Timing for unleaded on 1981 1800?

[Al Blake]

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

 

[Rob Munach]

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.

 

[Al Blake]

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.

 

[S]

Hi Al.

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.

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