zKars

The A11-600 000 ECM works from all 75-78 North American 280's. If that maximum ecu is working for you, relax. Drive it and forget it. It's tune is for a smaller engine, so your mixtures might not be "correct" but if your plugs look okay (brown, not white or black), your mileage is reasonable, and you've had it working fine for a couple of years, be happy. If you really want a A11-600 000, let me know. Some say I'm cheap, I call it affordable.

Wow that's hard to believe! Its scored all the way around! Its not clear just how close the chain must be to the cover until you see something like this. Does this mean it was loose enough to be "floating" off the teeth enough to be rubbing the cover over that much of its circumference? Hard to imagine how this looks running, but there's the proof. I haven't really looked under the cover of mine, other than to note how black and grundgy is looks.... I'll report back.

I agree. Chain tooth jumping was just a dirty rumor for me as well until now. Though it seems to take quite a combination of a loose chain and some "help" apparently. Thanks for the additional support to the "it ain't ALL my fault" threory as well....

Hi everybody! It's me, the "I can't believe I did that" guy..... :stupid: Well, believe it or not, I have another "learning experience" to share. So grab a coffee and get comfy. Working on a new friend's 78z over the last few days, trying to get it ready for an "out of province inspection". Your Canucks will know what I mean. When moving a car to new province, everything has to work, and no rust holes or no insurance. Quite a challenge for most Z's, this one is no different. While doing a million other things, we decided to investigate a small engine "rattle" that happens under any amount of power "on" application. Not good. Bad bearing, slap happy piston, loose valve train? Let’s find out. Started with a valve lash check and setting. Off comes the valve cover. Well, it came off but the gasket didn't so much, had to be scrapped off. Then there was some RTV stuff left over that was doing a great job of gasket sealing to peel off, and we all know how you don't want those little tendrils of that crap getting in the oil, so while I was peeling and digging it off, I stuffed a standard blue shop rag sheet in front of the timing gear to prevent RTV bits from going down there, cuz most of the RTV was on the front part. Finished the clean up and proceeded to start checking valve clearances. Right away I notice that #1 rocker is super loose. Have to jack up the adjuster about 6 feet (slight exaggeration) to get .010 clearance. Yeah, because the valve is stuck partly open, the spring pack is about 0.10 lower than its mate next to it. I can push it down and it pops back easy enough, but right to a nice stuck position. Alright, there’s the rattle source. Stuck/bent exhaust valve. Proceed to start spinning the engine with my remote start button and checking a few more looking for loosy gooseys . Just about then, the car's owner who's working with me tells me to hold it, that blue rag is caught up in the timing chain/gear. Sure enough, I'de left that thing down in the timing cover and it got dragged up and is now nicely distributed over the cam gear between it and the chain. We're talking a thin synthetic blue towellete here, we just grab its bits and spin the engine and get it clear. Its shredding into bits and pieces its so thin and weak. No biggy right? Read on.... Finish setting the valves, which are all somewhere from spec to spec x 3 too wide, slap the cover back on with a new gasket and try to start the car. It cracks but we're getting no fire. Nothing. Ok, what did we do? First I had just yanked the plug wires off, didn't check what order they were in, they were just zip tied together, not in nice ordered clips, so who knows how the PO had left the timing or drive spindle. Could be anywhere. So set the engine to TDC and the dizzy is pointing to one, so just put them back on again in stock order and position. Still no go. Check spark, good, all cylinders. Check each injector with noid light. Flashing. Check fuel pressure. Good. oh oh...... What the hell have I done. Swap ECM's. Nope, same. Threw timing light on #1 and check while cranking. Yup, right at 15' ish, good enough. Hmmmm, spark, fuel, timing, what else do you need? Compression???? Pull the plugs and stick the comp gauge on #1. I know its going to be 0 with that bent valve. Sure enough. Then I check #2. Its 0 as well..... ?????? And 3..... and 4 ...... oh no...... and 5, and 6, all = 0.000000000 How is this possible? To make a long story short, hour and half later, heads on the bench, all 6 exhaust valves are bent. Yup, all six. Nice nick in each piston, nice shiny spot on each valve face. The timing chain slipped on the cam gear by about 5-6 teeth when that thin, feather weight, POS blue paper towel got in between there, causing a not too surprising detrimental effect on piston/valve clearance. When you think about the force required to stretch the chain to make that happen, I initially dismissed it as impossible. No way that piece of fluff did anything bad. Yeah, right. What I hadn't considered was the incredibly loose stretched timing chain on this old well worn L28..... I can *almost* slip a tooth by hand it's so loose with no tensioner pressure. Just took a little old piece of near-nothing to bunch up "just so" and make it happen. I'll bet you couldn't do that again if you tried on purpose all night long. I had actually noticed that the cam seemed out of time earlier but didn't catch on. When I was setting TDC to check timing and dizzy alignment after it didn't start, I was peering in the oil filler hole for #1 bunny ears, and noticed that the centerline of them wasn't at 12:00 at crank TDC, more like 10:00.... So all you engine tinkerer's out there, beware! Even the slightest mis-step can lead to disaster without you even knowing you done it... Runs, set the valve, doesn't run. How do you get that wrong? Of course now I’m thinking about that initial stuck valve that I found before the engine turned with the rag in it. Just how did that happen? Maybe the chain had already slipped a couple of teeth before I got there due to that crazy loose chain, just enough to take out that one valve, and my rag trick just finished off the other 5 by slipping it a couple more. Let’s just say that’s true and not ALL my fault.. Yeah, that feels better. A little…. Well It’s a good thing I have all them old heads in the shed..... Eenie meenie minie moh...

Smooth beveled end (37 deg) is -4 AN fitting. Look in the hose and see its mating surface. The seal occurs where the male bevel meets the femal metal, not on the threads, hence teflon tape on those threads does nothing. The NPT threads rely on the tape to seal as the threads interference fit when tightened just right. Google -4 AN Fittings in Google images to see many many examples. Check out http://www.anplumbing.com as well to see what's available.

Jordan: You're doing a pretty good job so far but there is more to do. You won't see much of a signal with a volt meter at that junction box. Its not a 12v on or off signal there, its a very low voltage waveform from the magnetic pickup in the distributor. I'de just pull the coil to dizzy spark plug wire from the center of the dizzy cap and put it near a ground (1/4 in) and crank to see if you have spark or not. Does the car die instantly (ignition loss) or does it run worse and worse and finally die (running out of fuel, though happens quick with an FI car). You can check for +12 at the coil + terminal when running, and not there when you're in the "dead" condition with the key "On". This will tell you if power supply from the key switch is staying on or not. There are five components in your system that might be heat failure related. In order of likely hood they are : -Bad dirty/hot connections that work when cool, but lose connection when heated. Clean every connection to the coil, ballast resistor, dizzy and ign module. -Ignition Coil internal failure. Needs replacing. -Transistor ignition module. passenger side kick panel up above right foot on the right side. Not in the engine bay, so less likely to heat affected as much. -ECM module that runs the Fuel injection. By drivers left foot on the side. It controls the fuel though, not the spark. If you are losing spark, its likely not this. -Distributor pickup coil. There's some leads, now go out and start methodical testing.

I love a good mystery. When you say the starter engages, does it crank continuously when you put the key to the lock position, and does it everytime? Does it stay cranking when you pull the key out? Do you have to go all the way to lock before this occurs Pull the switch off the back again, and with the key in the cylinder, grab the little retangular tab in the back that goes into the switch with your fingers and work the key from Lock to Start. Does the tab move in perfect sync? With the switch in your hand, but hooked up to the wiring, use a flat blade and pretend you're the key. Does it work normally in all positions? No hanky panky when in the Lock position? THe only electrical "connection" between the lock position and wiring harness is the two (black) wires on the side of the lock with male spade connectors that work thewarning buzzer with the key in. You didn't hook them up to something you shouldn't have did you? Are they pinched in the mounting of the lock somehow? There's some ideas to mull over. and its not Winterpeg now, its mosquitopeg....

Setting up to be a battle royal. Supporters from both camps are already trash talking. Trying to think of the most appropriate movie parody where an old timer comes back to thrash the young current champion. Must be 100 likely candidates. I am also keenly aware that the John/Greg battle is real life... Just gonna live the dream along with everyone else. SCCA runoffs at Road America Elkhart lake Wisconsin. Sept 20-22. 2013. Nice two day drive from here. Hope to be there, God and wife willing! PS : John will indeed need his vintage hair and those dark thick rimmed glasses he wore in the Datsun commercial. Gotta make sure I bring some.

Charlie, Float levels are key, then make sure the front choke is not still "on" compared to the rear. The cable choke mechanism pulls the jet tube down, effectively moving the needle farther up richening the mix. If the front jet tube that gets pulled down is gummed up on the outside and dirty, or the cable mechanism is not adjusted right, then the front tube may be partially left down even though the chokes are "off". Use the chokes and look and see if the tubes are both drawn down equally and return to be fully up when the choke level is all the way to "off". Take off the air cleaner and backing plate if you haven't already to clearly see what's going on. If the jet tubes are both all the way up, then re-set your mixture on both carbs to be the same at least as a starting point. Turn them all the way in (CW looking from the bottom) then out 2 1/2 turns. ztherapy.com sells a wonderful and much respected DVD on the topic of tuning and re-building SU's. There are also many many posts on this forum on the topic.

Ideas: -Losing coolant? But not to the overflow? Do a leak down test for sure. Is one cylinder disposing of the coolant due to a HG failure and causing the mis-fire? Plugs might be a clue if one looks different than the rest. -Bad hoses, ie collapsed lower hose on the suction side. -Front cover damage in the impeller area causing poor pump performance. Check for chips and cavitation caused pock marks in the impeller housing area. -If using a thermostat, take it out and see if problem changes/improves.

I think this is a great idea. I'm contributing to the cause for sure. And not just for the T-shirt....

What Steve says.... Safety is in YOUR hands with these cars.

Plywood spoiler and lawn edging? Now we're breaking the inventiveness barrier wide open! What's next? And are you really running with no rear hatch glass? Or is it just super clean? Can't imagine that's good for aero...

What a great experience. Congrats on what you accomplished. Nice trouble shooting too!. Isn't that interesting about the fuel rail. Turns in a restriction or fuel boiling receptical it seems. Well well well... Do only one thing, that is replace just the return line and see if its still fixed. I wonder if you have a slightly weak fuel supply volume and a return hard line that maybe didn't have the restrictor orfice and something and you were dumping too much fuel back to the tank. I love these mysterys that turn out to be something you wouldn't guess.....

I suppose I'm in trouble for using one as a welcome mat...

Just trying to be fair persimmon. We have the makings for a reality show FULL of whacky Z people around here.

Great to hear Bad Dog is getting some well deserved exposer. Don't mind Stacey's show, its a bit of an obvious vendor advertizing platter though. Those two idiots on NPR are a riot to listen too. Caught them by accident one day on a weekend roadtrip and just about lost it in traffic laughing at them. Maybe we should start our own YouTube channel advertising our own amazing Z parts vendors. Everyone send me samples of your products for free and I'll talk them up every Sunday morning while I install them on my car. Deal? You tool vendors, send me free tool boxes, welders, metal working machines, etc and I'll have them in the back ground during the taping, just like Stacey! Oh, and I'll need a wacky side kick too. Auditions start Saturday when I get back.

Back from a day of "fun in the sun" as they say... I'm done, take me out of the oven... I've reviewed the day's progress. Glad the float level whie running is now correct. You mentioned your fuel pressure is 7 psi? That's too high! You are lucky the needle valve holds that, the things are designed for 3-4 I'm pretty sure. They may be sporatically letting too much in. Need a reg to control that. It's not about pressure, its about having enough volume to keep the bowls full when the needles do open. The 2 feet of hose trick is cool. Coil it up in a tight little pack to keep it out of the way. Hey submerge it in a can of cool water or ice prior to the race to get cold dense fuel.

The raise the piston test is a very subtle effect. If it bogs totally, its too lean. Richen it up a tad. Don't know much about MG carbs... The knob on the bottom is the only spot for our SU's. Sorry I'm out of touch for the rest of the day. Play!

Don't play with the mix knobs to compensate. Mix adjusts AFR, not the supply volume. The running condition doesn't care about the static level. Low level means less in reserve when you need it during high demand periods, that's all. Do what you can to get the dynamic running fuel bowl levels close first. T into that bottom little hose with a vacuum T, zip tie the clear hose to the side of the bowl, leave it there!

We are forgetting a couple of simple things. Check the level with the car running, ie fuel coming in and going out in the balanced dynamic state. This means having a site tube either in the drain (if there) or T'ed into the hose. Static settings of the float with the methods you're using are a good starting point but may not reflect the real time operating condition. You can also take the bowl vent hose off and stick a Q-tip (no fuzz on the end in the bowl) in the nipple to probe the float to see a, if its free to bounce and staying steady when running, and b, what the level is, of the float, not the fuel level. Compare front to rear at the very least. A standard Q-tip (if there is such a thing) will have about 3mm of clean stick showing below the top fuzzy part with it touching the float top. When the engine is running, the fuel is constantly flowing out of the jet tube as long as the venturi pressure is less than the pressure in the bowl above the fuel, the static fuel level is no longer "important". This only has a minor minor effect of the extra pressure drop in the venturi that has to overcome that extra 5mm of fuel rise in the jet tube during run-time. If your running level is 5mm low in the float bowl, then Blue's ideas of increasing the storage capacity in the bowls will compensate well. Like most things, you can't really tell how the car will run until you do that long full throttle pull and see if the float bowl stays full.

Gotta ask two questions. Are you measuring the float height with the car running? How are you measuring it? Changing pressure will not affect fuel levels, until its high enough to overcome the valve, or so paltry low that its barely there. Both carbs behaving the same way? Only thing in common is the fuel supply. wish I was home to send you some carbs....

Great suggestion Darrel, all time savers. I'm even brave (stupid?) enough to remove the gasket entirely until the level is right. If the level is below the lid, you're not going to get any leaks. Even if you did they'de be minute. When done, put it back in. Remember you'll be moving your fuel level up by that extra 1/2 mm of gasket thickness when the gasket goes back.

Another stoke of brilliance. An example of "thinking out of the float bowl"? Sorry... I dream of a floatless SU fuel supply. Maybe someday... Ive had a couple of experiences with sticky float valves too. Also the back one. Others near me as well... More heat back there?

The separation Darrel speaketh of is between the outer metal shell, and the rubber. Look at the bottom, and check for separation around the circumference. Some, a little bit is normal from age. If you can probe into one of the gaps and make it worse easily, that's too much. The only true test is to put it all together and jack up the car, and let the struts and wheels dangle, so that weight of them is pulling directly on the insulators and that bond. 24 hours with no change in the separation and they are likely just hunky dorey. Wheels on the ground in the morning is bad news... This is the closest thing to stock replacements. Motorsport! Street Camber Kit, Front, 70-78 240Z-260Z-280Z - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts