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My rich running problems are almost over...

Well... After chasing vacuum gremlins and verifying fuel pressure was correct, the only other thing was the float height.

After reading a less than descriptive Edelbrock manual, emailing Edelbrock's tech (non)support, and consulting you fine people, I decided to pull the top of the carb and have a go at it.

First thing I did was run over to Home Depot and get a set of sliding calipers to measure the float height. After getting the airhorn off and flipping it up-side-down, i measured the float height at exactly

7/16"--exactly what the manual says it should be. Flipped right-side-up, the floats hung much lower than the recommended 15/16"-1". More like 1-1/4".

Based on the manual, the range of motion should be somewhere between

1/2" (7/16"-15/16") and 9/16" (7/16"-1").

Now, I was advised to try setting the float height at a higher setting, say 3/8". This didn't make logical sense to me. It runs rich...that means too much fuel. Setting the floats higher would only let even more gas in there.

So I increased the distance between the float and airhorn gasket, then bent the tab on the backside to limit its range of motion to within about 1/2" from there. I double, triple, and quadruple checked the measurements carefully.

I popped the airhorn back on (had to remove the metering rods to get it to seat) and bolted it all back together. After reattaching all the linkages and the fuel line, I was ready to fire it up.

As soon as I did so, I stuck my head out the window and looked at the tailpipe. The usual gasoline steam wasn't shooting out, which was good; my girlfriend's car is parked right next to it :-)

I smelled the fumes, waved them towards my eyes...no burn, no intense stench of gas fumes. It simply smelled like normal, good old fashioned exhaust.

After that, I came inside here to type this up and take a well deserved grape soda and Marlboro Light break. I still need to go back out and reset the timing back to somewhere close to stock, and reset the idle speed. After that I'm going to take 'er out for a spin and see how she does on the road.

Thanks to all who have helped, it's been a long road. Thank God it's almost over.

:-)

~jp

Reply to
Jon Pickens
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Reply to
Shep

Well, it's definitely running leaner. Still not great, but a step in the right direction. I was mainly trying whatever it took to cut the fuel intake back some.

As far as how it runs...it's OK... I noticed that when I'm in "cruise mode" at interstate speeds (55mph and above) and try to accelerate, it stumbles and shudders quite a bit. The manual suggests going to the next stiffer step-up spring on the metering rods. Otherwise it accelerates fairly evenly. I still think I should be feeling a lot more power. I'm comparing the power to its original 18 year old 305ci motor, with compromised headgaskets, with a 3.08 rear axle ratio.

Now I've got a year-old 290hp / 350ci motor with a 3.73 gearset in the rear. As I recall, that 305 was rated around 185hp. Personally, I think the difference should be rather dramatic. I could be wrong, and truly the only way to verify that would be to slap it on a dyno, but still...

I tried pulling the timing back some from the 15 degrees BTDC it's currently at. It ran like crap. My previous vacuum issue...well I'm not 100% certain that it's fixed. It still resides somewhere between

14" and 15" Hg. I'd like to see that higher. From what I understand, the hotter cam I have can cause a lower vacuum condition. But I don't yet understand cams enough to know why though.

Either way, you are probably correct. Jetting probably could have helped, and I likely adjusted the floats out of spec to compensate for something else. Maybe if I knew the specs (jetting, metering) on the original carb (Quadrajet) and was able to lay the specs for both carbs out on paper, something might jump out on me. I've learned quite a bit just in the last couple of weeks or so. Cam and carb theory is pretty interesting stuff though, so I seem to be able to digest it easily enough.

If I can get a better understanding of the size of the jets and how they affect everything else, I'd be likely to try it. I'm going to try to pick up a spring kit for the carb on Monday, so another set of rods and jets maybe would be good to pick up as well.

~jp

Reply to
Jon Pickens

Reply to
Shep

Even if they can't. The Cam Manufactor should be able to. As well as how much lash the valve train should have if not using hydralic lifters. Charles

Reply to
Charles Bendig

I still need to try re-jetting the carb. Unfortunately the only place that has the parts is too far away to get there during my lunch break, and traffic would make getting there during the evening rush hour all but impossible.

I think I'm going to just order a calibration kit online and have it delivered. That way I'll have an assortment of jets, springs, and metering rods to experiment with. Before I install them I'll reset the float height to what it should be.

~jp

Reply to
Jon Pickens

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