Hello,
I have a 53' 308 with a twin H set-up.
On the intake manifold there is a horizontal tube that "connects" the 2 carbs. Towards the front of this there is a port. In mine the port has a plug in it, but in many photos I have seen the port is connected to the fuel pump. I'm wondering if this is the reason the car is not running well. Does anyone know what this port is for?
Any input would be helpful.
Thank you.
Jason,
It's a port for connection to the vacuum side of a double diaphragm fuel/vacuum pump. The purpose of the vac pump was to assist in maintaining vacuum to operate the windshield wipers under high engine loads, like pulling a hill. Back in the day, we'd have to let up on the throttle once in a while to let the wipers take a swipe or two, then pour the coal to her which would slow or stop them again. The Vac assist wasn't entirely effective, but better'n nuthin'.
Ahhhhhhhh. The good ol' days when the sweet smell of blow-by was like perfume to a gearhead.
Frank
Thank you,
So does this port also effect the amount of vacuum on the carbs?
I seem to have a vacuum leak somewhere and am trying to figure it out.
Maybe this is the issue.Do you think by taking the plug out and adding a tube between the manifold and the fuel pump I would see any difference on how the engine runs?
Jason, if that port is plugged, where does the vacuum line from the wiper motor connect? Or do you have electric wipers?
Hello,
The port I am talking about is not the vacuum port on the rear carb that connects to the wipers.
It is on the the pipe that connects the 2 manifold sides.
There is a port towards the front on the motor that connects to a top opening in the fuel pump.
Thanks.
That connection on the rear carb is supposed to go to the vacuum advance on the distributor. When you don't have the dual gas/vacuum ;pump, the wiper motor hose should go to a fitting on the intake manifold.
Jason, that port on the carb is supposed to be connected to the vacuum advance unit on the distributor. (Most Twin-H engines I've seen have had the ported carb on the front, but I don't think it matters). When you don't have a dual fuel/vacuum pump, the wiper motor hose should connect to the end of the "balance tube," where the plug now is. Might look a little cleaner if the balance tube were swapped around to put the fitting at the rear.
Thanks.
I sound like mine is hooked up wrong.
My front carb is connected to the vacuum advance on the distributor and my rear carb is connected to the wipers.
And the balance tube just has a plug.
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