I am still learning. I bought a dwell meter, and set the dwell to 30, (it was at 25). So now I also have a vac tester, so I hooked it up to the vac. advance and it held 25inches of vacuum. So when setting the idle mix screws via the vac guage, I connect to the hose that connects to the vac. advance and adjust from there? I did this and played with the screws a bit and the most ammount of vac im getting is 5inches with 800 rpms. in park and i adjusted the screws until the idle lowered, just want to double check if this is correct. I didnt have a chance to test drive her yet. For the hell of it, I installed a new points and condensor set and the car wouldnt start, So i put the old ones back in and she fired up (im guessing the dwell is way out of wack?) Which plugs would yall recomend and with what for the gap? Ive seen pretty broad gap settings 44 to 60 and that has me concerned. As a reminder here are the car's specs. 72 Lark 350/350 TA intake 800 CFM carb TA headers Flowmaster Exhaust peg-leg rear end (stock) open element air filter. Thanks again in advance!:grin:
I have the same questions about vacuum. I have zero at idle (650rpm) and around 14 at 2000rpm. Nivek Since you are using a points dist., I don't think you should gap more than .040. Those bigger numbers are for HEI distributors. MARK
"wrong port" zero or 5 at idle = wrong port = ported vacuum.(unless your running some realy radical set up)And none of you are doing that! Conect the guage to the one that conecks to the transm. vacuum modulator or the vacum canister on the firewall, and you will be better off tuning! :TU: Lars
I'm using NGK (dont rememder the number,just the cheepest recomended R plug)in my -68 350 no problem! (but im just a dumb Swede) :spank: AC R45TS allso worked (just more expensive here) Had luck with Bosch (H10BC), but they changed them and wanted twise as much $ thats when i NGK:ed:Brow: Plug gap with stock points ign. i beleve is .030'' = 0,76mm. Installing new points = adjust max open gap to .016'' (you have to turn the crank by hand) start it up, adjust dwell to 30* :Smarty: NOW YOU MUST CHECK YOUR IGN.TIMING , CHANCES ARE WERRY BIG THAT IT WILL NOT BEE THE SAME AS IT WERE BEFORE YOU CHANGED THE POINTS! due to manufacturing and brand diferenses. :stmad: Lars
:Comp: This is my motto: A day without learning is a wasted day = your not the onley one still learning! Lars :TU:
Nivek, There are 2 ports to connect your vacuum advance to on the front of a Q-jet. The drivers side is ported vacuum, it is very close to if not at 0 at idle, increase as you open the throttle and goes to 0 at wide open throttle. The passenger side port is full manifold vacuum. It is high at idle, and drops off as you open the throttle under load, to 0 at wide open throttle. This is the port you should connect your vacuum gauge to. Full manifold vacuum with a mild or stock cam, should be 15-18" at idle. When you adjust idle mixture, turn the screws in slowly until you see the vacuum drop off, then back out until you get a maximum reading on the vacuum gauge. Adjust both screws, one at a time. Usually, a new point set is adjusted so the car will at least start. If you try to install them again, turn the engine until one of the high points of the distributor cam opens the points, and take a look at the point gap. It should be about the width of a matchbook cover. If not adjust with an allen wrench until it is the proper gap. The car should start then. Finish the adjustment with the dwell meter. Maximum plug gap, for points is .040. If you want to try a different plug, try the Champion RV17YC. It is a projected nose plug, that positions the gap closer to the center of the chamber. It fits all Buick V8's from 67-76, and gives a definite performance boost in alot of engines. Try them.
Thank you Larry, That was the vacuum question I needed answered. Listen up Nivek, There are some really talented people on this board. MARK
Hmmm, interesting about the vacuum ports. Should I have the vac. advance plugged into a specific port considering the mods above or does it really not matter since the at WOT the vac is 0 in both ports. Kevin
Vacumn advance should not be hooked up to manifold vacumn. If you are going to run it use ported vacumn.
I agree with Chris, "stock" ( - none modified) distributor = ported vacuum! Idle mixture tuning (air screws on carb) = guage conected to full manifold vacuum! I "borrowed" this picture somewhere..........(sorry...?) manifold vacuum and a stock (not modified) distributor = the "ping" thing (detonation) for sure. :Smarty: arrow = ported vacuum Lars
To keep it, simple...Use Intake Manifold Vaccuum port, adjust timing to highest vaccuum reading, adjust point dwell to 28-30 Deg., adjust carb. as 70GS said. Drive it! (Warm Engine.) If engine "Knocks", back off timing 1 Deg. at a time until no more "Knocks"(and/or use higher octane fuel) Re-check Dwell-angle. Your engine is now, at it's Best! I, DO NOT EVER, recommend "Champion" Plugs! AC,Autolite,NGK,Nippondenso or Bocsh(SP?) MUCH...Better! Have, FUN!!!
Don't let IgnitionMan Dave see that you've told people to use ported vacuum for your vac advance. He'll eat you alive:laugh: Run full vacuum with the $20 Crane adjustable vac advance kit. I mady my own advustable vac advance as per Dave's instructions and the car never ran better!!! Listen to the pro who does it every day (Dave, not me).
Nope, don't care which port you use, but...don't even say a word when the ported way doesn't work right, not one word. I've posted how to do it right at least 20 times here, but some just can't understand that ported vacuum is only for EGR valve'd engines and those whom hang on all those dyno hero's every word when they "find" that the engines on dyno's actually want more timing and jet, for dyno testing only, and not in the real world. So, connect it up the way you want, just don't bitch about it when it proves to be ported and wrong.
What does the EGR valve have to do with choosing a vacuum advance source? Also, should the EGR valve be on manifold or ported vacuum?????????
65 Sky, Just curious why you dislike Champion plugs. I know Jim Burek posted they were more fragile than other plugs, they broke when dropped on the floor. Not sure whether that makes a difference to most people. I know one thing for sure, my car makes noticeably more power with the projected nose Champions(RV17YC, RV15YC4) than with the AC R45TS. That is why I use them. I have been back and forth a few times, and there is no mistake, there is a big difference. I wish AC made an eqivalent plug, they don't, I've checked. The R45LTS is not the same in case anyone is thinking that. I know the difference in power that I'm experiencing is from the projected nose design. Adam Whitman was kind enough to inform me that NGK makes projected nose plugs for our cars(UR4, UR5, UR6). I will try them next just to see. I have never had a misfire, fouling problem, or performance issue with the Champs. My car loves them though. Just my experience. Have you tried these type plugs. I know the ignitionman has good things to say about the projected nose design plugs. Just my .02 Let me know what your experience has been.:TU:
?? sumary on vacuum advance ?? I will try to X-press my self right and make some kind of summary on the vacuum advance issue. :bglasses: On a stock (not modified vacuum advance) distributor: use ported vacuum, . BUT, if you want more omp especially at lower rpm and a smother idle, and as a bonus: higher vacuum for the brakes when at idle/low rpm/low load, and better MPGthen the Ignitionman/ full manifold vacuum with restricted movement method is the way to go! Ooo, almost forgot; the rotor is in a better position vs. the cap (at least so I vas told, never checked this my self) . For me, this "vacuum modification" combined with all in at (in my case) 2600 rpm, total mec timing 34* made a lot of difference. :3gears: Ether with the cheap and good, home made limiter, or how to do it the correct way if you are using the crane vacuum timing limiter plate. Him who SEARCH will find the previous posted pictures, or why not get in touch with Ignitionman him self. And why not let him fix the entire distr, vile youre at it? A ready to run matched to your engine need distr cant be wrong. I did mine my self, but the non points conversion would have been very nice and to be honest, it took some hours to get it all the right way...... not a coffe brake fix. :Brow: . When tuning with full manifold vacuum, any one who experience a ping/nock problem under wot, (and did not have it before) he/she got to small carb or vac. secondaries not opening fast/big enough. BELIEVE ME, I have been there.. But if so, dont be sad. Fix it; tune the secondaries, bigger carb or what ever it takes. The engine is just telling you it got some hidden horsepower youre not able to use until you correct this situation. . This post is not intended to upset or offend anyone; it is a summary of what I learned this last summer. Feel free to hang me out to dry if any one disagrees Lars :TU:
Larry An aircraft engine plug will swallow a car plug and it may break if dropped. We stake our lives on them (two per cylinder). Most are made by Champion.
Thanks Jim:TU: That's good to know. If they are good enough for an aircraft, they are good enough for my Buick:TU: I know you just can't pull over at 10,000 feet if something is amiss up there.:laugh:
