At 04:45 AM 7/17/2000 PDT, simon hurley wrote:
>.... How do I tell if the rings are worn and need replacing? The
cylinders are in excellent condition, no scratches etc.
Carefully remove the top ring from a piston. Put the ring into the
cylinder about one inch down from the top. Check the gap at the the ends
of the ring. With a fresh bore and a new ring and cold parts the gap
should be about 0.014". If you have a new ring in a somewhat used cylinder
the gap should be no more than 0.024".
Wear on either the cylinder wall or the ring will increase the gap by
0.00628" for every 0.001 wear on the radius. A typical example would be
0.005" wear on the wall and 0.010" wear on the ring, which would yield a
whopping 0.094" + 0.014" = 0.108" gap. This is not particularly unusual in
a well used engine, but it also does not necessarily indicate a terminal
condition. Unless you have a new ring for this test you cannot tell how
much of that wear is on the wall and how much on the ring. For a good
answer you need to use a telescopic gauge to measure the bore in several
places to determine wear on the diameter of the bore and out of round
condition.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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