Changed oil myself. Stupid question follows.
 

With the nice weather on Friday, I figured I would change the oil in the 930 myself. All went smooth, and I felt that warm glow that only comes from tackling a really tough project like an oilchange yourself ;) . . . And then I started thinking about it last night.

When I drained the oil I didn't pay particular attention to the crankcase drain plug and the oil tank drain plug. They both went in fine, but I am now wondering if I switched the two and if so what are the problems.

Are they the same thread size? Same pitch? Is it even possible to confuse the two? I figure I'll wait until this problem is solved before beginning the full rebuild next week.

They are interchangable.

Tom

At least you didn't do what I did yesterday... I changed the oil in my car without jacking it up or anything, so reaching the sump drain plug meant laying on my back... in short sleeves... where my bare inner forearm bumped up against the very hot muffler.

Oops.

Yes, they are the same. I replaced the one on the tank with a magnetic plug so that both crank case- and tank plug are magnetic and catch the tiny metal particles.

Congrats on the oil change! Coincidently, I did my very first one yesterday. Took the advice here and made sure I had a container big enough to hold all the drainage. I bought one of those 5 gallon coolant pans with the built in pourer. It worked great, but there's still the "splash factor", so next time some newspaper will be spread. :)

When I was finished, I too had second thoughts. I forgot to remove the sump screen and check it. Being as this was my first oil change on the car I bought 3 weeks ago, I wanted to ensure half of my rings weren't stuck to the screen. It's going to have to wait at least 5K miles now......

My plugs are same size thread, but different size heads and both magnetic. I did find a pinhead size piece of metal on the oil tank plug. Hoping it's just a piece of slag as it looks like it could be.

I checked a little bit on this and Pelican lists two different parts. The crankcase bolt is listed with a 944 part number and is O.D. 19.85 mm. The oil tank bolt is a 911 part with an O.D. 21.85 mm.

I'm not trying to answer my own question but would these two bolts really be interchangeable on an '86 930? Is a 2mm difference small enough that the bolts would still fit the threads? And the bigger question: Am I just wasting my time worrying about this?