[Healeys] Right rings and pistons?

[Michael Salter]

Hi Rafael,
I don't think the piston in your picture is an original Austin piston. I
have never seen an original piston with the "slipper" shape or one with the
groves on the body that yours has consequently, the ring package is not
what would normally be used.
The top ring is indeed a compression ring but the others are all what we
used to call "cord" rings and are I believe designed for oil control not
compression. I'm pretty sure that all original pistons had 2 compression
rings.
That said however there is no good reason why they should not work.
Although the picture is not very clear it would also appear that the piston
is slightly "domed". I'm pretty sure that the original pistons in a
tri-carb were flat top so I would strongly recommend that you check the
actual compression ratio to ensure that the engine has not been modified so
much that it will not run well on pump fuel.
I'm sure that your machine shop knows what they are doing but the cylinders
should not be "polished" but honed before reassembly.
Hope that helps.

Michael S
BN1 #174
http://www.netbug.net/blogmichael/?p=445

On Thu, Jan 8, 2015 at 8:43 PM, Rafael Abugattas <rafaelabugattas at yahoo.es>
wrote:

> Hi all,
>
> I just started a nut and bolt restoration on my 1962 BT7 Tri Carb. Today
> we took the engine apart and sent the block and head to the machine shop.
> On a first inspection, it seems that the cylinders do not need to be bored,
> only polished.
>
>
>
> My mechanic is concerned about the pistons and the type of rings it uses.
> Enclosed is a picture of one of the pistons and the three set of rings.
>
>
>
> I am no expert but according to his explanation: Starting from the right,
> the first thick ring on the picture is the compression ring. The middle or
> second set includes two additional thin compression rings and what seems
> like an heptagon that I understand helps keep the rings open. The third set
> includes three lubrication rings.
>
>
>
> He mentioned that the middle set of two thin compression rings with the
> heptagon is not a very common configuration. He was wondering whether they
> could be substituted with one regular compression ring.
>
>
>
> He has worked before on a Healey engine and he doesn´t recall pistons with
> the grooves on the side like the one on the picture. I guess the groove
> design helps with the lubrication and cooling of the pistons. Are these
> original pistons? Would you recommend changing them?
>
>
>
> Thanks in advance for your comments.
>
>
>
> Best regards,
>
> Rafael
>
>
>
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-- 
*If you can't fix it with a hammer, you've got an electrical problem.*
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