Need help - vacuum connections on heater hose vacuum switch

ClanCassidy · Post by **ClanCassidy** » March 9, 2007, 10:00 pm

Hy guys,

I'm reconnecting the vacuum lines and can't quite remember how they went. This is a 2-ported switch connecting one of the heater hoses to the intake manifold. I'm guessing one goes to ported vacuum and one goes to manifold vacuum but don't remember which goes where.

Thanks for the help.

John.

ICEMAN6166 · Post by **ICEMAN6166** » March 9, 2007, 10:10 pm

i never saw that setup on a slick.you must have a later year engine.i would have to look up how they go, but if it was mine i would plug the vac ports on the carb and intake and find a plug or leave the switch in , it wont leak.

ClanCassidy · Post by **ClanCassidy** » March 10, 2007, 8:29 pm

Sorry. It's an early 70's 302.

Hawkrod · Post by **Hawkrod** » March 11, 2007, 1:29 am

Sounds like your talking about a TVS. It is one of the greatest devices Ford ever came up with. Some people will tell you its a smog part and needs to be removed but they are just blowin' wind out of their backsides. The switch is specifically designed to help reduce overheating especially at low speed. It changes the vacuum source from ported in the carb to manifold vacuum if the engine gets too hot. This causes the vacuum advance to kick in which speeds up the engine slightly and reduces heat soak. This allows water to travel a little faster, the fan to spin a little faster and more heat to go out the exhaust instead of being absorbed by the engine during combustion. It is a great item and I would not run an engine without one. The center port connects to the distributor and usually the top one to the carb port and the bottom to the manifold but it is easy to check because unless the engine is overheated vacuum will only flow to the center port from the one that is supposed to go on the carb. Hawkrod

ICEMAN6166 · Post by **ICEMAN6166** » March 11, 2007, 12:58 pm

somehow i just knew there would be an opposite side to this.
i did not say it was a smog control piece.i dont know if that still means i am blowing wind out my rear or not .
i have had no overheating problems without it, and i have been removing , disconnecting or not replacing broken ones, which i have seen many of, for as long as i have been working on fords.
of course i only ever have 2 vacuum hoses anyway, one big one for pcv and one for vacuum advance, so maybe i have a built in bias towards them.
could be it works good in the overheated areas of the country,but i have no experience with that so i cant say.i also dont spend any time stuck in traffic or at stoplights so im not worried about not having one.

i should have just looked up the proper hose installation and posted it without comment on whether it was really needed or not. i certainly would not want anybody to blow up their engine because they listened to what i say or do.

Hawkrod · Post by **Hawkrod** » March 11, 2007, 1:22 pm

My post was not in response to yours. You did not mention smog but many others will. My comment was definitely not pointed at you. Hawkrod

ICEMAN6166 · Post by **ICEMAN6166** » March 11, 2007, 1:32 pm

Hawkrod, you did give a good explanation of how the tvs worked. i see nothing wrong with your point of view on the subject either.