Honestly, it seems like there's no limit to the amount of adjustment you can do to it. I'm not sure why John Osborne says he's giving up building them if you can even adjust the pull-offs like Ruggles suggests.
I fired it up last night and it was really rich! cough, cough, burning eyes. The lean condition was definitely gone! :laugh: I was thinking float level, but that is pretty hard to get wrong. I think I will check to make sure the power piston is being pulled down. I picked what seemed to be the lightest spring that was in the kit. They are color coded, but there is nothing to tell you what is what, so I had to guess. Having the TA 212 cam, it isn't radical. My vacuum has been in the 15" range. I can't imagine drilling out the holes for the mixture screws to .090 as outlined in the book would cause it. I ordered what he calls his performance rebuild kit for $80.00. It comes with a pair of idle tubes. (which was good because I destroyed the originals getting them out.) Accelerator pump piston with the ethanol resistant blue cup. Secondary metering rod cam and spring. The normal assortment of gaskets etc. that any kit comes with. Filter and new hardware.
Sounds like a good kit. My carb already has the mixture screw holes at 0.090 and, as far as I know, the previous owner didn't have any problems with the carb in it's previous life on the stock motor. However, I've measured all the idle circuit orifices (except for the idle tubes which I haven't attempted to remove yet) and I'd love to know if they are stock, or if the carb has already been modified. I can't imagine that it has, given that it is presumably the stock carb on from it's stock motor... but the mixture screw hole size has me wondering. I'll find my measurements later and post them. Keep us posted on your adventure :TU:
For those of you who want to remove the idle tubes, this proceedure can be done in about 15 minutes or less. 1. Use a small punch to drive the tube down into the collar about 1/8". Tap very lightly and be sure the punch is smaller that the collar. Driving too deep will damage the small tip of the tube as it hits bottom down inside. 2. Set a small drywall screw into the collar with a firm twist. 3. Use sidecutters to grab the screw and with the screwdriver laying under the side cutters, lever the screw up and out with the collar and tube attatched. 4. Use the plastic screwdriver handle to tap the tube back into the collar flush using many light taps against the small tube tip. 5. Drill the small tube tip to .037-.039 or as specified in a recipe. 6. Use fine sandpaper to polish down the collar for easier installation. 7. Reinstall the tube/collar with the butt of the plastic screwdriver handle until totally flush with the top of the carb body. 8. If you tear everything up trying this, Call Cliff Ruggles and have him send you some fresh drilled tubes. Also see what I went through on a 1979 buick 800cfm carb in the Q-jet section labled "2 Ruggles Recipes...one big problem"
Well, I finally got around to try removing the idle tubes... and proceeded to screw them up pretty bad. The tubes didn't want to drop down like they should and the screw that I used didn't work too well either. I shoulda heated the casting before I beat the collars up with the screw so much... ou: Oh well, the upshot is that I e-mailed Cliff Ruggles late last night with a question about the his carb kits and general question about a "recipe". I got a response this morning and just now I spent a good bit of time on the phone with him talking about Q-jets and 455 motors and gettin' down the track. Quite a guy. He was so laid back and willing to shoot the breeze... I had to keep reminding myself that he is the one who wrote the book and not my neighbor or something. :grin: Anywho, I'm getting the same kit as Dale got. Has tons of stuff that the CARS rebuild kit did not have plus the idle tubes that I'll probably need after I'm done my hatchet-job. Seems like a no-brainer that Cliff's the place to go for rebuild kits. I checked the power piston earlier and it wasn't down all the way during idle, but nothing changed when I pushed the piston down the last 3/8" or so. I'll be putting a lighter spring in, or cut a coil off... By the way, my carb's idle circuit measures: Idle Tube: unknown, so far Idle Down Channel: 0.046 Upper Air Bleed: 0.055 (in main casting), Lower Air Bleed: 0.080, Idle Bypass: 0.106, Holes under Idle Mix Screws: 0.093, Holes in Throttle Plates: none Cliff simply suggested larger Idle Tube and down channel orifices. When I get this thing running right, I'm-a-gonna be mighty happy!
Finally got the idle tubes out. Got a propane torch (Happy Father's Day!) to heat the carb in the area of the tubes and got a whole box of drywall screws (only needed one) and they came out. Took a lot more force than I thought, so the screws really had to be IN there... Idle tube restriction is 0.040" This whole carb seems to have idle restrictions larger than I've seen elsewhere. Check out the final specs on the Pontiac 400 from the article I called out earlier... Final Calibration Upper Idle Air-Bleed 0.052 inch Lower Idle Air-Bleed 0.070 inch Idle Tube 0.037 inch Down-Channel Restriction 0.052 inch Throttle-Body Bypass Air 0.100 inch Primary Metering Jet 0.073 inch Primary Metering Rods 0.043 inch Secondary Metering Rods 0.410 inch "CE" code Everything is smaller than my carb. Of course, the cubes are less and the cam has slightly less duration than mine (216/228 vs 223/230) but it still makes me question having to enlarge things... I guess the only things left to check before dilling out the idle circuit is to check for vacuum leaks right? I should probably re-torque the intake and look harder at the casting to check for warpage.. Anything I'm missing?
OK, Here's where I'm at now: Idle Tubes: 0.043" Idle Down Channels: 0.052" Upper Air Bleed: 0.055" Lower Air Bleed: 0.080" Idle Bypass Air: 0.110" Holes under Idle Mix Screws: 0.096 Put the carb on earlier this evening and she ran a lot better. I was able to back off the throttle plate adjustment screw a ton (probably to where it ought to be... I'll check to see how much of the slot is exposed when I take the carb off again). Initial timing is at 13 deg and idle is nice in neutral at 750 rpm. I used the 8 in HG power piston spring from my calibration kit (the strongest one in the kit, but not as strong as the stock spring... anybody know what the rating is for the stock spring?) The engine smelled a little rich so I worked the idle adjustment screws, and at 1 1/2 turns out the smell seemed to dissipate. The only negative is that the idle still drops a good bit when it goes into gear... but it stays running which is an improvement! I forgot to check the vacuum. I wonder if it's higher than the 11 in I got before. If so, I wonder if I can go back to the stock power piston spring. At this point, I'm thinking a bit more Idle down channel and a bit more Idle bypass air. I'm over worrying whether things needed to be opened up or not. The answer was YES. Stay tuned...
By the way, I haven't received the rebuild kit from Cliff yet. The idle tubes were pretty torn up up top but, after I opened up the lower portion of the tube from 0.040" to 0.043", I chased the upper portion with my 0.050" bit (remember, I measured them up top by accident before...) and cleaned up the brass enough to be satisfied that no loose bits would go astray. Other than that, I used Gary's instructions to tap them back in. I'll save the rebuilt kit for the core that I bought recently for a backup.
Doug, I would stick with .039-.040 MAX with the Ruggles idle tubes. A healthy 455 will be fine with that size and a .055-.058 MAX down channel. Your progress is looking good on the rest of your choices.
Thanks Gary, What do you think max is on the Bypass air? I'm trying to think what would have more effect on idle in gear at this point... more down channel or more bypass? maybe both? It seemed odd that the idle tubes were already at 0.040". But, as I think I mentioned earlier, it seemed odd that a lot of the idle circuit sizes were already as big as they were. I'll refrain from making the tubes I'm getting from the kit too big. Thanks for the advice.
In the 1970's, you will see some odd things. Engines had reduced compression, funky camshafts, and retarded timing. The lack of sucking strength to the carb resulted in some larger than expected orfices here and there. To create a little extra suck power, the secondary air flaps often were set to open just a little over halfway at an also limited "wide open throttle" and float levels were all up and down the scale. You can build a recipe to a float or float to a recipe but that is for engineers with mega budgets. I stuck with a reasonable range recipe and stayed with a 1/4" to 9/32" float. I'm also using 80 degrees (not 90) on the air flap. I think a wide open air flap hinders fuel flow from the nozzles. I'll bet I won't be needing super skinny secondary metering rods and fighting secondary top-end leanout. I can use .039 to .044 secondary rods on a G hanger. My idle air bypass worked fine from .096 to .110 and should work fine on any street drivable engine that can idle on ported vacuum. They are not super sensitive in a range of .015 or so. As for idle: (read my "2 Ruggles Recipe Projects" in this q-jet section.) make sure you have throttle shaft bushings that are Tight. Set the throttle shaft idle adjuster screw all the way off then run in till the verticle slots in the bore show a pinhole above the throttle blades ( try like hell to get your idle set with turning the screw no more than 1/4 MAX..Make sure you torque you'r "unwarped" q-jet to about 75 INCH (NOT FOOT LBS) and the carb is sitting on sturdy gaskets and spacers. thick gaskets must have plastic buttons at the boltholes. An open spacer made of plywood gave me NO IDLE until I removed it. (read "2Ruggles recipes....)
I've about given up on mine. I went to a softer power piston spring. Still rich. Lowered the float from 1/4" as outlined in the book back to 3/8", still so rich there was raw gas sitting in the intake after I pulled the carb off. I'm beginning to wonder if the .135 fuel inlet that came in the kit is just too much? I don't know. I've tinkered with these things for about 30 years now and have never had such trouble! I put the old carb back on in the meantime. Maybe that core I used was just possesed to begin with. Hoping it works out for you Doug. It's back to the drawing board for me. :idea2:
Dale I feel your pain , been there done that . At the risk of sounding like a smart a-s , did you check to make sure no warpage on the throttle plate or top cover . I have used two gaskets before to help with leaks there . Good luck with it .
I learned long ago that it's a good idea to check both. I have a machinists straight edge for just that purpose. Not a smart a** question at all. :beers2: Fortunately, I had a few cores laying around. I'm tempted to try another, since I seem to be a glutton for punishment. I should really just leave it be for now and get started sanding the body to at least get primer on it this season. Ok, I feel like I am starting to hijack here. Sorry Doug.
