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Mirek,
I had this same issue 20 years ago when I rebuilt my engine and I made the
decision to omit the lower ring. I felt the 5th ring would just be
additional drag and didn't really serve any purpose. I've had no issues.
I'm not sure if it made a difference.
Mark Fawcett
1959 BT7
On Fri, Apr 16, 2021 at 10:37 AM m.g.sharp--- via Healeys <
healeys@autox.team.net> wrote:
> Hi all,
>
>
>
> More on the rebuild of my BT7 engine. A number of years ago I purchased
> +0.030=E2=80=9D AE pistons in anticipation of this rebuild. The AE pisto=
ns have
> 5 rings: 3 compression and one oil control above the wrist pin and one oi=
l
> control lower on the skirt, below the gudgeon pin. The pistons that came
> out, which were the originals, had the conventional 3 compression rings a=
nd
> one oil control ring.
>
>
>
> I am wondering about that second oil control ring below the gudgeon pin
> and whether I should fit it or not. I am not building a performance
> engine, just want the highest quality job possible. The original pistons
> functioned fine and I never had oil consumption issues in the 110,000 mil=
es
> I put on them. This engine had a bit of piston slap, which was typical o=
f
> them. I wondered if the extra ring lower on the skirt was to address
> this. Perhaps it was a complaint from Austin Westminster owners wanting
> quieter engines? Was the 5th ring for another application? I also
> wonder whether wiping the oil off the bores by the lower control ring is =
a
> good thing or whether it is better to have some cylinder wall lubrication
> from oil splashing onto the cylinder walls.
>
>
>
> I have searched for a service sheet on these pistons (thanks Scott!!) but
> found nothing. I also searched the List Archives, and there are a few
> older postings that suggest fitting all 5 rings, but no reasons why.
>
>
>
> I doubt we can really know what is going on in there as the dynamics are
> complex, but I would be interested in any experience anyone has had with
> the 5-ring pistons. Theoretical discussion is always welcome!
>
>
>
> Best, Mirek
>
>
>
>
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<div dir=3D"ltr">Mirek,<div>I had this same issue 20 years ago when I rebui=
lt my engine and I made the decision to omit the lower ring. I felt the 5th=
ring would just be additional drag and didn't really serve any purpose=
.=C2=A0 I've had no issues. I'm not sure if it made a difference.</=
div><div><br></div><div>Mark Fawcett</div><div>1959 BT7</div></div><br><div=
class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Fri, Apr 16=
, 2021 at 10:37 AM m.g.sharp--- via Healeys <<a href=3D"mailto:healeys@a=
utox.team.net">healeys@autox.team.net</a>> wrote:<br></div><blockquote c=
lass=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px soli=
d rgb(204,204,204);padding-left:1ex"><div lang=3D"EN-CA" style=3D"overflow-=
wrap: break-word;"><div class=3D"gmail-m_6753917049390335519WordSection1"><=
p class=3D"MsoNormal"><span lang=3D"EN-US">Hi all,<u></u><u></u></span></p>=
<p class=3D"MsoNormal"><span lang=3D"EN-US"><u></u>=C2=A0<u></u></span></p>=
<p class=3D"MsoNormal"><span lang=3D"EN-US">More on the rebuild of my BT7 e=
ngine.=C2=A0 A number of years ago I purchased +0.030=E2=80=9D AE pistons i=
n anticipation of this rebuild.=C2=A0 </span><span lang=3D"EN-US">The AE </=
span>pistons have 5 rings: 3 compression and one oil control above the wris=
t pin and one oil control lower on the skirt, below the gudgeon pin.=C2=A0 =
The pistons that came out, which were the originals, had the conventional 3=
compression rings and one oil control ring.<u></u><u></u></p><p class=3D"M=
soNormal"><u></u>=C2=A0<u></u></p><p class=3D"MsoNormal">I am wondering abo=
ut that second oil control ring below the gudgeon pin and whether I should =
fit it or not. =C2=A0=C2=A0I am not building a performance engine, just wan=
t the highest quality job possible.=C2=A0 The original pistons functioned f=
ine and I never had oil consumption issues in the 110,000 miles I put on th=
em.=C2=A0 This engine had a bit of piston slap, which was typical of them.=
=C2=A0 I wondered if the extra ring lower on the skirt was to address this.=
=C2=A0 Perhaps it was a complaint from Austin Westminster owners wanting qu=
ieter engines?=C2=A0 Was the 5<sup>th</sup> ring for another application?=
=C2=A0 I also wonder whether wiping the oil off the bores by the lower cont=
rol ring is a good thing or whether it is better to have some cylinder wall=
lubrication from oil splashing onto the cylinder walls.<u></u><u></u></p><=
p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p><p class=3D"MsoNormal">I have=
searched for a service sheet on these pistons (thanks Scott!!) but found n=
othing.=C2=A0 I also searched the List Archives, and there are a few older =
postings that suggest fitting all 5 rings, but no reasons why.<u></u><u></u=
></p><p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p><p class=3D"MsoNormal">=
I doubt we can really know what is going on in there as the dynamics are co=
mplex, but I would be interested in any experience anyone has had with the =
5-ring pistons.=C2=A0 Theoretical discussion is always welcome!<u></u><u></=
u></p><p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p><p class=3D"MsoNormal"=
>Best, Mirek<u></u><u></u></p><p class=3D"MsoNormal"><u></u>=C2=A0<u></u></=
p><p class=3D"MsoNormal"><span lang=3D"EN-US"><u></u>=C2=A0<u></u></span></=
p></div></div>_______________________________________________<br>
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</blockquote></div>
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