John Deere four twenty proper valve adjustment

racinchad

New User
Any help with the proper procedure to adjust the valves would be greatly appreciated. Installed a new cyl. hd and it runs but want to make sure they are correct.
 
i adjusted them like I have many sbc engines. The intake valve when the exhaust begins to open and the exhaust when intake has opened and just begun to close to .015 cold
 
Diesel 0.18 in and ex, gas/lp 0.15 in and 0.28 ex. Now roll engine over till the TDC lines up in the timing window and the flywheel, Start at the end with the first three valves that are loose, adjust these three, then skip one do one, skip one do one, skip one do one. THEN roll the engine over again so the TDC is lined up then start from the other end and start adjusting like you did before. chris
 
If I'm not mistaken they should be set at
12 like an M and 40. Won't hurt anything
like it is but you might hear a little
ticking.
 

Well, there's only two cylinders, so remove the timing window and rotate the engine until TDC is in the window. With the valve cover removed, see which set of rocker arms are loose. If you want, you can pull the spark plugs out (the engine will turn over easier), and feel with your finger which cylinder is coming up on TDC. Once you've determined which cylinder is on TDC compression, adjust those valves. Then rotate the engine one full turn and adjust the second cylinder. With the spark plugs out, you can turn the engine over with the generator belt if it's tight enough. As they said earlier, adjust the clearance to .012". HTH
 

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