Thread: what it might be

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What might cause the engine to pop, kinda sounds like backfire from most cylinders, when i let off the gas , like coming to a stop, but idles fine and no hesitation on accelaration or misses,otherwise runs fine except when i let off gas then pop pop pop,before you ask heres what i did, got heads redone,set valves the way the book said, by cranking the bolt till you can barely spin the pushrod, then 3/4 turn,set the distributor to #1, set timing to 8 degrees btdc, brand new edlebrock carb , no adjustment made, checked for vac leaks none to be found, distributer vac hooked to non manifold port on carb

If the lifters were bled down (no oil in them) you have to little clearance. I usually adjust hydraulic lifters with the motor running until the ticking stops the another half turn.

If you quickly let of the pedal and have a good carb return spring, you can lean out an engine suddenly when the throttle blades slam to idle.

If the pops are coming out of the exhaust, it could be air leaks in the exhaust system.

Originally Posted by cammerguy

If the lifters were bled down (no oil in them) you have to little clearance. I usually adjust hydraulic lifters with the motor running until the ticking stops the another half turn.

That might be it, i did not prime the lifters, plus i do have a good return spring thanks guys, ill keep messing with her

I would not think the lifters are your problem I go 1/2 turn, no more...but 3/4 likely wont cause you any problems, whether they were pumped up or not. And it's just a personal preference, but it makes a terrible mess to adjust lifters while the engine is running, and I dont like to make messes. If you adjust like you did, and give a 1/4 to 1/2 turn, you'll be fine.

I agree with Hotrodpaint

Would leaks at the header do that?

I would look anywhere "upstream" from the exhaust opening, all the way to the header flanges.

Originally Posted by hotroddaddy

Would leaks at the header do that?

Yup. I guess I need @ least 10 characters. yup