2640 selective control valve

cowman79

Member
I have just finished rebuilding my valve and was wondering if the 4 set screws on top of the rocker assembly is an adjustment or just tighten them. The set screws I am talking about are under the top cover.
 

What exactly is being adjusted with these screws the full. Open position of the spool or the valve stops.
 

The clearance between valve & seat very similar to engine cylinder head valve adjustments. SCV adjustment is in thousands of an inch set with a dial micrometer.
 
As the others said they need set properly, I back-feed the valve with shop air pressure and set them that way,
you will need to remove the 2 side plugs, go in and loosen the cam just a bit so it can float, then plumb up
an air hose to say the left side, with the lever in nutruel there should be no air escaping ( mind you now
this is with the valve "off" the tractor),now tighten one of the adjusting screws a little at a time till air
escapes,"slightly" then back off the valve a half turn, do the same on the other screw on that side, I turn
them just a bit evenly one to the other so it doesn't get set lop-sided, then do the other side the same way
when your done re-tighten the side cam screws..
 

When feeding this valve with shop air is there ever a time when you have a small amount of air escaping from inside of the valve before and after making the adjustments to the poppet valves. I plumbed air into the pressure port of the valve and made the adjustments as you recommended. Before adjustment and replacement of the poppets themselves I had air coming from the ports of the valve going to one of the remotes of the tractor. Replacement of the poppets fixed the air leaking from the port of the tractor but i still have a small leak under the cams and am not sure if this is normal or not. I have installed this valve on the tractors and it is giving me some fits. I am thinking I may not have adjusted that cams properly.
 
Some times you need to kinda "pop" the lever a bit to let the valve seat when using air to set them, and when
adjust ing them you need to turn each valve adjustment evenly top then bottom to keep the cam from being
"tipped" too much,, If you want give me a call to talk about it, or box it up and send it to me I will go
through the adjustments and bench test it for you,, [email protected]
 

It appears that I had misadjusted cams on the poppets. I would like to thank Tim S for the over the phone support.
 
I'm always glad to help some one help themselves and point them in the right direction...
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top