--===============8177058241321215300==
--00000000000038e18c0643bf353c
Content-Transfer-Encoding: quoted-printable
Hi Steve,
Having read your update and seeing that you have eliminated the cylinder
head as the source of the issue, I wanted to take another shot at the
problem.
The recent compression test results may be shedding light on the issue.
Based on your readings, the ratio of the lowest to the highest compression
is 75% when cold (120/160) and 79% when hot (130/165). While not an
absolute rule, a general rule of thumb for a smoothly running engine is a
ratio of 90% or greater. A freshly rebuilt engine showing 75% is not a good
sign. Could you try adding a small amount of oil to the third cylinder and
retesting the compression?
If poor piston ring sealing is causing excessive blow-by, this increased
pressure in the bottom of the engine could overwhelm the crankcase
ventilation system.
Though I'm not an expert on the BMC A-series engine, I recall the crankcase
breather usually attaches to the tappet cover on the side of the engine. It
sounds like the current breather setup on your neighbor's engine=E2=80=94lo=
cated
where the old fuel pump attached=E2=80=94might be too low and too close to =
the oil
in the sump. Does this engine have a breather on the tappet cover, and does
air pass through it easily?
Good luck with the continued investigation.
Regards,
Harold
On Sun, Nov 16, 2025 at 1:14=E2=80=AFPM Michael Salter <michael.salter@gmai=
l.com>
wrote:
> In my experience Steven, that's not how it works with piston rings.
> Rings are specific to a particular bore size. If the bore is say 0.010"
> oversize then 0.010" oversize rings are what must be fitted.
> Installing an oversize of ring without accurately measuring the bore and
> checking that the pistons and rings are correct for that bore just won't
> work.
>
> M
>
>
> ------------------------------
> *From:* Steven Kingsbury <airtightproductions@me.com>
> *Sent:* Sunday, November 16, 2025 2:24:30 PM
> *To:* Harold Manifold <manifold@telus.net>
> *Cc:* Michael Salter <michael.salter@gmail.com>; Healey Mail List <
> healeys@autox.team.net>
> *Subject:* Re: [Healeys] Sprite question for my neighbor
>
>
> The engine was a fresh rebuild when bought. The car was sold because of
> the excessive oil blowing out after the fresh rebuild. The head was taken
> off and examined at a local machine shop and passed with flying colors. T=
he
> pistons and rings were also taken to the shop where the machinist remarke=
d
> that the rings might have been too small and suggested 10 over rings. New
> rings went on, everything put back into the engine and again, it runs
> great, just blows the oil all over the place!
> Michael, compression test today after a bit over 100 miles with the new
> rings: 160, 148, 120, 130. Saw some suggestions on an MG forum for fixing
> crankcase ventilation. Will see what my neighbor decides to do and will
> update later. Thanks all for the words.
> And just now, after driving the car another forty miles or so, the
> compression now sits at: 165, 155, 130, 150. So that's getting better. Wi=
ll
> definitely take a closer look at the rocker shaft and bushings. Again,
> thanks to all for the possible foibles facing this engine.
> Steven
>
> On Nov 16, 2025, at 8:52 AM, Harold Manifold <manifold@telus.net> wrote:
>
>
> Hi Steve,
>
> The issue you described with your neighbor's 1275 engine may be related t=
o
> a similar problem I've encountered.
>
> I know of a recently rebuilt engine that experienced comparable excessive
> oil blow-by. The cause, in that case, was a poorly refurbished and refitt=
ed
> rocker shaft and bushings. Without adequate restriction between the rocke=
r
> shaft and the bushings to regulate the oil flow, it resulted in an
> excessive amount of oil being pumped to the top of the engine.
>
> I hope this provides another avenue for investigation.
>
> Regards,
> Harold
>
> On Sat, Nov 15, 2025 at 1:12=E2=80=AFPM Michael Salter <michael.salter@gm=
ail.com>
> wrote:
>
> Hi Steve, what you describe sounds to me like excessive blow-by.
> I would recommend a compression test before going too much further.
>
> M
>
>
> ------------------------------
>
> *From:* Healeys <healeys-bounces@autox.team.net> on behalf of Steven
> Kingsbury via Healeys <healeys@autox.team.net>
> *Sent:* Saturday, November 15, 2025 3:33:19 PM
> *To:* Healey Mail List <healeys@autox.team.net>
> *Subject:* [Healeys] Sprite question for my neighbor
>
> My neighbor bought a bugeye that had a 1275 engine put in it. It runs
> well, but blows oil like crazy out of the oil cap on the valve cover. It
> does not have a timing cover ventilation valve, but a fitting was made to
> fit onto where the old fuel pump fit on the side of the crankcase/block.
> When he hooked the hose from that fitting to the carbs, oil was no longer
> being blown out, but oil was then being sucked into the carbs and he was
> burning oil like crazy.
>
> It seems the pressure in the crankcase is so great it is pushing oil up
> the push rods into the rocker assembly, out the filler cap and all over t=
he
> engine. I'm not familiar with the 1275 and have no ideas on how to vent t=
he
> pressure in the crankcase. Can anyone of you guys point me to a possible
> solution? Thanks in advance for the advice.
> Steven Kingsbury
> BN1
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation $12.75
>
> Archive: http://www.team.net/pipermail/healeys
> http://autox.team.net/archive/healeys
>
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> http://autox.team.net/mailman/listinfo/healeys
>
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/healeys/manifold@telus.net
>
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation $12.75
>
> Archive: http://www.team.net/pipermail/healeys
> http://autox.team.net/archive/healeys
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com
>
>
>
--00000000000038e18c0643bf353c
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr"><div>Hi Steve,</div><div><br></div><div>Having read your u=
pdate and seeing that you have eliminated the cylinder head as the source o=
f the issue, I wanted to take another shot at the problem.</div><div><br></=
div><div>The recent compression test results may be shedding light on the i=
ssue. Based on your readings, the ratio of the lowest to the highest compre=
ssion is 75% when cold (120/160) and 79% when hot (130/165). While not an a=
bsolute rule, a general rule of thumb for a smoothly running engine is a ra=
tio of 90% or greater. A freshly rebuilt engine showing 75% is not a good s=
ign. Could you try adding a small amount of oil to the third cylinder and r=
etesting the compression?</div><div><br></div><div>If poor piston ring seal=
ing is causing excessive blow-by, this increased pressure in the bottom of =
the engine could overwhelm the crankcase ventilation system.</div><div><br>=
</div><div>Though I'm not an expert on the BMC A-series engine, I recal=
l the crankcase breather usually attaches to the tappet cover on the side o=
f the engine. It sounds like the current breather setup on your neighbor=
9;s engine=E2=80=94located where the old fuel pump attached=E2=80=94might b=
e too low and too close to the oil in the sump. Does this engine have a bre=
ather on the tappet cover, and does air pass through it easily?</div><div><=
br></div><div>Good luck with the continued investigation.</div><div><br></d=
iv><div>Regards,</div><div>Harold</div></div><br><div class=3D"gmail_quote =
gmail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Sun, Nov 16=
, 2025 at 1:14=E2=80=AFPM Michael Salter <<a href=3D"mailto:michael.salt=
er@gmail.com">michael.salter@gmail.com</a>> wrote:<br></div><blockquote =
class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px sol=
id rgb(204,204,204);padding-left:1ex">
<div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
In my experience Steven, that's not how it works with piston rings.=C2=
=A0</div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
Rings are specific to a particular bore size. If the bore is say 0.010"=
; oversize then 0.010" oversize rings are what must be fitted.=C2=A0</=
div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
Installing an oversize of ring without accurately measuring the bore and ch=
ecking that the pistons and rings are correct for=C2=A0 that bore just won&=
#39;t work.</div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
<br>
</div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
M</div>
<div id=3D"m_-871980063844760471ms-outlook-mobile-body-separator-line" styl=
e=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Roboto,Arial,Helve=
tica,sans-serif;font-size:12pt" dir=3D"auto">
<div style=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Roboto,Ar=
ial,Helvetica,sans-serif;font-size:12pt" dir=3D"auto">
<br>
</div>
</div>
<div style=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Roboto,Ar=
ial,Helvetica,sans-serif;font-size:12pt" id=3D"m_-871980063844760471ms-outl=
ook-mobile-signature" dir=3D"auto">
<div style=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Roboto,Ar=
ial,Helvetica,sans-serif;font-size:12pt" dir=3D"auto">
<br>
</div>
</div>
<hr style=3D"display:inline-block;width:98%">
<div id=3D"m_-871980063844760471divRplyFwdMsg" dir=3D"ltr"><font face=3D"Ca=
libri, sans-serif" style=3D"font-size:11pt" color=3D"#000000"><b>From:</b> =
Steven Kingsbury <<a href=3D"mailto:airtightproductions@me.com"; target=
=3D"_blank">airtightproductions@me.com</a>><br>
<b>Sent:</b> Sunday, November 16, 2025 2:24:30 PM<br>
<b>To:</b> Harold Manifold <<a href=3D"mailto:manifold@telus.net"; target=
=3D"_blank">manifold@telus.net</a>><br>
<b>Cc:</b> Michael Salter <<a href=3D"mailto:michael.salter@gmail.com"; t=
arget=3D"_blank">michael.salter@gmail.com</a>>; Healey Mail List <<a =
href=3D"mailto:healeys@autox.team.net"; target=3D"_blank">healeys@autox.team=
.net</a>><br>
<b>Subject:</b> Re: [Healeys] Sprite question for my neighbor</font>
<div>=C2=A0</div>
</div>
<div>
<div><br>
</div>
<div style=3D"color:rgba(0,0,0,0.88);font-family:"SF Pro Text",sy=
stem-ui,sans-serif;font-size:17px;font-style:normal;font-variant-ligatures:=
normal;font-variant-caps:normal;font-weight:300;letter-spacing:-0.37px;text=
-align:start;text-indent:0px;text-transform:none;word-spacing:0px;white-spa=
ce:normal;background-color:rgb(255,255,255);text-decoration-style:initial;t=
ext-decoration-color:initial">
The engine was a fresh rebuild when bought. The car was sold because of the=
excessive oil blowing out after the fresh rebuild. The head was taken off =
and examined at a local machine shop and passed with flying colors. The pis=
tons and rings were also taken to
the shop where the machinist remarked that the rings might have been too s=
mall and suggested 10 over rings. New rings went on, everything put back in=
to the engine and again, it runs great, just blows the oil all over the pla=
ce!=C2=A0</div>
<div style=3D"color:rgba(0,0,0,0.88);font-family:"SF Pro Text",sy=
stem-ui,sans-serif;font-size:17px;font-style:normal;font-variant-ligatures:=
normal;font-variant-caps:normal;font-weight:300;letter-spacing:-0.37px;text=
-align:start;text-indent:0px;text-transform:none;word-spacing:0px;white-spa=
ce:normal;background-color:rgb(255,255,255);text-decoration-style:initial;t=
ext-decoration-color:initial">
Michael, compression test today after a bit over 100 miles with the new rin=
gs: 160, 148, 120, 130. Saw some suggestions on an MG forum for fixing cran=
kcase ventilation. Will see what my neighbor decides to do and will update =
later. Thanks all for the words.</div>
<div style=3D"color:rgba(0,0,0,0.88);font-family:"SF Pro Text",sy=
stem-ui,sans-serif;font-size:17px;font-style:normal;font-variant-ligatures:=
normal;font-variant-caps:normal;font-weight:300;letter-spacing:-0.37px;text=
-align:start;text-indent:0px;text-transform:none;word-spacing:0px;white-spa=
ce:normal;background-color:rgb(255,255,255);text-decoration-style:initial;t=
ext-decoration-color:initial">
And just now, after driving the car another forty miles or so, the compress=
ion now sits at: 165, 155, 130, 150. So that's getting better. Will def=
initely take a closer look at the rocker shaft and bushings. Again, thanks =
to all for the possible foibles facing
this engine.</div>
<div style=3D"color:rgba(0,0,0,0.88);font-family:"SF Pro Text",sy=
stem-ui,sans-serif;font-size:17px;font-style:normal;font-variant-ligatures:=
normal;font-variant-caps:normal;font-weight:300;letter-spacing:-0.37px;text=
-align:start;text-indent:0px;text-transform:none;word-spacing:0px;white-spa=
ce:normal;background-color:rgb(255,255,255);text-decoration-style:initial;t=
ext-decoration-color:initial">
Steven=C2=A0</div>
<div>
<div><br>
</div>
<blockquote type=3D"cite">
<div>On Nov 16, 2025, at 8:52 AM, Harold Manifold <<a href=3D"mailto:man=
ifold@telus.net" target=3D"_blank">manifold@telus.net</a>> wrote:</div>
<div><br>
</div>
<div><br>
</div>
<div>
<div dir=3D"ltr">
<div>Hi Steve,</div>
<div><br>
</div>
<div>The issue you described with your neighbor's 1275 engine may be re=
lated to a similar problem I've encountered.</div>
<div><br>
</div>
<div>I know of a recently rebuilt engine that experienced comparable excess=
ive oil blow-by. The cause, in that case, was a poorly refurbished and refi=
tted rocker shaft and bushings. Without adequate restriction between the ro=
cker shaft and the bushings to regulate
the oil flow, it resulted in an excessive amount of oil being pumped to th=
e top of the engine.</div>
<div><br>
</div>
<div>I hope this provides another avenue for investigation.</div>
<div><br>
</div>
<div>Regards,</div>
<div>Harold</div>
</div>
<div><br>
</div>
<div>
<div dir=3D"ltr">On Sat, Nov 15, 2025 at 1:12=E2=80=AFPM Michael Salter <=
;<a href=3D"mailto:michael.salter@gmail.com"; target=3D"_blank">michael.salt=
er@gmail.com</a>> wrote:</div>
<blockquote style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204=
,204,204);padding-left:1ex">
<div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
Hi Steve, what you describe sounds to me like excessive blow-by.=C2=A0</div=
>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
I would recommend a compression test before going too much further.=C2=A0</=
div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
<br>
</div>
<div dir=3D"auto" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sys=
tem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(33,33,33)">
M</div>
<div id=3D"m_-871980063844760471x_m_8735642865022924963ms-outlook-mobile-bo=
dy-separator-line" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-sy=
stem,Roboto,Arial,Helvetica,sans-serif;font-size:12pt">
<div style=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Roboto,Ar=
ial,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
</div>
<div id=3D"m_-871980063844760471x_m_8735642865022924963ms-outlook-mobile-si=
gnature" style=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Robot=
o,Arial,Helvetica,sans-serif;font-size:12pt">
<div style=3D"font-family:Aptos,Aptos_MSFontService,-apple-system,Roboto,Ar=
ial,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
</div>
<div>
<hr style=3D"display:inline-block;width:98%">
<br>
</div>
<div id=3D"m_-871980063844760471x_m_8735642865022924963divRplyFwdMsg" dir=
=3D"ltr">
<div><span style=3D"font-family:Calibri,sans-serif"><span style=3D"color:rg=
b(0,0,0)"><b>From:</b> Healeys <<a href=3D"mailto:healeys-bounces@autox.=
team.net" target=3D"_blank">healeys-bounces@autox.team.net</a>> on behal=
f of Steven Kingsbury via Healeys
<<a href=3D"mailto:healeys@autox.team.net"; target=3D"_blank">healeys@au=
tox.team.net</a>><br>
<b>Sent:</b> Saturday, November 15, 2025 3:33:19 PM<br>
<b>To:</b> Healey Mail List <<a href=3D"mailto:healeys@autox.team.net"; t=
arget=3D"_blank">healeys@autox.team.net</a>><br>
<b>Subject:</b> [Healeys] Sprite question for my neighbor</span></span></di=
v>
<div>=C2=A0</div>
</div>
<div>
<div>My neighbor bought a bugeye that had a 1275 engine put in it. It runs =
well, but blows oil like crazy out of the oil cap on the valve cover. It do=
es not have a timing cover ventilation valve, but a fitting was made to fit=
onto where the old fuel pump fit
on the side of the crankcase/block. When he hooked the hose from that fitt=
ing to the carbs, oil was no longer being blown out, but oil was then being=
sucked into the carbs and he was burning oil like crazy.</div>
<div><br>
</div>
<div>It seems the pressure in the crankcase is so great it is pushing oil u=
p the push rods into the rocker assembly, out the filler cap and all over t=
he engine. I'm not familiar with the 1275 and have no ideas on how to v=
ent the pressure in the crankcase. Can
anyone of you guys point me to a possible solution? Thanks in advance for =
the advice.</div>
<div>Steven Kingsbury</div>
<div>BN1</div>
</div>
</div>
<div>_______________________________________________</div>
<div>Support <a rel=3D"noopener noreferrer" href=3D"http://Team.Net"; target=
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</blockquote></div>
--00000000000038e18c0643bf353c--
--===============8177058241321215300==
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_______________________________________________
Archive: http://www.team.net/pipermail/healeys
http://autox.team.net/archive/healeys
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--===============8177058241321215300==--
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