Thread: valve noise

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do valves start to make noise when they get out of adjustment. I'm asking about by grand cherokee v-8 with 150,000 miles on it. For some reason when I step hard on the gas, even if its on the highway and the rpm's stay constant, I hear the rapid tapping of something.
It has nothing to do with rpm, just throttle level. I don't know what this is.
Could the valves be out of adjustment from the age?

Originally posted by tcodi
do valves start to make noise when they get out of adjustment. I'm asking about by grand cherokee v-8 with 150,000 miles on it. For some reason when I step hard on the gas, even if its on the highway and the rpm's stay constant, I hear the rapid tapping of something.
It has nothing to do with rpm, just throttle level. I don't know what this is.
Could the valves be out of adjustment from the age?

sounds like spark knock to me, try a better grade of gas and see if it stops.

if the chain is stretched, wouldn't that make the intake close a little later, bleeding off some of the intake charge?
reducing compression?

hmmm, I'll try the 89, see if that does it.

I would suggest also,,,Take it to your friendly garage mechanic,,or mechanic friend,,,,could be more serious,,,always pays to be sure.
If the tapping happens between gentle accelaration,,and decellaration it could be piston wrist pin, or connecting rod bearings,,,I found out the hard way many moons ago thinking it was just timing,,,my motor ATE it'self on the highway.