72' 240

Nuteman, Tell me if this NAILS IT!!! I have one solid rolling 240 (when the engine is running...and that's my problem). I went through SEVERAL angles with my shaking wheel. It would seem to vary only slightly. It occurred at the speeds that all of you have mentioned. I tried everything that I've seen listed so far with great frustration. It was always still there no matter what I tried! It got so annoying that I just did not enjoy driving the car that much. I got stuck in it one day for quite a long drive (25+ miles). When I got out, the front right (It could be either or both) caliper seemed a bit too hot for the amount of breaking that I had done. I then KNEW it was BRAKE RELATED! As you know, your pads NEVER lose "slight contact" with the rotors as the car is driven. They are designed that way. The problem occurs when the "slight contact" is too great; it developes heat; enough heat to warp and swell-up the rotor, and even overheat (believe it or not)the whole caliper set. Mine ruinedtwo caliper sets before I found the cause. This higher than normal heat closes the tolerances, and exaserbates the problem. It starts a chain reaction eventually resulting in a warped rotor that encounters the pads at every revolution ("high spots") causing a slight drag that is transfered to the steering wheel as a shake! Many times my wheel felt fine until I built-up sufficient heat to close the tolerances, which began a GRABBING that felt JUST LIKE a severe balancing or other front-end problem. This does not get better as you apply your brakes or bump the pedal, etc. The fact may be that the car is performing perfectly...what I mean is that IT IS DOING EXACTLY WHAT IT IS SETUP TO DO! Follow me here- The 240 and some later models have not 1 but two (2) BRAKE BOOSTER ADJUSTMENTS!!! Many of you may already know about this. There is the one that All of us are aware of at the pedal, and shaft... but there is also one (hidden) between the brake booster and the Master cylinder! Carefully remove the master cylinder, and notice that the "plunger" coming out of the booster HAS WRENCH FLATS ON IT! Be careful not to let the plunger fall, or get pulled out of the booster. This can become a MLSB ("Major League Set-Back"). If you simply and carefully screw the tip of the "plunger" in only a 1/2 - to 1 turn to start with, (thus shortening the plunger) you will in effect cause the "resting" position of the booster to be looser. This will release your braking system (at rest)! You probably will not notice any difference in the throw length or feel at the pedal when braking. JUST NO MORE SHAKE!!!! Nuteman, I sincerely hope that this has helped you and a few others. It was a "life changing experience" for me. Now please, if anyone can help me with my "Idles, but sputters at slight throttle-up" problem listed on this site, I will be forever indebted to you...

Presuming that you are hearing the injectors clicking just before shut-off, my thoughts lean towards air flow sensor. My son and I rebuilt a 78' and once we were half way between Birmingham, and Nashville in 35 degree temp and stalled out after we filled-up with fuel. Later he told me that he had inadvertantly jared the sensor lug (at the front drivers side area of the engine compartment) as he was tinkering around looking for "the" problem that stalled us out. It would start after cool down, run 20-60 seconds(badly), then stall again. We replaced 4 fuel injectors, and 2 cans of "Heat" trying to remove the condensate that we were sure was contaminating our fuel. Anyway, just a thought. sometimes that lug gets corroded, and resistance builds-up.

Don't give-up "guys", I'm still not rollin....

Thanks Brian for the thoughts. To answer the question, it starts like I'm flipping a switch; (right up). Then refuses to throttle-up; even after warm-up. I'm bumfuzzelled.

Well, add the fact that my alternator checks out at 15volts(+), and the problem still remains. I wish I had better news, but the alternator was not the culprit either. Hmmm, two carbs failing at the same time doesn't seem likely. I guess at this time, all I can do is ease-up on the float levels a bit, and see if I'm just starving the thing. Any more ideas out there? As AxtellZ said, "we'll fix it if we stay at it. Don't feel bad; I've been bugging a friend here in Birmingham half to death with this, and he has few new ideas. The difference is that he is known all over the city as "The Car Doctor", and used to be heavily involved in NASCAR many years ago. He has a repair center close by. Some may ask why I don't just leave it with him... Well, at this point I feel alot like I should, it's just that driving it over at "idle speed" would be a bit tricky. The bigger reason is that I will be admitting that I can't work through it myself. Ugh! Sorry that I couldn't report that I drove the thing today. It was a great day outside in Birmingham today; sunny, and 70. (Sorry Jeremiah!) 72 240 At Large (with no wheels!)

Thanks folks for all the suggestions. Jerimiah, man thanks for the tip on contacting Bruce. "Beandip"... Dotto. I've grown optimistic at the thoughts of running a few tests on it in the morning (Sat.). Beandip, 10 deg. is about right, and I've run NGKs aswell. The carb cleaner is a great suggestion. It will be easy enough- thanks curtis. I've got a bit of that around the shop; I'll try that. I just feel real optimistic about the alt. I have a "new" one in a box in the shop, so I'll slap that on at some point as well. Sorry for all the excitement, but it is amazing how stressed it makes me knowing that for every day that car sits, the problem gets no closer to being solved. I am sure many of you have felt that way before. A small yet ever present reminder that something "just ain't rite" as some of my fellow southerners might say. My wife and family are patiently and (somewhat) silently waiting for this to end as well, so thanks for the help... We are making great progress I think! Thanks again- Frank

Jerimiah, Thanks again for putting your thoughts to the problem. By the way, what a great Family/Z photo. Atleast you have your priorities in order. I believe that the car was on your right side... Now Back to MY woes. First, the "default" setting I spoke of was taken from Clymers "Datsun 240-280z & zx". "1970-1979 Shop Manuel"; "A152 Clymer Publications" Page 98; bottom right side of page. Jerimiah, they give a pretty sharp diagram "Figure 16" on Page 99. It really seemed helpful, as they describe the proper position of the nozzle to be 2.2mm or 0.087 in below the "Jet Bridge". That seems to be the starting point from which they feel that proper mixture is reached. I still seem to blacken my plugs a bit, so I don't know. Ah yes, I almost forgot... I LOST my copy of "Just SUs"--- wow. Keep thinking! I need the help! Thanks, Frank

Thanks Jayru, I have had probs in the past also with alts. As you know 50 AMPS is just not enough. As a result, I have been running a "successful" zx internet upgrade. I have been exceptionally pleased with the upgrade, but through all this time of testing, I may have Asked too much of it. I'll look that direction for a while. I'll pull it, and run it down to the shop and have it tested.

Jerimiah, thanks for your thoughts. Yes the carbs were "adjusted" by me (I know what you're thinking). I have a vacuum air flow meter, so that is easy enough. But the mixture, that's another issue all together. I restored "default" settings regarding the Jet height within the venturi. The front jet is, despite quite a bit of work and lubrication, a little hesitant to pop right back up as the choke is released. I do believe that the mixture is still a bit on the rich side. Having been around grossly rich running cars, I've noted that they are usually running, they smell bad, and exhaust black, but though poorly, they usually do run don't they?...? I wonder about firing order, but I,ve checked that until I can't see straight anymore. It is such a helpless feeling to see this car go from a vehicle I thought nothing of driving on a 1000 mile round trip to the N.C. Mountains, to this useless state. The floats float, well they seem o.k., and undamaged or "gas logged". They may not be allowing enough fuel into the bowels(scratch that) ...bowls to allow throttle-up, only idle. It is very hard to check them out. I have mounted the bowl caps on glass jars and checked the needle/seat operation, But measuring fuel left in a bowl after fighting off one of those caps while taking into account that there will be a certain amount of fuel clinging to the float as you remove it as well... Oh well.

The problem first manifested after it sat for about 3 weeks. I took it to dinner one evening and it uncharacteristically stalled at a light. After dinner, it stalled again, but was very hard to start back up. I later probably fixed this problem when I was chasing the follow-up problems when I replaced the condenser. At this point It will start like I am switching on a light. It will also idle ( Fairly smoothly at that). It will not even consider a slight throttle-up. It chokes very quickly as if to stop, but as I return the Throttle to idle. I idles smoothly again. I cannot even idle-up at the set screw. It's crazy. Below is a list of the actions that I have already taken, and parts that I have thrown at this issue. Thank you for your help. *New Mallory Distributor (ran 6 months well with this same Dist.); I have even replaced the stock distributor with no change in situation. *"Running" a sweet New L28 From Motorsport in a clean 72' with stock SUs (Cleaned and polished, new gaskets needle/seats etc. *New coil *New Points( Set at Approx. 22 thou.) *New Cap *New Condenser *New plugs *New Rotor Button *New Cap-to-Dist. Wire *New Fuel Filter *New Fuel Pump *New rubber lines, even at the bowels (Also from Motorsport ($$$ wow!) *New external Resistor (The coil is set-up for the external- wiring was easier) I've: -Drained the Tank -Run a bypass line to the engine from a large tank of high Octane -Checked fuel flow to carbs -Blown all lines out, even to the tank -Cleaned the windshield -Removed both carbs and cleaned thoroughly -Called Motorsport Tech folks (O.K.) -Called "Pierre Z" in Calif. (suggested that I lower point gap to... 16 thou!) (Ruined a new set of points, didn't help the condensor any either) (Mallory tech got me back to 22 thou.) -Removed the exhaust at Manofold joint to make sure that the air flow/exhaust was not impared.-Not Helpful either...Just noisy! -Obviously I've kept an eye on the dempner oil. I am leaning towards fuel levels in the bowels... I feel like I've leaned about every way possible... WoW! I will take any and all suggestions. Thanks guys.... & gals (my daughter is sitting beside me and she also likes our z's).

Tom, One thing that you probably have already noted is that all these plastic gears are not the same color. For instance, you may have removed a red one and received a yellow one from the dealer. These differ in the degree of "cut" angle and or tooth size. That is to ensure that the speed reading that is picked-up at the tranny is accurate as there were several trannys produced in 4 and 5 speed. I am not exactly sure which color is compatible with yours, but this may be contributing to the failure. Also older cables either from salvage yards or even still lying around these dealerships (God bless them all) may have gotten waxy or stiff, and the gear simply spins the teeth off. Hope that's helpful- 72' 240