VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1940 distributor remove

Hello from Germany,

today I made some experiments with another carburetor and while adjusting the idle after change I did see that the vacuum spark advance at my distributor is out of order.
Some month ago fortunately I ordered a new vacuum unit at FS just to have it in stock, part FS 173, and it seems now it is the right moment to be happy to have it.

My question: Is there anything special to know about the change of that part? I guess I must get out the distributor to change the new FS 173 vacuum unit which is the bracket and the vacuum device in one part.

The original repair shop book does not say any word about how to get out the distributor, but I have another book, *fix up your Chevrolet*, 6 or V8 engines, 1940 to 1960, and it says:

"Remove cap and all cables. Crank the engine until the rotor points directly away from the engine (at 90 deg. from the block), scratch a line at distributor housing in line with the rotor ( I guess as a re-install mark). Disconnect the the primary connection from the side of the housing. Loosen the adjustment clamp and pull the distributor."
Sounds easy.
Is there anything else to know? Any hidden traps?

Have still in my mind the disaster I had with an aircooled VW beetle engine long years ago.
Had to change the distributor because it was worn out and did not know there is a washer at the lower end of the shaft. While pulling the distributor the washer got lost inside the engine and as followup I had to disassemble the whole engine to get out the lost washer. A "just few minutes" job did expand to a "one week job", just horrible.

Now I hope not to do any stupid mistake like that again.
Better I ask before beginning about possible mistakes or hidden traps while doing that change of the vacuum unit.

All knowledge to learn more is welcome!

Stefan germany

There is a washer below the distributor. When dist. is installed it is between the bottom of the dist. and the oil pump. This is often missing.
The most difficult and important thing is when installing the dist. the tang on the dist. must engage with the slot on the oil pump so the dist. must be all the way down. See what it looks like now so when installing you know where you are at. Some times it drops in place with the first try and sometimes it takes ten attempts.

Good morning,

thanks for reply! Seems it could happen the same diasaster as it happened about 30 years ago with the VW engine. The washer got lost inside the motor when I pulled the distributor.
The connection between dist. and oil pump is important because the oil pump will not work otherwise, am I right?

Since I learned my washer lesson 30 years ago I did never again pull a distributor of an installed engine. Did pull it only if I had the engine in parts because of the washer and before re-install I did "glue" the washer with some grease at its place.

Am a bit scared now about what could go wrong again...

Stefan germany

some hours later;

was downstairs in the underground garage where it is strictly forbidden to work on cars (another problem) to check out the situation.
The original vacuum can for spark advance is a seperated part, connected with the bracket by bolts and screws.
I guess I should better forget to pull the distributor to get in the new FS 173 spare part which is one piece, bracket and can riveted together.
Better I find a way to seperate bracket and can as it is at the original one and adapt the new one for mounting like the old one by bolts and nuts. There is no need to mount a new bracket as long the original one is good.

For me it is too much risk to pull the distributor and maybe loose the described washer anywhere inside the engine.

As well I MUST reduce the work on the car to a minimum, at least at night not to get in trouble with the rude housekeeper.

Will need some days to create an idea how to modify the FS 173 unit. Will let you know what happened later.

If the oil pump is in place it will keep the washer from dropping into the oil pan. Good luck getting the repair done before the housekeeper discovers you.

If a washer falls into the pan there is nothing to worry about as it will stay on the bottom and not harm anything.
Actually in the later years no washer was used.

Hello Stefan,
sorry for taking over your Thread, but its the same theme i guess. Yesterday want to reinstall the distributor on the restored engine. He was a little bit rusty ;),



The points I changed because the spring was broken. Removed the breaker plate to check the function of the Advance Mechanism, too.



Its my first time see a Distributor in Details and so i have some Questions for the right Installation. If i understand the Thread above right, the crankshaft must be in defined position to install the Dis. correct. Because at the moment he doesn´t fit correct



The washer, as you can see in the Photo is for the right position to the oil pump?
What means A and R?



The Metall Cap is filed with graphit grease to lubricate the Distributor. Shaft?



Is it necessary to dismantel the complete Distributor, clean it and do new grease

The A and R is advance and retard for adjusting the octane selector (timing) so theowner could set the timing for the grade of fuel being used. (see shop or owners manual),. The washer I refered to is between the oil pump and dustributor housing down inside of the engine. There is no washer used at the location of the red arow in the picture.
Graphite grease is not necessary at that location. If you just clean the old grease out of the cup it will be OK as the passage is short and will not contain much grease. The cup is to be turned down a turn or two every 1000 miles.

Hello Stefan,

I understand your concern with losing the washer. It mainly serves as a flat bearing surface to raise the driven gear on the shaft slightly. This gives better alignment between that gear and the gear on the camshaft.

As always, Gene is giving good advice. If the washer falls it will go directly to the bottom of the oil pan and not cause any problems. It will be resting well below the dipper troughs and the screen on the oil pump will prevent it from getting into the oil pump.

My experience is that the washer either stays in place or actually sticks to the shaft and bottom of the gear due to the oil on everything. If it stays in place I simple stick a magnet retriever tool in the hole and pull it out. When I get ready to reinstall the distributor I hold the washer on the shaft and gear with a little grease.

Based on your posts I know that you have the skills and knowledge to quickly remove the distributor with no problems. Just mark where the rotor is and do not turn the engine while the distributor is out. As you pull the distributor out you will see the rotor rotate slightly due to the bevel angle in the gears. That is where you need to position the rotor to start the reinstall of the distributor. You will need to check the timing when you reinstall the distributor.

I would suggest that given your work situation you should remove the distributor. You can do that in 15 minutes and then take it home so you will have plenty of time to work with the vacuum advance unit, If you are like me you hate being rushed when you work on a car because that is when you make mistakes. Plus it reduces the
fun" factor!

Hello Rusty,
Stefans post is from 2014, think the problem is no longer a problem

Thanks for letting me know. I apologize that I missed that date. I only looked at the dates for your and Gene's posts.

Hi Gene, thanks for Reply. Can´t remember that there was a washer when disassemble the motor. Look at the arrow on the picture, is this the right place for it? How can i check the right measurement of the washer?Cant find anything in my manuals.
The grease theme makes me wonder, than there is grey grease inside, so i thought this was graphit grease



@Rusty 37 Master - No Problem

Yes, there is an oil pump thrust washer at that location. The information regarding the oil pump thrust washer is in the Chevrolet parts book. The washer is 1/2" I.D. x 7/8" O.D. If you don't have a Chevrolet parts book you might look into purchasing one.

Yes, there is a flat washer at the location. It is the demensions mentioned above and 3/64" thick.
I would bet that the washer is missing on more than 1/2 of the cars where it is required.

Graphitereaseay have been used by some one in the past but cup grease is what is specified. I use wheel bearing grease in my cars.

Hey guys. I'm going to add something else to the "missing thrust washer" scenario. I used to think like everybody else, that it really didn't matter much if it's missing. But then I saw an article that brought up a new point of view and it made a ton of sense to me.

You can find my discussion POSTED HERE. While I have it posted as a comment for 1931 Chev owners, it is also applicable to all years of cars. The KEY to the issue is that the distributor has HELICAL gears. So when you move the distributor UP or DOWN (due to a missing thrust washer), it changes the timing of the distributor. I agree that it's not much, but still, if you are trying to get optimum performance out of your OLD engine, then you need to pay attention to all of the clearances -- including the thrust washer. Let the discussion begin.

Here's the relevant paragraph on my web page.

I have disassembled 5 or 6 engines through the years and do not ever remember coming across the oil pump thrush washer in any oil pan or still on the distributor shaft. Thanks all for calling attention to this potentially missing part and its importance. It does take a village to understand some of the engineering behind our cars. Here is a picture from the online 1929 -1954 Master Parts Catalog of our oil pump with the washer clearly displayed (part # 1.666) Oil Pump Illustration

I guess I need to add this to my list of repairs I need to make on my 41!!!

Best wishes to all, Mike

P.S. Great pictures Andre. Also be aware of a very small part in the grease cup called the Bakelit Plug Illustration of Distributor Parts from 41 Shop Manual. I have found it missing in some of the distributors I have refurbished (cleaned up). Personally, I would take my distributor all apart to give it a good cleaning, painting, and lubrication, since you have already removed it from your engine. Lots of luck finding your oil pump thrust washer!!!

Great, much response, thanks. I have all books and manuals about my Chevy. Now I know, what I have to look for and will find it too
Next time will post more news about my frame off Resto.

Another question, I don't get any information when you answer my posts, what is wrong?

The PM Email service is no longer working .

Hi all,

Does anyone have a source for the washer mentioned in the above posts (part # 1.666)? I tend to look on the McMaster-Carr website for this type of item, but my math skills are not up to the challenge when a 3/64 thickness is mentioned and McMaster's uses mostly decimal points in there listings. I did see McMasters also supplies Thrust Washers. Is this specific type of washer also important to use on our distributors? The Filling Station stocks a Thrust Washer for 29 to 36 oil pumps, but does not list them for other years . Chev's of the 40's does not list the part.

I guess it is lunchtime so will use that as an excuse to not try to figure this out myself.

Thanks, Mike

Just this moment seen this at the start page

Hi Bill, thanks for this helpful information. Indeed my DIS has this clearance and when i think about your story this makes sense for me.
@ Mike - much better Illustration than in my 1929-1940 Parts Catalog. There is no thrust to see - only the number 1.666. Think i have to refurbish the DIS complete, to get out the old grease. It is really interesting to learn every day more about the specials of my/our cars

P.S: Bill, you know i am the Picture Man Sometimes they tell more than words..

To see a picture of the washer go to the oil pump picture rather than the distributor picture.

There ist a little Problem refurbishing The Dis. The gear Pin is hammered...?? And it seems there is no Bakelit Plug

Carefully grind the "hammered" surface and then drive the pin out the opposite side.

So i thought, but i had some fear to destroy the shaft. But no problem, the Distr. is disassembled.



Found the Bakelite plug too, but its not in good condition - is it possible to use it again? What is the Function of this? Reduce the grease amount? The plug has worn the shaft a little bit, but that should be no problem for the function.



In the cam Assembly i found another plug, not Bakelite but like Air Filter Material?!



The washer under the Vaccum Advance will not use again....

All Distributor Pictures - https://flic.kr/s/aHsmhJWJzL