When to adjust valves
- Thread starter Rick
- Start date
A 'valve job' suggests remove the cylinder head and take to machine shop. There we renew valve guides, seals, valve spring tension, and also test seat integrity (meaning the valve seat surface matches the outer diameter of the valve.) That way the valve will seal to the valve seat very well. The bonus is that renewing guides and stem seals means valve runs up and down true thus oil consumption is reduced to the minimum.
A 'valve adjustment' means to check that the rocker arm clearances are not too small (or rarely too large) thus that the cam shaft lifts the valve to the designed height which is correct for fuel intake and exhaust out take. This is adjustable without any dis-assembly and In my view needs to be checked every 200 -500 hours. The motor manufacturer publishes how often. You cannot adjust too often but you can fail to adjust not often enough.
First check and set clearance, then check compression, then decide.
Charles
A 'valve adjustment' means to check that the rocker arm clearances are not too small (or rarely too large) thus that the cam shaft lifts the valve to the designed height which is correct for fuel intake and exhaust out take. This is adjustable without any dis-assembly and In my view needs to be checked every 200 -500 hours. The motor manufacturer publishes how often. You cannot adjust too often but you can fail to adjust not often enough.
First check and set clearance, then check compression, then decide.
Charles
Best to check it a bit more often.. Yanmar recommends every 500 hours.. The problem is that usually when valves wear the clearance decreases and they make less and less noise ... until the seat burns from not enough seat sealing pressure.. then it is a pretty big (and expensive) job to fix.. a good mechanic can do a check in less than an hour ..
It is an easy job that you can do or learn to do pretty quickly too.
It is an easy job that you can do or learn to do pretty quickly too.
