Hey guys
Would love some ideas on this situation. Im playing the situation around in my mind trying to find a logical explanation but would like to see what everyone else thinks about it.
Heres the sitch:
A12 runs totally normal, drive it for a while and everything is fine. Then, randomly, not at any particular situation, it dies. It stops firing, or should i say stops for the most part firing. I can keep it running by engaging clutch and vareying the accel pedal. then pull over and sit for a bit. Check the float bowl and its level. Checked plug connection etc. Continue to drive and it drives, then would do it again.
The wierd part is that it hasnt really been happening before, maybe a slight hesitation on accel.

Ive had a large backfire twice before which leads me to believe that its not sparking and petrol is still entering then it fires and backfires the build up of fuel.

Background:
About 2000kms on new plugs, condensor, points, cap, coil.

I really think its an electrical problem and my thoughts tend to point to either a bad connection, a bad setting, something not working efficiently.

I set the tappets about 1000kms ago aswell as timing afterwards.

Some direction or previous experiences would be awsome. A series are so easy to work on/fix that its quite a pain that i cant determine the exact problem

Cheers

adjust all your settings in the dizzy probably will help

I had a car like this years ago...turned out to be that the ignition coil was on the way out....sometimes good, sometimes bad.

If it backfires through the carb, then it's running lean at those times & I would suspect the fuel filter first & the rest of the fuel system if it persists after a new filter went on.

If it backfires out the tailpipe, then the spark is quiting & unburned fuel that is being supplied by a perfectly good fuel system is accumulating in the exhaust & being ignited when the spark cuts back in.

It it's spark, then bring your variables under control. New points [if used] with correct dwell angle, coil in known-to-be-good condition, even new rotor [I had one leak spark out the bottom to the shaft] cap & leads if they are suspect in any way.

Have a real good look at the balast resistor too. Datsun ignition switches have been known to cause grief & fortunately the switch itself is secured with one small screw at the bottom of the ignition barrel.

Even better is the fact that they are all the same for 1972 & up 1200's [with acc position] 120Y's, B310 Sunny's 180B's, 200B's & probably a few other Datsun models as well from that era. If the switch is suspect, then it's dead easy to change & I suspect that more than a few old Auto Sparks might still have a new 'replacement' one in the shelf somewhere.

ive had similar problems with all the datsuns ive owned, one was a dodge coil that was overheating and breaking down (new coil fixed it)
another was with bad electircal connections and another with ignition switch.

Another thing is what brand plugs and points did you use? i have always had problems if i hadnt used ngk plugs in the engine.

Several occasions where on various cars i've had the same problems.
1. Overheating coil (new or not)plus is it the right type?ie.ballast resistor or non ballast resisted.
2.These old Dattos have been around for a while now and have a tendancy the accumulate crap in the tank and suck it into the tiny little outlet causing a partial blockage,stopping the engine,once the engine stops it can then float back into the tank as theres no pump trying to suck it thru.
This situation has happened twice in the last 2 cars put together this year.
It also happened to a friend at Morgan Park historic races only last Sunday in a 180B SSS.

Have fun,be methodical
Cheers

I would certainly check all the previously mentioned things... but you might also want to check that your earth straps are all good. I have experienced some pretty wierd problems in old cars before that have come down to a poor earth... unbolt the earth points and check for rust / poor connection ie. loose etc.

These are all things that i thought would be playing up and its good that you all point them out as problems you have had before.

I checked and brushed up the connections to the ballast resistor this morning and checked all electrical connections i could and amazingly it drove like a normal standard a12 (slow) all the way to uni apart from one small hesitation.

The coil is a new (since i got the ute) bosch gt40rt, also im pretty sure they are ngk plugs cant remember off the top of my head.

Also the backfire is definately exhaust with the temporary seese fire of the plugs, scared a few people walking near the road haha

Might have to have a good look at it this weekend. Might put on a new ballast resistor on it that i have lying around. I also had trouble with bad connections to the resistor in my wagon when it was my daily.

Im slowly loosing patience for the utter slowness of the utes a12, accel isnt that horrible with the final drive ratio i have now but i suspect the ute a12 has a different cam to the wagon to produce more torque as its no match for the mighty wagon when it was rolling

p.s. viva le vb110!

I had the exact same problem by the sound's of it, and it turnd out to be rust in the fule tank!

I thought it was fule line so I changed all of them.

I chnaged fule pump. I put a much better one on so it work better for a bit (longer gaps betwean it cutting out)

Are you running a carbie with a wire ( black I think)connected to a long hexagonal thingy sticking out of it, (anti dieseling valve Ithink its called)
Anyway if you have one check the connection. Hope this may help.