Which power piston spring to use?
Thread Starter
Pro
Joined: Jun 2001
Posts: 672
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From: Quebec
Which power piston spring to use?
I just bought a set from edelbrock. The kit didn't include a chart for the vacuum rating at which the spring would operate the piston. The guy at the speedshop gave me those numbers; golden 4"hg, orange 5"hg, black 6"hg and yellow 8"hg.
I thought Lars said that we should take our vacuum at idle and go with one that is 1.5 to 2" hg lower.
I don't think an engine would be running at 6"hg of vacuum at idle(if I apply that to the golden spring).
My engine vacuum at idle is 18" hg. Did the guy got mess up with the numbers or is there something wrong with what I remember.
Thanks
Stephan
I thought Lars said that we should take our vacuum at idle and go with one that is 1.5 to 2" hg lower.
I don't think an engine would be running at 6"hg of vacuum at idle(if I apply that to the golden spring).
My engine vacuum at idle is 18" hg. Did the guy got mess up with the numbers or is there something wrong with what I remember.
Thanks
Stephan
Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Re: Which power piston spring to use? (American Boy)
Those values are correct. I don't understand how to interpret them or give advise based on those ratings. I've heard that you want to pick the one that is 1/2 of your idle vacuum.
You basically want to try them out. I'd start with the black one. If it is too stiff, the carb will flood and/or surge at idle. If it is too weak, you will bog off idle under load. Other than trial and error, I don't know how to select the "correct" one.
Are you experiencing any problems with your current setup? Did you change your cam? I'm just curious why you are wanting to change.
You basically want to try them out. I'd start with the black one. If it is too stiff, the carb will flood and/or surge at idle. If it is too weak, you will bog off idle under load. Other than trial and error, I don't know how to select the "correct" one.
Are you experiencing any problems with your current setup? Did you change your cam? I'm just curious why you are wanting to change.
Thread Starter
Pro
Joined: Jun 2001
Posts: 672
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From: Quebec
Re: Which power piston spring to use? (Chris A)
Are you experiencing any problems with your current setup? Did you change your cam? I'm just curious why you are wanting to change.
Thanks
Steph
