Holley 600 Vac Sec Probs !!

[trik 66]

Hi Gang !
Have some issues with the New Holley 600 vac secondary i had replaced my old one with on the 289 ( motor just recently removed to make way for a 302 roller cam with alloy heads replacement !!)
Now the new motor is in it feels like the Motor wants to get up and go but has come to my attention that the secondaries may not have been opening at all !! ( Even with the old motor ??)  Does anyone have any words of wisdom or know any Holley Experts that can sort out my "No Show Secondary" problem and maybe see that the jetting is right for this motor ?? I am in the south east suburbs of Melbourne !! Cheers Trik  

[66 Hertz]

What makes you think they are not opening?

[Trans-Am]

Hi trik 66,

The vaccum secondary spring may be too heavy, not allowing the vacuum-operated secondaries, which utilize and increase in load and engine vacuum to gradually pull open the secondary throttle blades.

However, if your engine has an extremely large-duration camshaft where low-speed vacuum (or lack thereof) is an issue, the vacuum secondary set-up may not always be the ideal setup.


Cheers,

Trans-Am:cool:

[shaunp]

Are you sure they don't open? if they don't you may need to change the spring so they come in sooner. They won't open if you are just free reving it.

[booah]

try putting a paperclip on the vertical linkage on the diaphram actuator rod. if the secondaries are opening they will push the paperclip down the rod and when you check after driving the clip should have moved down the shaft.

if this is unclear go to Holley TV and follow the links to get a short video that explains.