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alfcoal

le sabre 350cc

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can you tell me douse my 1968 le sabre run on 

unleaded fuel or douse it need a additive  350 cc

it was a north Carolina car thanks

membership no  R O A 15125

  alf murphy  great Brittan  

 

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1968 was 2 years before unleaded was introduced in the US. So your car was not built for unleaded. Do not panic, unleaded will not ruin your motor. If you are worried add some Redex, Marvel Mystery Oil, or your favorite upper cylinder lubricant to the gas.

 

High octane fuel is recommended especially the high compression, 4 barrel carburetor model. The standard 350 with 2 barrel carb has 9:1 compression, marginal for regular but you could try it and see how it works. High perf and 4 barrel models have 10.25:1 compression and definitely need high octane fuel.

 

Can you tell me the octane of the regular and high octane fuel in your area?

Edited by Rusty_OToole (see edit history)

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If Alf is in the UK, the premium pump petrol is 97 ron. The regular stuff is 95 ron. There is approx. 5-7% ethanol content depending on source.

 

I always buy the regular petrol. Including when I had a 1960 Buick Electra with the 401 engine and a 4 barrel carb. I suppose the premium petrol might let you run a bit more ignition advance. I tend to put in some lead replacement additive when on a long journey where everything might get hot, but valve seat recession does not seem to be a problem in local driving, especially given the tiny annual mileages involved.

 

I would be very interested in your thoughts Rusty.

 

Adam.. 

Edited by Alfa (see edit history)

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Your 1960 Buick engine had a 10.25:1 compression ratio. That year Buick made engines with 8.5, 9, and 10.25:1 compression, yours was the high performance, high compression variety. I'm a bit surprised if it runs well without pinging on acceleration if the timing is fully advanced. But you should use what works best.

 

It's a question of matching fuel octane to the octane requirements of the car, which usually means compression ratio. Your fuel octane should look like the compression ratio of the engine. For example the 9:1 compression, 2 barrel carb Buick V8 would need about 90 octane. The 10.25:1 4 barrel carb engine would need about 102 octane. Naturally, this is not a hard and fast rule, just a guide.

 

Your gas is a lot higher octane than we get here in Canada. I would suggest using the regular gas in the standard engine, premium in the high compression engine. But, you will want to experiment to find out what gas suits your engine best. Sometimes the brand makes a difference, some engines run better on one brand than another.

 

I would also suggest adding some upper cylinder lubricant to pre 1970s engines running on unleaded, for peace of mind and to protect the valves. Redex, Marvel Mystery Oil, Bardahl or your favorite brand. It probably isn't necessary since you won't be running the car hard enough to burn the valves but, better to be safe than sorry.

Edited by Rusty_OToole (see edit history)

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Interesting. Thanks very much.

 

I have a 1966 Sunbeam Tiger which has the Ford 289 V8 with a two barrel carb. It is a standard engine. I find that it runs happily on the 'regular' 95 ron octane fuel, but I am thinking that I will try it on some of the premium stuff when it comes out of winter hibernation. (It is currently receiving a new radiator, hoses and water pump, which were well overdue). I don`t expect that a change in fuel alone will make any appreciable difference, but I envisage that I may be able to run a little more ignition advance on the premium fuel without any pinking, but I will see what happens.

 

Adam..

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