I have a 1989 2.0L Ram 50 that smokes, that I've been trying to troubleshoot for nearly 2 weeks. It started with an engine I bought
off a guy out of state to swap into my truck. Everything went well with the swap until I looked back and saw smoke billowing out the
of the tailpipe. It follows a pretty consistent pattern; little to no smoke on startup, smoke increases with RPM without much regard
to engine load, and is most visible when shifting at high rpm. I've done several things to test and remedy the issue but so far I've had zero results.


  • Cold compression reads 185, 180, 179, 182 on cylinders 1 through 4
  • reads a steady 21 in/hg of vacuum at idle
  • swapped the pcv off the old motor, neither of them seemed to be blocked, no change in smoke
  • previous owner cut and welded the jet valves, I suspected these might have been the cause as they had been welded on the combustion chamber side and cut flush just under the stem seal. I welded the tops and installed them with new orings, no change
  • pulled the head to redo the valve seals, bores are in excellent shape, crosshatching still visible and none of them differ more than a thou (measured with a t-gage and mic in multiple spots)
  • rebuilt the carburetor (practically brand new weber, used in on my previous engine shortly before I pulled it)


The only thing I can't rule out is an issue with the oil control rings that isn't effecting the compression rings. I'm wondering if there's
anything at all I could try before I tear it apart and start pulling pistons out of it.