[TR] Stag missing a beat at speed but not at idle

[Geo Hahn]

On Sun, Mar 12, 2017 at 11:08 PM, Sujit Roy <triumphstag at gmail.com> wrote:

...I noticed the car missing a beat and ran rough at about 70 mph....  what
> else should I look for?
>

Could be many things but I'll mention what I found when I had a similar
problem on my non-TR six cylinder engine.  I was getting some cross fire
from my ignition wires.

I was able to nail down the cause by making additional timing marks in
white and yellow at 120° away from the stock mark in each direction.  Does
not have to be precise.  You can then use a timing light in the usual
fashion and watch the timing marks at high RPM.

What I saw was that in addition to the correct firing I was also seeing
extra firings - obvious because the other marks were each different.

It doesn't matter if the extra spark occurs on the exhaust stroke but if it
occurs in the compression stroke you are basically getting timing advance
of 130° BTDC.  That will be something you can feel.

All this is much easier to check with a timing light with an advance dial.

Geo
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