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Re: 1967 Tach Drive Distributor Repair and Lubrication
Steven,
Sounds like you did your research before starting on the project. I would like to see what others say about using a tach gear with a brass tip against the brass button, that would be my only concern. Usually the arrangement is the hardened gear against the brass button so I am not sure about that.
I think any motor oil for the upper bushing is fine and the 20wt compressor oil will work with the gauze. I use moly grease on the tach cross gear, you can get a pint at any auto parts store for a few dollars, it's the only lube the gears will ever see but it's the gear alignment that makes them strip and you have accounted for that by milling the button flush with the inside housing. With a stock cross gear and the brass button flush inside there should be some play in the gear but the thrust is inward and that's where the mainshaft/cross gear alignment is important.
When you assemble the distributor make sure to not use any grease on the autocam and advance weights, just make sure they are free and wipe them with some wd40 or similar product. Also, install the lower gear in the same orientation as it came out unless the vacuum advance control was hitting the coil bracket or intake manifold. -
Re: 1967 Tach Drive Distributor Repair and Lubrication
The oil and gauze is basically a nineteenth century homemade grease. Chevrolet may have used that in the early days, but it was later replaced by a commercially made grease. I prefer GM 1960954 Distributor and Starter Motor grease (note the word DISTRIBUTOR in the name) for both the upper bushing grease well and tach drive gears. The lower bushing is lubricated by oil splash.
In the absence of 1960964, which is long out of production, use a synthetic NGLI #2 grease like Mobil 1.
Search for a thread started by me, Dec. 2012, L-79 distributor blueprint/overhaul.
DukeComment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
Thank you for the replies. I've seen many references to using a grease for the upper bushing, and the stuff that I dug out of the well wasn't going to provide any lubrication that I could see. I'm curious as to how the upper bearing survives with a grease and such little lubrication. The bearing bronze must be fairly substantial as well as not having much of a lateral load.
Duke, you referenced two numbers, 1960954 Distributor and Starter Motor grease and 1960964. Is the 1960954 still available?
Thanks,
SteveComment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
Steve, 1960954 shows up as "obsolete" - http://www.delcoremy.com/find-a-part...etails/1960954Comment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
I meant ...954. It was discontinued about 20 years ago.
I've been amazed at how many distributors I've disassembled and found nothing but a few flakes, which are the solids in the originally installed grease, and there appeared to be little or no bushing wear, but there have been many reports of bushings being worn and needing replacement. That bushing does take a cyclic load of two to three pounds from the points.
DukeComment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
It is my understanding the brass buttons came out to save the housings from the wear of the harder original type steel cross gear and were tougher than the nylon originals (added on later models by GM). Then, these cross gears with the brass tips showed up and are billed as new improved design. My take on all of this is it depends on what shape the housing is in at the cross gear wear point. I have read that brass buttons and the steel gear is a bad combo (I believe Lars said that) and when the buttons wear they deposit metal shavings which can ruin the shaft and lower bearing. So with a steel gear, I prefer to use a hardened steel seat. I think the brass ended cross gear could be good on a housing that did not already have a wear point as the gear tip would theoretically wear first and save the housing. In this case, brass on brass may also work just fine if the clearance is sufficient, but I would be interested to see the long term results. I doubt a steel insert with an original style steel tip gear will fail in our lifetimes and the end play can be dialed in. DanLast edited by Dan B.; November 25, 2016, 05:10 PM.Comment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
I haven't had to rebuild a distributor in about 6-7 years now. I have several of my own I went through and at the time I bought the new brass tipped cross gears to use. I found they didn't mesh at all. When I called the supplier I was told they had to file fit the brass to set the mesh. I didn't I would have to do that but I set the new gear up and faced the brass plug a few thousands at a time. It didn't work, so I removed the brass plug and installed a new longer one and faced that through the range again and again it didn't work. I tried 2-3 if I recall and all were bad. I ended up finding a good used GM gear and that worked perfectly.
Have any of you had issues like this today? The mesh was so bad it bound up. I even replaced the main shafts and had the same issue. It was the cut on the gear.Comment
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In Appreciation of John HinckleyComment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
In my case, the housing was slightly damaged to the point that if I tried to use a gear with the brass tip without addressing the housing surface that the gear rides against, it would have eaten the brass tip, and I believe, in short order. After minor machining, I am in the process of putting the distributor back together with a brass button in the housing, and a brass tipped gear in the original coupling. I could use the new coupling I received, but decided to use the original as it was not damaged, and gives a closer gear to button clearance of around .015". I am not worried about the clearance so much, as the gear is going to ride against the housing surface due to thrust anyway, or in this case the brass button. I ordered the tach drive gear from Corvette of America, as they had the part in a kit with the brass housing button, a steel washer and it was available at the time. I have done a dry fit of the assembly, and when assembled, the mainshaft turns smooth as silk with no apparent binding. The one thing I didn't do was to drill and tap for a set screw to allow adjustment of the clearance. I have confidence in the brass on brass arrangement. I would not have that same confidence in a hardened steel on brass as was mentioned. Hardened steel on hardened steel would probably work as well, but I don't know of anyone manufacturing a hardened steel button for the housing.
SteveComment
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Re: 1967 Tach Drive Distributor Repair and Lubrication
Steve, I have not seen a hardened steel button, but there is a kit that basically allows you to drill and tap for a 3/8 steel insert (set screw) which can be used with the original type steel cross gear. You set the insert and adjust the end play, and then you can fill the backside of the hole for an invisible repair to the housing. DanComment
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