TCS Solenoid Removal

[HeliRN]

I’m in need of some help/direction with my ‘72 Custom 10! I have done TONS of reading about the TCS and I understand it’s not necessary to have a normal running engine. My question is.. what do I do with the hose running to my carb?? The remaining hoses were gone when I got the vehicle and I’m not even sure if I need to look for/cap off any other connections.
I’m a nurse, not a mechanic but I grew up around vehicles and have a basic knowledge of things. A little guidance would be so helpful! Thanks in advance. I’ve attached 2 photos for reference.

[68 P.O.S.]

Remove it and cap it off.

[WETOWM]

What he said

[HeliRN]

Besides the one connection at the carb.. is there somewhere else I should be looking for a port that also needs to be capped? I just see the second nipple on the TCS that was missing a hose, so I assume there’s a second connection point.

[Steeveedee]

The other is for clean air at the carburetor. Reference page 6T-2 of this manual, which was graciously uploaded by a member. You can download it for free!

http://67-72chevytrucks.com/vboard/s...ghlight=hatzie

[AussieinNC]

AS others have responded, just remove it and cap the vacuum source....

I am attaching a pic of the full hose routing as a matter of interest...trust me, you are better off removing it and just capping the vac line at the carb....

[HeliRN]

I can’t say thank you enough!!

[jaros44sr]

I wouldn't throw it out, just put it on the shelf, someone may need it for a complete restoration. first thing I did when I bought my truck was to throw out the bucket seats, as I thought they were useless. check out what the prices are for junk bucket seats, just never know

[68 P.O.S.]

There's the part in the pic you already know about, there's also a relay on the driver's side firewall (some are in engine bay, others under dash above fuse block by horn relay), a switch in the trans, a temp switch on the passenger side head, and extra wiring by the fuse block. If you use the search, there are several useful threads you should read.

Aussie, you may start a war posting a pic that shows the vacuum advance connected to manifold vacuum

[Ironangel]

If you ever decide to go with a HEI distributor the pink 10 gauge wire is a ready made 12 volt power source...

[AussieinNC]

Originally Posted by 68 P.O.S.

There's the part in the pic you already know about, there's also a relay on the driver's side firewall (some are in engine bay, others under dash above fuse block by horn relay), a switch in the trans, a temp switch on the passenger side head, and extra wiring by the fuse block. If you use the search, there are several useful threads you should read.

Aussie, you may start a war posting a pic that shows the vacuum advance connected to manifold vacuum

Lots of debate about ported or manifold vac sources...that image is direct from a GM manual....

"War"...never...I am more of a lover than a fighter....

Each to their own...

[Steeveedee]

Originally Posted by AussieinNC

Lots of debate about ported or manifold vac sources...that image is direct from a GM manual....

"War"...never...I am more of a lover than a fighter....

Each to their own...

Technically, it's "ported" vacuum, since the vehicle won't get vacuum advance until it is in high gear. That's even worse than regular old ported vacuum, really. Guess that could start a "heated three-way discussion"!

[AussieinNC]

After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed. All manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.

If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more.

Enjoy everyone!