How do you handle corrosion in distributor cap contacts?

[jmcajmca]

I find the contacts in my distributor cap getting corroded fairly rapidly. I warm up my engines every couple of weeks, and I find a layer of green corrosion on the contacts after a couple of months. I clean with contacts with a Dremel brush and the green corrosion comes right off. The engine starts and runs nicely with the distributor cap cleaned.

Have you faced the same problem and how do you solve it? Is it okay to coat the contact slightly with dielectric grease to prevent the corrosion?

Thanks,

Joe

[mister_larry]

Before you start greasing the distributor contracts, try something else. Get a drop light and place it next to the distributor so you get a little heat on the unit.

Every once in a while we hear stories about folks that "warm the engine" up regularly, but really don't warm it up. When this happens water vapor and moisture in the crankcase (who knows where it comes from) rises up the distributor shaft. When the humid air reaches the distributor cap is collect there. When the cap cools down after the engine is shut off, the moisture condenses and reacts with the metal contacts.

Some external heat, like from a light bulb left on when ever the boat is in cool conditions, should prevent this condensation. I would guess you could turn the light off in a day or two after the moisture has found its way out of the distributor cap. Then, some day when you are working on the engine, pull the distributor and check/replace seals, bearings, bushings, etc.

FYI - the moisture in the crankcase completely evaporates when you have the boat out on the water and everything is really warmed up. Your problem usually appears only after short warm up cycles when things do not really get HOT for an extended period: enough time to totally dry out the crankcase.

Happy boating.

[builderdude]

Not sure I'd recommend leaving a lighted light bulb in the engine bay of a gasser, or any other boat for that matter. Sure it'll put off some heat but thats actually what may cause a bigger issue :whistle:

[SKUA_28_Contessa]

In general, either run your engine at speed for a half hour or more, or don't start it at all. Anything else simply invites condensation. See it all the time with customers cars. They start it and run it for 5-10 minutes to warmit up, every few weeks when not driving it, to "charge up" the battery / circulate the oil. All they really do is accelerate rust and corrosion.

[jmcajmca]

I have been running my engine on muff for about 15 minutes until it reaches operating temperature. Interesting that short runs will cause condensation. Instead of a light bulb in the engine room I can put a Golden Rod which some people use inside their gun vaults. In fact I have one inside the cabin running all the time.

Joe

[grey.wilfong]

A spritz of Water Displacement formula 40. it does exactly what it was designed to do. I spray a little in the cap and on the points, blast any excess off with air and its good to go.

Chevy 350's are notorious for not liking moisture, especially at the coil and distributor. The WD 40 helps keep the airborne moisture away.

[Centerline2]

"grey.wilfong" post=812894 wrote:
A spritz of Water Displacement formula 40. it does exactly what it was designed to do. I spray a little in the cap and on the points, blast any excess off with air and its good to go.

Chevy 350's are notorious for not liking moisture, especially at the coil and distributor. The WD 40 helps keep the airborne moisture away.

good quality caps and wires make a big difference in damp environments.... go with the best quality available (not always the most expensive) and it will minimize the problems..

and I agree that moisture can set down under the mounting plate and turn to vapor and condensate on inside the cap... remove the moisture and try to prevent moisture from getting in again..

[mister_larry]

Go ahead and try the Golden Rod. You are into the experiment NO $$ since you already own one.

As for WD 40, I have been told to not use it on anything electrical. Spray silicone does not conduct electricity. Although you are talking about 20,000 plus volts through this circuit, there could be a time when you need all the oomph you can get. WD 40 could impede that process. In addition, if the Golden Rod works you don't need to pop the distributor cap whenever you bring the boat back home.

[jmcajmca]

Thanks for your responses. I have another thought: what about enclosing or wrapping the distributor in a plastic bag and put some descicant inside to absorb the moisture? That is a cheap and easy thing to test out.

Joe

[driz]

I just pop my cap every year or so and hit the dremel with the dremel and 1" stainless wire wheel . Every 5 or more years I toss on a new nap and rotor. Never an issue really but it does get really furry on the contacts.

Those wire dremel wheels are the cats meow . I buy them by the bag of 20 for about a buck apiece when I run out. Fantastic for cleaning corroded terminals in all my vehicles.

[mister_larry]

Wrapping the distributor in a plastic bag (with desiccant in there too) might work. I might ask that if you follow up on this experiment you keep us posted.

We now have two suggestions as to the source of the moisture: under the mounting plate, or up the distributor shaft from the crankcase. Your plastic bag will fix one but not the other.

For your sake I hope you don't need the bag because that results in one more task you need to perform before you can fire up the boat: removing the thing.

[desuch]

Heat lamp on engine year around its really does stop all moisture

[TerryW]

"jmcajmca" post=812790 wrote:
I find the contacts in my distributor cap getting corroded fairly rapidly. I warm up my engines every couple of weeks, and I find a layer of green corrosion on the contacts after a couple of months. I clean with contacts with a Dremel brush and the green corrosion comes right off. The engine starts and runs nicely with the distributor cap cleaned.

Have you faced the same problem and how do you solve it? Is it okay to coat the contact slightly with dielectric grease to prevent the corrosion?

Thanks,

Joe

I get that on my 2452 (5.7 V8) all the flaming time. It maybe takes 4 to 5 months for the spitting to start. I just keep two caps, one perfect and one in use. I just cycle them when I start to get a misfire. I spray the inside of the cap with WD40 which reduces the propensity to grow green lumps on the contacts. I have a tiny file that I use to clean the freshly removed cap and prepare it to be my hot replacement. I am pretty sure that the wd40 is helping.

[Cool_Beans]

Never had the problem with any gas engine I've owned in a boat. At least with the engines I've run, the distributors were sealed (ignition protected) so no moisture would build up. Are you running automotive gear or marine?

[jmcajmca]

All of my parts are from marine sources. I don't remember what brand is the distributor cap. The cap came with a gasket but it is a little bit flimsy. Do you think three are differences in materials between auto and marine caps? Or may be there are difference between different brands of marine caps?

Joe