Unlead gas in 1953

[july76]

   I have some doubts of the kind of gas to fill in the tank of my 1953 62. It seems that using unleaded alone it entails
   to redone first the valve seats and guides. Would I obtain the same results using a good lead substitude or additive?
   With regard to octane, with a 8.5:1 compresion rate I suppose that 87 would be the recommended one. Sadly in Spain
   there is only avaliable 95 and 98 octane (RON) that is equivalent to more or less 89 and 92 AKI in the US. What's the effect using
   a much higher octaned fuel? Thanks 

[Roger Zimmermann]

The situation is similar in Switzerland: either 95 or 98. I'm using the 95 fuel in my cars; additive? sometimes...I'm not convinced that this is necessary. It depends also if you are driving a lot and at high speed or not. For the few km I'm driving each year, the additive is really not needed.
I believe the additive subject was debated here some time ago.

[Julien Abrahams]

Here in the Netherlands, I use RON 95 unleaded with a lead substitute. I have used 98 in the past, but to me it appears that it does not make much difference. I know that they are adding ehtanol to just about all the fuels that are readily available. The effects of this ethanol has been discussed many times by classic car owners, although no one really knows what the consequences for the engine are (if there are any). However, the general conclusion is that it is not good for fuel lines and tank (due to the extra condensation effects of the ethanol). And these effects get worse when the vehicle sits for a longer period of time (say longer than three months). My solution is to try and drive the car at least once a month and keep a closer eye on fuel lines etc. especially considering the facts that 1) there is not much you can do about it and 2) the percentage of ethanol is most likely going to increase in the coming years (on average it is 5% now, and in some countries like France and Germany they have already gone up to 10%.

[Jay Friedman]

Here in the US, since I frequently drive my '49 at high speeds and on long trips, to deal with unleaded fuel I had my '49 cylinder heads rebuilt with hardened exhaust valve seats using "Stellite" steel.  I've had no problems.  On the other hand, a friend who also has a '49 and who also drives it at high speeds did not have hardened exhaust valve seats installed and has not had problems either.  So I don't know what to conclude; either I have been overly careful or my friend has been lucky.   

[Roger Zimmermann]

Jay, it was already dicussed here. The conclusion was that the cast iron used by Cadillac for his engines is an alloy and of better quality than low price GM engines. Is that true? I don't know...

[bill06447]

Amoco premium was unleaded since the 50s. Unleaded should be ok for most normally operated engines. Not that there's much choice, as world production of lead fuel additive has shrunk to one lone plant in China.

Bill

[Jon S]

Amoco premium was unleaded since the 50s. Unleaded should be ok for most normally operated engines. Not that there's much choice, as world production of lead fuel additive has shrunk to one lone plant in China.

Bill

Amoco was unleaded and as high as 101 octane, but included other compounds for octane boost and valve lubrication that are absent in today's unleaded fuels.  It is the valve lubrication we are discussing.