Super and LRP fuel is being phased out this week in Australia. I know that our 1981 1800 4WD Wagon can use unleaded with just an ignition timing change. Standard timing for leaded fuel is 8 BTDC for leaded (Super) fuel.
Can anyone tell me what the timing should be for unleaded on this engine?
Thanks Al Blake, Canberra, Australia
Just keep backing it off until it has a light ping under heavy load.
Thanks Rob. Just to confirm I understand......by 'backing it off' do you mean move it towards TDC (ie less advanced) so the ignition occurs later......? What happens is I get to 0 (TDC) ?
Thanks Al.
My '81 engine (currently in an '83 chassis) runs just fine on the 85 octane "regular" unleaded/oxygenated (10% Ethanol) fuel we get around here (Colorado, USA). I have the static timing set to ~12 degrees BTDC to compensate for the thinner air at 7000 ft elevation. I don't think you'll need to worry about the timing unless you notice the engine pinging under load (tho how you'd hear it above the usual engine noise I'm not sure). Run a tank thru and check your plugs; unless they come out white, you're fine. If you notice pinging, or if the plugs insulators are burned clean (white), retard the timing in 2 degree increments til the engine is happy. The plug insulators should be a medium tan color. Does the engine in your car have an O2 sensor, and the hi-speed/lo-speed duty valves? (Just curious.)
ByeBye! S.
Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101
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