L3940 Engine Valve Lifter adjustment

   / L3940 Engine Valve Lifter adjustment #1  


Silver Member
Jan 9, 2007
Saskatoon, Saskatchewan
I have my tractor in for that differential repair. The dealer suggested that the lifters should be adjusted, he said it should be done every 800 hours, I am at 1,450 hours, I don't know if the 800 hour adjustment was done, I bought it when it had 900 hours.
His quote was really quite high, $800, all labour and I think there shop rate is $140.
I've watch some Youtubes on the subject, it doesn't seem hard. Has anyone done their lifters? The ones I've seen have had Kubota out of the tractor. Can you move the crank from the front of the engine?
I have never done lifter adjustments but my Deere Z920 mower had lost power and eventually would not start. I spoke to the service mgr at the dealer and he said it was most likely the lifters, he said they should be checked every 400 hrs, the mower had 450 hrs. He was perfectly correct, once I adjusted them it started right away and has good power. I have a couple honda water pumps, both are getting to be harder to start so I am planning on checking the lifters.
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Is it low on power does it rattle do you change the oil regular 800 dollars lot
Of money for a valve adjustment
Got 3000 hours on couple m5-111 still running strong
Even with def
   / L3940 Engine Valve Lifter adjustment #3  
I've adjusted valves on a lot of different engines. It's not difficult if you take your time and think it through.

You will need to remove the fuel injectors or glow plugs in order to turn the engine by hand to the correct positions. I suggest removing the glow plugs so you don't get air into the injectors.

Buy a quality set of feeler gauges. If they are marked both in inches and mm, make sure you're not using the inch gauges but with the metric numbers. You will have loose clattery valves.

You need a way to know that the valve you're working on is fully closed. One way is to turn the engine until the other valve for the same cylinder is wide open. On tractors and other low performance engines there's little to no valve overlap, so you know the closed valve is on the base circle. Unless it's way too tight the rocker should have some play.
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Stepped Go/No-Go feeler blades make adjustments easier.
Good Luck!
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I have a write up on how I did mine. you can search my username. fuel tank and tank frame has to come off so don't fill up just before. definitely pull the glow plugs instead of the injectors. unless you want to get them tested. might not be a bad idea with the number of hours. I had only a few that were slightly out of adjustment at 900 hrs
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I have a L3540HSTC, my mechanic did mine last fall. I have a manual on my tractor, explains what you have to do. One thing is you have to take off the FEL mount on the right side to see the timing mark.
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I did it without looking at the timing mark. as you turn the engine you can tell which valve is moving and whether you are at top dead center or not. but you are correct, I had a hard time finding where that access plate was to see the timing mark in the manual.