[Healeys] To fit or not to fit 5 ring pistons

[gradea1 at charter.net]

Here is a note found on the web. Kinda explains the reasoning.
However, I would talk to your machine shop and see what they recommend
as technology has changed in 59-60 years. Today everything is about
less drag. I have seen some folks leave off the bottom ring...I'm a
purist, so I use original parts as they were manufactured. Hank

	* The oil control ring at the bottom actually consists of two rings
and a spacer. The main trade off is, the 4-ring piston will have less
drag on the cylinder walls, but the 5-ring piston will seal better. A
better sealing piston will keep more power in the cylinder, but you'll
see additional frictional losses.

	-----------------------------------------From: "m.g.sharp--- via
Healeys" 
To: "Ian Hey"
Cc: 
Sent: Friday April 16 2021 12:18:04PM
Subject: Re: [Healeys] To fit or not to fit

	Hi Ian, 

	Thanks for responding. I am not going to another piston manufacturer;
the older AE pistons are excellent quality and have a good reputation.
You can’t judge the quality of castings and machining from an
illustration, and half the time what is illustrated is not exactly
what is sold anyhow. Omega pistons are also excellent and I have
fitted them to classic BSA and Velocette motorcycles when I was doing
a complete balance, Carrillo rods, bench flowing the head; the whole
nine yards. However, with the Healey, unless you are building a
performance engine, I do not see the need for forged pistons. That
said, if I did not have the AE pistons, then I would have gone with
the Omegas. 

	I would still like to hear about the purpose/wisdom behind the change
in piston design that led to the introduction of the 5th ring. They
would not have spent the extra money to switch up the machining if
there was not a good reason. 

	FROM: Healeys  ON BEHALF OF Ian Hey via Healeys
SENT: April 16, 2021 2:09 PM
TO: healeys at autox.team.net
SUBJECT: [Healeys] To fit or not to fit   

	In a recent engine rebuild of a standard BJ7 engine which was fitted
with four ring pistons, when I looked at replacement pistons they were
pictured with five rings, which did not seem good to me. 

	I fitted Omega pistons from Denis Welch. These have three rings with
a total width of 3.2mm compared with 9.8mm for the four rings. (For
the oil rings only the width contacting the cylinder bore is measured)


	Since friction is in proportion to ring width (possibly due to the
lower pressure required to make thinner rings seat against the
cylinder wall) this represents a reduction in losses to heat and a
power increase (small). 

	Another, much more expensive, option for consideration. I also have
no doubts about the quality of the pistons, whereas I am not sure
about the four or five ringed replacements. They seem very cheap to
me. 

	Ian
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