AWAUDIO

@barts I wish I had one of those! As the tank drained dry without any debris, I'm going to try blowing out the lines @siteunseen I'm waiting for the Amazon gauge with 3/8" "T" fitting and using hose clamps. My best friend lost his Z when a fuel line ruptured onto his exhaust manifold, and damn if that engine didn't keep running, pumping gas, until it was a total fireball @madkaw As a matter of fact, I do have a spare. And it's easy. I thought I had this pegged as a fuel issue, but pending fuel line cleaning, the possibility of a collapsing coil was at the back of my mind, especially when it occurred under "hot sink" conditions. By sending unit, do you mean fuel pump? Standard clear fuel filter was changed twice (does only fill 2/3 full…..???) if there is another sending unit, let me know. FSM just shows a million vent hoses, main fuel outlet fitting, and fuel float assembly. Thanks again for bearing with me. Was good to see clean fuel. I had thought about running the engine from a 5 gallon can, by passing the fuel lines & tank and going first into the filter and then around it direct to fuel pump. But I really want to avoid running the engine where there is a possibly of major FUBAR. If I can make it safe, I may try that while waiting for my fuel pressure gauge. Here's one more thought, I just remembered I had a similar problem with my 1948 Plymouth years ago. Turned out to be my gas cap was vacuum sealing the tank, and removing the gas cap made it run perfectly. Replacing gas cap was the solution. I wonder? Thank you all again for bearing with me, Andy

From what I understand, you can disable your vacuum advance, and run it that way. It's also intermittent, which compounds the problem: runs perfectly for x amount of time, then loses its mind: lurches, bucks, will not accelerate, but will idle along ok. Will also rev and idle and look good in driveway w/o a load. On the road, either perfect or perfectly disgusting.

Ok sports fans, It's NOT the tank. My tank had fresh drain plug and washer. Looked like it had been dropped. Straps all clean and threads very clean. Drained the tank completely. Drained it and filtered gas thru 2 screens to check for any debris………there was none, zilch, nada. Refiltered it thru finer mesh before returning it to the tank…….nothing! That gas was so clean it looked like spring water (kinda). For future drainers, drain with gas cap on, it's slower, but lets you control the outflow so you can switch cans. So now I'm going to clean line between engine filter and rear flex hose to tank. I'm also going to check tank hose for cracks, as air leaks could be sabotaging me. Keep the comments coming. Andy PS Have fuel pressure gauge coming from Amazon. Do Not buy the Napa version, it's set up for vacumm, not 3/8" fuel lines.

For what it's worth, here are references to SAE white papers about ZDDP. http://papers.sae.org/2004-01-2986/ And this has a good reference to how much ZDDP to add. With math included: http://www.forabodiesonly.com/mopar/showthread.php?t=83428 Scroll down to "slantsixdan" for the meat of the math. Andy

Researched cleaning and dropping the tank. It appears some folks just pull plug and flush the tank in place. One person said they did it with a garden hose in the tank. Stuck it in thru fuel filler and pressure flushed. Kept flushing until no more debris came out. Not sure I want to use water, but if I let it dry out I don't think there would be a problem. Vent lines are all up higher. As long as I don't damage fuel float sending unit, and only fill it with a gallon or so of water, it looks like a good first try before dropping tank. Would not be offended if someone pointed out this is a bad idea…. Andy PS Yes, I know, no sparks or flame source anywhere near an empty tank. There are still enough fumes to easily ignite. And yes, disconnect the fuel outlet line at the tank to prevent water from getting in the lines.

@blue I'm going to check those filters as Bruce sent me a bunch of gaskets! Thanks, your posts are always spot on. Andy

@siteunseen THANKS I use the same 50/50 solution (I also have a Jeep I'm working on), so absolutely that is what I do before starting. BTW I've found for frozen bolts, if you heat them up, and squirt the solution on them hot, it will wick into the threads. Do it a couple of times and bingo…breaks free. Also, first thing I'm doing is the pressure test which should be at 3.41 lbs, and volume test, which should put out 3.71 quarts of fuel, at 1k idle in under a minute (per FSM). Then to the drain plug, cheap slosh and look for debris. FSM says there's a gas strainer in there. Thanks for the the tank reference. Andy PS are you on BAT?

Hi all, once again thanks for the thoughts and suggestions. As the problem is intermittent, points are new, coil voltages look ok, plugs look good (front 3 and back 3 the same) and it pulls like all get out when it runs, I'm going to try the tank and then filters screens on carbs. I think the fact it was bucking so bad last time, cleared the debris so I could get home. The first time it happened I replaced all the stuff mentioned above, it ran great. 2nd time it happened, I replaced points, rotor, condenser, ran great, then failed. So I'm hitting the tank first. I've looked at dropping it, any advice along those lines? I have both FSMs/Chiltons/and yet a 3rd manual, but pointers from those who "have been there, done that" are always appreciated. Thanks again for your time and suggestions. Andy

Ok then, as I'm confident of the electrical (new crimped connectors on resister, coil, dizzy), it's drain fuel tank time. And yes,, it runs perfectly with a full tank topped off, but clearing itself sure looks to point to debris moving around. BTW, great pic on the scale of the debris field. Can't get to it today, but will report back when I've tried that. Thanks for all your suggestions. Andy

Thanks for the responses. After it acted up the first time, I replaced all the items mentioned above: cap, rotor, points, condenser, wires, plugs, and fuel filter. It does idle perfectly when this happens, accelerates ok, but under load it's a no go. Didn't try to run with choke. Coil voltage: into resistor 14v, out of resister 10 volts, main to points 8 volts at idle. I didn't write these number down when I was looking at dwell/rpm/idle….but I think they're close. My meter has 8 scales on it's face and 4 different switch settings. Timing at 5 degrees BTDC, dwell @ 41 degrees. This is set per FSM for an engine with pollution paraphernalia. Deceleration devices plugged, no manifold leaks. The fuel tank, hmmmm I don't know if PO dropped the tank and cleaned it. Let me ask a foolish question, how would one meter fuel flow from the tank? Or would measuring it at the manifold after the fuel pump do the trick? I was leaning towards a failing coil, but fuel flow could do it. Another question, I'm going to pull out the FSM in a minute, but does anyone know off the top their heads what the fuel line pressure/volume be after the pump? Thanks Andy

1972 240Z all stock with a full engine rebuild 4 years ago. I'm about to go crazy on this one. Replaced points/plugs/condenser, have rebuilt carbs/new fuel filter (twice), new plug wires. Plugs burning perfectly across all cylinders. Checked wiring from coil to dizzy, recrimped connections. Cleaned all coil contacts. Here's what happens. Some days it will start up perfectly, pull great, I drive it for an hour on back roads. It's perfect, pulls hard and fast. Idles great. The world is good. Park it for an hour, start it up and it's like the engine has lost its mind. Won't accelerate, bucks, bounces, and just will not run. I can barely limp home. Swear at it, cover it up and attack it the next day. Double check point gap, timing, etc. Everything is perfect. Start it up and it's good. Nothing wrong. Drive it, can find nothing wrong. I'm thinking this is a "hot sink" problem…….until one morning after a cold start it did the same thing. Just wouldn't go. Really pissed me off, so I drove it humping and bucking for 20 minutes. Stopped, pulled cap/rotor checked gap, put it back together and YES voila…. she pulls perfectly again. I can't jiggle any wires to make it happen. And finally today, after the usual great run for an hour, stop, start up, soon complete bucking and bouncing starts, I nurse it towards home. Within 2 blocks of home she's running perfectly again. So it happens under both "hot sink" and "cold start" conditions, and now between those extremes. Any thoughts? Coil? Fuel pump? It's driving me nuts. Totally intermittent. Sigh AW

I did a lot of research on the ZDDP question after my engine was rebuilt. From what I gathered from a white paper on oil additives was that 4 oz of Redline ZDDP (not a whole bottle) added at an oil change, provided the necessary chemicals to enrich your oil to 1972 SAE standards. I use it with Valvoline racing oil (NorCal-no low temp issues). Usual disclaimers about it trashing cats, etc. etc. But fine in my Z. AW

Was curious if yours was malfunctioning? Mine is………1972 240Z all restored, stock. It is keeping my idle high at various times for no reason I can easily figure out. Not a constant problem, but becoming one. AW

Hello All, Posting to see if anyone here has a source for a front right bumper guard for a 1972 240Z, or perhaps a spare they would like to sell. My front guard was bent up by a "touch tone" parker and MSA etal seem to be out of them. Mine is pretty deformed but I'm going to try and salvage it (don't have high hopes). Bumper is ok (as bracket is right behind it and it kept its shape. Any help or leads would be appreciated. Thank you. Andy awaudio@yahoo.com

Thanks to all who responded to my inquiry! I hadn't consider the flying projectile aspect - thank you Mike. Drive safely, may we never need to use an extinguisher, all the best, Andy

Just wondering if anyone has found a fire extinguisher they like, which will actually extinguish a fire, and is easy to mount for 240Z cars? Also, where do most of you mount yours? Have decided it's time to add one after reading about another Z which succumbed to an engine fire. Thanks, Andy

Has a similar problem on my 1972 240Z. Turned out to be a bad connection between the coil secondary and the condenser/points at the distributor. Redoing the spade connector and tightening screw solved that one. Good Luck. Andy

Just another thought, remember to replace the small hose (about 2" long as I recall) that attaches to the heater core. I think they refer to it as a transfer hose (MSA catalog). It's also easier to do if you loosen the blower motor or remove it if you can. The front bolt on the blower is up against the rear of the glove box, so good luck with that (w/o removing glove box). Patience and a fair amount of contortion will get you thru it. I'd also replace the firewall grommets and go to standard hose clamps. Easier to deal with in tight spaces. Good luck. AW

Hi All, Thanks for the courteous responses. My 1972 has no electric pump. All lines from tank to engine have been redone. Even with a cleaned tank, I still have to replace filter at least once a year. The filter slowly fills with crud...from where I don't know. So I replace it. This is my 2nd clear filter. I can change it before it gets too bad, which is a good thing. Just noticed today, after a long hard drive, that the fuel level was closer to the top. So it could be a non issue. Am still curious if it's air in the system, or unpurged air from the change. Seems that the fuel pump should evacuate all the air. Another mystery. Thanks again for responding. Andy

Just replaced my side walled mounted solid white fuel filter with a clear one. The fuel level in the filter is only about half way up. Car runs fine, starts easily, accelerates ok (no popping in the exhaust-knock on wood). Is this normal? With the original solid filter one doesn't know what the level is. New rubber feed/return lines from tank to solid fuel lines. Solid connections on filter hoses with screw clamps. No cracks or leaks from filter to pump. Just an air gap in filter itself. Any thoughts? Andy

Just a thought, something I don't seem to have seen anyone reference here. Ran across a Datsun TS73-10 which indicated on the !972 240Z with manual transmission, float bowl HJG46-R8B, that the front and rear carbs have different float bowl heights. Front carb 15.5 to 16.5 mm, Rear carb at 11.5 to 12.5 mm. Just throwing it out there FWIW. You seem to have tried everything else. Good luck on your odyssey. Andy W.

For all you 1600 fans, the Lucha Libre Racing, La Carrera Panamericana 1967 Datsun 1600 Roadster is available on BAT http://bringatrailer.com/2012/02/02/bat-exclusive-la-carrera-panamericana-veteran-1967-datsun-1600-roadster/ No personal connection, just an FYI for all of us Datsun lovers. Thanks, Andy

Two good suggestions! I've seen folks working at car washes use some pretty nasty stuff out of bottles with "Danger" warnings all over it. Didn't ever want that stuff near me or the car. Thanks. Andy

Well, here's one for group. Finally got my new suspension and tires on my 1972 240Z, and after "spirited" but safe driving, have tire rubber bits and dust coating the sides of the car and lower panels. Was looking for the easiest and least harmful way to remove the melted residue without scrubbing off the paint. Heard WD40 works, but was looking for the least destructive way to remove residue after driving. I'm sure guys that track their cars have a way of dealing with this, as their cars always look great. Thanks, Andy

On my 1972 240Z, I installed the Tokico shocks with the Tokico linear 280 springs (cut to length per BetaMotorsports), had spring compression checked at a spring shop, installed without bump stops, drives and handles like a charm. May take additional 1/4 turn out of front springs to lower profile, but she's fine as is. Hope this helps Andy