Bad plugs

[Mike Przano]

Hello all,
Can the coil or ballast resistor cause too much voltage and knock out the plugs? Here's why I ask, I start my 283 small block every other week just to keep it oiled and the battery charged while I finish the resto on my 61. About a year ago after letting the engine sit for a month without starting it I couldn't get any spark to three of the plugs (plugs were R45's, brand new and not fouled)so after many hours of electrical troubleshooting I decided to try another fresh set and the engine started right up. Now after moving across country and having the car in storage a few weeks it started but ran very rough. Once again I checked the spark to the plugs and found a couple that wouldn't spark. After replacing them she started and runs just fine. Should I be using a different type of plug? Visually, the bad plugs look fine and are very clean with no apparent damage to the electrode. Any ideas would be greatly appreciated.
Thanks,
Mike

[Doug Flaten]

Re: Bad plugs

I cannot see how the coil or ballast resistor could damage the plugs. I would look for four things. 1) fine cracks on the insulators that may indicate previous damage or damage while installing. 2) Plug wire connection at tip of spark plug could be a loose fit or getting corroded or poor connection. 3) Plug wire condition and making sure that the crimped ends are not loose or wires not broken. 4)Distributor Cap condition. Check towers and terminals on inside. I would think it may be something to do with the spark plug boot or wire itself. It sounds like you are getting good enough connections when you put them on and then the connection degrades, possibly with a few heating and cooling cycles. Other than that, I am at a loss too.
Has it been the same plugs each time?

[Jack H.]

Re: Bad plugs

I doubt the problem stems from coil & ballast 'overdriving' the plugs.... Plugs are very healthy creatures and the applied voltage swings to them virtually doubles when you consider initial cranking with the ballast out of circuit compared to the ignition switch 'run' position with the ballast in circuit.

You don't report cracked ceramic insulator tower and you don't report 'fried' electrode(s). My hunch is there's some other 'funny' out there that's affected (comes and goes) when you attempt to diagnose and begin moving wires around (like intermittent contact).

Since the symptom of the problem is: won't start/won't run, it's time to look 'downstream' of the ballast since it's switched in/out of circuit during crank/run operations. The highest up the 'feeding chain' you can go is the bottom side of the ballast that connects the starter solenoid bypass wire and the coil feed wire to the ballast output.

[Larry Barickman]

Re: Bad plugs

Here's what I had expierience with.. I ordered a lot of stuff on line to tune up our Lumina mini van. When I got the order They had only sent one A/C spark plug. (strange).... I was only charged for one. Rather than wait for another order I opted to go to a dicount auto place. I got 5 A/C delco plugs in the boxes. When I opened them and compared them to the one from the Delco dealer these plugs looked like junk counterfits. The electrodes were all off center and different sizes among other cosmetic blemishes.. I contacted the A/C Delco rep. He asked me to send him the suspected bad plugs. A couple of weeks later he called and told me that these plug came from one of their "offshore facilities". He refunded me the purchase price and said these got mostly to the discount chains. He said if I wanted to be assured of first quality plugs, get them at a dealer. I had some bad luck with a set of plugs a few years ago now I know why. Maybe that is your problem.

[Mike Przano]

Re: Bad plugs

All,
Thanks for the suggestions. The first set of plugs came from CC, the second and third sets from two different Autozones. The distributor cap, rotor, points, condenser and plug wires also from CC. Close examination for micro cracks inside the distributor cap and plug ceramic did not reveal anything. Ballast resistor wiring appears to be correct. Hate to toss parts at a problem but maybe the plug wires which appear to be cheaply made need replacing. Any suggestions on the type and supplier.
Thanks again,
Mike

[Michael W.]

You might want to

change your maintenance habit of frequently starting the engine - it does not need or benefit from short runs. Any theoretical gain from moving the oil around will more than be offset by the stresses of a start and subsequent partial thermal cycle.Your alternator/generator was not designed to frequently recharge a low battery, and you're just adding more wear and tear on the starter to boot. There's no real reason to run an engine unless you're going to go out and drive the car! If your battery is discharging that quickly, you may want to chase down that problem first. If you just want to keep it fully charged, buy one of the low amperage maintainers and leave it connected.

It could be that your plug problem could be due to the cumulative effects of short engine runs (minor fouling due to low peak plug temperature) possibly combined with a marginal coil, the two being just too much for them to fire.

I learned my lesson when playing around with finicky '60s vintage 2 stroke engines.

[Mike Przano]

Re: You might want to

Thanks Mike,
Your probably right about the start ups. Maybe I should opt for removing he distributor and inserting a driveshaft to spin the oil pump at least until I'm ready for the road. Also, I should invest in one of those trickle charges.
Mike

[Jim T.]

Re: Bad plugs

If some AC plugs are made not in the USA, the place of manufacture should be on the package right? Seems like having problems like this with AC plugs purchased from other than a GM dealer would prompt someone to change to a brand with more quality control. Interesting information in that the best AC Delco plugs can be obtained from a GM dealer.