I've got a ranger with an engine knock. sounds like its coming from the top end. Are the valves adjustable? Anyone have this problem?

Make sure your EGR system is working properly. Pull your throttle body and clean the massive accumulation of black sludge that's clogging the EGR port in the throttle body. That's a start.

did you ever solve your spark knock problem??

I have a 1990 with the same problem. I am about to address this and some other things that need improved. FYI, my mechanic once told me of another vehicle I had that the problem is the rocker arms under the valve covers. They need tightened or replaced and he could do that. But, that I could live with it and get another 100,000 miles like that without problemjs.

replace ur lifters i have the same problem with my 91 ford ranger