Don,
Any relation to Tom Witt (wittsend@jps.net) ?
The discussion of the correct grade of gasoline has been around since
there was more than 1 grade.
A correct answer is that octane at which pre ignition does not take
place (pinging). Any more
is a waste of money. Determining if your engine has a high speed
detonation is sometimes very
difficult at maximum output, due to competing noises.
For the factory stock Tiger, a regular grade is adequate. Changes to
the engine, or incorrect timing,
can alter this. Correct the timing first, it isn't helping.
Of greater concern is the elimination of the lead content of gasoline,
which was the primary
additive for cheaply increasing octane without better refining. A
secondary benefit of leaded
gas is the coating, hence lubrication, of the valves and seats with lead
deposits. Once a good
coat is formed, unleaded types of gas are acceptable. As I recall, in
these engines Ford did not
use hardened valve seat insets, but did use a flame, or induction
heating, of the cast valve seat area.
With a nice lead coating from prior leaded gas use, don't worry.
These statements only apply to the original factory heads that have not
had the protective coating
removed through machining, valve replacement, or grinding.
Steve
___
Steve Laifman
Editor - TigersUnited.com
Witt wrote:
>Greetings all,
>
>Pardon another 'rookie question' (with many more to follow...) but what type
>of fuel do you run in your Tigers? Sorry, I can't remember when unleaded
>fuels started. Does the engine respond better to higher octane?
>
>(I did check the on-line manual from the TigersUnited web site before
>bothering the group, but didn't find it)
>
>don w.
|