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ROUGH IDLE

 
wally0143
My first time was in a Chevy
Posts: 186
Joined: 07/09
Posted: 06/07/11 03:05 PM

My 70 chevelle has a 350 with a Q-Jet, and the old points ignition. I recently changed the points hoping to correct a rough Idle and being down on power,but have seen no change. The car barely breaks tires loose from a stop. It has good vacuum at idle with an occasionally bouncing needle- which is the way it always has been. The engine has 198,000 miles on it and has had a chain, gears,pushrods,cam,lifters,rockers,and oil pump at about 160,000. It does use a little oil ( about a half quart every 2000 miles) It is a 1 owner car and was maintained Impeccably,when I got it it had 156,000 mostly highway miles. The plugs look pretty good and probably have less than 20k miles. The carb was rebuilt 2 yrs ago by JET performance. Suggestions?  
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Ron1973
I have an SS396 tatoo
Posts: 257
Joined: 09/10
Posted: 06/07/11 06:15 PM

Hi Wally, I did a lot of work on my RR since last fall, To make this short i bought a new Eddy carb and put on it because i was having a lot of problems with the old AFB, It just wouldn't start and run the way it always did, Even shorter! You may be surprise by putting another set of plugs in it, i see that they havent been in all that long but you also said it does use some oil... Just a suggestion and hope it helps... Sometimes those plugs can be our worse enemy, even looking as new as mine looked, and were.. Sure made a big difference for me last week. I use AC-Delco in my Camaro (350) and they for what ever reason give me the best out of any other plugs in a GM, Auto-lite i use for the Mopar. Good luck.  
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redneckjoe69
Everything in my driveway’s a Chevy
Posts: 612
Joined: 02/10
Posted: 06/07/11 06:44 PM

whats up wally & ron?     20,000miles on plugs is a long time.   i would put a summit $100.oo hei on it & save the points ignition to keep it original if need be.   new plugs & wires, check the total timing.    you might try more pump shot from the q-jet too from the accelerator pump.    what rear gears are you running wally?    that bouncing needle could be the sign of a small vaccum leak?    i hope all else is well.  

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Ron1973
I have an SS396 tatoo
Posts: 257
Joined: 09/10
Posted: 06/08/11 09:10 PM

Seen you was here Joe, its late but wanted to say howdy back to ya... Did you learn how to do the email thing yet? Ummm?   Tsk LOL... Talk to ya soon.. G-night! Ron.  
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wally0143
My first time was in a Chevy
Posts: 186
Joined: 07/09
Posted: 06/11/11 04:46 PM

Hey, Joe- Do you happen to know how to get more pump shot out of my Q-jet? I don't know much about adjusting them. My gears are 3.42's  
Nobody knows everything but everybody knows something

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 06/11/11 06:01 PM

In the day 5,000 miles was about maximum on plugs,but we did run colder heat ranges. If you are using champion plugs with a J-8 go to a J-9 or even J-10. Or equivalent in an Autolite or NGK. I'm assuming those are the 13/16 spark plugs and no one has changed them. If they are the smaller 5/8 plugs go to a AC Delco R45-TS. What did you set the point gap at? On a dwell meter it should be 28 to 32 degrees. If you are using a feeler gauge .016 to .018 should get you there. If in dout get the engine running now either turn the allen wrench in or out to get the best idle. I'd do that first to make sure the carb is really giving you the problem. If the carb has a 198,000 miles on it? It is probably the throttle blades an/or the throttle shaft. They sell rebuid kits for them, but you better know what your doing. Give that a try and GOOD LUCK Confused  

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 06/11/11 06:14 PM

The vacuum jumping around could be a meriad of things. From your carb something internal in the engine. You guys have so many choices today for ignition systems. Like the redneck said throw that old point distributor away and put in a fire breathing HEI. You will see the difference in gas savings alone.

Needle bouncing could be the carb, the distributor, a cam going away, a tight lifter,or a burnt valve or a combined problem!  

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redneckjoe69
Everything in my driveway’s a Chevy
Posts: 612
Joined: 02/10
Posted: 06/12/11 08:20 AM

Icon Quotewally0143:
Hey, Joe- Do you happen to know how to get more pump shot out of my Q-jet? I don't know much about adjusting them. My gears are 3.42's

with them gears you should be able lay some nice smoke shows with ease.    been awhile since i ran a q-jet.  i think the adjustment is on the front of the carb, on the drivers side.  look toward the top of the carb & youll see a lever with 2 or 3 holes in it.  its the lever that pushes down on the accelerator pump.  i think a little cotter pin holds the rod in.  you can try moveing it to get more pumpshot.     another thing you might wanna check, with the motor off, look down the carb & give it full throttle.  is it getting any pumpshot?   there is also a small hidden adjustment for your vaccum secondaries.  kinda hard to describe it on the internet.  i forget what side its on & the initial set-up.  i think you unloosen the set screw & let the spring pressure unwind.  its about a half a turn on the spring screw, if memory serves me correct.  if you have an old q-jet laying around, turn it upside down, youll see what im talking about.  q-jets are good carbs once you get them dialed in.   i know were not all rich, but i would consider getting an hei.  

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redneckjoe69
Everything in my driveway’s a Chevy
Posts: 612
Joined: 02/10
Posted: 06/12/11 08:20 AM

oops.  double post.  

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redneckjoe69
Everything in my driveway’s a Chevy
Posts: 612
Joined: 02/10
Posted: 06/12/11 08:35 AM

Icon QuoteRon1973:
Seen you was here Joe, its late but wanted to say howdy back to ya... Did you learn how to do the email thing yet? Ummm?   Tsk LOL... Talk to ya soon.. G-night! Ron.

nope, not yet ron.  lol.  i must get 100 e-mails a day & rarely check them.   my e-mail adress is my old business, so i get lots & lots of junk/spam mail with people trying to sell stuff.   i will be starting computer lessons this week, so hopefully ill be up to the 21st century soon.  lol.   thank you for the push to learn more & more.  Wink  

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68scott385
I have an SS396 tatoo
Posts: 325
Joined: 07/09
Posted: 06/12/11 09:16 AM

Anybody remember the line at the end of the G.I. Joe cartoons?
Knowledge is power, GO JOE. Grin  
68scott385 68scott385 68scott385

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Ron1973
I have an SS396 tatoo
Posts: 257
Joined: 09/10
Posted: 06/12/11 09:54 AM

Drunken Smilie  
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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 06/14/11 12:00 PM

DID YOU FIX YOUR PROBLEM?  

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wally0143
My first time was in a Chevy
Posts: 186
Joined: 07/09
Posted: 06/24/11 04:21 PM

It is a lot better after a plug change. The HEI idea is out, as it wont fit with my 14" open element air cleaner. The points distributor is only 4 yrs old, and that design worked fine for the last 41 yrs. so no need to start throwing things away just because I can't make them work yet. If everyone threw something away because it was old, there would be no muscle cars to drive.  
Nobody knows everything but everybody knows something

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 06/26/11 10:12 PM

The Q jet carb should have three holes in the accelerator pump arm. You can move it in or out to change the shot. Walley I ran a duel point Corvette distributor in my race car up to five years ago. I've been racing for 30 plus years. (Of course I was only going a 1/4 mile at a time).It worked all the time for me too. Pertronics wants so much for their modifacation kit for a few dollars more you can buy a new electronic distributor. Go with what works, you may want to consider a competition set of points. Vent the cap to. Did you use a hotter plug when you changed them?

Remember it takes 8460 bolts to build an automobile, and one nut to schatter it all over the highway! GOOD LUCK! Cool  

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