i have an 71 302 and i removed the head to change head gasket and i see the top of piston was full of carbon so i removed the piston (all of them) and lots of carbon was inside ring groove and between ring and top of piston. my question is the engine has a little vibration before but if i remove most of the carbon on piston and in the ring grouve do you think if can fix the vibration ? Sorry if i made some mistake english is not my first language. thank you
excessive carbon buildup,generally wont cause an engine vibration.It can cause misfireing (If it builds up on the valves) or pre-ignition also known as spark knock/pinging or detonation.If the build up is as severe as you describe...I would say its time for a re-build since it sounds like the engine probably has an oil consumption problem.Bad piston rings and or valve guides will cause the oil problem.You said you replaced a head gasket.Was the engine consuming coolant? Overheating? Was coolant getting in the oil.Was oil getting onto the coolant? If so,this would cause the excessive carbon you are finding as well. As for the vibration...A common problem on high mileage 302s' is the harmonic balancer will slip on its hub.I suggest you inspect it carefully where the outer ring is attached to the inner hub...You will see a thin rubber piece between the inner and outer.If this rubber is pushed out or lookes cracked/dried out...It may have been the source of your vibration. Question: When did you feel the vibration...Under what circumstances was it most prominent or was is constant no matter the situation???
to do a short story at first i was thinking to use the head on another engine but i changed my mind so nothing was wrong with the head gasket. When i was driving the car or its on neutral i fell no vibration at all only when the car is engaged and i am waiting at red light the car is shaking a little.
Sounds like you need to throw a good tune up/carb cleaning at it.I dont think you have a mechanicle issue.You have a engine tune/carb tune issue.
Often times a good scrubbing in the venturis with carb cleaner and an old tooth brush can work wonders.Do a good examination of all vacuum lines (look for cracked/broken ones) Pull a few spark plugs to see what they look like.Put a new gas filter on it too.Do you own a timing light? check the timing as well before just throwing a carb re-build at it.Allways asess condition before throwing money/parts at the car.It can get expensive and drive you nuts.Good luck!!!
Might be something like a vacuum leak. Check all the hoses, and check the transmission modulator valve. If it is bad, it might be sucking fluid into the engine, which will cause white smoke, and can lead to the carbon problem you described. Good luck!
