Zed Head

I have a minor exhaust leak on my engine but it seals up and goes away once the engine warms up. It might even be a crack, I won't know until next time I take things apart. But it sounds pretty bad when the engine is cold. You might let the engine run for a while, and listen to see if things get worse or better as it warms up. Also, if you hold your hand close to the manifold-head pipe connection you might be able to feel the pulse of the exhaust leak, if it's there. And, if you have the old manifold gasket take a look to see if it was leaking. If ti wasn't and the noise is the same as before you can discount a leak at the head. If ti was leaking before then it should be quieter now if the leak is fixed.

Captain Obvious had the same problem and built his own spray bar (link below). I notice that the eBay bar is straight and sets the squirt holes farther back from the lobes. It seems like Nissan put a lot of effort in to getting the bar closer to the lobes than a straight bar does. Nissan could have made a straight bar for cheaper than their multi-piece bar, I would guess, but didn't. http://www.classiczcars.com/forums/engine-drivetrain-s30/44750-camshaft-oil-spray-bar-redesign-rebuild.html

There's a procedure in the Engine Mechanical chapter of the FSM also, showing an illustration of the notch and groove at the camshaft that atlanticz pictures show. Those two resources together should allow you to check, without removing the front cover. You can also adjust for stretch without removing the front cover as long as you wedge the timing chain and tensioner before you remove the sprocket.

Did the engine run before without the noise, even for a little while, then the noise appeared after the valve adjustment? Kind of sounds like an exhaust leak, especially as you backed away. Also possible that you didn't get the lash quite right. Might be worth re-measuring.

Here's a thread with a spreadsheet of part numbers, put together by a CZCC member. http://www.classiczcars.com/forums/electrical-s30/34192-280zx-distributor-advance-curve-reference.html Probably the most important part of any of those would be the vacuum advance breaker plate. The bearings get rusty and cause the plastic bearing retainer to break. If you find some that are intact, don't try to make them rotate. Take them home, take the plate out, take it apart and clean it up first. Or throw it in the rat hole until the appropriate time. If you try to force rotation it will probably break. Any original E12-XX module is probably on its last legs. The centrifugal weights and springs are interchangeable. The weights are stamped with the maximum advance they'll allow. The mounting bases are handy to have, at least one of each style. The magnetic pickups are a little spendy for the 280Z's, probably worth saving. The turbo distributors are worth keeping. With the cap off you won't see anything except a blank cover, protecting the optical stuff underneath,.

Don't forget interacting variables. Not enough data to draw a conclusion yet. The more stories, the better. CrazySwede, do you have heat shields over your headers? Siteunseen has his heat shields intact, as you can see in the pictures. Edit - also, we're really just working on about a twenty minute window where there's too much heat. Right on the edge. It could be some small thing that is enough to stay below the threshold. Who knows, if it's radiant heat that's the problem, ceramic-coated injectors might do the job.

Just to tweak your thinking process a little bit - the position of the oil pump shaft only matters in that it allows you the proper range of rotation for the distributor. You could make the timing right by removing the adjustment screws to allow more rotation, setting the damper pulley to zero (or ten degrees before zero), turning the distributor until the teeth on the distributor trigger are aligned, then setting the plug wires so that the rotor is pointed at the #1 spark plug wire. That's what the FSM description is trying to make happen, without going in to all of the details. IF you do that, it will also give you and idea of how many degrees off the spindle is, or may also show you that one of the plug terminals can be used, by turning the distributor until two different teeth align. A spark happens every time the teeth inside the distributor align. Your job is to get the spark to jump to the correct terminal of the distributor cap. The basic procedure, in few words, is to set everything up so that a spark happens at ~ten degrees BTDC, then set the spark plug wires to distribute them correctly.

Sounds like you might just have the plug wires off one hole. OR Which distributor are you using and does it have the mounting base that matches? Z and ZX distributors have a different base with holes for the adjusting screws in different spots. If you have a ZX distributor on your 1975 280Z base,or vice-versa, it might cause problems like you're having.

Started a new hot-start survey thread - http://www.classiczcars.com/forums/fuel-injection-s30/51835-hot-start-issue-efi-who-has-who-doesnt.html#post452360 I'll let people post their own details so I don't screw them up. SU, I remembered that you had not had issues. Referred back to your post in this thread from the new thread. If you could re-post over there that would be most excellent.

Many people have reported having the typical 280Z EFI hot-start problem, where after ~10-20 minutes after shut-down (hot engine), the engine starts but runs very rough for what seems like 5 minutes but is actually about 30-40 seconds. Some people with EFI though, report that they don't have the problem (see #43 here - http://www.classiczcars.com/forums/fuel-injection-s30/51601-hellfire-status-release-date-annouced.html#post452357). If we collect enough information, maybe a common solution (or non-cause) will appear. So far, headers and a straight fuel rail seem to be common to one engine that does not have the problem. If you have the hot-start issue, or if you don't, and have the time, please report here what you're running on your 280Z/ZX EFI system engine. For the sake of the passengers in these embarrassing situations, please. 1. Me - 1976 280Z, stock EFI system, stock fuel rail, 1978 stock injectors, 1978 stock exhaust manifold and 1976 intake with heat shields intact. Consistent hot-start issues if the cooling fan (my own modification) is not turned on

I've wondered if the heat isn't coming from the bulk of the exhaust manifold. I also bought some used headers to experiment with but they need work. A survey of behavior with headers and EFI versus stock manifolds and EFI might tell something. We're filling superlen's announcement thread with hot-start discussion.

Yes it squirts when the starter circuit is hot. The injectors also squirt a little extra, supposedly. It's shown at page 10 of the Engine Fuel chapter in the FSM. 3) "Start" enrichment.

Actually, I've also primed "forever". Until the bubbles in the tank stopped plus more. No effect. I've also rigged up a perforated tube and a fan to blow air directly on the injectors. Which works for me. That's why I think that it's the injector's getting hot that is the problem. What exactly happens when they get hot is unclear. It could be electrical; the solenoid gets weak when it gets hot, or mechanical; something expands or warps and the solenoid can't move it, or physical (like physics); gasoline flashing to vapor before it can get through the orifice. Somebody check my punctuation, I've never used that many semicolons at one time. Not an English Major.

You might have had two problems going on - the original plug-fouling and "copious amounts of smog", and now the more normal hot-start issue. The hot start issue doesn't usually produce the haze. It's one of the first things I noticed about the situation since I've had many old cars that used to flood occasionally. With hot-start the car runs like it's flooded or flooding but there's no copious gassy haze. With all of the work you did you should just reset and see what the current state of affairs is. The CSV is run by the Thermotime switch. The "thermo" part describes the bimetal strip that opens the contact when it's hot. There's also a heater wrapped around the bimetal strip to make it open after a certain amount of "time" with current running through it. So the engine doesn't flood when trying to get it started. It only gets current when the starter is turning. Kind of ingenious.

Your problem sounds more like leaking injectors. They do that when they get old. The typical hot start scenario is not a starting issue but a rough-running problem after it starts. The engine starts right up but runs really rough. Fouled plugs and no-starts are typical of too much fuel getting in to the cylinders. You might just need new injectors. Fingering the AFM at idle tells you what the engine wants at idle. There's an adjustment screw on the AFM for idle air adjustments. Adjusting the spring changes fuel enrichment over the whole air flow range.

I get the feeling that you're not a motor-head. Does the engine turn over? Is the electrical system intact (do the headlights work)? You haven't given any info on what you've tried so far, to diagnose the problem.

I only added the "smart" part to give some sense of how it's not as simple as it seems. I hope you come up with something. One way to add fuel everywhere would be the cold start injector. Then it would be a hot start injector instead. Dual function.

Just an observation - the AFM pictured in UFL's Post#6 is A31 624 000. EuroDat added a picture of an A31 625 000 in Post #12.

Something to think about on the hot start issue - it might not be that all of the injectors run lean, it might just be a one or two. I have the potentimoeter on my coolant temp. circuit installed for this specific reason and I can not get the engine to run smoothly by adding more fuel. If the coolant sensor was just overheated, the pot. should work. It seems more like a few injectors just refuse to behave. Not to destroy anyone's dreams. I've found some more modern style injectors that might offer a clue. I'm building a fuel rail so that I can install them and do some experiments. But many smart people have tried to solve this problem and none have solved it simply. Most solutions revolve around removing heat from the engine bay, or running a colder engine. Running at a higher fuel pressure would be worth a look,which you can do with the HF. It could be one reason the automakers went to 45 psi or higher. Views tend to be that they did it for emissions, but you can get a super fine mist of fuel with 36 psi, so that doesn't fully fit.

I was going to reply but I have EFI and you're running a carb fuel system. 5/16" (8mm) is right for the EFI system also.

The standard timing setting for the 1975 engine, warm, was 7 degrees. Many people bump it up for a little better overall engine performance but it should still run fine at 7. There's the ignition module possibility. They tend to show signs of failure at high RPM. Could just be coincidental that it happened near the time you adjusted the valves. You probably went out and ran up the RPM to see how things were working and might have pushed it over the edge. Usually the tachometer gets goofy also when the module goes bad though. The modules tend to fix themselves when they cool down, then go bad again when they get warm. Makes them hard to diagnose.

7-12 miles might be something has come loose. Kind of sounds like a vaccum leak, with the high idle, the backfire and the lack of power at high RPM (fuel mix off). Maybe check all potential leak spots, like the PCV hose from the valve cover, and the valve cover gasket, etc. Check for hose splits also, the old hoses get brittle.

How soon after the valve adjustment did the problem happen? If it was immediate, then it was probably something you moved when you took the valve cover off, or you didn't get the adjustment right. As for the throttle hang, that doesn't sound like BCDD if it goes away with a tap on the throttle. More like you got a plug wire stuck in the linkage, or broke the return spring, or something. Next time it hangs, leave it idling high, open the hood and see what's stuck. You've kind of taken a shotgun approach to possible causes, with BCDD and timing. If it ran good before, then a before and after focus might be better. Look at what you touched during the valve adjustment process.

Might be stuck on the dowels, or even paint on the dust shield, or paint on the dowels. Maybe spray some PB Blaster or Liquid Wrench in the holes and around the interface. If there's any gap opening up at all anywhere you could stick a plastic wedge in it, or piece of wood (something soft), to get the leverage to work on the other areas. You might have to move it a fraction of a mm at a time. If you're handy you might also be able to work up a pulling device, from a gear-puller, to stick in a bolt hole and pull on the edge of the transmission. But that might also break the housing, so it's risky. A dead-blow hammer has a similar risk. A sledge tapping a piece of wood might shock it free. Same breakage risk, don't hit too hard.

If you're really lucky, your cam survived and you can just fix the spray bar, or get another one. If you need to change cams, and get a used one, get the rocker arms also, and keep each rocker arm with the cam lobe that it was riding on. The cams are notorious for destroying themselves if things aren't just right after they're been moved around. Sometimes they still self-destruct.