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Help With Setting Valve Clearences

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Old 11-14-2017, 11:03:19 PM
wxyoung2008 wxyoung2008 is offline
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Default Help With Setting Valve Clearences

The following at the bottom was taken from the Service manual of an Onan DJC

Line B states to align the TC mark with the with the timing pointer then turn an additional 10-45 degrees.

It also states that the piston will be in its power stroke ? How can I determine that this has happened ?
Does this mean that I can go an additional say 30 degrees and set my tolerances from that point on cylinder 1 ?

Also It states that " The timing mark for this position must be set ."

Does this mean that I establish a new set of temp timing marks and simply turn the flywheel 180 degrees to set #2, followed by an additional 180 degrees to set #4 and then another 180 to set #3 ?

I know that this has to be simple but the 10-45 degrees has thrown me for a loop.

a. Turn flywheel until cylinder which is to have its
valve adjusted is on its compression stroke,
which follows closing of intake valve.
b. Turn flywheel until TC (top center) mark on
flywheel lines up with timing pointer on gear
cover, Then turn flywheel in a clockwise
direction for an additional 10 to 45 degrees.
The timing mark for this position must be
established. In this position, the piston will be
in its power stroke with both valves completely
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Old 11-15-2017, 12:20:36 AM
Heins Heins is online now
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Default Re: Help with setting valve clearences

You can set your valves by turning the engine the way it runs and watching when the exhaust is just about closed and the intake is starting to open, that is valve overlap on that cylinder. Mark the flywheel with chalk, turn the engine one complete turn and that will be TDC on that cylinder and both valves will be closed to be adjusted. You can do that with each cylinder. If that is an inline four cylinder, turn the flywheel 180 degrees and the next cylinder is ready to be adjusted #3, 180 #4, 180 #2. If you started with #1
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Old 11-15-2017, 12:23:08 AM
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Motorhead Motorhead is offline
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Default Re: Help with setting valve clearences

On any engine with a distributor, you remove the distributor cap and turn the engine and point the rotor to each position on the distributor and cap where a plug wire connects to the distributor cap. Then follow the plug wire to the cylinder that the rotor pointed to. That cylinder is ready to have the valves adjusted. On a JB, JC engine, the intake valves are the two in the center of the head and the exhausts are on the outside of the head. Set them cold.
My 1939 WILLYS Pickup.
Bought in 1971
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