Vacuum Questions
Thread Starter
Le Mans Master
Joined: Oct 2006
Posts: 8,941
Likes: 35
From: El Cajon California
Vacuum Questions
I have vacuum questions
1978 L-48 ....
1. I want to make sure that the distributor vacuum advance is connected to ported vacuum.
2. I want to make sure the other connections are to the correct vacuum source.
3. Is the check valve bi directional, in other words doe it matter which way it faces to the carb?
4. The TVS units, does it matter if the vacuum source is either on the top or bottom of the unit, or does the unit just open?
5. I can turn the TVS unit's ports, is that ok?
IS THIS OK?
1978 L-48 ....
1. I want to make sure that the distributor vacuum advance is connected to ported vacuum.
2. I want to make sure the other connections are to the correct vacuum source.
3. Is the check valve bi directional, in other words doe it matter which way it faces to the carb?
4. The TVS units, does it matter if the vacuum source is either on the top or bottom of the unit, or does the unit just open?
5. I can turn the TVS unit's ports, is that ok?
IS THIS OK?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
1) Why? It will just run hotter and use more fuel when at idle. (just because 'the factory said so' is not a good reason)
2) OK. You have the diagram to do it.
3) No; and Yes...the end you can 'suck' through goes toward the intake fitting. If you can 'suck' through both ends, the check valve is bad.
4) ??? [Not sure what a TVS is.]
5) ???
2) OK. You have the diagram to do it.
3) No; and Yes...the end you can 'suck' through goes toward the intake fitting. If you can 'suck' through both ends, the check valve is bad.
4) ??? [Not sure what a TVS is.]
5) ???
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I have vacuum questions
1978 L-48 ....
1. I want to make sure that the distributor vacuum advance is connected to ported vacuum.
2. I want to make sure the other connections are to the correct vacuum source.
3. Is the check valve bi directional, in other words doe it matter which way it faces to the carb?
4. The TVS units, does it matter if the vacuum source is either on the top or bottom of the unit, or does the unit just open?
5. I can turn the TVS unit's ports, is that ok?
IS THIS OK?
1978 L-48 ....
1. I want to make sure that the distributor vacuum advance is connected to ported vacuum.
2. I want to make sure the other connections are to the correct vacuum source.
3. Is the check valve bi directional, in other words doe it matter which way it faces to the carb?
4. The TVS units, does it matter if the vacuum source is either on the top or bottom of the unit, or does the unit just open?
5. I can turn the TVS unit's ports, is that ok?
IS THIS OK?
1.) On a Q-jet, the ported vacuum is on the front of the carb, pointing straight forward, on the driver's side of the carb. On a Holley, it should be directly above the idle screw on the passenger side of the carb. I recommend hooking your vacuum advance to full manifold vacuum.
2.) Sorry, can't help ya there.
3.)If you don't understand that a check valve is, by definition, a one-way valve, then you probably don't understand the function of the check valve. All it does is allow the vacuum system to be exposed to manifold vacuum when the engine is running, but when the engine is off, atmosphereic pressure can't get into the system, "saving" the vacuum in the system. On a properly operating vacuum system, you should be able to open and close the headlights a few times, just on the residual vacuum in the system.
4.)I have no idea what a TVS unit is.
5.)See #4.
Hope this helps,
Scott
Burning Brakes
Joined: Mar 2010
Posts: 943
Likes: 15
From: Valdosta Georgia
TVS is Temperature Vacuum Switch, and it controls the EGR and EFE on these engines. As the engine warms, the switch controls vacuum signal to the heat riser and the EGR valve, and in addition the evap canister. You have a great diagram, so hook it up the way the diagram shows with the lines going from the appropriate ports to the equipment it controls. Turning the ports on the switches may result in snapping them off, so proceed with caution.
Racer
Joined: Nov 2004
Posts: 485
Likes: 1
From: Oakville ON
Scotty - here goes
I just spent over an hour answering your questions in detail but CF ssems to have dumped my answers.
If you want to phone me after 12:00 EST I will be happy to walk you thru it. 905 338 1434
Richard Rich's'78
If you want to phone me after 12:00 EST I will be happy to walk you thru it. 905 338 1434
Richard Rich's'78
Last edited by Rich's'78; Jul 17, 2011 at 09:56 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Rich's 78...
Just some feedback: If you were taking that long to write a response, chances are the system automatically 'dumped' you....assuming that 'no activity' for that long meant you were no longer on-line. I don't think a moderator pulled the plug on you. I've had the same thing happen; I think about 15 minutes or so is the time limit.
Just some feedback: If you were taking that long to write a response, chances are the system automatically 'dumped' you....assuming that 'no activity' for that long meant you were no longer on-line. I don't think a moderator pulled the plug on you. I've had the same thing happen; I think about 15 minutes or so is the time limit.
Racer
Joined: Nov 2004
Posts: 485
Likes: 1
From: Oakville ON
Rich's 78...
Just some feedback: If you were taking that long to write a response, chances are the system automatically 'dumped' you....assuming that 'no activity' for that long meant you were no longer on-line. I don't think a moderator pulled the plug on you. I've had the same thing happen; I think about 15 minutes or so is the time limit.
Just some feedback: If you were taking that long to write a response, chances are the system automatically 'dumped' you....assuming that 'no activity' for that long meant you were no longer on-line. I don't think a moderator pulled the plug on you. I've had the same thing happen; I think about 15 minutes or so is the time limit.
I was at the computer the whole time. Pi**ed me off!
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Thread Starter
Le Mans Master
Joined: Oct 2006
Posts: 8,941
Likes: 35
From: El Cajon California
Rich -
I can give you a call tomorrow after 12:00 tomorrow. I don't have an AIM book, maybe in a few weeks I can look into that. Sorry the system timed out on you.
Mark
I can give you a call tomorrow after 12:00 tomorrow. I don't have an AIM book, maybe in a few weeks I can look into that. Sorry the system timed out on you.
Mark
Burning Brakes
Joined: Mar 2010
Posts: 943
Likes: 15
From: Valdosta Georgia
Sometimes its best to write long posts in WordPad or some other word processor, then paste it in here. That way you don't lose all that time and effort, and if you ever need it again, you have it saved on your hard drive 