worn valve guide

[tmar04]

How can I tell if valve guides are worn enough to cause excessive oil consumption and smoke.(blue/white) Have ym2500 w/3t80 eng, 1000 hrs, runs great, starts good even on coldest of days, but uses 1 qt oil in 8-9 hrs!! seals replaced recently. old seals looked good. Head just checked, no problems. I have changed oil several times, used MMO, synthetic oil and now have 30 W. in it. still uses oil. I hate to tear engine down(overhaul) til I know for sure problem is not in valve train. thanks for the help.

 

[kenmac]

If /when you had the head checked . They should have checked the valve guides

 

[tmar04]

is this something that is obvious to the experienced eye? or could they be worn beyond specs, enough to cause excessive oil consumption. like 1 qt in 8 hrs. thanks

 

[1danny]

is this something that is obvious to the experienced eye? or could they be worn beyond specs, enough to cause excessive oil consumption. like 1 qt in 8 hrs. thanks

Valve guide to valve stem clearance should be 0.04 - 0.06 mm or .001578" - 002363". Wear limit is 0.15 mm or .00590". new valve guide ID is 7.00 mm - 7.02 mm or .2758" - 27658".

Danny

 

[tmar04]

Thanks, Danny. I will get some measurements on my guides when I get head removed. If clearance has exceeded maximum, would that allow oil consumption to be excessive? tractor runs great other than oil usage and smoke.

 

[1danny]

Thanks, Danny. I will get some measurements on my guides when I get head removed. If clearance has exceeded maximum, would that allow oil consumption to be excessive? tractor runs great other than oil usage and smoke.

Do you have much blowby?

Danny

 

[1danny]

Thanks, Danny. I will get some measurements on my guides when I get head removed. If clearance has exceeded maximum, would that allow oil consumption to be excessive? tractor runs great other than oil usage and smoke.

It would be hard for me to pull the head off and not replace the piston rings.

Danny

 

[careyo63]

I agree with danny.It is hard to detect worn oil rings with good compression or good compression rings.It would be IMHO to replace the rod bearings and piston rings while I had the top end off and checked then you should have years of service life.If the engine is using oil valve seals or rings since there is no visble signs of leaks.Worn valve stems or bad seals will be oily and dirty inside the head easily visible with the head off. Valve guides essessive valve noise and poor performance the valves will not seat or adjust properly and wear from the movement.I by no means am I an expert but found over the years these thing to be true.I also would check the transmission housing for oil your rear main seal could be leaking I believe there is a drain plug you can remove.

 

[tmar04]

Thanks so much for the kind reply. I already have the new rings and rod bearings to install. Might as well bite the bullet and do it. Tractor does not leak a drop of oil. blowby is minimal. no restrictions in the blowby line. Could be either worn oil rings, broken oil ring and stuck oil rings. just my opinion. will advise more later after dissassembly. Thanks again to all.