Distributor top bushing lube
 

I came across a Chevy forum post discussing Delco distributor top bushing oiling. Seems this Dave guy might know what he's talking about and figured I would post the information and see what you all think.

https://www.camaros.net/threads/how-...arched.303273/


Question:
It will be quick of a question: How does the grease in the 5 cavities gets to lubricate the top bushing and shaft? There seem to be no path from the bushing to those greased cavities...?

Also, what exactly does the top felt o-ring do? Is it supposed to release some oil down to lubricate the shaft? If that is right... I guess the felt would get dry pretty quickly.

Dave:
The bottom bushing gets lubricated by the engine oil... but the oil can't make it's way to the top of the distributor...
The felt just under the point plate IS NOT there for the upper bushing, but, to lubricate the plate to slip over the body as the vacuum advance moves the point plate/outer reluctor.

The area under the felt, that is packed with grease, usually evacuates the grease fairly quickly. As the engine runs and heat is built up, the grease liquifies and runs into the bushing, which is a composite oilite/phosphor bronze, or open cast steel. That lube works for about a year, then is all gone. The bushing is then lubricated by engine oil mist that travels to the bushing from inside the distributor post.

NOTE: no matter what some "experts" say, not all GM bushings are oilite/phosphor bronze, more than a few were an sintered cast steel. These are the magnetic ones, and work the same with any shaft, are designed to work with lighter weight/viscosity and/or synthetic oils. The sintered steel bushings usually last far, far longer than the bronze ones do, and are more favorable to the steel center shafts. I see far fewer worn out steel bushings/shaft wear than with the bronze bushings/shaft wear.

Some main shafts have a spiral cut into them to help migrate engine oil mist up the shaft to lubricate the upper bushing.

Question:
I'd have a last question for you: I read, at different sources, that I should fill the grease cavities with gauze or felt soaked in oil. You suggest using grease. What is your opinion on that? Would you continue packing it with grease and do it on a yearly basis?
You think that any wheel bearing grease should do? Waterproof or not?
Use a good grade of waterproof wheel bearing grease for the grooves.

Dave:
I use a good grade of boat trailer waterproof grease in the grease holders, and a 30 wgt engine oil for the point plate felt lubricator. If you look closely at either the point or HEI points plate/reluctor holder, there are 3 areas that are open from the circlip area downward into the felt area. These are there so a person can add oil to the felt during normal maintenance of the distributor, that nobody seems to do, probably because the same "experts" tell others that they don't need routine maintenance, especially with the HEI distributors.

Please note, with the upper bushing the way it is, oiling the point plate/reluctor WILL NOT lube the upper bushing below the felt, as the felt is held in place by a plastic seal under it, above the grease.

All bushings are of a compound that doesn't need direct oiling/grease lubrication, MIST lube, as in air/oil in the crank case is sufficient to lube the bushings/shaft.

When I had mine apart on my '65 (stock cast iron unit) I used high temp red wheel bearing grease. So far, so good. Sure beats what was left of what was in there.

Xs two with the above for 35 years.

1. GM has used a variety of "grease" formulations, including oil-wetted sawdust in the upper bushing lube cavity. When it's me, I tend to use plain ol' white grease. No need for "high temperature" since the distributor is only going to get to 250F-ish at most, and probably not that hot. Oil temp might be higher, but the grease is held in the part of the distributor that's exposed to air to cool it.

2. Aftermarket cheap-junk distributors may have the upper bushing, and the grease well. Maybe they even pack the thing with grease. But some of those distributors AREN'T DRILLED between the grease well and the upper bushing. There is NO WAY for the grease to reach the bushing. Thanks, Communist China "Receive and Duplicate"; and thanks to the Communist Collaborators in the USA who can't manage to find these problems before they're released for sale.

3. Expect to have to fabricate a new plastic grease seal over the top of the grease well. Those used to be a fifty-cent part at any GM parts counter. GM discontinued 'em a long time ago. Now the Corvette specialty-houses get a fortune for the few remaining NOS units. The original is probably too old 'n' brittle to remove without shattering.

Geeteeoguy, it kind of makes sense that the wheel bearing grease would work. The part I found interesting was the top bushing is only initally lubed by the grease in the well and then relies on oil mist lubrication to last the next 500 000 miles many factory units do. Looks like Steve has had the same results. I have been using wheel bearing grease for years no issues either.

Schurkey, thanks for your advice and input as always. For the Chinese distributors I wonder if they just apply grease to the shaft and drop it in and some grease ends-up being forced into the grease well. Maybe the bushing is of different material as well I am wondering.

The interesing part was regular oil added to the felt (and the three access holes) but never any grease has to be added to the well as regular maintenance. Seems to support what Camaros.n3t Daves post is saying. It also looks like no magic grease needed either.

Have a look at the top of this section in the “street- tech thread archive”.

I think you’ll find something in there that will tell you all you need to know about it, and likely more than you wanted to know.

Read the sticky thread on distributor grease and had a lot of good info. Just nothing saying the grease is not really needed like Camaro Dave stated in his post. From his information the adding of grease is more a feel good exercise than one of purpose. The part that I have problems reconciling the above information is:

1) Thousands of Chinese distributors in service with no grease to the top bushing and almost zero problems supports oil mist lubrication. Bad electronics.

2) Types of bushings GM used do not require grease to function correctly. Top bushing is under low load as well.

Makes me wonder if coating the shaft with a light film of grease is all that is needed and what the Chinese do now.

Has anyone pulled a distributor that they filled the wells with grease and still has them full after a year? And then repacked the wells as needed to keep them full? If this were the case in the design, should the top bushing grease well not have a grease zerk for regular maintenance?

Running that dry, is equal to running an engine with no oil.

You wouldn’t do that, so not sensical to try.

It’s 1:00 pm here and I’m on way to machine shop to get a couple issues corrected. (Yes, the guy that owns the shop and I are that tight)

I’d like to come back to this later today. Plus if anyone is interested, it probably be a good thing to update some 13 year old info anyhow.

Honestly, as far as the offshore stuff is concerned, aside from the fact that I regularly correct their engineering goofs, I could really give one tinkers damn how they perceive the engineering on the junk they ship over here.

They aren’t dumb. They just figure if we’re too stupid to buy it then we deserve whatever conglomeration of junk they stuff in the box they send.

And historically ….
We keep buying it.
Bout like Charlie Brown kicking that football Lucy says she’s gonna hold…. Lol

It would seem to me that you would want to use a grease that has a low melting point. Since initially, the grease needs to melt and coat the distributor bushing before their oil mist takes over.

:noidea:

Just use some grease/lube that mixes with oil. It can not hurt, only can help. Going dry would be stupid.
Lots of overthinking being done here.

Didn't the cast iron versions have an oil tube?

In here somewhere, or at least at some point in all this, I’m sure I’ll hit in several issues that resonate with those of you reading this.

If you’re not into what I’m typing, that’s fine, nothing wrong with that… move on. If you’ve stuck around this long, let’s see how all this unfolded and where we are in 2023.

Should we even worry about packing that “grease well” with grease?
Of course we should.
Why?
Because that’s the way the GM distributors were designed to work.

Hmmm….
Well here we go.
Ford distributors don’t have anything parked up there. And they do fine….

Dodge distributors don’t either , and they’re fine….

Here’s the deal, And I could honestly spend days and at least a hundred pages on this.

First of all Ford distributor shafts are hard chrome plated day one from the factory. It’s somewhat quite rare to find a Ford distributor shaft that is worn appreciably. Their bushings are a whole different ballgame. We will include dodge stuff in that same category.

The GM shafts never were plated. However the design has always incorporated a grease well in later years or a cotton oiler wick and chamber just beside the bushing on the early early stuff.

In practice all of the GM, Ford, Chrysler designs work in their intended applications just fine.or since “just fine” really has no meaning, I guess I should say they worked well in their respective design parameters.

As we came into the 1955 era most of the GM distributors had up until around 1963 a felt wick oiler/tube affair that was simply a cast iron distributor with a small portion of the bushing wall ground away where the distributor shaft was exposed. On the outside of the distributor housing was a threaded hole that a steel tube with a Gitz Bros. Oiler was screwed into on the housing.there was a round cotton wick that was pushed in that touched the exposed distributor shaft and the wick held oil that was manually placed in the tube. There was an initial lube charge when built and then periodically every 2000 miles the tube was serviced with approx 15 drops of 30W engine oil to rewet the wick.

These worked wonderfully well if the service interval was kept up.

Later they got rid of the oiler tube deal and simply cast a cavity in the top of the distributor housing. GM ran cast iron housing distributors across the board approx up until 1966.
The latest Pontiac iron case distributor I’ve seen was dated early august of 1966. Then they went to aluminum housings across the board, with one big exception… tach drive corvettes used iron case distributors up until 1974. And I’m sure big C60 Chevy dump truck chassis may have used iron also.

At the inception of the aluminum distributors there was a 5 cavity grease well in each and every housing that was to be packed with grease and covered with a plastic grease seal to hold in the grease and keep contaminants out .

I have intentionally posted after typing awhile because in the past this server will time out and I am not retyping all this again if it gets timed out so bear with me here.

It seems GM pretty much used the same type bushing in all the iron case distributors. I’m going on a limb and gonna say something like a 660 oilite type bare bronze bushing. You can usually tell if a bushing is porous by placing it in a hot plate and watching the oil wick out onto the plate. I’ve got a couple of GM prints on these somewhere in a folder that stipulates exactly what they were.

They pretty much ran this deal until the switchover to the aluminum housings, where they kept the same deal for several years after. Somewhere up in the 1976-77 year range, we started seeing a new top bushing appear that had a chrome plated outer jacket. These are carried all the rest of the way through production until Delco ceased manufacturing of the GM housings that we know.

Early on the distributors upper bushings had a single 1/16” hole in them in line with the bottom 1/3 of the grease well. It is worthy of note to explain that the cast iron housings had more of a round trough cast in the upper housing. Therefore one single hole did fine as the hole was supplied access by the whole trough.

The later aluminum housings went to a lighter weight design with 5 distinct cavities, all fairly well sharing access to each other. These designs utilized the commonly seen bushings with 2 individual 1/16” holes opposed from each other.

Over the years the grease changed composition roughly 3 times and very early on the grease was actually a sawdust pickled in heavy weight gear oil. The grease never was of the high temp type for reasons explained later in this text.

The old sawdust packing was to be serviceable for the “life” of the housing . If it dried up, all that was to be done was to reset the base material with heavy weight engine oil and you were back in business.

Later on in the service procedures they stipulated if at any time the “packing” was removed refill with the GM gear and shaft lube. All the while bearing in mind to verify clear unobstructed oil holes in the bushing before filling with gear and shaft lubricant.

I’m not real sure exactly when Delco discontinued Pontiac , Buick, olds, cadillac housings but suffice it to say it obviously was a good number of years before they ditched manufacture of the Chevy distributors. The last true Delco supplied Chevy housings I can remember was somewhere around 2005. After that everything was subcontracted out and this began the appearance of the offshore stuff.

Once upon a time in a land not so far away a guy could wake up and decide since a complete distributor was no longer available from GM, well, he could build one from parts. So that necessitated nothing more than a quick trip to the local Delco supplier. A housing with both bushings installed ( the ONLY way possible to buy bushings from GM was a complete housing) was a mere 34.00. And a complete shaft assy was another 27.00.this was in 1987 dollars but the stuff was there new US manufactured for the mere taking.

This is about when the offshore stuff started showing up around 2005/6

With GM out of the picture, reman distributors were clearly still all over the place. This lasted several years , but the writing was clearly on the wall to be seen. Most of the reman stuff had already been redone(cycled) on average 3 times already. Well something had to give. If you got an average gm reman distributor you were lucky to find remnants of the original ID number left visible on the unit. Notice I said visible, legible was an entirely different world. This started creating all sorts of goofy problems… caps not sitting or registering on the housing correctly, etc.

About this time I’m thinking “ oh boy, this is gonna get ugly fast”.Then one day, someone sends me a new offshore Dist to fix.
Well this is cute. It’s all “new”.
It certainly looked like they were trying to make this thing look the part…since then I’ve seen better, and worse…and a bunch “in between”.

The one thing they’ve never done here, that I’ve been bitching about since day one…. What the hell happened under this pickup coil???

At first, and this is no joke. They were putting the plastic grease seals on these things shipped with no grease under them. That lasted about a year and a half. I probably worked on about 20-30 like that in a year and a half. People still had ready access to originals and somewhat sorta decent remans still.

Soon the things started showing up with no seal AND no grease. Still they were too new to see what was about to happen right off. About 3 years after these things started to be “everywhere” you looked, I get one in that had run about 15,000 miles….and the gentleman was apparently having some issue and wanted it looked at.

I pulled the drive gear off and pulled the shaft and out comes the shaft assy……
Along with it was the pickup coil…
The retainer clip….
And the bushing….
The rest of what was the housing was just kinda powdered up in what used to be the grease well cavity.!!!

This obviously won’t work anymore.

I didn’t really understand what or rather how I was gonna explain this to the guy. But when these things get hot enough they WILL friction weld the bushing to the shaft. And when that cools off, it’s good still….
Until tomorrow when you hit the key, and the starter spins the entire mess and now the housing becomes the top bushing until there’s nothing left. Wash, rinse, and repeat I guess. Pay the little eBay guy his 75.00 and start over…

It took me awhile to put numbers on it but I found that after one drives these things somewhere between 8,000-15,000 miles, one will have serious signs of imminent failure. I got one at work that had only gone approx 300 miles and it already has visible signs of distress at the top shaft.

Now, is it possible that one could design a different bushing and plate these shafts to engineer a viable workaround for this problem? Yes I suppose. But for 75.00 you’ll not see it happen.

These guys are good a copying things I’ll grant you that.
Hell, they copied the thing ringer down to the chrome plated upper bushing like what GM used on the last ones they made.

….but somebody either didn’t understand the engineering behind that desk or possibly didn’t care. GM was smart enough to drill two holes in theirs, these knuckleheads missed that memo I guess.

Of course no need to drill holes, if there’s no grease, which, you wouldn’t need if you weren’t putting in a grease seal, that you don’t need if you don’t install the grease….

The grease itself is a whole other matter. But like was said before. Don’t over complicate it, but I think one needs to understand why it’s there, for what purpose, and how to do it correctly.

I’ll get into that tomorrow.

God bless you and yours, Sun Tuned.

I do not know exactly. But I run iron points (triggers my CD box) distributors. Its hard to find one all worn out. Maybe they oil the bushings better. Maybe they have a larger bushing.
I just know I have found plenty of aluminum PMD distributors worn out in comparison.
All the iron units I have come across have been in good shape and they are older than the aluminum ones.
My brother was having distributor/HEI issues on his bracket sbc. I found him a iron Chevy distributor and let him use a Crane HI6 ignition box I had, cured it.
Simple is good.
Not to say he could not have gotten the HEI working well.

The cast iron body points distributor and seeing little wear is what Camaro Dave was also saying. Me thinks a better bushing material is the key not the grease, or maybe a combibation of both?

Makes a guy wonder if he took two distributors, replaced the bushings and used good shafts with one filled well of grease (and holes drilled) and the other the other just a smear of grease on the shaft during install, if there would be any difference in overall wear?

Also, I never did suggest running a dry top bushing. The top bushing grease well focus seems like it could be splitting arse hairs as my uncle would say. The ol warm fuzzies not an ROI.

Not checking the bushing to shaft clearance or manufacturing quality before commie distributor seizing makes the lack of grease being the cause just a guess really. With everything the commies get wrong are we now assuming their machining, part quality, and installation are correct and that grease would have had that distributor bushing/shaft/housing live a long trouble-free life?

I run all dull body distributors but guys around town have the shiney lifetime warranty ones in service for years and have had no issues. Makes a guy wonder...

I know this is an old thread, but it's the only one I could find on the subject and it doesn't really contain an answer my question. My question is specifically about how the upper shaft bushing gets lubrication - and specifically on the aluminum housing units. The upper well is filled with sawdust impregnated with oil - but - there are no holes drilled from the well through the upper bushing and it is definitely steel and not a permeable material. I know someone stated there's a 1/16" hole, but none of my '69 or '70 distributors have one. The only possible scenario is that the oil seeps down along the outside of the upper bushing until it reaches the bottom where it could migrate onto the shaft. It would then need to wick back uphill to lubricate the shaft-to-bushing contact area.

I agree that wear to the upper shaft does not seem to be a problem and I have seen galling and wear to the lower bushing much more often. I'm inclined to trust the factory engineers and restore it the way it was designed. Dave Fiedler at T.I. Specialty recommends cleaning out the sawdust and repacking with gauze before adding oil which seems reasonable. There needs to be some absorbent medium there to meter the flow of the oil. I don't trust that randomly substituting with grease will provide a steady supply of lubrication, if any at all.

Hi Tekuhn,

As was mentioned in my first post. The grease well was used for the first year until the oil mist primary lubrication takes over. Also, the shaft would be installed lubricated as well for start up so lubrication everywhere for different durations. Keeping in mind the above was the system GM used based on the part technology back then.

The waters are muddied now by the use of sintered oil impregnated bushings in new distributors (soaking in oil before install) to replace the old grease lubrication. Otherwise the internet would be full of posts of guys with seized shafts on new distributors that just stab them in and drive. And this just does not happen with the distributors being sold now. I am sure there were problems with unknown sourced parts (skip white 2010ish?) distributors that he would just send you a new one if the one he sold you crapped out or didn’t work. Probably cost $8 to make and are still floating around in garages and guys hordes today. :D

There are so many incorrect assumptions and statements s steers about in the beginning of and during this thread that theres no way I can properly address the original question until later when I get home from work.

At which time I’ll be most glad to try and clear it all up.
Theres stuff that’s close, and some stuff that’s just simply wrong.

Back later this evening….

After spending a good 35 minutes exposing the answer to your question, when I hit the post reply button….
Nothing!
Gone!

I now know why a bunch of the heavy hitters that used to be here ,arent here any more, and I’m about to be one more added to that list.

What a joke

That has happened to me as well. Sorry about that, but I appreciate the effort....

I checked a 1962 cast iron body that I have, and there is most definitely a small hole drilled through the body and upper bushing so the oil has a pathway from the sawdust to the shaft. That makes complete sense. They could use the proper weight oil for the application and the sawdust meters the flow. The aluminum bodies that I have do not have the hole. D-R would not go to all the trouble of installing the oiled sawdust in that cavity if it was not doing anything. The oil must reach the shaft - I'm just curious what the path is.

I really don't want anyone to spend a lot of time on an answer - I'm currently building a mag-pulse distributor for my '63 project and I'm faced with how to lubricate it. I just get obsessed when I see something that doesn't seem logical.

After a couple decades or more creating posts on various forums I’ve made it a habit to hit the ‘preview post’ button several times while making a long post. That resets the timer.

Don’t type the whole thing. Do it as you compose.

Either that or copy your entire post before submitting it, if it happens to disappear you can just paste what you copied and post it again.

It ain’t all that bad….. :)

Preview post is a good thing. Even then, I can still screw it up.

I was looking forward to your post Sun Tunned and I am sorry to hear your reply was lost. This has also happened to me more than once and started my long replies in Word then paste in to the site.

Anyhow, I hope we do not lose you over a technical issue as you are a huge resource to everyone on this site and a great guy that shares information. Don't let jerks like me drive you off either

I was also looking forward to Sun Tuned's reply!

Lube
 

Picked this up off eBay years ago.

I have had problems with my long posts as well. It is infuriating. But we NEED you on the forum as well as others. I don't do Facebook and likely never will. Don't need the drama and the wasted time.

Been here too long to quit now…

Just chapped my arse.

I haven’t messed with too many distributors pre 1935 , but I’ve had my hands on some 4200+ or so built after 1950 for sure. And I can tell you guys, out of all those, I’ve never seen a factory GM aluminum housing distributor where they’ve oopsed and forgot the 1/16 holes in the top bushing . In a manufacturing deal that’s pretty damn amazing I think.

I promise you theyre there. Now I will say they’ve pressed a good many in where the hole was partially blocked by the support stanchions between the 5 cavities. That will make it look like there arent any if you’re not on your A game looking. The only way I’ve not seen any was either someone in the past replaced it, or a rebuilder replaced it.
GM got it right.

The first of the “modern cast iron distributors utilized a 660 bronze oilite type bushing that was raw bronze and had a notch cut right into the side of the bushing where a cotton wick was pushed in beside the bushing. You could literally see the lump inside the bushing bore when the shaft was removed. This wick was fed by an oiler tube and you were to put 8-10 drops of a heavy grade of engine oil down the tube at every oil change interval at around 2000 miles.

From there they went to the same type bushing without the bitch but then began packing the “well” with sawdust and still utilizing the cotton wick , it just didn’t penetrate the bushing bore. Between the cotton wick holding oil and the oiled down sawdust up top, ypu were pretty good.

Up for pretty much the whole time gm said the distributors “ needed no periodic maintenance outside an occasional 8-10 drops of oil in the oiler tube”
Well… that may in fact have been a bit optimistic. But it’s hard to argue the durability of the things early on.

About the time the sawdust packing showed up was when they started drilling a couple 1/16” holes in the bushing. Now this worked pretty good. I believe it actually worked a bit better than the cotton wick running up against the bare distributor shaft in that people were not quite keeping up on the maintenance an adding oil periodically as they should.

They did that sawdust packing deal for the rest of the iron housing production and I’ve never seen a factory iron housing with regular grease in it unless someone outside gm put it there. They actually ran that on into a few years of the aluminum HEI housing production. Every so often I’ll get an aluminum housing HEI that’s still got the sawdust type packing. You could actually re oil the stuff and replace the plastic grease seal and get on with it. I would however advise bending a small piece of Ty wire in an L shape and as always verifying the two 1/16” holes were unobstructed before I finished that up and replace the grease seal.

I think somewhere around 1978 they finally went to just filling the well with shaft lubricant grade grease. And I’ve seen several color variants of the grease used up until they quit building distributors altogether. That grease post I had in the street sticky section goes into greater detail on that.

When I rebuilt my Apr '68 distributor it did have a pair of 1/16" holes in the wells, and the wells were packed with a sawdust / dried up grease mix. As suggested I ran a fine wire through the holes.

All that junk out of the way, they tried several different things on the shafts to “direct” some trace amounts of oil up to the base of the top bushing. The biggest expenditure they made was a series of spiral grooving at the top end of the shaft just under where the top bushing is.
This deal lasted about 2 maybe 3 years and then you never saw it again.

This business of oil being “sprayed” upwards from the bottom of the shaft is nonsense. Theres none there , not even any decent amount of pressure at that interface anyhow. So just forget that idea.
There is a fair amount of splashing going on around that bottom bushing though, and this was used to their advantage at the bottom to lube it.

There is one situation I will mention that causes oil to pool in the top bowl of the housing… if you have a clogged or inop pcv system or your engine has suddenly developed a severe crankcase pressure event, oil can and will be forced up through the top bushing and puddle inside the bottom of the distributor housing. It is important to note distributors do not suck oil but they can be pressurized to move it up there. This is a bad deal and not a normal occurrence.

So the only thing lubing that top bushing is the little bit of base oil in that grease packed in that 5 cavity well at the top.

And folks have tried all manner of stuff at the top. Ball bearings, needle bearings, bushings , just all sorts of stuff.
Ball bearings are good for a radial application such as a water pump, but not the best for a distributor. They found that as simple and archaic as a lowly bushing is, in the end game a plain old bushing is really the best deal to put in there , as long as it’s not run out of lube or severely undersized for the application.

There will be some folks come by here in a bit and argue this point but that’s fine. I’ve seen the GM data on this, it’s not quite as glamorous for the ball bearing as you’d think. Plus as it ages out and starts to degrade the “junk” that gets produced in a sealed bearing… stays inside and helps to create more junk , faster still.

As far as bushings are concerned, the last ones GM did for the large cap HEIs in Chevrolet was the chrome looking outer jacket, that may be a sintered iron material I’m not sure… I do know when you put a couple of em on a hot plate the oil comes out the middle of the bushing ends and most assuredly NOT from the outside of the chrome plated outer jacket. This tells me if it don’t leak outside the jacket , you not readily gonna put it back in through it either. That’s why they drilled the 1/16” holes in there .

This aftermarket copied stuff… whatever they make the bushings out of , the inside finish of them reminds me of looking at an old style fresh pair of full metallic brake shoes. And when worked I can tell you they just don’t quite spin as free and smoothly as the GM distributor does..

The old ball bearing 985 tach drive Chevrolet distributor was a nice piece. Upper ball bearing in an iron case. There may have been a version of that for the 409 engines, but that I am not sure about. I bet our own Skip Fix would have much better insight on that.

There just wasn’t much in my opinion to be had there as far as meaningful gains over a bushing vs bearing deal. I do believe the bearing was better for high RPM no doubt, but honestly it wasn’t by a large margin. Certainly not given the cost involved. I think ultimately the bushing was plenty satisfactory for performance vs cost and likely the reason they pulled the bearing setup.

I believe Chevrolet was in fact the only gm division to incorporate an upper ball bearing in the housings of their ultra HP units.

I won’t get into the grease thing ,as I think it’s covered rather well in that distributor grease sticky at top of street section.

Maybe this will answer some lingering questions and we can put this to bed once and for all.

distributor knowledge
 

you are an asset to the Pontiac community.

Gerry

Thanks Gerry!

I try to be anyhow.

For arguments sake, does the oil coming out of the top to the distributor shaft in high oil pressure situations not prove there is a path for the top bushing lubrication via droplets?

Virtually none at all.

GM even incorporated some spiral grooving or channeling if you will up at the top near the bushing in an effort to “try” and direct some oil that direction….
Nope, that deal only lasted a couple years at best. If it truly worked theyd have kept that deal going. It crashed and burned graphically.

The oil mist you speak of is in fact a thing… but when you take high mileage distributors apart youll notice that there’s only oil sludge approx half way up the shaft.close, but no cigar as far as spraying or migrating to the bushing. It’s just not making it that far up there, and a Pontiac and olds, and Buick are the shortest housings in the fleet. The chevys are a good 3” longer at least. So the chevys are even worse in that reguard.

As it was designed it worked fine the way they did it. The only thing I would have told them to change would have been change “no periodic maintenance required” to at 100,000 miles replace the grease packing in the grease well around the top bushing. But then they weren’t in that department… you were supposed to buy a new car instead, or if you wrecked a distributor housing theyd be glad to have Parts network sell you a new 32.00 one.

Thank you for your response and clairifications Bob.