350 engine just wont cooperate

[CamaroRS92]

Im having issues with a 350 engine(carbureted) not running correctly and can't find what is wrong. It just acts like it doesn't know what to do with the fuel when accelerating. There is no power and it sputters, chokes down and sometimes pops thru the carb. if you dont back off the accelerator.

The mechanic repaced the entire ignition system with new AC Delco parts plugs and wires. Did a compression Check, and while not perfect it was within reason and all cyclinders are very close to the same. Replaced the Carb with a new Edelbrock Performer 600 cfm with electric choke. The fuel system is clean (ie no water, trash, rust & ect. and the fuel is fresh). And the mechanic says it is timed correctly.

Im wondering if the timing could be changing and he is not picking up on that?


What is the procedure for checking for timing chain stretch , and fluctuations on timing ?
Also, how do you test if the lobes on the cam are worn down without doing a tear down?

Any other suggestions?

[wrightz28]

A dirty of the the valve timing is pull the dist. cap off and while cranking the motor watch the rotor movement, any jumps would be a fair indication of a chain problem.

But, I would think your pump is the prob.

There's some dirty little tricks for lobe wear too, but I don't think you need to go there, keep it simple.

[silicon212]

Originally Posted by wrightz28

A dirty of the the valve timing is pull the dist. cap off and while cranking the motor watch the rotor movement, any jumps would be a fair indication of a chain problem.

But, I would think your pump is the prob.

There's some dirty little tricks for lobe wear too, but I don't think you need to go there, keep it simple.

To be honest, it does sound like lobe wear to me due to experience I've got with the same. You can pull the valve covers off of the engine and start it up, and look for rocker arm movement on all 16 valves. If you see one or more that don't move with the others, then bingo. You might not be able to see the rockers move, but you can feel it by placing your finger along the rail alongside the fulcrum.

[pro_am]

I had a problem just like that with a cam lobe being worn down. Did similar stuff with timing etc. Drove me nuts. What a horrible day, my poor el camino with that beautiful engine that i so loved taken down cause of a cam lobe, horrible day. Glad we could talk about it. Hopefully you check your rockers while it's running and find that your cam is just fine. Good luck, hope it works out better for you!
Jake

[CamaroRS92]

Im definately going to be checking into it as soon as i can get a friend to help that knows a little more than i do about it. The mechanics of Internal engine repair just isn't what i want to be doing but it seems im going to be forced to do a bit of it.

While it would be unfortunate for the cam or timing chain to be bad, it will in a way be a blessing to finally figure out what the heck is wrong so it can be fixed once and for all, and get on to bigger and better things.

Thanks for the input

[wrightz28]

Don't forget to post the outcome