Expert: Brad Sears - 1/2/2011

Question
I HAVE A 1980 INLINE SIX 250 MOTOR. I WOULD LIKE TO CHECK THE ADJUSTMENT OF THE VALVES EVEN THOUGH THEY ARE HYDRAULIC TO RULE OUT OTHER ISSUES SINCE I JUST BOUGHT THIS TRUCK. I HAVE AND REPAIR BOOK BUT IT DOES NOT SHOW ME WHICH ARE INTAKE AND EXHAUST SO I DONT KNOW WHICH VALVES TO CHECK ADJUSTMENT WHEN ON THE ONE OR SIX MARK ON THE ROTOR CAN YOU TELL ME FROM FRONT TO BACK WHICH IS WHICH  THANK YOU FOR YOUR TIME

Answer
The easiest way to tell if it is an exhaust valve or an intake on any in line six engine except Nash is to look at the intake and exhaust manifolds. The manifold runners will point at the valve, for instance on your engine the first valve is an exhaust and the last valve is an exhaust. When I check valve adjustment I take the firing order and divide it into two. The firing order in your engine is 1-5-3-6-2-4. So 1-5-3 is the first revolution of the crank when the engine is running and 6-2-4 is the second revolution. This means that when number 1 if firing that number 6 is at the end of the exhaust stroke and the beginning of the intake. So, I turn the engine over by hand until the exhaust on number 6 is just closing and the intake is just opening. That puts both valves closed on number 1 and it is ready to adjust. Then roll the engine over until the valves on number two are just between intake and exhaust and adjust number 5, and so on. With that method you can adjust the valves on any engine without the doing the rotor routine. The valve adjustment specs for you engine is to loosen the adjustment screw until there is play in the push rod. Then tighten the screw until the play is just gone and then turn the screw down one full turn. However I prefer to do this adjustment with the engine running. Loosen the screw until a ticking is heard from the valve. Then slowly turn the screw down till the ticking just stops and then slowly turn the screw down the one turn. The engine will run rough as you turn the screw down so wait a bit until the engine smoothes out. If the engine does not smooth out after turning the screw down it indicates a collapsed lifter. If the engine smoothes out as you turn the screw out and runs smooth with a slight ticking noise then the engine should come apart.