timing of a leaded head running on unleaded - with aditive, on a 1981 998cc,
i (will) set the timing at 8 degrees as per haynes manual - but do i have to advance or retard at all if running unleaded with additive on a leaded head?
thanks
Ryan
timing of a leaded head running on unleaded - with aditive, on a 1981 998cc,
i (will) set the timing at 8 degrees as per haynes manual - but do i have to advance or retard at all if running unleaded with additive on a leaded head?
thanks
Ryan
Well if you get pinking problems you should retard it slightly I think. As it happens a few years ago my sister was running an 87' Mayfair and using Car Plan Additive and it ran fine with no adjustment, where as her daughter (my niece) was running an 85' Mayfair and that started pinking under load, so I just took it to a local mobile tuner and he sorted it out for a tenner and it ran like a watch afterwards.
Taffy
Hi Ryan
It should be fine if the additive has octane booster.
best method is to drive up steep hill in third at full throttle and listen for pinking,
If it pinks then retard the timing a little, (turn the dizzy anti clockwise ever so slightly)
repeat untill it doesn't pink!
Garages tend to set engines up to the factory settings that sometimes aren't quite right if you have modified the engine slightly or live at odd altitudes or temperatures!
Miniman
Hi, I agree with Taff and Miniman, Just drive the car, put it under load, if it pinks, then jump out , retard the ignition slightly,(turn dizzy anti-clockwise) and repeat the test, its got to be one of the quickest DIY fixes ever,
Note; timing lights and settings noted in books are redundant when doing this adjustment,
Fitzy
I had a similar problem, pinking like mad on 97 RON unleaded, worse on 95 RON both this additive plus Octane boost, It would net even start properly, Now running at about 15Deg BTDC @ 1500rpm with vacuum advance off
1986 998cc Mayfair std
But once you do get it right, it may be an idea to get a strobe on there anyway to find out what the timing is for future reference. Most additives claim that the timing needs no adjustment, but they tend to get that wrong.
HTH Jim
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