Which Octane Should I Use?

the lowest pump gas available will be fine if everything is in good condition. if you have carbon buildup in the combustion chambers, valves, or piston tops, you may get some run on/dieseling after turn off, or pinging even. Higher octane fuel helps alleviate the symptoms and let the engine live longer, but the root cause is still there and should be taken care of. Fuel treatment chemical additives may help a little, but they take a long time to work if they do anything at all.

Now that you've rear all that I can give you the short answer: use the lowest octane you can, that will not cause pinging or dieseling.

Anything above 87-RON, the 73 will run both leaded and unleaded. Even the pre -67 cars can run unleaded these days as the lead has been replaced with calcium(Sp?).

If you got carbon buildup you can lose this by trickling a bottle of carbonated water down the carb at high revs, just enough to not stall the engine. You can also use window washer fluid which contains a small amount of ethanol.

J.

I have been using Marvel Mystery Oil in the gas tank for over a year now. It is supposed to be a good cleaner.

I think I will try using '89' octane U.S. pump gas with the Marvel Mystery Oil.

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I run 87 in mine and it seems to go okay. Make sure you have your ignition timing/dwell/valves/carburetor set correctly so you don't have any pre-ignition/detonation.

Gotta love these old cars...I know I sure love mine. I don't see many of them on the road anymore.

Best,

Chris

I,ve heard about the decoke using carbonated water. Just had a laugh thinking if I used Coke my caffeine addicted young bloke would beat me about the ears and if I used beer my mates would have me committed.Ahhh, low alcohol beer, thats the answer John

Is this just in Norway, or does U.S.A. gas have calcium(Sp?) as a lead substitute also?

A long time ago I tried sing distilled water for this same purpose. It got into the oil and the guy at the local auto parts store would not let me turn in the water contaminated oil. Before you try this, find a place that accepts water contaminated oil, unless you might have some use for it.

Does 87-RON =3D 83 octane U.S.A. pump gas?

Is this lead substitute, calcium(Sp?), used in U.S.A. gas or is it used only in Norway?

A long time ago I did this with distilled water. It got into the oil. The guy at the local auto parts store would not accept the water contaminated oil.

I am not sure about the conversion, try bobistheoilguy.com or Google..

If my memory serves me right I found that info relating to Harley Davidson motorcycles, so I think it is the same in the US.

Hmm. I would think you had the revs to low, a stock T1 engine won't over-rew so I would go for WOT. Basically the water turns to steam. I have seen turbo engines with water injection opened, and they are squeaky clean. Some use window washer fluid as the ethanol content contributes to even better cooling, the piston tops and combustion chamber takes the color of the liquid, a bluish tint.

J.

In part of the USA where there is a winter, it is difficult to know what kind of gas we are getting because it changes seasonally. Gas would be less expensive to distribute and manufacture if they would stick to one formula.

Sorry that makes too much sense...

Tony

The Calcium content would still be there though, as it is a lead replacement to lubricate the valve seats and guides.

J.

Higher octane fuel does not give you any more power. If anything, it burns slower and doesn't ignite as easily.

The good thing about high octane fuel is, you can compress it more than low octane, and get more power THAT way. But if you do not compress it any more mechanically, then you don't get any more power. The only way to get more power out of it is by raising the compression ratio or dynamic (actual) compression, or by installing a turbocharger or supercharger to pre-compress the mixture outside of the cylinder, so to speak.

Modern cars have knock sensors in them, which retard the ignition advance when knocking or pinging is detected. With higher octane fuel, there is less pinging or knocking, and thereby less retarding... which results in more power, because the computer doesn't hold the advance back. Some engines show a "noticeable" power increase, while some don't seem to run any different.

But our old carburated non-computerized engines don't know what goes on around them and they don't make any more or less power on different octane fuels, unless you mechanically modify the engines to utilize the potential of higher octane. Then you can't go back to low octane anymore. Unless...... you lived near sea level and decided to move somewhere up in the mountains, like 5000 ft above sea level :) The less dense air at high elevations reduces actual compression pressure, so you can run lower octane OR higher compression.