weird distributor cap-eating thing, 85 Civic hatchback

So I have this Honda, US car, 352K miles, 1300cc engine, and for the
last few years the thing has been eating a distributor cap and rotor
once a year or so. The symptoms are very odd. The inside of the cap
is always kind of oily damp with a really sharp acid smell, the
aluminum contacts inside the cap are always really corroded with a
fluffy white oxide, and the carbon contact button that connects the
coil wire to the center of the rotor is eaten away nearly flat and
fused with the cap. The metal bits of the part that holds the
magnetic pickup are very rusty. And yet the thing starts and runs
amazingly well. Every so often I get in there and clean the cap,
scrape the contacts clean, etc. Eventually it will get to where it
runs to rough that I have to replace the cap and rotor, and then we
start all over.

Anybody have any idea what's going on here? The only thing that
occurs to me is that I recently had to have the head gasket replaced.
Is it possible that when the old gasket went bad, it was leaking steam
past seals or something and into the distributor housing from below?
If not that, then what the heck?

I'm hoping to make half a million miles on this beast, if it will
last.

Thanks quite a lot -

Edge

 

I don't have a direct answer to your question but here are some things to
check....

There should be a rubber gasket that goes between the distributor cap and
the distributor body. If this gasket is missing, broken, or dried up and
brittle then moisture can get into the distributor and could be causing some
of the corrosion symptoms you're experiencing.

The "oily damp" symptom could be caused by a bad oil seal in the
distributor. If this is the case, then you may be best off going with a
used distributor as, to the best of my knowledge, the seals aren't available
from either the dealer or the aftermarket.

Check the vacuum advance. This should hold vacuum. If not, then your car's
timing will not be correct.

Check the advance plate. When you pull vacuum on the vacuum advance (as
long as it's not leaking) you should see the advance plate turn a given
amount (I don't have exact specs for this but it's roughly 10° or so). With
as much corrosion as you're describing, I would be willing to bet that your
advance plate may be frozen. Even if it's not frozen, the bearing retainer
in the advance plate often breaks. This causes the advance plate to sit
crooked resulting in unequal or nonexistent air gaps with the reluctor.
Sometimes you can find the steel bearings stuck to the magnet when the
advance plate goes south.

Check the magnet. You'll need a small mirror and a flashlight for this
one. If it's cracked or broken then it needs to be replaced.

It's also important to check the mechanical advance. You should be able to
turn the distributor rotor 10° or so and then have it spring back. If this
doesn't happen, then the distributor will need to be disassembled so that
the mechanical advance can be cleaned and lubed. Note that the top shaft in
the distributor can go on in either of two orientations however only one is
correct. Make some hash marks on it with a carbide scribe indicating it's
orientation such that you can get it back together correctly. If you get it
wrong, you won't be able to time the car and will need to take things back
apart.

This diagram should help to give you some idea of how all the components are
stacked together, http://tinyurl.com/3tlr8. It's for an Hitachi distributor
from an '85 1300 49 state 5spd. The other possibility is that you could
have a Tek distributor. If that's the case or the diagram is not correct,
then put the correct info for your car into this page
http://tinyurl.com/6yprt.

Eric

 

Thanks, Eric. I will check some of these things. I'm sure there's no
rubber gasket between cap and body. I'm also sure the vacuum advance
is broken - I live in Canada and the mechanics here don't have access
to proper manuals, so when it had to pass the air pollution tests a
few years ago they just did their best and it worked. At the time,
they noted that the vacuum advance was broken so they just
disconnected it. (Except for roughness due, I think, to the corrosion
inside the cap, this thing runs VERY well - good acceleration, 40 mpg
in nice weather, starts on the first crank always.) But still, it
sounds to me like I may have multiple problems.

What are the good sources for used distributors? I'm pretty sure this
is a Hitachi unit - the cap is the kind where the cylinder wire
connectors come off the cap perpendicular to the axis of the
distributor shaft and not in line with it.

Thanks again!

Mark

 

Lol....
Really.

Steve
Ottawa.

 

The following site (= Majestic online) indicates, at least for a 2-door, that it
is a Hitachi with perpendicular wire connections:
http://www.hondaautomotiveparts.com/auto/jsp/mws/catdisplay.jsp (Check both auto
and manual. The site seems a little messed up for auto, but the part numbers
appear to be the same, as one would expect.

Have you considered online salvage sites? It seems most have online, free
searchable inventories. I had really good experience several weeks ago with one.

I just tried looking for your 1985 Hatchback's distributor at
http://www.autopartsearch.com/about.cfm .

For an auto transmission, three 85 Civic Hatch distributors came up, ranging in
price from about $55 to $138.

For manual, four 85 Civic Hatch distributors came up, ranging from about $55 to
$98.

Warranties are often offered on such parts.

Google for {auto salvage import search inventory}, and more searchable sites
come up.

Ebay often sells distributors but I saw nothing for a 1985 Civic today.

Updates welcome.

 

Yes, then that could be one possible source for moisture and corrosion in
the distributor.

At first glance the vacuum advance units might seem expensive, Majestic
Honda lists them at $40. However, consider that if the engine's timing is
incorrect and the engine is pinging that the piston ring lands could be
destroyed thereby requiring an engine rebuild. All of a sudden, a little
money spent on the distributor seems very reasonable.

The online sources that Caroline mentioned are a good place to start.
However, don't forget to check your local newspapers, little nickel, etc.
You may be able to find someone parting out a car with your distributor. In
that case, you may be able to pick it up for $10-25 or so.

Eric

 

Thanks everybody! All your efforts are appreciated.

Steve, I'm not exactly sure what your point is, but I'm just quoting
the actual mechanics who worked on it - they couldn't get the proper
manuals for this car. Nor could the dealers get the proper
distributor cap for this car. Perhaps Ottawa is a different universe
in this regard.

edge