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| Lean surge https://www.slantsix.org/forum/viewtopic.php?t=29021 |
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| Author: | Aggressive Ted [ Tue May 27, 2008 9:36 pm ] |
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Brennan, Don't feel bad, Juan has been after me to jet up. Each time I do, I get better gas mileage. So running lean is not good for many reasons. Did you ever build that hemholz resonator for your car? The short pipe that went 90 degrees to your tail pipe full of fiberglass? Just curious how that worked and what length and diameter you made it.......  It should quiet it down allot. |
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| Author: | argentina-slantsixer [ Tue May 27, 2008 9:41 pm ] |
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using the 390 metering block with no high speed bleeds could be an issue. Usually if the carb has been set up so it would require no high speed bleeds the metering block is tuned accordingly. Can you remove the plugs for high speed bleeds and install some? We have 2 ways of looking at this, one would be that you can swap bleeds wich doesn't require the bowls to come appart, and the other non bowl dismantle solution would be raising the float during cold months and lowering it during hot season. Of course to be able to use these 2 options that would imply going to high speed bleeds as an option. Lower/higher float levels directly affects how many emulsion stages are open. in your case those are open but the air leak (calibrated air leak but an air leak indeed) is not open. I would think that your 390 reworked metering block isn't at its best since you're not taking advantage of emulsion stages (4 in total as I see, one on the curve, 3 on the lower channel, I would rework this metering block up to 6 or 7 emulsion stages with fully ncustomizable emulsion jets, that's tops one afternoon working. I'll produce an artichle on metering block modification and their interaction with air bleeds and jetting. Let me get my camera and produce some pictures by the end of the week. I'm spamped with 5 URGENT I NEED IT BY TOMORROW sax overhauls and I'mr eally doing the best that I can. |
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| Author: | Bren67Cuda904 [ Wed May 28, 2008 5:10 am ] |
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Just to be clear there are no high speed air bleeds screwed in. They are not plugged. They are full open. Simply screwing in the biggest air bleed made would ineffect make the current air bleeds smaller. |
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| Author: | wjajr [ Wed May 28, 2008 5:38 am ] |
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Quote: The problem in the 1974 models was the acc. pump lever being not calibrated correctly and an undersized jet in the Holley 1945... in the 1974 318's with the BBD, and incorrectly set float was problematic since the A-bodies with this option tended to die going around corners or on quick stops...
All cars produced by the "Big Three" during this period were undriveable as delivered from the factory. And, I may add grossly under powered. They were all dogs thanks to the new pollution rules cooked up by Nixon's EPA. -D.Idiot I'm feel that we are headed for another round of dogs with the latest CAFE standards. |
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| Author: | argentina-slantsixer [ Wed May 28, 2008 4:32 pm ] |
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OK bren, just to be on the safe side, can we verify that the uncovered hole (no high speed bleeds) are indeed connecting with its corresponding holes in the face of the carb's body? I mean, those 4 big holes should connect to two small holes on the inside of each main booster holes. Now for the lean surge, maybe you where giving away power using no bleeds. The lean surge you describe could be easily cured by installing smaller (smaller than fully open hole) bleeds on those high speed bleeds countersink. See, your original metering block for that carburetor had no emulsion stages whatsoever. Maybe opening 4 stages is causing your car to be lean when you're cruising on the main circuit and there's no restriction but the calibrated holes in the emulsion passages. Now you might think that would be absolutely no effect in restricting something that it's indeed a restriction (the emulsion holes are calibrated) but the top air bleed on the carbs body (those holes are uncovered now) are a pre-restrictive, sort of an equalization device for the emulsion holes on the metering block. Take a shot on that without rejetting. Do you have any jet for those holes avalible? if so let me know sizes and perhaps I can guesstimate them. |
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