Mallory ignition 50% broken

That sounds very strange, I don't think it's a problem with the distributor. It would either work or not. It must be something else. Anyway, you can check the distributor this way:

Disconnect the distributor wire that goes to the coil.

Connect a 5W light bulb between +12V and the distributor points wire.

Turn ignition on, to power the distributor electronics.

Rotate the crank, or lift the distributor a bit and rotate it by hand. The lamp should switch on and of 4 times per distributor shaft revolution.

How did you check for spark on #3 and #4?

Bill Spiliotopoulos, '67 Bug.

I sold both of my new Mallory distributors, but I seem to remember that the Mallory distributors have 2 ign points in them. Is yours similar? If so.............Check both of the ign points and any possible distributor shaft play. Uhhh you did not buy that distributor from me did you? 8^o

I saw one distributor with electronic ignition and it had one dead miss. (No spark to one of the cylinders) I installed a Bosch 009 distributor and then the engine came back to life. :-)

let us know what you find!

Hi, Dr. Dave. Mine is the Unilite which uses a light that peeks through slits as the rotator turns. I don't know, but I suspect the light is constantly on.

Bill Spiliotopoulos, thanks for the suggestions. While the engine was running on #1, 2, I pulled the 3 and 4 wires from the distributor and there was no change at all in the running, sound, not anything.

Another thing - all the same distributors I have seen are installed with the Mallory logo facing back. Mine installs with the logo facing forward, and #1 is toward the front (of course). My engine is the type where you cannot install the distributor notches wrong because they are offset. (Yep, I made sure the distributor oiling hole alligns with the oil aperture (slot) in the case.) There has been no change in position, IOW, the clamp is good. And it was running very nicely, then I parked it, and the next morning it was half-dead. Strange.

I keep the original 009 distributor with points in the glovebox in case of electronics failure. I guess it is time to use for that purpose. Man, I am almost fed-up but I'm motivated because I have almost $40 worth of gas in the thing.

Silly question, but could the #3 and #4 plug wires be reversed? If so, neither one will be firing at the correct time ...

Or could the wires be faulty? Does happen, but two at the same times would be rare. Sounds like a circuit error in the Unilite electronics.

J.

The distributor electronic module works correctly. If it sparks for one cylinder, it will spark for all. This module recognizes slots, not cylinders. It will create a spark each time it detects a slot. Remove the rotor, which has the disk with the slots for the optical pickup, and check that the electronic module has not come lose and that the wires are not rubbing against the rotor disk. Reinstall the rotor seated properly all the way in, so that it can interrupt the light beam of the detector. The rotor has a very firm fit, and you must be carefull not to break it. For the same reason it might not be seated all the way in. Also check that the distributor is fully engaged to the distributor shaft in the engine case.

The "Remove spark plug wires / no difference in sound" trick, doesn't tell you you have no spark, it tells you that those cylinders are not firing. This could happen for many reasons. E.g. due to a vacum leak or clogged idle circuit in a carb, or short-circuited spark plugs.

When you pull the throttle and the engine revs to about 3000rpm does it make a difference in sound when you remove the spark plug wires? If it does, it is a carb related or vacum leak problem.

Regards, Bill Spiliotopoulos, '67 Bug.

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It could still be related to the electronic unit, think rise time or saturation time/rate. Could be a faulty condenser or the likes.

J.

There should be no condenser instaled with the unilite module, it is not required and if installed it will weaken the spark.

The detector creates a spark whenever the light beam is interrupted. Since it creates a spark for #2 and #1 (#1 fires immediately after #2) it means that there is no rise time - saturation issue.

In this case, the only way for missing the spark for #3 and #4 (if it is indeed missed), is when the slotted cylinder is not aligned properly to the detector or the sloted cylinder is broken.

Anyway, when a cylinder is not firing, it can be caused by many other reasons, besides missing spark.

Regards, Bill Spiliotopoulos, '67 Bug.

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It's always ok to ask. No, they aren't reversed.

I read you loud and clear. This is not to argue, just thinking out loud. The detector detects the first two out of four pulses, then needs time to (somehow) recover, skipping two pulses in the process..? Electronics/electro-mechanics never seize to surprise me..

J.

I find that hard to believe, but bare with me. If it were a saturation issue, I think the firing would be erratic rather than perfeclty on for #2 and #1 and dead for the others.

So, should I change out the coil? That's easy.

It is hard to believe, merely a chain of thought theory, and it would be the light detector or the controll electronics being at fault, not the coil. If it was the coil failing when warm it would be erratic, yes.

If you have checked the two H.t. leads of the non firing cylinders for conductance(also the plug caps) the problem lies within the dizzy, I think we all can agree on that?

J.

Bill's quite right, so I suggest that you do a test to check whether there is actually current going to the #3 & 4 spark plugs.

The easiest way to do this is with a timing light with an inductive pickup. I think most people have those these days. Just clip the pickup around each SP wire in turn and press the trigger switch on teh timing light. The timing light will only flash if CURRENT passes thru the SP wire inside the pickup.

If you do this on 1 & 2, you can see what they do, then move on to 3 &

1. If you get the same periodic flashes from each SP wire, then you know that the electronic ignition is working just fine.

If you don't get the same flashes on 3 & 4, check the resistance of each SP wire. There is a 1000 Ohm resistor in each SP connector, and if that resistor goes open the spark current can't flow. You should also check the dist cap for spark tracks inside and out. It's possible that there are some carbon tracks which are shorting those 2 terminals, shunting the spark current to ground before it can get to the plugs.

If all those check out, then you could still have a plug problem, but this is unlikely.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Hmmm so is this a dual port engine with those rubber/silicone boots on each side of the center intake manifold? I usually spray them with carb cleaner to make sure that they are not leaking. I just got through changing some on a '74 California Super.

And BTW I have seen one electronic distributor that had 1 dead spot. ;-) I also took it apart and reassembled it but it had that same dead spot. Engine got an 009 distributor and it is doing nicely to my knowledge.

I believe John has a dual kadron engine, if it is the same engine as in the message thread bellow. That's why I believe there is a big possibility that it is a vacuum leak or a clogged idle circuit problem.

Regards, Bill Spiliotopoulos, '67 Bug.

Well that kills my boot idea! ;-) Thanks, but I did not know he was running dual carbs. I agree with you about a carb problem then.