Hi all,
I have a1983 with a 22r. Very sluggish and low power, has loud pinging when throttle is above 50%. Starts well and idles will. Took it to a mechanic, it has no compression in cylinder 3 but 125-150 in cylinders 1, 2 and 4. Mechanic checked the rockers and cams and they appear to be working well. He noted that the carburetor is getting exhaust sucked into which is probably causing the pinging.

Any ideas on what this could be? Any thing I can check?

 

Very likely a bent or burnt valve. You could bring #3 to TDC and run air pressure through the spark plug hole and see where it cones out- exhaust or intake. Either way you’ll be in for pulling the head and getting a valve job. Machine work, gasket set, timing chain, labor. Swapping in a good running 22r might be a better option if available.

 

Thanks for the help. I've decided to take the head of and send it in to sunset automotive for a rebuild. Looking forward to a long wait time lol. Appreciate the insight, it matches the prognosis from a couple mechanic friends