Large O ring on dizzy? Rubber or other

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gdizzle

gdizzle

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I just removed and replaced the Electronic Dizzy on my Slant 66 dart. The hold down bar seems to be held (lightly) in place by a large O ring. This O ring is very hard, and has a crack in it. My questions: Is this supposed to be a rubber O ring? Or a hard o Ring (like metal). Then there is also a small narrow slot on the shaft that has a thin rubber O ring, which is rubber. But it is much narrower that the actual slot. Is the wrong size?? BTW this dizzy is a 1970s Chrysler NOS with vacuum pod.
 
The large O-ring doesn't hold the hold-down plate; that plate is held to the distributor with a bolt and to the block with another bolt. The large and small rubber (yes, they're rubber) O-rings are oil seals. The small O-ring being narrower than the distributor shank groove is normal.

Sounds like you're due for new O-rings. Use good quality, oilproof ones. If you can find an auto parts store with a good selection of air conditioning O-rings (often green or blue) you can usually find the sizes you need.
 
there ARE TWO SIZES ON 1/8 AND THE OTHER 3/32 you can tell by the grove size one is wider, the bigger o ring will fit but you will prob have a ground issue.
 
Great info guys. So right now I have a big thick (hardened) Oring which presses up against the hold down strap. Then on the shaft there is a groove, and in that groove sits a very thin oring, much thinner than the groove itself. I have never seen colored O rings at the Auto store, just the black ones. I have never seen any oil on the Large O ring, nor have I ever seen any oil leak from the distrib.
 
I used a very careful application of black RTV and made a contour shape using my finger to get the Dist to seal properly. Let it dry unmounted first and then install. No issues 10 years later.
 
Standard black O-rings are termed "nitrile" or "Buna-N". It resists oil, but not gasoline. Turns hard over time with enough heat. AC type are HBNR and come in various colors (grn, red, blu) though trying to standardize on green. They are tougher and handle heat better and I think are better than nitrile for most all applications. Viton are usually dark brown. They resist gasoline and last longer than nitrile. They cost more and are hard to find in larger sizes. Harbor Freight sells kits for each type (english & metric for nitrile). Your life will be easier if you buy each kit.
 
Nix on the Harbor Freight suggestion. I'm sure they do sell different-color O-ring kits claiming to be various different materials, but in reality everything they sell is Chinese garbage that doesn't come close to being what it claims to be. Do yourself, your wallet, and your cars a big favor and don't slog through that sewer.
 
I guess someone could run a test, soaking the Harbor Freight "viton" and "nitrile" O-rings in gasoline for a month. Seems I recall seeing where someone did that. I doubt they misrepresent the product and most HF products I bought have served well and most I would never have bought at Snap-on prices. Re Chinese, I bought 1/8" viton tubing for my M-B diesel injector return hoses off ebay. It has held up fine for over a year and I use bio-diesel (Propel HPR) which is more aggressive. It seems to truly be viton since everyone who has tried regular black vacuum hose (nitrile) found it swells in a week, even w/ regular diesel, and I saw that when I tried a little silicone hose "just to verify".
 
I am lost on the o ring by the hold down clamp, between the plate and the distributor?
3588dj5.jpg
 
hmm NEVER EVEN NOTICE THIS, EARLY DIST? @slantsixdan ? Don't think I ever came across a core with it usually just the small one.
pict0003-jpg.jpg
 
halifaxhops said:
A member I think here did a great thread on different fuses and when they they actually blew, some were way out of specs, really scarry.
Click to expand...

That thread is here. Also see here.

Halifaxshops, it's probably staring me in the face, but what are you asking me to notice about one or the other distributor in your pic, aside from one having and one not having the large O-ring?

Anyhow:

Chrysler P/N for the top O-ring is 2095 740, discontinued, and the inner diameter is 1.068". Buna-N is an acceptable material. Find it around as a "size 121 round O-ring", such as here (a hundred of them for under ten bucks) or here (one for 35¢, but shipping will probably make it more worthwhile getting the 100-pack, then when the end of the world comes you'll be prepared).

Chrysler P/N for the bottom O-ring is 2095 630, discontinued, and the inner diameter is 0.920". I'm pretty sure it's a size 021 square O-ring such as this (where you can also read about Buna-N material's characteristics), though it's been long enough since I scrutinized one of these that my recollection of them as square-section could be wrong—they might well start out as round and the outer diameter gets squished flat with pressure, heat, and time. Also possible it's an 020-size ring (outer diameter 1.004") or an 022-size ring (outer diameter 1.129").

These size numbers apply whether you're getting round- or square-section O-rings, so google searches are easy.
 
gdizzle said:
Great info guys. So right now I have a big thick (hardened) Oring which presses up against the hold down strap. Then on the shaft there is a groove, and in that groove sits a very thin oring, much thinner than the groove itself. I have never seen colored O rings at the Auto store, just the black ones. I have never seen any oil on the Large O ring, nor have I ever seen any oil leak from the distrib.
Click to expand...
There are many different colored o-rings, but they aren't part of a std. "kit". Some are different materials for different temp. & fluid compatibility, others are coated to help
ease of assembly. Look at some stock applications like fuel line quick connect fittings, they often have a mix of black,brown, or yellow o-rings. The yellow ones are almost
always the "back-up" ring, i.e. the first one You see inside, but the second one fuel would see trying to leak, that yellow is a coating that will come off if You try. A/C ones
can be green, blue, orange(also used in water fittings, and vapor/intake fittings), primarily green....and it is a coating to ease slipping the connections together.
 
Dan, Just I don't actually remember seeing that large O ring, is it just certain applications?
 
Every Slant-6 distributor needs one large and one small O-ring, and that's how every Slant-6 distributor was factory-installed, from the first one in 1959 to the last one in 1987. O-ring part numbers stayed the same that whole time, too.
 
Seriously don't think I ever had a core with one, thanks have to get some then.
 
thanks for all the comments. Update: So I took the old Oring down to Oreilys, the Dorman selection had 1 opened pack of Misc Orings, supposed to be a 12 pack of assorted, there were 4. There was also a special "Distributor" package with 6 oRings, some black and some Tan. Those were too small. So I went to the counter to complain about the lack of Oring selection, when he pulled out a red case , opened it and there was a nicely laid out selection of Orings. I found the right one (a little thinner than what I had, but the right size), he rang me up $2.20...for 1 oRing. Installed and no leaks.
 
slantsixdan said:
That thread is here. Also see here.

Halifaxshops, it's probably staring me in the face, but what are you asking me to notice about one or the other distributor in your pic, aside from one having and one not having the large O-ring?

Anyhow:

Chrysler P/N for the top O-ring is 2095 740, discontinued, and the inner diameter is 1.068". Buna-N is an acceptable material. Find it around as a "size 121 round O-ring", such as here (a hundred of them for under ten bucks) or here (one for 35¢, but shipping will probably make it more worthwhile getting the 100-pack, then when the end of the world comes you'll be prepared).

Chrysler P/N for the bottom O-ring is 2095 630, discontinued, and the inner diameter is 0.920". I'm pretty sure it's a size 021 square O-ring such as this (where you can also read about Buna-N material's characteristics), though it's been long enough since I scrutinized one of these that my recollection of them as square-section could be wrong—they might well start out as round and the outer diameter gets squished flat with pressure, heat, and time. Also possible it's an 020-size ring (outer diameter 1.004") or an 022-size ring (outer diameter 1.129").

These size numbers apply whether you're getting round- or square-section O-rings, so google searches are easy.
Click to expand...



Dan this is great info , can you tell me what the size is on the bottom seal of the 1972 - 1985?

nos - jpg.jpg
 
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