Distributor not advancing...so i fixed it!
 

I was having all kinds of trouble setting my timing. It seemed to work fine at 1K and i was able to set at 5 Deg BTDC to start. However, when checking at 6000 RPM, the advance only moved a couple of mm and was kinda boucing around. I have the mechanical centrifugal advance(i think)
Anyway, I removed the distributor, and then proceeded to inspect and break down the unit. Guess what, rust was eating up the inside and siezed up one of the advance arms in the bottom(not sure of the technical term for this item). I cleaned it all out, removed as many parts as i could, and cleaned(sanded) as much rust and gunk out of there. I got the advace mechanisms to move freely on thier pivot points with a light coat of grease on everything that looked like it could use it. I reassembled the unit and Viola!, i was able to check the timing at higher rpms and as i revvved the engine i could see the tick mark move like its supposed to.
I was ready to chunk the unit before I started, so I went in with both feet. I'm glad i did, because from start to finish, it only took me about an hour and a half and I notice a much smoother and stronger running engine. I wish I had taken pictures along the way, but things were going so good i forgot. I'm not the most mechanical person in the world and this was the first time for me to dig into a distributor. I would like to say thanks to the board members here for giving me the courage to tackle projects like this. Its nice to know there is a strong network of people that can get you pointed in the right direction when you have a problem.

Hey Congrats!

THe feeling of fixing something yourself rather than just replacing it or having someone else do it is what this place is all about!

Good for you, Kemo. I just wish you had taken pictures, I haven't been inside a distributor in 30 years, I could use a "refresher".

Jerry M
'78 SC

I might go back in and take some pics... i have a question concerning the springs...

they were not the same...

The distributor utilizes a two stage centrifugal advance curve. The springs differ - basically a light one and a heavy one. One advance beginning at 1000RPM and the second at about 5000RPM

tsuter,
thanks for the info. that is exactly what i saw...a small spring and then a much larger one with a big "hook-like" way of connecting. the "arm" that had the larger spring was the one that was rust frozen. I image both arms benifited from the cleaning.

Kemo:

GREAT JOB!

Tell me, did you drill and remove the pin retaining the pinion to the driveshaft? If so, what did you use to put it back together? Also, did you find plastic sleeves around the spring posts - with small collars at the top of each plastic piece? Or were these gone?

And remember NEVER chuck a '78 dist.: they are very, very unique even within the SC line (not sold anymore). The pinion has a gear pitch to it that was NOT used in later SCs: that's why you must match the dist. to the crankshaft. A different year dist. will not match the gear pitch on your crankshaft, leading to obvious expensive problems.

John

Jdub,
I actually have an 82' engine...found that out about 2 weeks ago.
I left the pin in there...it looked like too much work. I "attacked" the problem from the top. It would have been alot easier if i could have removed that pin down near the gear. Anyway, the plastic pieces were all in place and seemed to be in relatively good shape. I saw little small collars( not to be confused with cool-collars:) ) atop of the spring posts. I cleaned everything as best i could.

Kemo:

Tell me, how the heck do you remove the upper castellated ring? I pulled the snap ring but it did nothing to help get in from the topside. I would have far preferred to remove the ring and other bits and get into this from the topside.

So you were able to clean and reassemble without removing the driveshaft?

John

Jdub, im assuming you are talking about that big ring that is held in with retaining clips and looks like a big ferrous wheel. That took some work, i used 2 flat head screwdrivers, 180 degrees apart and "carefully" worked the peice off...that took me almost 20 min to figure out and about 5 min to do it. I clamped the unit in my trusty workmate clone to keep it steady. There is also a screw right on the top, hidden below some padding. It was a really tight fit and I had to use a deep socket combined with "light" tapping from a rubber mallet to get it back on.