Hesitating Holley

[Salvatore]

Hey Marlin. Call Pete (610)326-8322 He will help you out!

[YENKO DEUCE REGISTRY]

Sam; That's where I plan to go after I get the carb back on! I figure I will be able to bring it over to him on a Saturday morning to have him check it out, and go over the setup - if we could get a rain-free weekend around here!

[John Brown]

Marlin, just one more thing. If your accelerator pump spring (the one that has a bolt thru it that pushes on the acc. pump lever) is a late style Holley red spring with the bolt head on the pump arm and a chrome looking ny-lock nut on the top instead of the 1970 style spring and bolt set-up, then the spring is usually too soft, and you won't get an immediate pump shot. On most every Holley I do, I use the early style spring and bolt and tighten up the thru bolt a bit to make it firmer, then re-bend (in a slight curve) the arm that runs on the accelerator pump cam to get rid of slop in the linkage. [img]/ubbthreads/images/graemlins/burnout.gif[/img]

[Zman]

Hey Marlin,
Sorry to butt in....
There's been a lot of discussion regarding Holleys on the "other" site lately. THE largest contributer to an off idle stumble is the Power valve. There are a couple different recomendations, but I have found that if you start with a power valve rated about 1/2 of the manifold vacuum, you'll be pretty close. In your case, you have around 20" of manifold vacuum, so I'd try a 10.5 primary power valve. You may have to experiment a bit to find out which one works best, but they're cheap, and simple to change. I would NOT recomend blocking off the power valve for a street driven car.
Ignition man on Steve's site is an X Holley employee, and 64pronova seems to know his stuff, and has helped several guys get their holleys dialed in.
I just went through this same thing when I changed engines in my 69 nova. I have a pretty radical solid cam (548 lift adv. 304* 264*@.50 duration with 108* seperation) and I have only 7-8" of manifold vacuum. The new Holley double pump I just installed (on a Victor jr intake) comes stock with a 6.5 power valve. In my case, the power valve was pretty much open all the time, creating a rich condition at idle, and poor throttle response. I changed to a 3.5 power valve, and the idle cleaned up, and the throttle response improved dramaticly. I may experiment with shooter size, and acc. pump cams, but just the power valve alone made a big difference.
In your case, I'd guess the power valve is too low, and not opening soon enough. I think you're just masking the real problem by changing shooters, and acc. cams. The main jets will have little or nothing to do with the off idle condition. I would suggest that you put everything back to stock, and start with the correct power valve. THEN experiment with shooters, and pump cams until you're happy with the performance. I'd be willing to bet that with the correct power valve, you won't have to tweek it much to get the desired performance.
Hope this helps,
Dennis

[YENKO DEUCE REGISTRY]

Dennis;
Thanks a bunch, I will do exactly that - check the power valve to see what is in there. I didn't put the carb back together yet, so I will check it tonight. I have to get the carb back on the car soon, there is a show this weekend!

[Chevy454]

Upon reading this thread, and after having Pete and JJ tell me (for YEARS) how I need to set up my carb, I finally listened. I was planning on heading to Memphis Thursday night with a buddy of mine, and figured I'd try and "fiddle" with the carb a little since I was going anyway. So, I put a 6.5 power valve in the front, blocked the rear, and took a stab at the jetting.

The primaries were pretty close, but it took me a few trys to get the secondaries where they needed to be. But, I think it worked out ok...


I was rather impressed with the majority of my lights last night, as I had several 0's...

[COPO PETE]

Congrats Rob! 12.60's are just around the corner! Just think how fast these magazine cars of the late 60's would have gone if they actually had time to really dick with them! [img]/ubbthreads/images/graemlins/[/img]
Peter

[YENKO DEUCE REGISTRY]

Wow! Well done Rob!

I need to thank Pete as well! I put Pete's carb setup into my Holley this week, and brought it to work today. What a world of difference! Zero, none, Zilch hesitating, so very good throttle response, with very good power through the whole range - better than ever before. I didn't try any 'blast' runs on my way to work this morning in it, but will test it a little bit more on my way home at lunch. I noticed that it revved quicker than I was used to, I was shifting at 5k where I normally shift at 3-4k = fun!!

Looks like I need to get to a track! I'm waiting for your advice to Frank's post as well [img]/ubbthreads/images/graemlins/smile.gif[/img]

[sYc]

Marlin, Glad to see you have the carb problem sorted out. Its amazing what a little "massaging" will do to these cars. [img]/ubbthreads/images/graemlins/haha.gif[/img] Right Pete/Rob?

[hvychev]

Wow. Cool Rob! [img]/ubbthreads/images/graemlins/biggthumpup.gif[/img]