Greg's Pistons
> BTW these are the 5 ring pistons that Ken at British
> Frame and Engine says some people have had some
> trouble with. H-m-m-m...
Okay, I'm not an expert, but I'm not familiar with generic
problems surrounding 5 ring pistons. I hope that's not an
issue, because I just put a set back into my race car
that were fairly new (only 3-4 races). What I did find,
however, was that the expander spring behind the upper
oil scraper ring (fourth ring, just above the wrist pin)
wasbroken into multiple pieces on every piston. It was
the type that looks like flat piece of metal bent into an
octagonal shape (MG's revenge on my Austin-Healey?).
Grant is one supplier which makes this type (that I don't
like). Moss Motor (among many others) sells Grant rings.
To be truthful, the problem does not occur with "normal"
usage, it seems to happen when the engine is run at speeds
around or above 5,000 rpm. Red line on the Healey 6-cyl is
5,200 rpm, I try to keep it under 6,000 on the race track.
Discussions with local race shops resulted in the following
comment: Take the pieces and throw them as far as possible.
If replacement rings come with that type of expander, see if
they can be thrown even further. They recommended an
expander spring made to look like corrugated cardboard (wavy)
rather than the octagonal type.
There are two good choices -- One has a spring that goes
behind the oil scraper, the spring is "wavy." The other also
has a wavy spring, but the oil scraper is actually two thin
flat rings that go above and below the spring. Hastings is
one supplier of this type. I found these at Sports and Classics
(203/655-8731). There are certainly other suppliers, Speedpro
(sp?) was recommended by one shop, but I couldn't find them
for my Healey.
-- Dave L. HEALEY@OAKHILL.sps.mot.com Austin, TX
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