Distributor sitting for years at shop

[Mogordo]

I was looking for a used distributor for my '83 SR5 and found one listed on car-parts.com for a place about seven miles from where I live. I was a little surprised on calling the place to find they still had the part as I live in NE Pennsylvania and don't expect salvage type yards to have parts for my old cars. I went to check it out and on asking the fellow if they test them at all before selling them he told me it had been driven in. He offered to look up the year and I was pretty curious so I took him up on it. The car it came off of was driven to the place in 1999...It had been sitting on the shelf ever since. I really had fun finding that out and wanted to share it in case anyone else gets a kick out of it.

[dlb]

Did you get the distributor? How much was it? Are the vacuum advance diaphragms in good shape? Dizzy's are one of the spare parts I particularly like to keep around. Lots of little components in there that can fail so it's nice to be able to swap a known good one in and rule it out as the issue when problems pop up. Plus they're so easy to swap.

[rer233]

Yeah, whenever I go on a road trip, it's the only thing I carry (along with the tools to change it.)

[Mogordo]

I did get it. But I didn't check it thoroughly yet. I am curious about the vacuum advance diaphragms though. Since the car was "only" sixteen years old when the distributor came off I wonder too how the diaphragms are and if they handled the sitting around without deteriorating. I'll plan to let you know how they are after I get to checking them out. I'll have to get my head back in the Tercel dist. space. I was in it more when I was figuring out timing and vacuum stuff a while back but I haven't done much work on it recently and have been driving my Sentra more and been looking under it's hood a lot more than under the Tercel's. I'm glad the Tercel dist. swap is simple.

[dlb]

From my experiences, I suspect that the cause of the distributor advance diaphragms rotting is largely engine oil contamination from a leaking distributor o-ring. The oil runs down the dizzy and leaks into the advance unit and breaks down the diaphragm material. I've noticed that the tercels I've had that did had not had leaking dizzy o-rings had good advance units, while the ones that were covered in oil had bad ones. I obviously can't be sure that's the cause but I think it has something to do with it.

[Petros]

good find!

you can check each component per the FSM specs with a volt-olm meter. I would lubricate the moving parts with lithium or similar dry lubricant.

I would get some Armorall or similar rubber preservative into the diaphragm chamber to keep it soft. it should be good, but it could still dry out and crack because of the age.

[Nordical25]

This distributor could be also in very good shape if it has been sitting just in the shelf for decades. Some of the distributors mounted into cars have been already many decades in the use, which can result into lower lifetime expectations. But you never know before you test.

[Mogordo]

That makes sense dlb from what you have noticed as far as oil being likely a strong factor in the diaphragms deteriorating.
Does the distributor have to be on the car for any of the component tests? I tested the one that was on the car before removal to the best of my understanding and what I came up with for I think two out of three tests was not what it should be which is part of why I thought it was maybe not working right.
Nordical25 I was thinking similarly about it maybe being in pretty good shape with it only being on a car 16 years instead of 40.

[Mark]

The diaphragms are rubber-coated fabric. The rubber is probably neoprene, or maybe butyl. Both of those have a shelf life of about 5-15 years before they start to degrade. Our cars are about 40 years old, so with exposure to high temperatures near the engine and hydrocarbons, that rubber doesn't have a chance. I'm surprised some of my diaphragm-operated components are still functional.

[irowiki]

Yeah, whenever I go on a road trip, it's the only thing I carry (along with the tools to change it.)

This was one of the first things I learned on this forum way back when and it actually happened to me when the dist died on the interstate, and I changed it at the next exit and we kept going!