ABOUT SMALL ENGINE PISTONS RINGS
Small engine pistons have three rings,4 cycle engines that
is.Lawnmowers, tillers, generators, air compressors and water pumps.
The two top rings are compression rings, and the bottom ring is the oil
ring and it is usually the one that wears out first,causing your engine to
burn oil by not scraping the cylinder clean on the downward stroke,low
oil or not changing the oil causes premature wear.
Rings come in standard and over size, over size are used for worn
cylinders.You can get them in.010,.020 and .030 thousandths over size.
Usually standard size rings will work for a rebuild,one shade tree way to
tell is to take the cylinder head off of engine,rotate piston all the way up
and press your fingertips on piston and try to move it side to side against
cylinder wall, if you have substantial movement then its possible you
would need .010 thousandths oversize,to make sure of no oil burning
when you put engine back together
When installing piston rings, you must stagger the ring gaps around
piston in no certain order, just so no two line up, or otherwise
compression and oil will blow by rings so to speak, that goes for all
internal combustion engines.
A ring compressor must be used to install piston back into cylinder,it will
compress the piston rings back into piston enough to tap it back into
cylinder, any other way and you risk breaking one of the rings, since they
are breakable.
To get piston rings for any small engine you will need model numbers
from valve cover or flywheel cap, used to be just flywheel cover, but
nowadays a lot of the model numbers are located on valve cover on
briggs, kohler, tecumseh, honda, kawasaki.
Constant white or blue smoke coming from a small engine is a
troubleshooting sign of a worn oil ring and continued running in this
condition for a season or so will cause the cylinder wall to be scarred,and
the the cylinder must be honed to get rid of scarrs to ever stop burning
oil even with new piston rings,more expense than worth a lot of times.
