of technology. If the cover is chipped you might as well pry it off. There really is nothing holding it on but the silicone, not even a clip or two. It would probably fall off without the adhesive.

Just replaced my brake pads with some Beck Arnley 089-0020 pads, from Rock Auto, and after a few hundred miles I noticed some noise. It sounded a lot like a wheel bearing going bad, but other times it sounded like something small caught between the disc and pad, like a piece of gravel. Sometimes there was no noise at all. But it wasn't consistent enough to decide which source was most likely, so I took the pads back out to look, before changing bearings that had seemed fine before. What I found was that the paint, a thick coating, on the sides of the pads had debonded from the pad material and was sticking up like a reed, rubbing on the disc. Apparently, if the orientation and/or position was right it would make noise without the brakes being applied. With the pads off I stuck a razor blade between the paint and pad material and peeled/chipped off all of the excess paint from the sides of the pad material. Reinstalled and the noise was gone, I've put enough miles on to be sure it's for good. Just posting for future reference in case anyone has the same issue. I might guess that the pads were discounted to Rock Auto for excess returns, or were just old and the paint got brittle, or something similar, so this could happen to someone else. It's embarrassing to "scrich, scrich, scrich" up to a bus stop full of people, not really sure if they're looking at the Z or the noise.

You're right, it's not completely gone. It starts kicking in at about 3-6 inches of vacuum and gets full at about 11 or 12 depending on the distributor, by FSM numbers. Back to WN, it's funny that someone who hasn't checked that their timing works right is calling someone else an idiot for putting an inline valve in backward. Just sayin', maybe the frustration is misdirected. :devious: I like to pick on people who call names... p.s. Interesting side-note - my 76 280Z didn't even use the vacuum advance unless the car was in 4th gear. It actually has a solenoid valve on the vacuum line, activated by a switch in the transmission. Weird.

What brand/kind of tires did you get? Maybe the old cracked ones were of higher initial quality. If the rims with old tires were balanced, then the new problem might have come with the new tires.

Under heavy load, with the throttle open, the vacuum advance goes away. Vacuum advance comes in to play at partial throttle openings when the intake vacuum is high enough to pull on the diaphragm. You'll feel more "pep" at a partial throttle but probably not much when climbing hills or accelerating quickly. Check your mechanical/centrifugal advance mechanism. Easiest is with a timing light and the vacuum advance hose disconnected.

I need to learn how to use them emoticons. A lot of good information here anyway, as a result. I didn't know that the 260Zs were using EGR, it didn't show up on the Federal 280Zs until 77 or 78. I guess the EFI let Nissan back up a few years. Plus, the whole argument about not needing the switch if you don't need the extra distributor pickup becomes less relevant since the switch is used for EGR. No harm, no foul:beard:

I think that you're mistaking my quest for clarity and knowledge with a challenge to what you're saying. It's not. It's exactly what I wrote and the picture I posted. mousemedic said "only", I showed why he might have said that. Now, you have shown, with your references, that there's more to the story. This is the internet. The best way to get someone to believe the point you're making is with examples and references. Without those, how do you know if anyone really knows what they're talking about? And how do you explain it to someone else? "A guy from the internet said it was so". Thanks for the link to the EC section. Now we're learning.

Just trying to help people get on the same page. In this case, page EE-27 of the 1974 FSM.

It's hard to figure out what exactly you're describing. I don't even see the "wire in question" in your first post. You can test the headlight switch directly by taking the plastic cover off of the top of the steering column and measuring voltage in and voltage out at the switch. The wires and their soldered attachment points will be exposed with the plastic cover removed. Measure from the power input wire to ground, see if you have battery voltage. Turn the headlights on and measure the output wire, you should see battery voltage. If you have both of those, then move over to the dimmer switch on the turn signal stalk. That is the ground for the headlights, one for low and one for high. It's common for the dimmer switch to get gummed up and not provide a good ground for the high and low circuits, either one or or both. You can spray contact cleaner in the dimmer switch and work it back and forth sometimes, to get the headlights working.

mousemedic might be going off of what is said in the 1974 FSM. Kudos to him for checking the factory source. It says that the automatic only used the water temp. switch to switch pickups in the distributor. Of course, 1974 is the year of change so it wouldn't be a surprise if the manuals had the switch also, like the 280Zs do (auto and manual), or they added it to the manuals when they went to the big bumpers. To correct one thing in mm's post though, the timing is advanced when cold, then goes back to retarded when warm. My guess is it's another idle speed increaser, like the AAR. It's described n Engine Fuel, not Emissions. It seems like a lot of technology for an unexplained effect.

Pretty sure that's not the proportioning valve. It's only purpose is to show a failing brake system, by pressure differential between front and back. The proportioning valve is in a different location and does not have an electrical switch inside. You're right though, that is could be a source of brake light problems. I don't think it needs replacing if it's triggered though, it automatically re-centers itself when the pressure differential is fixed. The brake check warning lamp relay under the passenger seat could be involved in a brake light problem also.

You might be able to break the seal by knocking it on the side with dead blow or rubber mallet. It would help break up the rusted bolts also. Tapping back and forth would let any PB Blaster, etc. works its way in to the bolt holes. As Walter said, a drill will probably walk on off the bolt end and in to the aluminum housing. You might also put the thermostat cover back on the top and use it as a lever. I've had one that I drilled and removed but ended up with the through hole enlarged, and another that I was able to knock loose and work back and forth to get free. The rust from the bolts fills up the through hole in the aluminum but will come out as powder if you can get it moving.