[Public-List] Old gas engines

[dan walker]

wow, the things you can learn on this list!

--- On Tue, 8/31/10, Stephen Gwyn <gwyn at beluga.phys.uvic.ca> wrote:

> From: Stephen Gwyn <gwyn at beluga.phys.uvic.ca>
> Subject: [Public-List] Old gas engines
> To: public-list at lists.alberg30.org
> Date: Tuesday, August 31, 2010, 3:05 PM
> 
> Hi,
> 
> Just a quick note to remind people that for gasoline
> "high octane" = "less flamable" not "high power".
> 
> The point of high octane fuels (running from higher octane
> automotive fuels or aviation fuels like 100LL to jet fuel
> and highest octane of all, diesel) is not that they burn
> hotter, it is that they don't ignite prematurely in high
> compression engines.
> 
> In such engines, the increase in temperature of the
> fuel-air mix as it is being squeezed on the compression
> stroke can ignite low octane fuels before the spark plug
> fires, causing knocking. Tetra-ethyl lead was used as an
> anti-knock compound, decreasing the spontaneous ignition
> temperature of fuel. It is amazingly poisonous, (you know,
> lead poisoning, except now it's in the air you breathe) so
> it has been taken off the market except for limited amounts
> in aviation fuel (LL in 100LL stands for Low Lead).
> 
> The Atomic 4 is not a high compression engine, and older
> (is there any other kind) engines in particular usually have
> fairly low compression. If you want your A-4 to run well,
> use low octane fuel. If you use high octane fuel, it will
> burn poorly since it won't be at its correct temperature
> when the spark goes off, causing decreased performance and
> increased fouling to due incomplete burning.
> 
> If you want high octane fuel, you can always use diesel,
> which has a very high octane rating.
> 
> Stephen
> #495 Quasar
> (with a smooth running Atomic 4)
> 
> 
> 
> 
> 
> Still scraping by with the A4, while rebuilding the carb on
> the dock I met a lot of other people having engine troubles
> recently. I had a friend who is also a mechanic helping
> me.  He suggested the reason so many people are and
> will have trouble with older gas engines is the gas itself.
> These engines were built to run on leaded gas, the lead in
> the gas acts like a lubricant. The low grade gas at most
> fuel docks also has ethanol in it which would do just the
> opposite. You can purchase a lead additive from most
> automotive supply stores and if you can't bring in your own
> high octane fuel there is another additive to deal with the
> ethanol. Can't remember the name - it's blue.  These
> changes made an improvement in my engines performance.
> Thought I would share incase others are/were in the dark
> about this.
> 
> 
> 
> ------------------------------------------------------------------
>  Stephen Gwyn           
>      |  Tel: 1-250-363-3136
>  Dept. of Physics & Astronomy |  Fax:
> 1-250-363-0045
>  Univ. of Victoria           
> |  Cell: 1-250-885-6969
>  PO Box 3055           
>       |  E-mail: gwyn at uvastro.phys.uvic.ca
>  Victoria, BC  V8W 3P6       
> |  http://orca.phys.uvic.ca/~gwyn
> ------------------------------------------------------------------
> 
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