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#26 |
Registered User
Join Date: Feb 2009
Location: minonk illinois
Posts: 224
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Re: bad cam shaft?
follow lee's advice
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#27 |
Registered User
Join Date: Jun 2010
Location: San Diego Co.
Posts: 1,167
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Re: bad cam shaft?
Not sure about cam issues, but assuming it is your carb, just how hard are you getting on it when it bogs? The accelerator pump only supplements the primaries. If you are getting on it and opening the secondary side, your air flaps may not be adjusted properly via the adjustable tension spring, or the the choke pull off (which also regulates airflap opening rate) may not be adjusted either. Cliff's high performance recommends 1/2 to 3/4 turn clockwise on the spring tension after it just barely closes the airflaps. If your motor is stock or nearly so, the choke pull off should go from fully compressed to wide open in 2-3 seconds, and faster if a higher performance motor.
I have just rebuilt my q-jet and mine is set up this way for a stock motor, but I have yet to reinstall it and have it running. I got this info (and much more) from his book on rebuilding carbs. Also, be aware that q-jets are widely misunderstood carbs, and a great many mechanics do not know how to tune them properly. I may not either, but I am not a mechanic...just and eager learner want'n to get his truck back on the road. |
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#28 |
#16876
Join Date: Apr 2005
Location: Auburn WA
Posts: 12,266
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Re: bad cam shaft?
Forgive me if I repeat anything. I have not read the replies. Pop the valve covers and watch the rockers for a dead lobe. It's obvious. Nexts start off by adjusting the valves correctly. Not with the engine running. Any mechanic that has to bash others work is either a liar or desperate to justify their own work imo.
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Posted via Stationary Device '71 Custom Deluxe C-20 402. '67 Buick Special 455. '49 Plymouth Special Deluxe. "I love that old car smell" ![]() Some people are like Slinkies... not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs. |
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#29 |
Registered User
Join Date: Oct 2007
Location: Glasgow, Montana
Posts: 4
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Re: bad cam shaft?
I am with the silly old man. After hundreds of engines I still have never adjusted a lifter with engine running. Now for the Accel pump issure. look into the carb and jack the throttle. Does it have a healthy squirt into the front two venturies? So flat cam, timing issues or carb squirt, Fix what is wrong and the cruise. DanO
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1972 c10 SB 1968 c10 SB 1970 c10 LB 1971 k10 LB 1970 k10 LB 1972 gmc 2w LB Some projects, some should be. |
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#30 | ||
Registered User
Join Date: Jun 2007
Location: DFW (Forney)
Posts: 1,529
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Re: bad cam shaft?
Quote:
Quote:
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'58 SWB Fleetside...Front & Rear Porterbuilt Dropmember, 6.0 LS /4L60E. Accuair E-level, 20 Billet Specialties (Vintecs) '63 Buick Riviera ... AccuAir E-level, 20" Billet Specialties (Vintecs) http://67-72chevytrucks.com/vboard/s...=528853&page=5 |
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#31 |
Registered User
Join Date: Aug 2009
Location: Alden NY
Posts: 2,705
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Re: bad cam shaft?
Not trying to get in a pissing contest, but I suggested two different ways to adjust the hydraulic lifters - static or running. I'm an old guy too (59) and was taught 40+ years ago how to adjust them running. Quite frankly, a young inexperienced guy can more easily wrongly adjust lifters using a static method by cranking a rocker arm down when the valve isn't closed then he can with the motor idling. It can be messy but it is actually more accurate and is fool proof. I have a set of 67 and earlier valve covers with the centers cut out which cuts down on the oil. I also used to have a set of clips for the rocker arms which would reduce the oil splash but I can no longer find them. The valve covers work better. When I put an engine together I set them up static and then readjust warm and running. The fact that someone has never adjusted Chevy hydraulic lifters with a warm engine running does not make it advice worth dismissing.
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1961 C1 Corvette 1959 El Camino 350 TPI, 9" 4 w disc 69 Blazer K5 - sold July '20 2021 Durango RT 5.7 |
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