[Mgs] T-series work

[Richard Lindsay]

   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 at 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 loose
> as first thought.   Segmented belts grip better than the original wide
> belt-don’t look right but are easier on the dynamo.
>    Owner’s manual said to use grease in the brass fitting.  Others 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 its
> ability to put oil where it’s needed.  Some will drill a tiny hole 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 engineer
> 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 children
> and neighborhood dogs was considerably reduced.  In one of his videos, John
> 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 at 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 the
> 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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