73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: akp05 on December 14, 2010, 08:53:47 pm
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Have 83 k20 with auto trans. it has a 350 chevy 600 edelbrock carb and edel intake new distributor with timing set at 8 degrees. The motor has no power. When you mash it taking off it will either backfire or it will just die out. But when you take off easy it does fine fine but runs rough taking off and no power trought all gears it doesnt smoke or anything starting up.. I cant find any vacuum leaks and the fuel pump is pumping plenty of fuel.Im thinkin about doing a compression test on it. The truck used to be a diesel and now has a 350. Ive tried everything that i know to do thats on the outside of the motor just wondering now if it is internal i am at my wits end with this thng and tired of throwing parts at it
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Also, how many miles are on the engine? Maybe worn cam lobes? Valve seats? Timing chain like listed before? Do that compression test. If its low than maybe the valve seats?
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The engine was supposed to be rebuilt with like 15,000 miles on it but i think somebody lied to me. I only gave 700 for the whole truck and everything else works on it but no power from the engine. I will try and get a compression test done on it and let you know. How can i tell if the lobes are worn on the cam thanks for your advice
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Aside from no power, how does it run/start/idle otherwise? Did it just start doing this, or was it like this when you got it?
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The only way you can reall tell if the cam lobes are worn is pull it out. Maybe pull the intake off, pull a valve cover off, pull a rocker, pull a push rod, pull a lifter and look down in the lifter hole with a flashlight?
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Pull the valve covers and start it up. Look around quickly for a rocker arm not moving very much. You don't have long before oil starts making a mess, so do it quick. Backfiring can be a sign of a worn cam lobe, although it could be some other things too.
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http://www.youtube.com/user/amandasickles#p/u/3/SV91UH2Tpo4
This is my 400 with three bend pushrods and a worn out cam.
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What's your total advance? Do you have good fuel volume?
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When I first bought my 85 short wide it had that exact problem. The problem was that the prevous owner didn't screw down the rotor button. Check that first before you get too involved in tearing your motor down. Check the wires and for cracks in the cap itself. Check to see if your sparkplugs are tight. Also, if you have an HEI you can get water under the coil and it will cause problems like that too.