Setting Valves

Granted, this experience was more in the automotive feild, and maybe the IH tractor engines have different cam phasing, but on most 4 cycle engines, if you set them the way I posted, the lifter for the valve you're adjusting WILL be on the base circle of the cam which is exactly where it HAS to be for an accurate setting. My post was intended only to simplify a process which could possibly be intimidating to the average old tractor owner. It's not inaccurate, it's just a faster way to do the same thing, developed and used by racers who check or set their valve lash once a week or more versus once every few years. Your method is every bit as accurate(and the way I used to do it as well). People are free to use whichever they're most comfortable with.

The post below about setting them with the engine running is incorrect- that only works with hydraulic lifters. How do you tell if you have hydraulic lifters?- If your manual gives a spec for valve lash, you don't have 'em.

Link

• Chart

I haven't worked on a great many tractors but I've adjusted the valves on a bazillion cars and trucks. I have an 826 and recently adjusted the valves the way I outline below. I suspect you were out of sequence. so I would either double check yourself or use my method below. Anyway, there is another way to do it. I don't say its better than the way the book says, but I find it less confusing and I'm just plain used to it!

Go by the firing order. To make it easier to grasp the concept, on a scrap of paper, draw a circle. Put a big dot in the center. Equally spaced around that circle in a clockwise rotation, write down the firing order of the engine: 153624. Now draw lines connecting the cylinders in the firing order that are directly opposite: 1-6, 5-2, 3-4, making sure that line intersects the dot in the center. The cylinders opposite each other share the same piston position at any point in the engine rotation, but the valves are 180 degrees apart in the firing order.

Next, spin the engine around in clockwise rotation, watching the rocker arms until you find two rockers on any cylinder at the overlap point. Overlap is when one rocker is coming back up (exhaust valve closing) and the other is just starting down (intake opening). Move the engine until you find that center point between the one coming up and the other starting down.

Next, find the cylinder opposite the one on overlap and adjust the valves because that cylinder is on Top Dead Center and the ignition point where the engine would fire. The lifters are on the base circles of the cam.

Say you found #2 on overlap ... you would adjust the valves on #5. Now that you have found which cyinder is on TDC, you know that if you rotate the engine clockwise, #3 will be the next cylinder in the firing order to go to TDC and fire, so watch the rockers on #4 for the overlap point. When you reach it, adjust the vlave on #3. Continue around until you have adjusted the valves on all cylinders. You will make one full engine rotation from the point you started in 60 degree increments.

CAUTION: Always turn the engine in the normal rotation (clockwise for most) because some injection pumps can be ruined going backwards a substantial distance. I don't actually know if this is the case with the pump on the 826, hence my caution. I'd prefer not to put my injection shop tech's kids though college needlessly! Also, I made sure the engine kill rod was pulled out and secured that way so that it wouldn't accidentally start. It isn't likely, but I had it happen on a boat engine of mine while I was spinning it over to adjust the valves.

I won't argue with anyone whether this is easier or harder than the way in the manual. You turn the engine the same amount, but in shorter distances. I just find it easier to keep it all straight in my head .