edelbrock carb step-up springs

[Bob Halgren]

Hi: I'm running a 1409(marine 600cfm) carb on my 289 in a 55 wagon. It is set up as an r2. I've rejetted it to .098 pri. with 71x47rods and .089 secondaries and reset the float to 3/8" spacing with 3/4" drop. Does anyone know the proper step-up spring to use? Stock is orange(5" Hg). I have a calibration kit that has 3 to 8. Thanks' Bob

[DEEPNHOCK]

http://www.edelbrock.com/automotive_...ers_manual.pdf

Page 10 for stock AFB specs.
Page 15 for tuning guide.
Read pages 4,7,and 9 for a good description of the springs you are asking about.
(page 9 has the spring color descriptions)

quote:Originally posted by Bob Halgren

Hi: I'm running a 1409(marine 600cfm) carb on my 289 in a 55 wagon. It is set up as an r2. I've rejetted it to .098 pri. with 71x47rods and .089 secondaries and reset the float to 3/8" spacing with 3/4" drop. Does anyone know the proper step-up spring to use? Stock is orange(5" Hg). I have a calibration kit that has 3 to 8. Thanks' Bob

http://community.webshots.com/user/deepnhock

[bige]

I would say seat of the pants will ultimately tell you which is best. What your looking for is the best throttle response when cruising. In other words your driving along at 35 and you want to accelerate up a grade with just a little push on the pedal. If it feels a little flat then you need a stronger spring, if it's nice and crisp your good. If you had a very radical cam that gave you very little vaccuum at idle you would want a lighter spring.

The mechanics of it are that the rod is pulled down by vacuum into the jet restricting fuel and leaning things out until more fuel is needed. The spring is there to push the rod out of the jet as vacuum diminishes. The stronger the spring the quicker that happens. A car that doesn't develop much vacuum because of a radical cam would want a lighter spring so the rod isn't up out of the jet at idle.

I'm curious about the marine carb. Is it the same as a car carb inside? I know they are sealed like the R2 Carb.

ErnieR

[leyrret]

For best fuel mileage I would use lightest that will work without detonation or flat spot under load ( engine rpm high enough to have timing advanced) just prior to rod movement. A good vacuum gauge is necessary to know when it opens. Have engine well warmed up. If more concerned with power may want to open it sooner.(stronger spring)

[KOOL R2]

With an R2 you may want to consider going to .101 primaries and .092 secondaries. With todays fuels it is better to be on the rich side rather than lean. I run the orange springs but then thats my engine setup. I think Ernie gave you good advice on how to set up your car.

Peter

[Bob Halgren]

Thanks to all for your advise. I'm going to richen it up and start with the orange spring. As far as I can tell, the insides of the marine carb are the same as the car carb. I used some floats from an old afb as they had ribbed sides and appeared much stonger than the new smooth sided ones. Bob

[buddymander]

Bige, did you mean -so that the rod =isn't= up out of the jet at idle?

[bige]

Yes I did...[:I]

ErnieR

quote:Originally posted by buddymander

Bige, did you mean -so that the rod =isn't= up out of the jet at idle?

[bige]

I was curious to see if the fuel metering was the same. I know they don't have vacuum ports, unless the blocked holes can be drilled.

ErnieR

quote:Originally posted by Bob Halgren

Thanks to all for your advise. I'm going to richen it up and start with the orange spring. As far as I can tell, the insides of the marine carb are the same as the car carb. I used some floats from an old afb as they had ribbed sides and appeared much stonger than the new smooth sided ones. Bob

[Bob Halgren]

FYI I drilled and tapped the carb for the pcv and dist vac. connections. Bob