Hi Neil,
If you don't hear the engine knocking, you are doing OK.
Although the owners handbook recommended high octane fuels in
197______,
that's not necessarily necessary today.
The octane measure changed along the way. There are/were two measures
of Octane. I don't remember the names, but one gave a considerably higher
"rating" than the other. Naturally, it was the higher rating that was
posted on the pumps. Some time during the "gas crisis" the ratings were
averaged, so a given gas has a lower rating than it once did. Because of
that, you can run lower-rated fuel than you might think, yet still feed
the engine what it needs. Most MGB engines will run just fine on 87.
As to low lead and unleaded.....most owners feel that the no lead does
not have as serious effect on the engines as it was feared. It's the
valves that benefited from the lubrication effect of the tetraethyl lead.
While some additional wear is likely, it's not a catastrophic sort of
thing. If you think that your engine still has its original valves, use
ReLead in the gas. If your head has been rebuilt, it was probably fitted
with valve seats and hardened valves. No need to take off the head to
check, just have seats installed next time the head is rebuilt. I'm
running ReLead in my TD, with 87 octane (could probably use 78 if it were
available) as I know the valves are original. But, it's not a big deal
and they are not going to break off and eat your pistons because of lack
of lead in the fuel.
Bob
On Fri, 31 Oct 1997 14:17:57 -0600 (CST) "J. Neil Doane"
<root@yeah.indstate.edu> writes:
>Just curious, looking through some aftermarket manuals of my '73 MGB I
>see
>that "The Complete and Official MG" (I think that's the title) by
>Robert
>Bently recommends 91+ octane fuel, but discourages the use of reduced
>lead
>or unleaded fuels (warning that they could, in fact, cause so much
>damage
>as to render the engine inoperable.)
>
>How accurate is this? I'm not sure about the age of the manual and am
>wondering if 90+ octane unleaded fuels of today would damage the car
>in
>such a way (and most importantly, if the 92 octane unleaded fuel I
>filled
>up with yesterday is going be damaging. :P )
>
>Thanks!
>
>neil doane
>
>
>
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