50cc accelerator pump usage

[440beep]

Is anybody using the 50cc accelerator pump on their Six Pack setup with success? If so, could you enlighten me with what cam and squirter size you are running please. I swapped in the 50cc pump and I'm having a hell of a time dialing in the low end response from a dead stop. I just want to check before I pull the carbs off again and put the 30cc pump back on.


And yes, I already know that alot of people say the 50cc pump isn't needed, but its already on and I just want to see if anyone is using it with good results first first.

 

[lewtot184]

i've been using six-paks since 1970. there isn't any reason on the planet to put that large accelerator pump on that small center carb. those pumps were actually designed for REO truck engines and should only be used (in my opinion) for large carbs with a lot of plenum volume in a drag race set-up. a six-pak is neither of these situations.

 

[440beep]

:icon_salut: Ok, its coming off this weekend then, starting tonight.

 

[67 coronet]

only reason for a 50cc acc pmp is too cover up off idle hesitation in big cam motors with an open plenum intake.you need the extra squirt to cover the lack of air velocity when you hit the go pedal.

 

[lewtot184]

that little center carb (it's equilivant to a 273 or 316 2bbl) doesn't need anymore than a .025 or .028 squirter (stock was .031) and a white 218 pump cam. you probably have some other issues going on.

 

[440beep]

Prior to me putting the 50cc pump on the car was doing pretty well (with a 35 squirter and blue cam). However, I discovered when I removed the center carb (to fix the float), that my Six Pack is off a 340 Six Pack car so it had the smaller PV and main jets (hence probably the cause of the issues). But prior to knowing this my buddy recommended putting the 50cc pump on when I had the carbs apart. Well now that I have the 440 Six Pack PV and 64 main jets in, the car is much better, except for the initial start issue from the too big acc pump. From a roll, she's a beast when I stand on it now. However, from a dead stop there's a partial hesitation that I haven't been able to tune out because of the funkiness of the 50cc pump and the specific cams for it.

Knowing this now, the 30cc pump is going back on starting tonight. I'm glad for the assistance and knowledge about the 50cc pump now, makes sense and good info to know.

 

[lewtot184]

50cc pump is too much fuel when you stomp it. sometimes too much fuel will have the same symptons as too little. the off idle hesitation during normal driving is because the 50cc pump cam was never designed for light throttle tip in. there's no difference between a 440 or 340 power valve. the power valve channel restrictions might be different. if your using headers with a little bit of cam, 65 main jets may be better but nothing over 66. 64 main jets work good in near stock engines with cast iron exhaust manifolds and vacuum advance hooked up. yellow springs in the end carbs will give best overall performance. purples will give a little more mid range torque. plain springs and heavier are worthless and the light white springs aren't needed.

 

[440beep]

The PV I took out had a 2 and a 5 on it, so I'm assuming that's a 2.5 PV. I put in a 5 based on my vacuum readings driving around (yea, I misspoke about that PV). I've got purples in the secondaries now and kind of like it. May change back to the yellows and see how I like it.

 

[Meep-Meep]

A 50 cc pump that happens to fix a flat spot (in an application where you don't need that much pump) is like foot operated mechanical fuel injection system. It becomes a band aid. I agree with Lew; you have something else going on. Check your timing before you go fiddling with the carb. High overlap cams will tend to throw off the factory tuning requiring you to start from scratch.

 

[440beep]

Just got back from the test drive, and HOLY COW!!! The car is a beast now!!! Put the 30cc pump back on, but also purchased a new pump lever just because. Glad I did!!! Comparing the new pump lever with the old pump lever, and WTF?!?! The old lever was all bent to hell compared to the new pump lever. Could have been part of my old problems. So now the center carb has the 30cc pump, blue cam, #31 squirter, #5 PV and #64 jets. Car is much much stronger through its entire range now with no bogs!!!!

 

[lewtot184]

my '65 dodge has a 440 six-pak, a little solid cam, headers, automatic. i actually went down to a .025 squirter and a 218 white cam. it's a nice driver that'll blow the tires off. i like '69 coronets. i have a '69 r/t. engine is stock now but i had a six-pak on it for well over 20yrs. it was a whole lot more fun with that row of carbs.

 

[440beep]

Yea, I've got a lil cam with TTI 2" headers/3.5" collectors and full 3" back. I like the car now, so much better!!

 

[coloradodave]

FYI: Glad you got the problem whipped. A couple of months ago there was a good article, I believe in Car Craft, about fixing a problematic six pack set-up. It was interesting in that you can see just what kind of weird crap happens to cars that are as old as ours. I'm sure that if you go to their site you can pull it up. Knowledge is king...

 

[lewtot184]

FYI: Glad you got the problem whipped. A couple of months ago there was a good article, I believe in Car Craft, about fixing a problematic six pack set-up. It was interesting in that you can see just what kind of weird crap happens to cars that are as old as ours. I'm sure that if you go to their site you can pull it up. Knowledge is king...

if it's the same article i'm thinking of i did take a glance at it. i think the bottom line of that article is some idiot got a hold of the carbs and thought he "could make them better" or was trying to tune out a problem and couldn't tune. the carbs are simple but idiots make them complicated.

 

[440beep]

Yes, I'm finding that out. And learning a lot as I go along.

if it's the same article i'm thinking of i did take a glance at it. i think the bottom line of that article is some idiot got a hold of the carbs and thought he "could make them better" or was trying to tune out a problem and couldn't tune. the carbs are simple but idiots make them complicated.