Top Dead Center Help

[JRS]

Please be patient because I know this is probably a frequent topic, but I am new to the boards and need some help.



Iwatched the Cummins tech adjust my valves at 25,000 miles and took some notes. Now I am trying to adjust my valves at 75,000 miles. But I can't find TDC. I've located the pin and it moves like it should, but it won't pull in at TDC. I have barred the engine over several times using the alt. pulley nut like the Cummins tech did. no luck. I pulled the pin out to look at it, and confrimed it wasn't sheered off. I re-lubricated it and put it back in. It still won't pull in. Why can't I just adjust the valves per cylinder, if I make sure niether valve is being acutated by the rocker arm? (this is the way I adjust the valves on my Datsun race car. ) Thanks.



Joel

 

[Joe G.]

Joel,



You don't need exact TDC to adjust the valves. One way that works on any in-line six is the "partner" cylinder method. A friend reminded me of this one yesterday. The firing order for almost all in-line six cylinder motors is 153624. So 1-6, 5-2, and 3-4 are partners. Turn the engine so that the valves on #1 are loose and those on #6 are tight. That's real close to TDC on #1. Adjust those valves. Turn the engine so that the next pair are that way, etc. The next time around do #6 when the valves are loose and those on #1 are tight, etc. If you turn the engine with the alternator pulley it will be backwards thru the partner pairs.