Fuel

[Green67Alpine]

A re builder (carbs) told me that "hi test" gas(93 octane) is a waste of money and to use regular, when I first got this car it ran on after turning the ignition off.(dieseling?) As soon as I changed over to 93 it practically stopped doing that.
What grade fuel do most of you guys use ?

1725 with Stromberg 150's

Thanks !

 

[Nickodell]

AVGAS. 100 octane low lead.

The Alpine engine was designed back in the days when you could get the equivalent of AVGAS from your local gas station. After I finished Matilda's (SV) restoration you could still get Golden Exxon, Sunoco 260 etc. Within half a dozen years they had all gone.

The general rule is that if an engine was designed for leaded, using unleaded will cause valve recession, but several posts in the past have asserted that Alpines had hardened valve seats from the start, so that shouldn't be a problem.

The trouble with lower octane fuel is detonation. A sort-of fix is to reduce the ignition advance, but this robs the engine of power and causes overheating. If your state allows an exception for Limited Use, Antiques and Classics, you could use AVGAS too.

 

[Bill Blue]

The engine is telling you what it needs. The mechanic is telling you what he thinks it needs. Listen to your engine.

Bill

 

[husky drvr]

Green67Alpine,

Is there a possibility that your rebuilder was born after your Alpine was built?

When the Alpines were manufactured, leaded regular was 93 octane or higher.

 

[lemansvk]

I use 98 Octane unleaded in my Alpine - anything less causes detonation. The engine was setup on a dyno by mechanics who know what they are doing (been dealing with them since the '70s).

The Vogue (same basic engine) will run on 95 Octane, mainly because the head hasn't been reground as often.

Cheers, Vic