My 79 sat in the pasture for 10 years while I went and lived a life of adventure and of course it kinda degraded during it’s long nap. When I came home I put a battery, some fresh non ethanol gas in the dry tank with a little Stabil, some Marvel Mystery oil in the crankcase, and spun her over. Surprisingly it busted right off and I drove it to work for the next few months until I bought a newer truck.

While it was my DD I generally spent most weekends and lots of evenings fixing the stuff that broke during my commute. Carb kit, fuel pump, dropped the tank and cleaned it out, fuel lines and filter, brakes from the firewall out, new steering pump, plugs wires and cap, a new ignition switch and DS2 module when my old one melted, general tuneup stuff for these trucks.

The main issue now is that I’ll get it running decent and drive it a while and it’ll develop a miss or fail to start. Every time I’ll pull the cap off and all the contacts will have big white fuzzies growing on them. Scrape them with a pocketknife and BOOM! It’ll bust off, if it’s not flooded or the battery is low from cranking.

I’ve put a new stator in the distributor, new cap and rotor, new plugs and wires, and a new coil. No change, still grows buggers.

It’s a 400 with no mods aside from an Edelbrock intake and carb and dual exhaust. All the smog stuff went bye bye back in the 80’s. I don’t have any crazy stereo or lights, basically nothing electrical aside from the aftermarket 8track that sadly gave up the ghost a while back.

Any ideas?

 

That is weird. I noticed that aluminum contacts are more prone to corrosion, I've heard it's caused from Ozone generated by the sparks or lack of airflow through the cap something like that.

How many miles does it take to cause the trouble? Brass contacts might last a little longer between cleanings.

Do you live somewhere real humid? Normally it takes a long time to buildup, though it isn't unusual after many miles.

 

I always put Di-electric silicone on the contacts in the distributor. I think brass ones would help.

 

Any critters making a home in your cap's vent? Maybe the lack of ventilation and general humidity is having it's way inside there.

Paul

 

Might also try some WD-40 in there to see if some water is perhaps sitting there underneath the advance plate. It would not be enough to cause any trouble running initially, but the added moisture would cause some mischief I would think.

Paul

 

No critters, I’ve tried two new caps with no changes.
It’s fairly humid here in SWOK but nothing like the Deep South or even eastern OK.

It’s certainly a strange problem and I’ve tried everything I’ve been able to come up with to no avail. I’ll have to get some grease and try that.

 

I have read somewhere that if the alternator is overcharging some , that it can cause it to build up quicker under cap ,

 

Post up a pic next time you notice it.

 

couple of ideas in this thread https://www.yotatech.com/forums/f2/w...ide-cap-38665/

 

Yeah, "sat in the pasture for 10 years" is kind of a tell, maybe. Full of water in the base? Maybe pull the distributor and give it the once over.

 

I know this sounds dumb but that sounds like the spark is jumping the wrong direction. Like it's jumping off the contact back to the rotor. Meaning it takes some material with it each time.

Did you ever do any rewiring lol ?

 

If you think the cap needs venting drill a 1/8" hole in the top.
Some cars the cap is vented from the factory.
After you feel it may be dry you can put a little sealer over the hole or just leave it open.
Dave ----

 

I haven’t done any rewiring, by some strange miracle no mice set up shop. Had a good sized Yellowjacket nest between the door and the fender but that was it for creatures.

The cap I got at NAPA has a vent and I’ve had the distributor all apart when I replaced the stator and didn’t notice anything down inside that seemed wet or corroded.

Like I said, odd issue that has me scratching my head. I think I may be close on to jerking the motor out for a rebuild and hopefully I’ll solve the issue then. I’m on the verge of giving the whole rig a cash infusion to take care of the wheezing 100k mile plus 400, sloppy steering that’s just begging for a Redhead, and the minor rust issues before they become major.

Appreciate the help guys.