I had a clicking noise from the engine on my 97 sub, 2.2 l, 145 K mi. It was very loud and I was hoping it was tappet noise. So yesterday, I pulled the passenger side valve cover and reset the valve gaps. I was hoping that I would find one or more way out of spec. But actually, I was disappointed to find all 8 valves only about 2 th. [.002 inch] more then spec. The intake valves are supposed to be 8 th +- 1 th and they were about 10 th gap, for example. I didn't think that much of a variance could account for the noise.

 

But, surprise, resetting the gap to spec greatly reduced the noise! I never heard or read that such a small out of spec gap could make so much noise.

 

Does this seem reasonable?

my experience setting up my old volvo or vw ...2th larger then spec would make a difference...in my case I have to check the gaps when the motor is "hot" while my friends chevy has to be checked when the motor is "cold"