Profile Picture

How sensitive is the vacuum advance ?

Posted By BPoland858 15 Years Ago
You don't have permission to rate!
Author
Message
BPoland858
Posted 15 Years Ago
View Quick Profile
Normally aspirated

Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)Normally aspirated (35 reputation)

Group: Forum Members
Last Active: 11 Years Ago
Posts: 29, Visits: 1.7K
After raising the hood on my 1957 T-Bird, I realized that it has a power brake booster that is evidently not working.  The pedal is hard and you about have to stand on it for brakes.  The hose that connects the vacum line from the intake manifold to the booster was collapsing.  At the local auto parts store the guy behind the counter tells me that the original hose has a blockage in it.  Well it won't be blocked anymore I said.  I installed the new hos and viola I now has responsive brakes.  The only problem is that, with the new hose hooked up, the engine will not accellerate.  It just boggs down.  Its loke the vacum advance isn't working.  At least thats what I think.

If the engine timing was set with the power brake booster inactive (vacum hose blocked), would unblocking the hose going to the booster make a difference in how the engine runs.  If it shouldn't, then my guess is the booster has a vacum leak somewhere.  A vacum leak would explain the degrading of the engine performance, with the power brake booster working. 

It's been many years since I worked on an engine (more than I would like to admit), and I need some guidance.

Any help would be appreciated. 

Bill Poland

312 V8 - in a 1957 T-Bird

Baltimore, Maryland

Ted
Posted 15 Years Ago
View Quick Profile
Co-Administrator

Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)Co-Administrator (13.3K reputation)

Group: Administrators
Last Active: 14 hours ago
Posts: 7.4K, Visits: 205.7K

The vacuum to the distributor only works when the idle speed is increased.  As setup from the factory, there is no vacuum to the distributor at idle.  Using a timing light and speeding the engine up with the vacuum advance line hooked up and disconnected and comparing the readings will validate whether the vacuum advance chamber on the distributor is doing its job.  The '57 distributors are also notorious with the ball bearing advance plate freezing or locking in place and preventing the vacuum advance from functioning.

Lorena, Texas (South of Waco)




Reading This Topic


Site Meter