Unleaded benzin

IS it possible to use unleaded benzin in non catalyzed engines in a 900. I guess they might have the hardened ventils seats. I ve read that most of alloy head cylinders has hardened ventil seats. Can anyone confirm this?

what year is the car manufactured?
model?

1984 900 turbo

as i understand so 16 valve from -84 is ok for unleaded fuel and the 8 valve from -85 is ok ( or late 84, engine number E51661 carburator engine only ).
i think it is an good idea to have a god check/kontroll of the valveclerance from time to time

I read that all cars with aluminium cilinder head (H engine after 81) has hardened ventil seats. But your information says only after 84/late 84. So is unclear the reason for this change. Also all american cars use unleaded from late 70, does this mean that Saab produced different head cilinders depending markets?

I take the oppurtunity to recommend the least read book in the world. The instruction manual.=)
It should be possible to find the fuel information there. Most manuals are available on the net. I would start looking there.

I don't think there will be any references to unleaded fuel in the Swedish manual from 1984. It was still illegal to run a car with catalytic converter at that time, and unleaded fuel didn't arrive anywhere near Sweden for another 3-4 years.
Perhaps if one can source a US manual, things might be clearer on the subject, but in any European manual: probably not.

Perhaps the workshop manual for the year could give hints, but the chance of finding one might be slim.

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Ursprungligen postat av darwinland

I read that all cars with aluminium cilinder head (H engine after 81) has hardened ventil seats. But your information says only after 84/late 84. So is unclear the reason for this change. Also all american cars use unleaded from late 70, does this mean that Saab produced different head cilinders depending markets?

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yes i have read it too
but I also remember that Saab approved for unleaded fuel from the year 85 but only a few years later when we in Sweden started using unleaded fuel
it is also most likely that saab has had different cylinder heads depending on the market specification
saab has different heads depending on engine specification / type / power level

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Ursprungligen postat av LarsLars

yes i have read it too
but I also remember that Saab approved for unleaded fuel from the year 85 but only a few years later when we in Sweden started using unleaded fuel
it is also most likely that saab has had different cylinder heads depending on the market specification
saab has different heads depending on engine specification / type / power level

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You mean perhaps few years before Sweden aproved unleaded benzin, my guess is that unleaded benzin inSweden was approved in 87. Perhaps it have sense that Saab started prepare engines (late 84), ventils seat hardened but no catalyzed yet, years before unleaded was approved in Sweden.

California mandated catalytic converters from what? 1976? So, SAAB must have had hardware ready for unleaded fuel at that time, long before the c900.

Yeah, thats my thought, if they use cilinder head aluminium alloy, why do they have to produce different ventil seats regarding if the market is leaded or unleaded petrol

the answer to that is probably: money
Valve seats in hardened / stainless steel are probably more expensive than standard, so two different versions are made
there is also a difference between "Swedish" cylinder heads depending on whether it is injection or turbo (turbo> sodium-cooled valves, for example)
all manufacturers (not just car manufacturers) are "frugal" and if they can save money, they do so unless it is regulated by legal requirements or by market / country / regional rules

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Ursprungligen postat av LarsLars

as i understand so 16 valve from -84 is ok for unleaded fuel and the 8 valve from -85 is ok ( or late 84, engine number E51661 carburator engine only ).
i think it is an good idea to have a god check/kontroll of the valveclerance from time to time

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What do you mean with that engine number. All following engine numbers are valid for unleaded petrol? What do you mean only with carburator?

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Ursprungligen postat av darwinland

You mean perhaps few years before Sweden aproved unleaded benzin, my guess is that unleaded benzin inSweden was approved in 87. Perhaps it have sense that Saab started prepare engines (late 84), ventils seat hardened but no catalyzed yet, years before unleaded was approved in Sweden.

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The first cars with cat was sold as MY1987 in Sweden, so probably the unleades fuel was available before that ?

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Ursprungligen postat av darwinland

What do you mean with that engine number. All following engine numbers are valid for unleaded petrol? What do you mean only with carburator?

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yes all engines above that number is ok for unleaded fuel
only carburator is just only carburator and not fuelinjected engines

also from EPC: if your car is equipped with exchange cylinder head artikelnumber 7896905 it is suitable for unleaded fuel exept 900 turbo -81-82 without APC

To my knowledge unleaded bezin starts 1987 in Sweden

- - - Uppdaterad - - -

To fully understand all engines above E51661, no matter injection or carburator?

I found a US manual, but I didn't find the answer myself. Here i a link to more info: Vintage Saab Manuals Online