docmirror

Some of you may recall that last winter I had a stumble that just wouldn't go away completely. I found I had some bad gas, and I also found I had a coil that was weak. Last month I replaced the coil and it got better for a while, so I knew I was on the right track, but still not fully clean bill of health.

So, I've already done the wires, coils, coil amps(up front), and cleaned the caps and rotors. Nothing left except the plugs. so I bought some copper Champion plugs, and when I start pulling the insulators out of the plug wells, they are pretty oily. In a few holes, had oil right up near the tip connector.

I found a way to flush most of the gunk out of the well, but made a hell of a mess. After that, pulled the old plugs out, and cleaned the rest of the stuff out of the hole. Ran the engine around a few times to preclude hydro-lock, and install new plugs. Cleaned all the plug connector/insulator parts, and put it all back together.

Now, lots of power down low. No more stumble at all.

After I warmed it up, I just floored it from about 2200 in second and it will now light up the tires nicely. Before, it would pop, then go, then stumble then go, then pop, and sometimes go into limp home if it was too cold. I haven't looked it up, but clearly motor oil has a lower dielectric constant than air, and I was loosing spark to the oil and into the housing rather than down to the spark plug tip.

So, now I have to plan a intake/cam cover refresh this fall. Yippee, more dirty work. I want to get the parts done in anodized, but I'm also leaning to just engine paint. Red with gold lettering.

hacker-pschorr

It sounds more like valve gides / seals are in your future. That much oil getting into the combustion chamber is NOT a good thing. Can lead to (if not already) detonation.

Unless this is just the cam cover seal leaking into the back side of the plug? How did the plug tips look?

Tom928

Doc,

With all due respect;

DK for air = 1
DK for oil (petrolium) = 1.8 - 2.2

docmirror

Oil is not getting into the combustion chamber, but in the plug well.

Thanks Tom. That's what I thought too, it was higher. Must be something in the breakdown voltage as DK is usually specced for AC current. I know things react differently with spikes than with AC, and also when things get above 20,000 Volts. Hmmm, interesting test - I could fill up several plug wells with motor oil and make sure it comes back. Naaaaaah, I like it running right.

ZEUS+

http://www.freepatentsonline.com/6858975.html

Jim bailey - 928 International

Oil will suck away the spark, 318 BMW has a similar spark plug well and if filled with oil no sparky ...three cylinder car !

Peter F

Had exactly the same learning experience with my wifes BMW V8 with coil on plugs technology.
Changed plugs and found a mix of oil and water in the plug wells.
Removed and cleaned everything up and car ran very smooth afterwards.
Later replaced the valvecover gaskets and it's been good since.

/Peter

SeanR

I have the exact same issue with the '88. When I went to do the plugs/wires, I pulled the cap and 2 of mine were filled with oil.

So, yes, cam cover gaskets are in my future also.

docmirror

Let's make it a party! My place or yours? I have air tools........

SeanR

Ditto here. We should make it mine for logistical reasons, Rog is closer to me. hehehe

Sounds good to me, only reason I've not jumped in to it, is due to the potential of only having 2 running cars. The way Ang's craps out at the worst times, I can see us being down 2 of the 3. I suppose if we have a nice gathering we could get them done in one day.

FlyingDog

I had a SAAB 9000 that filled all the spark plug wells. It started stuttering at the point when the oil had filled the Direct Ignition cassette and was pouring out the end. It took me quite a while to figure out why the oil level was dropping... over a quart of oil was in the ignition electronics!

SharkSkin

I'll add this to my list of "advantages of having an OB"... no oil gasket around the spark plug well!

dr bob

I think Champions are great in Mopars (old ones, with hemi heads and the like...), sometimes OK in lawnmowers. Not good for much else in my experience. In my early P-car ownership periods, it was easy to find Champions to install, but tough to get them out of the heads once they had been in there a while. Turned out the thread was cut slightly differently than the Bosch and Beru plugs that came in the car originally. Of course, I'm sure theyve cleaned up that little detail in the intervening forty-some years. But that's still a lingering memory. I generally install what the manufacturer put in. In our 928 case that's Bosch.

I'm sure this is somewhere just south of the "what's the best oil for my car?" question.

----

I used to tell customers that Champion makes a great plug. Then they make another great plug. But no reason to believe those those two plugs are the same, especially their resistor plugs.

whall

I replaced my valve cover gaskets and did not replace rubber seals for the plug wells - very dumb. Within minutes, car ranlike crap and oil filled spark plug wells and car ran like crap. After replacing the plug seals in valvecovers, problem fixed....

Angela R

Sean here, posting on Ang's comp.

I'm running the platinum +4's in mine, been pretty happy with those.