Harold and Susan Vordos wrote:

"Tom" wrote in message
...
Christopher Tidy wrote:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris

The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.

Tom

That could be true in this instance. It all depends on how it fits the bore.
If it's the largest in diameter, it very well could be a wiper. With the
typical 4 piece sets, the thin rings are the wipers, and are made of heat
treated steel, not cast iron. You've likely seen them.

Harold

Steel ring inserts for either adapting narrow rings to wider grooves
and enabling worn grooves to be turned out to fit standard width rings
are commonplace. Using a steel wiper in conjunction with a cast iron
oil control ring, well, that is singular indeed. Spacing rings seat on
the bottom of the groove and do not protrude past the ring land.

Harold, what's this I hear you're reluctant to put Colchester bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom