engine trouble

[Guest dherde26]

Last night I noticed a knocking noise. So I adjusted the vavles to the right tolerances didnt go away . it starts at about 2500 and as you give it more throttle it increases in noise level. i am also running 93 octane. I also noticed that it knocks regularly under load but when it is not under load it is kind of a hit or miss thing.

[PeterZ]

Not much to go on but I'll bite. Since you adjusted valves and run good fuel you seem to think it is an internal noise not related to ignition. If you can duplicate the noise in neutral by lighlty "blipping" the throttle try looking for one of two things: Cancel ingition to one cylinder at a time by shorting the ignition wire through a test light (you need to give a place for the spark to go) and blipping the throttle to duplicate the noise. If the problem goes away you have the found the cylinder with possibly a bad rod bearing. If the noise doubles you found the cylinder with a worn wrist pin bushing. Done anything odd recently like road race one quart low on oil? Of course, I could have rocks in my head or you could have rocks in the exhaust like a catalytic converter that destroyed itself from leaded fuel. What is the car?

[schwiplarkin]

what is your timing set at?

[Here comes trouble]

pinging or knocking...big difference. If you have an ohm meter check your resistance out on the spark plug wires..one of them maybe bad causingognition pinging.......knocking may be the beginning at those RPM's of a rod or main bearing going bad... you can use a medical type stethoscope to listen for metallic knocking ... you can drop the pan a use "plastic guage" to check rod and main bearing tolerances by loosening and removing bearing nuts and bolts and placing the plastic gauge strip on the bearing surface and re-tourqing to spec. and then removing nut to measure the width of the flattened plastic guage strip on the bearing surface.