spruce Deere
Veteran Member
- Joined
- Feb 1, 2009
- Messages
- 1,168
- Location
- Northmost Idaho
- Tractor
- John Deere 790 with loader LS xr3140h also with loader plus a cab
The 790 hit the big five double ought a little while back. It still had light duty chores to do, weed spraying 'electric powered pump' and some light dirt work so it just plugged along till they were done.
Before the volley of heavy pto powered work, garden tilling and a BIG blast sprayer for bugs in the tree fields I figgered I had check the valves as per instructions at 500 hours. So I detached the loader to make working in the motor much easier and headed for the shop.
Got the valve cover off, turned the engine by hand with a 1/2 inch ratchet and socket from the bolt head on the front of the crank holding the pulley/balancer on till top dead center of no.1 came up. The allowance for clearance is .008 or 2mm between arm and valve. The .008 feeler gauge slid right threw but the .009 feeler was tight. I adjusted it the valve lash to the spec and moved to the next cylinder T.D.C.
The rest of the cylinders followed the exact same suit, .008 feeler flew threw .009 tight. A person probably could have just ran the engine WAY longer before any adjustments be made. After I was finished, it fired right up with the only extra noise coming from the exhaust manifold, cause I wanted to hear it roar without the muffler on:thumbsup: And then all was quiet with the muffner installed
I have adjusted valves on 6.8L deere engines and others and have found that very same thing, only off by a mere .001~.002 seldom ever much more. To me, it Almost seems odd too chech valves that soon, but I don't have to warranty engines neither.....
Before the volley of heavy pto powered work, garden tilling and a BIG blast sprayer for bugs in the tree fields I figgered I had check the valves as per instructions at 500 hours. So I detached the loader to make working in the motor much easier and headed for the shop.
Got the valve cover off, turned the engine by hand with a 1/2 inch ratchet and socket from the bolt head on the front of the crank holding the pulley/balancer on till top dead center of no.1 came up. The allowance for clearance is .008 or 2mm between arm and valve. The .008 feeler gauge slid right threw but the .009 feeler was tight. I adjusted it the valve lash to the spec and moved to the next cylinder T.D.C.
The rest of the cylinders followed the exact same suit, .008 feeler flew threw .009 tight. A person probably could have just ran the engine WAY longer before any adjustments be made. After I was finished, it fired right up with the only extra noise coming from the exhaust manifold, cause I wanted to hear it roar without the muffler on:thumbsup: And then all was quiet with the muffner installed
I have adjusted valves on 6.8L deere engines and others and have found that very same thing, only off by a mere .001~.002 seldom ever much more. To me, it Almost seems odd too chech valves that soon, but I don't have to warranty engines neither.....
