The timing may be set a bit advanced. There may be too much slop in the distributor gear/shaft/rotor. Try setting it back a touch and see what happens before tearing things down. And as mentioned, it should not be run at full advance at idle and some think it should never be run at full advance.
Engine runs worse when spark is advanced
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Mike V. Florida
Well-known member
I know on my car if I pull the lever all the way down it won't run right and
I've been told that unless you are running the engine at max RPM all the way down it too advanced and you can damage the engine as it could fire way too much advanced of top dead center the power stroke will start too early and damage the babbit. Like I said on by car with the timing set as discribed in Marco's web site, it runs best at a little more than half way down.
I'm not up on electronic ign but did it have auto advance, because it sounds to me like it is working just as it should.
Please let us know what you find.
I've been told that unless you are running the engine at max RPM all the way down it too advanced and you can damage the engine as it could fire way too much advanced of top dead center the power stroke will start too early and damage the babbit. Like I said on by car with the timing set as discribed in Marco's web site, it runs best at a little more than half way down.
I'm not up on electronic ign but did it have auto advance, because it sounds to me like it is working just as it should.
Please let us know what you find.
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sonny30coupe
Senior Member
I have a clear cap on my distributor, I got it on ebay a few years ago. It looks cool at night when the rotor spins and sparks.
steve s
Well-known member
Seems to me these are crucial clues.
Timing gears don't jump teeth while parked.
If the coil is really not getting "power" it wouldn't run at all. If the connection is dicey (presumably, the primary circuit) that could explain why it runs with original but not electronic ignition; the latter requires a better coil and a very definite ground. Sounds like a bad connection in the primary ignition circuit to me: feeble fuse block clips? loose ammeter nuts? and, although this is downstream from the coil, it's still my personal favorite--seen many--a bad ignition switch?
Unless the circuit is completely broken/open, checking voltages with a multimeter can be tricky; a feeble connection can let you can get the correct voltage reading under no-load conditions, but may not permit a useful amount of current to flow when the unit is operating.
Steve
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gearloose
Member
I bypassed all and went to the module from the battery with power and ground as recommended by the manufacture. no joy. the coil gets it's power directly from the module still no power at the coil. all the components, module, trigger set up and coil were sent back and test good. reinstalled with same problem. reinstalled point system and the car runs, what does that tell you?
1931 flamingo
Well-known member
Pigtail wire on dist pate shorting when spark advanced? Are you running a "pop-out" sw?
Paul in CT
Paul in CT
MCHinson
Senior Member
Without the benefit of seeing and hearing exactly what it is doing, If I had to guess, I would think that 1931 flamingo probably is correct. I would change out the pigtail wire. If that does not fix it, I would also try swapping coil and condensor one at a time to make sure both of those are not causing the problem. Other than that, I would suspect a fuel supply restriction. Over the years, those seem to be common problems causing similar symptoms.
steve s
Well-known member
What it tells me is that something is wrong with how the electronic system is hooked up. The problem is not the cam or fuel or other non-ignition candidates. I don't think it's the pigtail either; my recollection of how my electronic system is set up is that the pigtail wire is irrelevant. The electronic system demands that you install its own, more reliable ground.
Which electronic system are you using? I am only familiar with the Pertronix. I don't understand "the coil gets its power directly from the module." Unless there's specific directions to do that, I would want the coil to have a straighter shot from the battery. I once tried to install a small indicator light in parallel with the ignition primary circuit, which thereby totally disabled the car.
One possibility I'm not sure of is whether the electronic setup is timed as well as the original system apparently is. I agree with others that the symptoms do sound a lot like the timing is too advanced.
Steve
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pat in Santa Cruz
Well-known member
This is a good suggestion. The cam could be one of the older repros from Argentina...they were mis made. Check point gap on each lobe to see if it is consistent. If there is any play in the top plate or the shaft, it will cause the point gap to vary when you advance it.
Check the top plate arm and see if it rests against the stop in the distributor body when at full retard and full advance. The adustment is made on 30/31's by loosening the steering column and rotating it until the arm travels in its correct arc. On 28/29s, the arms and rods are bent to accomplish this job. Do not try bending the repro steering column arms as they will break. If you do move anything to change the travel of the top plate, you will have to re time it again.
One other area that causes trouble is the wire under the top plate can fray, or come loose and short out against the distributor sides or the spring. When retarded it clears, but when advanced it shorts, sometimes only intermittently, and causes rough running.
If you place a mark on the pulley and use a timing light, you can see how much advance you are getting. It should start at zero idle around 15-20 degrees, and run at top speed about 32 degrees with a stock head, less with an HC head, perhaps 28 degrees.
another tactic is to start replacing things like carburetor, condenser, filter screen, distributor body, rotor and cap as a process of elimination.
Model A Man
Well-known member
I know on my coupe I have a High compression head and I dont need to advance the spark very much at all
gearloose
Member
The car now starts at the touch of the starter and runs like a good Model A should. After following and checking all suggestions I found the fuel inlet filter in the carb to be mostly pinched off by the fuel line protruding too far into the carb body. When I unscrewed the filter it twisted off because it was pinched too much. I reinstalled the filter plug mines the filter and the car fired right up and now runs smooth. Thank you Randy308 ! I think the electronic ignition is faulty because it runs with the point system BUT why didn't it run bad before with the filter restricted? It has been this way for some time. Was it the filter all along or what?
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just plain bill
Senior Member
Sure glad you found that problem, I'm exhausted with all of the worrying and work suggested by the good fellows on here. Just knew we'd get 'er fixed!
sonny30coupe
Senior Member
Send it to me, I will let you know how it works on my coupe.
1931 flamingo
Well-known member
Glad you found the problem!!!!
Paul in CT
Paul in CT