Low vacuum...
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,298
Likes: 1
From: Sodertalje/Sweden
Low vacuum...
Today i connected a vacuumgage to my system.I think i`ve read some were that the vacuum should be around 13-20 inc Hg.My system run about 5 :crazy: .I have a very nervous hydralic cam.I also run with a Holley 850 and my friend said that i should change the"power valve" to one that will fit my engine.The Holley is a brand new one..Any thoughts? :cool: :cool: :cheers:
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
Re: Low vacuum... (BB wowbagger)
yeah if you really have 5 inchs of vacuum your power valve is open at idle ..very rich condition and wasting gas and probably washing down the cylinders with fuel...id check to see if you have any vacuum leaks first and then go from there...hows it idle rough?
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,298
Likes: 1
From: Sodertalje/Sweden
Re: Low vacuum... (pats406nitrovette)
Its really rough.I`ve checked for leaks and ive found a couple (Bubba missed to close of som unused t-connections).But now its seems to be no leaks.I have the idle at 1000 rpm,because under that its not stabil..How does the "powervalve"work?Whats its function? :cool: :cool:
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
Re: Low vacuum... (BB wowbagger)
here go here and read it it tells you good info... http://www.holley.com/HiOctn/TechSer...o/TI-222A.html http://www.holley.com/HiOctn/TechSer...fo/CI-121.html
[Modified by pats406nitrovette, 3:43 PM 3/30/2002]
[Modified by pats406nitrovette, 3:43 PM 3/30/2002]
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
Re: Low vacuum... (BB wowbagger)
it should help you out some...is it reallly rich at idle? black smoke when idleing black soot around the tail pipes..?
what cam are you using,and is it automatic or stick
[Modified by pats406nitrovette, 3:45 PM 3/30/2002]
[Modified by pats406nitrovette, 3:46 PM 3/30/2002]
what cam are you using,and is it automatic or stick
[Modified by pats406nitrovette, 3:45 PM 3/30/2002]
[Modified by pats406nitrovette, 3:46 PM 3/30/2002]
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
Re: Low vacuum... (Alwyn678)
Which Cam are you running if its a com cam 292, there is no way it will idle below 1100 rpm. But you should still get a reading of 10 to 12 with that compo. Thats the cam I am running I also removed the holley and installed the Q-jet.
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Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,298
Likes: 1
From: Sodertalje/Sweden
Re: Low vacuum... (73-454)
Yes,there are some black sot around the tailpipes,but it doesent smoke when i start it.The cam i`m using is a Erson hydralic with 251 duration intake,.581 valve lift/260,7 duration exhaust with .581 lift. :yesnod:
I run with a Holley 850 and a manuall tranny...I checked it more carefully today and I´ve got a vaccum around 3 inc Hg..Its pretty low..What size of power valve sits in the carb from factory? :confused:
[Modified by BB wowbagger, 2:31 PM 3/31/2002]
I run with a Holley 850 and a manuall tranny...I checked it more carefully today and I´ve got a vaccum around 3 inc Hg..Its pretty low..What size of power valve sits in the carb from factory? :confused:
[Modified by BB wowbagger, 2:31 PM 3/31/2002]
