Ported Vacuum Switch

[Olds luvr]

Hello all,

As the winter projects begin on the convertible another part I am unsure of where to find is the ported vacuum switch. It seems that the aftermarket ones do not have the connectors on the top. Where can you find these and if not what are the options? Mine has a busted port (the very bottom one closest to the manifold)

Does anyone have a used one for sale?

Thanks as always!!!!

[ent72olds]

I see them on e-bay quite often...

[Olds luvr]

I have been looking but have not found any on there in a couple months or so and just wondering if there are other options. i have even considered trying to repair that port as that is the only this wrong with mine

[New'n72]

Olds luvr,

Are you speaking of the Distributor Vacuum Control Swith, with the one port in the center of the can on top and three ports on the shaft?

[Olds luvr]

Yes that is the one....Here is a picture just to be clear

Thanks,

[New'n72]

I have a 1972 also and I wanted to replace this switch but have yet to find a source. Mine is not necessarily bad ( I wanted a spare) but if this is the switch you are asking about, I was told that it was only used on the 1972 model year cars and finding one will not be easy. Probably a take-off from a parts car would be the easiest way to find one.

I have yet to see one on E-Bay.

There are ways to baypass portions of this switch but you will have to talk to someone more knowledgable about this than I. I know it can be done because it was bypassed on mine by some mechanic years ago and I put it back to original when I got the old girl running again, last year.

[Olds luvr]

Thanks for the reply. i wonder if mayber tyring to repair mine may be the best bet as of right now the port is open with no vacuum line running to it as it was busted off flush with the shaft when I bout it and there are no capped lines or open lines so I am sure that I have a leak somewhere and maybe that is why the car is very sluggish at a start?

Any other Ideas?

[New'n72]

I don't have a way to scan the page from the 1972 Olds Service manual so I'll try and do this with words.

The bottom port on the shaft goes to the manifold. It is labled Port - MT

On my engine there is a small 5 or 6 inch hose connected to this port on the switch that runs to a "T" connector. The right side of the "T" (looking at it from the front of the car) goes to a fitting, right/front, of the carburator, on the engine manifold.

The left side of the "T" runs back towards the FireWall.

If it was a little nicer weather here I would back it out of the garage and try and get some pictures but it's cold and I'm nursing a cold so......

Hope this helps?

[Olds luvr]

No problem I appreciate the help none the less. I guess another thing missing from mine would be the "T". I assume yours is all original and the T is right into the manifold?

[New'n72]

This is a digital photo from the Service Manual.

I appologise for the lack of clarity but it was the best I could do.

I think you can read everthing. The drawing is not in perspective. The attachment to the manifold is over on the right front of the carburator but at least you can see where the ports go by name.

Vacuum Switch.jpg

[Olds luvr]

Ok Thanks,

So The T is just a plastic one in the lines. I guess I will add to my projects a complete vacuum hose and routing as I do not believe mine are right. i am not sure that the original owner had going on but there is no t and the busted port is just open.

here is a question that may sound dumb but in the picture it say "to modulator"....What modulater are they refering to?

Thanks again

[New'n72]

Somehow I just knew you would ask that question.

I don't have a clue.

I will copy the written discription out of the service manual but I can tell you now the written discription does not mention the "modulator".

If it ws a bit warmer and I felt a little better I would pull the air cleaner and snap a couple photos. Maybe tomorrow or sunday. That way you can see where the hose goes and we don't have to worry about 'names'.

Text discription to follow.......

[Allan R]

Originally Posted by Olds luvr

Hello all,

As the winter projects begin on the convertible another part I am unsure of where to find is the ported vacuum switch. It seems that the aftermarket ones do not have the connectors on the top. Where can you find these and if not what are the options? Mine has a busted port (the very bottom one closest to the manifold)

Does anyone have a used one for sale?

Thanks as always!!!!

Sorry, I posted wrong information, so i deleted it.

[New'n72]

Ok, here's the text from the service manual. and a photo of the switch with the ports labeled.

DISTRIBUTOR VACUUM CONTROL SWITCH

All cars except 350 cu. In 2Bbl. Manual transmission, non-A/C cars will have a distributor control switch assembly. This unit is used to advance the ignition timing when the transmission is in third or forth gear or when high coolant temperatures are encountered at idle.

With the transmission in first or second gear the solenoid is energized, the valve plunger is sealing off port “C” (carburetor), opening port “V” (vent) to atmosphere depleting any vacuum that might be present in the vacuum advance unit. In third or fourth gear, the solenoid de-energizes allowing the valve plunger to move down sealing off the vent port. When this happens, vacuum is directed from the carburetor through port “C” and out port “D” to the distributor vacuum advance.

When the engine coolant temperature reaches 210 degrees F, the valve plunger begins to move upward sealing off the vent port and opening up the port “MT” (manifold). At 218 – 224 degrees F, full manifold vacuum is directed to port “D” (distributor) and the vacuum advance unit regardless of transmission mode.




Vacuum Switch 002.jpg

[J-(Chicago)]

Do a search on here for: TCS or T.C.S.
(transmission controlled spark)

The modulator is on the transmission, to vacuum control the shift points.
There should be a metal line going from the trans modulator to the top of the intake manifold near the distributor somewhere.

[Olds luvr]

Thank you J. I do have that line running from the trans connected to the manifold. Is it supposed to run from the trans to the vacuum switch or to the manifold?

[New'n72]

The metal line runs up to the top of the engine. I can see where the hose connects to it without removing the air cleaner. A short section of hose connects it to one side of the "T" connector. The other side of the "T" goes to the manifold and the post of the "T" goes to the bottom port on the switch.

That first photo I attached show this.

[Olds luvr]

Ok, Looks like I need a T for my manifold as well as the modulator line just runs into a single port on the manifold.

So looks like I was right about having to do all the vacuum lines as who knows what has been modified.

[J-(Chicago)]

I have 2 extra TCS units here in my garage. Since they were a 71-72 only option, they are fairly rare. I have seen them go on Ebay for over 120 bucks. You don't NEED them, but folks who are sticklers for perfect restorations on their cars will pay top dollar for them so their car will be factory correct.
I suppose you guys need to decide if your cars are going to be trophy hunters, plain old drivers, or race cars. That will help determine if you need to replace yours or just eliminate them all together.

[Olds luvr]

J,

That is a very good question and I know I have to figure that out. When you say you have the tcs are you referring to the vacuum shitch or the silenoid on the tranny. i hear that switch called a few different names so i want to be sure and PM me and let me know what you want for one.
In addition if I bypass it what has to happen?

[J-(Chicago)]

Here you go.
http://classicoldsmobile.com/forums/...-solenoid.html

The transmission modulator is nothing special. a new one at the local auto zone probably sells for 10 bucks. The 4 port switch is the rare piece.
As far as price goes, I'm not sure what to sell them for yet. I figured I'd put them up on ebay and let the country decide what they're worth. The economy is n't the best, and maybe people will think twice before spending hundreds of dollars on unnecessary parts, maybe not. I don't even know if they work yet, because I always just take them off and bypass them. I've probably thrown away 10 of those things in my lifetime. You should have seen my face when I saw it sell for over $100.
I was mad.... in a confused sort of way. Why in the world do people want THAT thing? Whatever. If it makes someone happy I guess.

People think I'm a moron for fixing 80's Delta 88s Just one of those aspects of life that are never quite understood I suppose.