Problem with WD45 diesel, I think?

Went out after work raking hay with the 45 diesel and second pass around the field, the tone of the engine changed to a distintive tick.   I stopped right away, and got off the tractor.   Tick seemed to be coming from the bottom of the intake manifold.   Looking down there, the one brass bolt for the intake heater was missing.   Although I have never had the heater hooked up since I have had it, I still remember it being there the last time I recall.   Limped it back to the house idling it, and started to tear it down.   Took the heater off and no bolt to be found inside.   I was hoping that if it popped lose, the zigzag pattern of the heater element would have trapped it, but after pulling it off that wasn't the case.   Took the hood off, took the valve cover off and started it back up.   All the valves and rocker arms moving like they should and it appeared all the valves were coming back up. I don't know if the bolt was the issue or not, but it still seems as if it is missing on one cylinder but it is hard to tell.  I am going to go back outside now and check the valves.   Might try to pull off the intake manifold and take a peek and see if I can find the bolt that may or may not be missing.    Any other suggestions?   It still runs good, but not right, and I would rather be more on the cautious side on this one, especially with all the money that was put into this engine to rebuild it the last time. 

Hate to hear that Chuck. Check all the cells to make sure one of them isnt leaking, the sound they make when leaking sounds just like a heavy tick. Any individal port exhaust leak will sound like a tick but the sound should coma and go with loading.  Before tearing it down I would try to isolate the noise, to many times the cause of a tick will not be obvious and there you sit almost clueless because the engine cannot be started, obviously if the nut went through it the marks will be obvious.  Loosen the injector lines one at a time. You can run the engine with the manifolds off and you might be able to narrow it down by watching and listening to the exhaust.

Edited by Butch(OH) - 31 Aug 2011 at 8:51pm

IF YOU HAVE ANY FRIENDS THAT HAVE TO A BOROSCOPE.PULL YOUR INJECTORS OUT AND HAVE A LOOK  INSIDE THE COMBUSTION CHAMBER,THIS WILL TELL YOU A LOT...

You may have gotten really lucky and that is where the nut is from that bolt you lost.  It may be impacted in the seat, and that is why the valve won't close.  Hopefully you get out of this mess with nothing more than a valve, seat, and a few gaskets.