[Mgs] Petrol

[Paul Hunt]

As already said if you have a low compression engine then lower octane 
should be fine.  If high compression then you will get the benefit of 
better performance and economy with higher octane.  Low ethanol is 
better in both cases.

Because the fuel today is so different to when these cars were first 
produced the original timing specs are no longer relevant. If you get 
pinking then back off the timing until you don't at any combination of 
throttle opening, revs and load.  With high compression and high octane 
try advancing bit by bit until you get pinking, then back off a bit till 
you don't.

You are less likely to get pinking on low compression even with low 
octane fuel, so if you can run the book figures for timing without 
pinking then do so.  You might get a bit better by advancing, but you 
can advance so far that it stalls the starter but still doesn't pink.  
That's obviously too far.

PaulH.

On 20/09/2023 16:32, i erbs wrote:
> I just got my B running for the first time and have a newbie question. 
> I have looked online and got confusing answers.
> What grade petrol do I use? Must I use premium grade? Can I use regular?
> Thanks.
>
> Ira Erbs
> Milwaukie, OR
> 1959 Austin Healey 100-6
> 1967 MGB Roadster
>
> _______________________________________________
>
> Mgs at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/mgs http://autox.team.net/archive
>
> Unsubscribe: http://autox.team.net/mailman/options/mgs/paulbhunt73@gmail.com