oldtin 0 #1 Posted July 30, 2011 Still messing with my 1979 C121 to get it to run under load correctly [ earlier thread] and now I'm into the valves and the intake is set correctly but the exhaust has no gap at the tappet to valve. I have not taken the head off yet. Is it possible the tappet unajusted itself or should I be looking for something else? Thanks. Share this post Link to post Share on other sites
WH nut 553 #2 Posted July 31, 2011 Still messing with my 1979 C121 to get it to run under load correctly [ earlier thread] and now I'm into the valves and the intake is set correctly but the exhaust has no gap at the tappet to valve. I have not taken the head off yet. Is it possible the tappet unajusted itself or should I be looking for something else? Thanks. Its possible the seat has been hammered out and the valve is setting lower in the seat reducing the amount of clearance Share this post Link to post Share on other sites
oldtin 0 #3 Posted July 31, 2011 FINALLY found the problem,the outer lip on the exhaust valve is burnt off letting the valve go deeper in the hole. How do I know what valve to buy since this one is destroyed? Thanks :woohoo: Share this post Link to post Share on other sites
WH nut 553 #4 Posted August 2, 2011 Order it according engine serial and spec number Share this post Link to post Share on other sites
oldtin 0 #5 Posted August 2, 2011 Thanks, got the valve and have it lapped already,going to pull the intake valve and clean it up. :woohoo: Share this post Link to post Share on other sites
rmaynard 14,864 #6 Posted August 5, 2011 Remember, there has to be a reason why the exhaust valve burned in the first place. While you have it out, check to be sure that the valve spring is not weak or installed upside down. You might just want to replace the spring with a new one. The problem that you were having (as I stated earlier in the other post) may have been a weak spring. Share this post Link to post Share on other sites
