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Re: Unleaded Fuel

To: Tigers@Autox.Team.Net
Subject: Re: Unleaded Fuel
From: TigerCoupe@aol.com
Date: Sun, 2 Aug 1998 21:06:10 EDT
In a message dated 98-08-02 18:54:35 EDT, Jan Harde wrote:

>  put half a tank of Leaded & half
>  unleaded in your car, this mix will cause a chemical reaction and cause the
>  Octane rating to increase from 87 in the unleaded to over 100 octane...

I am certainly not a chemist and know absolutely nothing about fuel octane
ratings other than what I read, and here is what I have read: It is true that
mixing about 30% leaded and about 70% unleaded gasoline will increase the
octane rating of unleaded fuel about 2-4 points. That is quite a bit less than
Jan claims for a 50/50 mix.  Perhaps the chemical experts among us can clear
up how this happens without having to confuse us with molecule structure, etc.

I have 2 289HP's, one with flat top pistons, the other with 351 Windsor heads
and pop-up pistons. The compression ratio of both engines is nominally about
10.5:1. Neither has hardened exhaust valves or seats.  I use 92 octane
unleaded pump gas with completely satisfactory results. I usually tear an
engine down for some reason or another at least every 50,000 miles, and I'm
confident that my present ones will last at least that long, even though I use
unleaded.  In fact, I predict that the next tear-down will reveal the cleanest
engine I've ever seen, with little or no erosion or burning of exhaust valves.
We'll see.

So if it doesn't ping, runs clean, and doesn't cause premature valve/seat
wear, why put lead in your gas?

Just curious.

Dick Barker

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