VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 polarity reversing switch - 1948 Style Master

hey guys ,, i have a 1948 Chevy Style Master 6 volt , and i have a question that how to install the polarity reversing switch,,

Welcome to Chevy Chatter!

Do you have a 1948 Chevrolet Shop Manual?

no dude ,, trying to find it

I will share my experience with a reversing polarity switch. I had found a NOS switch and thought I was hot stuff. I got my car on the road in the late 90's. At first the car worked fine. Eventually you would being driving along and the car would just die. Drift off to the side of the road, hit the starter and it would start right back up and you may finish up the drive with no more problems. I thought I was having a gas issue. Installed an inline filter back at the tank and still same issue. This went on for 2-3 years. The wife said many times get someone to fixit. I said you can't fix it till it totally dies. Finally one day it did just that. I called a friend who worked for a Chevy dealer ship in the 70's. He came, rips off the cleaner, puts his hand over top of the carb and says turn it over which I did. He say well its not a gas problem. Walked to the other side of my car, shines flash light down in at the switch and immediately says there is your problem. He started at a Chevy dealership in 1970 and one of the first things the shop manger told him was if you see a car come in with one of those damn things on, take it off and throw it away. I took him back the his shop and he got some jumper wires, by passed the switch and the car fired right up. I hooked up the car without the switch and she has been purring every since.

The switch was first used in 1941, Caused roblems. After WWII an improved version was used. Still caused problems. Chevrolet at last discontinued the switch in MID 1948 so not all 1948's had one.
The cars that were factory equipped with a switch used a diffeent set of points due to reduced room in side of the distributor.
When it is remove a ground wire must be connected to one of the terminals on the dist. and connected to the block for ground.
If I had a car that still retained this "feature" I would be sure to disconnect it.

The Filling Station has the 1948 Shop Manual. Price is $22. TFS

If your starter case is original it may have the two small bolt holes for mounting the Reverse polarity switch. If so then to keep it original, I would not remove the switch but install in in such a fashion to make it appear as though it is functioning. I don't know how to do this but I intend on learning.

The switch is fine up to a point. I don;t think they need to be thrown away merely they sometimes malfunction. Remember you are not in as perialess positon as if you were flying or out at sea. knowig the cause of the problem and how to fix/bypass it will save you most of the apprehension involved when you don't.

As the vacuum shift mechanism, the RP switch should not give any reason of undue concern.

just my two cents worth.

Charlie

BTW: And this is the reason for the edit. jD'd recommendation on owning a shop manual is excellent advice. I engourage you to heed his advice and get one. They are worth their weight in gold when needed.

It was found that the switch severd no good purpose other to leave the owner stranded with a car that would not start.
The original purpose of the switch was to feed te current through the points the opposite way each time the engine is started. This was thought to make the points last longer.

It would be possible to kind of disconnect the wiring but make it look functionable....but thr added ground wire necessary to make the engine run and usually was connected to a side cover bolt would be a give-away.

That must be the reason my 48 doesn't have one.

wow thank you guys ,, it seems this is an active forum ,, so guys you recommend to buy a shop manual + the polarity switch keep it as show only not function ,,

actually this is what i did i bypass it but my customer was asking me to connect it to keep the car as original ,, but if you guys recommend to bypass to avoid problems on future i will inform him that,,

ok guys the shop manual for these cars can be clear and good quality with colors or hard to find ?

There are online catalogs at this web address. Chevy Old Car Manual Project Another source is ebay 42-48 Shop Manual

Good Luck, Mike

[quote=41specialdeluxe]If your starter case is original it may have the two small bolt holes for mounting the Reverse polarity switch. If so then to keep it original, I would not remove the switch but install in in such a fashion to make it appear as though it is functioning. I don't know how to do this but I intend on learning. [/quote]

I found this it might help. I haven’t tried it yet but I was wondering how to wire my ignition and found it

http://1954advance-design.com/Web%20images/CSN-Oct-48-Polarity-Reversing-Switch.pdf

Corbie

Gene,
Was one of the wires from the RPS to the distributor as a ground? If not why couldn't one of the wires be used as such? Then just bypass the rest. That way there wouldn't be no wire from the distributor to an engine side plate bolt.

This would prevent the use of a ... say 1940 or 49-50 distributor instead of a 41-48 distributor which would carry an incorrect number on its oval ID placate.

Just wondering.
Thanks,
Charlie

To disconnect the switch it is necessary to ground the distributr plate. It can be grounded by running a wire from the terminal that is directly across from the grease cup to a ground on the engine or starter.
The wire (hot wire) from the coil gets connected to the terminal above the grease cup.

Gene,

We know all that. What I'm saying is that the distriburor must be brounded if the RPS switch is disconnected. Why not use the ground wire that is used in the wire harness and then provide a jumper across the hot posts of the switch and thereby provid hot wire to the distributor. The distributor should then work with on reversing of polarity. And one may thereby eleminate the ugly going over to the side pan bolt.

Think this can be done as I have described?

Charlie

I don't have a car so equipped to work with, have not done the surgery for many years so what wire reaches to what, etc. I can't help with. Actually my post was and answer to the original poster as he asked for the wiring.

okay, thanks anyway.

Charlie