I think the snap ring is like a wave washer + was never flat. You can reuse it, it's not a critical fastener. The Corvette places have most of the parts like the seal available. Good job! Wait a minute......where's the ground wire that should be soldered onto the breaker plate?
Thanks Frank! This has been an interesting job, for sure. The funny thing is that I didn't set out to rebuilt it, I was just going to clean it. After getting it apart though I'm glad I'm rebuilding it. I think I'm going to try using vinegar to remove the rust instead of the WD-40 rust soak, will report back how it goes.
Be careful with chemicals near the shaft bearings if there is acceptable side play now. You don't want to change those if possible.
There was no side play that I could feel. The manual says to soak the metallic parts in solvent. What type of solvent do you suggest? I was thinking I would degrease everything in solvent first. Then, use vinegar or the WD40 rust soak to get all the rust off. How does that sound? On a side note, what's the grease for under the seal and felt ring? It doesn't look like there are any ports for the grease to escape and lubricate the upper bushing. I didn't look super close though.
About that grease on the weights. Use the points cam grease. Rub it on, then wipe it off. Just a micro film to prevent rust. A slight smear on the resting points under the weights for smooth movement.
* Brass bushing: My old points distributors had a plastic bushing that pressed onto the pin, that fits in the slot, that limits mechanical advance. No one has mentioned this yet....... Some advance 'curve kits" have a brass bushing in the kit along with new weights and springs. I always selected kits that had the brass bushing and installed them onto the pin, because the old plastic ones were broken or gone due to age. The advance specs posted above, were likely determined with a plastic bushing on the advance limiter pin. If my ASSumption is correct, you may need that bushing before you can achieve the desired timing advance as quoted in the above posts. No bushing = more mechanical advance and less available initial timing. I always prefer extra initial and limited advance movement, like 12 initial and 30 advance. Not achievable if bushing is missing. * Shaft spacers: "Excessive shaft end play causes timing variations", so I have heard. If the shaft of a distributor has excessive up-down movement (fully assembled), I always used some distributor shims to get a movement of about .015-.020". There is a shim kit available and I have used shims from junk distributors to do this.
I have a Mr Gasket (I think) recurve kit that has three sets of springs and the brass bushing, so I should be ok there. I was going to order the adjustable vacuum advance kit from Crane Cams which includes the springs but no bushing. I figured I could really dial in the vacuum advance that way with a handheld vacuum pump. Regarding the end play, we measured .065" between the existing shim and the top of the gear. It's not as tight as your spec but would that be considered excessive? If so, which shim kit do you prefer? I didn't see anything in my manual about the end play.
Dave, you'll have absolutely no use for that bushing. That distributor already has little mechanical advance. I like the Crane springs better.
Thanks, Larry! Good to know. Is the endplay of .065" alright or should I expect to get some shims also?
I found this on a Corvette forum. It looks like the distributor end play was/is quite the topic. http://www.ncrs.org/forums/archive/index.php/t-67622.html From ncrs.org: "Lynn----- For whatever it's worth and perhaps to the consternation of some, I repeat something I've mentioned many times before. GM never specified a distributor end play in SERVICE specifications. However, the Delco-Remy PRODUCTION specification for these distributors was an end play of 0.025" to 0.096". Every NOS GM distributor I have has an end play of right at 0.060" which is, curiously, right in the middle of that range. ...not true, Joe. The 1963 Corvette Shop Manual (page 6Y-29) has a boldface note that distributor end play should be .002-.007", and it is not specific to FI engines. I agree that none, except maybe FI distributors were built to this spec, but it sure makes the distributor work better. Duke" Also, here is some info about the symptoms of too much end play (spark scatter): "Duke Williams (22045) February 22nd, 2009, 07:21 PM 'Initially this was my first thought. However afer re-timing the motor, running it up and down, I found little scatter at idle. At most it moved a degree or two.' That's typical for the sloppy as-built end play. Shimmed up to the .002-.007" spec in the 1963 Corvette Shop Manual, the timing mark should be dead nuts on at any engine speed and not show any noticeable scatter. Duke" I think I'll aim for the .015"-.020" range that Gary and Larry pointed out. I haven't had much luck finding shims though, and I don't have any junk distributors to draw from. Would some high quality washers work if they were the same size?
There is a very heavy grease used under the plastic seal that the service manual never mentions because they never thought anyone would get that far into it. I have taken many apart and always thought it looked like wheel bearing grease. So after spending hours cleaning out the old that is what I packed it with. Appears to work.
About that bushing: http://www.corvetteforum.com/forums...-bushing-in-distributor-advance-curve-ki.html POST # 4 ..... "Put the bushing on there and check see what value it has. It can vary with the weights you have in the distributor. Some or most OEM stock Delco with the high cap distributors had a rubber limit bushing standard. These tended to break or otherwise disappear over time. If it had a rubber bushing and it's gone now, you can bet you're over advancing." I agree with the above comment........ The factory installed advance limiting bushing is included when the factory advance is determined. The loss of the bushing results in more advance than the factory intended. The brass bushing is supplied in some kits to remedy the out of spec advance problem. What to do? Measure 1 3/4" to your right from the top dead center groove on the crank balancer/damper and mark a thin line or make a scratch to indicate a 30 degree advance location. With soft springs on the weights, you can rev the engine until the advance stops moving, to about 3000 rpm, and see your second mark advance into the area of the timing marks on your front cover. With the vacuum advance plugged, a 4 degree (or whatever) mark aligned to your scratch mark is actually 30 degrees plus the degree marking it aligns with (34 degrees or whatever). A dial back timing light is not needed with the 30 degree mark on the damper. You can assemble and test your distributor without the bushing, then press on the bushing if the timing spread is excessive. Plug in your vacuum advance and now you can rev to a steady 3000 rpm and get the full total of Initial+ Mechanical+ Vacuum advance. Now you can install heavier springs, if you want, and test those at higher rpm(disconnect vacuum), to see where the peek mechanical advance occurs for road-ready operation.
I soaked the metallic parts in mineral spirits this afternoon but I need to find some pipe cleaners to get down in all the nooks and crannies. I was able to get most surfaces with my small brass wire brush. They are looking much cleaner now but still some work to do.
What do y'all think about the Accel adjustable vacuum advance? The pdf instructions indicate that there are springs and a bushing included even though they aren't shown in the photo. This one looks pretty much the same as the Crane Cams version but appears to be about $10 less. http://shop.accel-ignition.com/igni...s/adjustable-vacuum-advance-gm-points-v8.html
Ok, here's some updates: I soaked the metallic parts in white vinegar for about 5 hours yesterday and the surface rust is now gone for the most part. However, I wasn't able to submerge the main shaft fully. When I came downstairs to check on the progress, the exposed end of the shaft had rusted significantly. I quickly took it out and rinsed it in water to neutralize the vinegar. I was using a plastic coffee can rather than a flat pan and I had put the lid on which trapped the vapors. I guess this is what caused the part to rust so quickly. I didn't get a photo, sorry. The rust came off easily using my brass wire brush and a green scotch brite pad but the exposed surface was not as shiny and I could see a line where surface of the vinegar was. I hope I didn't screw up the section where the lower bushing rides. The moral of the story is fully submerge all the parts you intend to de-rust. There was a black coating on the gear and the weights (I think) that came off with the rust also. I guess that's ok. The smell was pretty strong so I turned a fan on and opened the garage door. After scrubbing with the brass brush and vinegar, I rinsed all the parts off thoroughly in water, dried them as best I could and then soaked them in WD-40. A couple of the parts started to flash rust within a few minutes prior to the water rinse while I was still scrubbing the other parts. Not a big deal but I got a jug of clean water to drop the parts in while I was still scrubbing. This prevented the flash rust instead of leaving the parts in open air for the vinegar to dry on. I also got an old mascara brush from my wife and used that to clean the housing around the lower bushing and in the grease well. Check out the crud that came out. I wouldn't want that junk in my oil! I guess these are the impurities from decades of oil vapor condensing in the tube. I read that the oil condensation is supposed to lubricate the lower bushing as it runs back down the housing. After using the brush, I put the housing in to soak in some no-vapor paint thinner, not milk. I'd still like to get a larger nylon pipe cleaner brush to scrub the housing tube in between the upper and lower bushings. We'll see how it turns out. I'm planning on ordering the Crane Cams vacuum advance Tuesday so I can hopefully get this put together this weekend.
