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Thank you Bob. Great to know on all fronts. Regarding valves, generators
and pumps,
A bit more valve clearance is typical of racing cams. Doing so is a
little noisy but despite a few mils less valve lift and an all but
unmeasurable timing delay, the valves 'snap' open faster. Cam wear can may
be accelerated. All of the above is a bit more applicable to direct action
overhead cam designs. But you know this.
Bob's sage advice has encouraged me to un-mount the generator for a
rebuild. I knew about the looser drive belt tension since that advice is
true even for later model cars with alternators. Lateral stress on the
bushings is minimized. And you know that too.
I replaced the waterpump when I rebuilt the engine a few years ago.
Thanks again Bob,
Rick
On Sun, May 3, 2020, 8:00 AM Robert's New iPad <mgbobh@gmail.com> wrote:
> Hi Rick,
> The dreaded dynamo sound is heard again. It is good that you heard it
> before damage was done to armature or field coils.
> Thoughts that others have shared about the dynamo:
> Fan belt should be as loose as it can be w/o flipping off. Another
> measure of tension is to turn on all electrics, then spray water on the
> belt. Make it just tight enough to grip, not slip, which is about as loos=
e
> as first thought. Segmented belts grip better than the original wide
> belt-don=E2=80=99t look right but are easier on the dynamo.
> Owner=E2=80=99s manual said to use grease in the brass fitting. Other=
s say
> that oil, used frequently to wet the felt, is better. Most agree that
> original bushing was an Oillite or equivalent. Many of the replacement
> bushings are not. Many believe that reaming an Oillite bushing reduces it=
s
> ability to put oil where it=E2=80=99s needed. Some will drill a tiny hol=
e right
> through the bushing, hoping that oil will get to the moving armature more
> easily.
> Do you know the clearances for valve rockers? .019 and .012 were MG
> specs for original camshafts. Other clearances were specified for other
> cams. It is not helpful to tell you that I got a Crane camshaft that made
> so much noise with its specified clearances that called Crane. An engine=
er
> told me that those clearances were for racing; that for normal use to
> reduce by three or four thou. I did, and the fear factor in small childr=
en
> and neighborhood dogs was considerably reduced. In one of his videos, Jo=
hn
> Twist said to use .015 for everything, unless one had specific knowledge.
> Happy motoring!
> Bob
>
> > On May 3, 2020, at 8:35 AM, Richard Lindsay via Mgs <mgs@autox.team.net=
>
> wrote:
> >
> > Hello again friends,
> > I have decided to do a bit more maintenance work on my MG TD before
> driving it much. The reason for this decision is because of two sounds.
> There is a 'shhhhh' kind of sound coming from either the water pump or th=
e
> generator. It's the sound a dry bushing or bearing makes before the
> squealing begins...maybe. The second sound is more typical. Valve lash
> chatter.
> > The second noise is an indication of needed routine maintenance. The
> former hints at a needed repair. Both issues will be addressed...if after
> the 308GTB work and before the 1800E arrives.
> >
> > Rick
>
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<div dir=3D"auto"><div>=C2=A0 =C2=A0Thank you Bob. Great to know on all fro=
nts. Regarding valves, generators and pumps,</div><div dir=3D"auto">=C2=A0 =
=C2=A0A bit more valve clearance is typical of racing cams. Doing so is a l=
ittle noisy but despite a few mils less valve lift and an all but unmeasura=
ble timing delay, the valves 'snap' open faster. Cam wear can may b=
e accelerated. All of the above is a bit more applicable to direct action o=
verhead cam designs. But you know this.</div><div dir=3D"auto">=C2=A0 =C2=
=A0Bob's sage advice has encouraged me to un-mount the generator for a =
rebuild. I knew about the looser drive belt tension since that advice is tr=
ue even for later model cars with alternators. Lateral stress on the bushin=
gs is minimized. And you know that too.</div><div dir=3D"auto">=C2=A0 =C2=
=A0I replaced the waterpump when I rebuilt the engine a few years ago.</div=
><div dir=3D"auto"><br></div><div dir=3D"auto">Thanks again Bob,</div><div =
dir=3D"auto"><br></div><div dir=3D"auto">Rick<br><br><div class=3D"gmail_qu=
ote" dir=3D"auto"><div dir=3D"ltr" class=3D"gmail_attr">On Sun, May 3, 2020=
, 8:00 AM Robert's New iPad <<a href=3D"mailto:mgbobh@gmail.com";>mgb=
obh@gmail.com</a>> wrote:<br></div><blockquote class=3D"gmail_quote" sty=
le=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Ric=
k,<br>
=C2=A0 The dreaded dynamo sound is heard again. It is good that you heard i=
t before damage was done to armature or field coils.<br>
=C2=A0 =C2=A0Thoughts that others have shared about the dynamo:<br>
=C2=A0 =C2=A0Fan belt should be as loose as it can be w/o flipping off. Ano=
ther measure of tension is to turn on all electrics, then spray water on th=
e belt. Make it just tight enough to grip, not slip, which is about as loos=
e as first thought.=C2=A0 =C2=A0Segmented belts grip better than the origin=
al wide belt-don=E2=80=99t look right but are easier on the dynamo.<br>
=C2=A0 =C2=A0Owner=E2=80=99s manual said to use grease in the brass fitting=
.=C2=A0 Others say that oil, used frequently to wet the felt, is better.=C2=
=A0 Most agree that original bushing was an Oillite or equivalent. Many of =
the replacement bushings are not. Many believe that reaming an Oillite bush=
ing reduces its ability to put oil where it=E2=80=99s needed.=C2=A0 Some wi=
ll drill a tiny hole right through the bushing, hoping that oil will get to=
the moving armature more easily.=C2=A0 <br>
=C2=A0 =C2=A0Do you know the clearances for valve rockers?=C2=A0 .019 and .=
012 were MG specs for original camshafts.=C2=A0 Other clearances were speci=
fied for other cams. It is not helpful to tell you that I got a Crane camsh=
aft that made so much noise with its specified clearances that called Crane=
.=C2=A0 An engineer told me that those clearances were for racing; that for=
normal use to reduce by three or four thou.=C2=A0 I did, and the fear fact=
or in small children and neighborhood dogs was considerably reduced.=C2=A0 =
In one of his videos, John Twist said to use .015 for everything, unless on=
e had specific knowledge.<br>
=C2=A0 =C2=A0Happy motoring!<br>
Bob<br>
<br>
> On May 3, 2020, at 8:35 AM, Richard Lindsay via Mgs <<a href=3D"mai=
lto:mgs@autox.team.net" target=3D"_blank" rel=3D"noreferrer">mgs@autox.team=
.net</a>> wrote:<br>
> <br>
> Hello again friends,<br>
>=C2=A0 =C2=A0 I have decided to do a bit more maintenance work on my MG=
TD before driving it much. The reason for this decision is because of two =
sounds. There is a 'shhhhh' kind of sound coming from either the wa=
ter pump or the generator. It's the sound a dry bushing or bearing make=
s before the squealing begins...maybe. The second sound is more typical. Va=
lve lash chatter.<br>
>=C2=A0 =C2=A0 The second noise is an indication of needed routine maint=
enance. The former hints at a needed repair. Both issues will be addressed.=
..if after the 308GTB work and before the 1800E arrives.<br>
> <br>
> Rick<br>
</blockquote></div></div></div>
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