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Valve Adjustment


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Hey J motor guys. I am working at replacing gaskets on the leaky J13 and while I have the rocker cover off, I would like to adjust the valves. The FSM manual seems to give me very vague instruction on this process. I am trying to figure out a more scientific way of making sure the pushrods are all the way down (back of the cam lobes) before setting the gap. Is there anyway to do it other than simply hand cranking the motor until you see each cylinder stop falling? I want to get it right so I don't burn valves.


Another question loosely related is that I have drained the oil from the engine approximately 3 weeks ago to start this process. Will I do any damage by turning the motor by hand? How long before I am in danger of things getting frozen up as a result of no oil? I am assuming that there would be a fine coat of oil remaining on everything that should keep me safe until the process is done. But I need to do the timing cover and crank seal yet, and I will have to remove the radiator and all that, so it will take a bit more time.


Any advice appreciated.

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Set the motor to top dead center (TDC) on the #1 cylinder. Both #1 valves should be fully closed. If not, turn the motor ONE full turn ahead to TDC. Both #1 cylinder valves should now be closed. Adjust the following valves:


In. and Ex. on #1

In. on #2

Ex. on #3


Now rotate the motor ONE full turn ahead to TDC and adjust the remaining valves:


Ex. on #2

In. on #3

In. and Ex. on #4..... done


There no harm in spinning the motor by hand there is plenty of oil still on the bearings. I've pulled motors apart that have sat for years and the crank and rod bearings are wet with oil.

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Here is another idea. The pistons on cylinders 1 and 4 move up together, and on 2 and 3 move up together.

Take the valve cover off. Watch the rocker arms for Cylinder 1. and cylinder 4 as you approach TDC. As you approach TDC, the exhaust valve rocker on either cylinder 1 or 4 will be moving. When you hit TDC, the intake valve rocker will start to move. If the rockers on cylinder 1 are moving, adjust number 4. If the rockers on 4 are moving, adjust number 1. Turn the engine 180 degrees, at the crankshaft. If the rockers for number 2 move, adjust 3. If rockers on 3 move, adjust 2. turn 180 degrees again, adjust either 4, or 1 whichever one you did not just do. Turn 180 again, and adjust cylinder 2 or 3.

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