Re: Recommended Gas

Posted by Mike flanagan on June 10, 1997 at 10:27:22

In Reply to: Recommended Gas
posted by Leo Stacks on June 10, 1997 at 07:21:32

: I have a standard Model A engine.
: Has anyone ever experienced trouble by not useing a lead
: substitute in today's gasoline?Any thoughts?I replaced my
: valve guides @ six months ago, would those guides be hardened?
: which octane rating seems to work best?
Leo, on the subject of lead I concur with Bob. We paid them to put lead in the gas then we paid them to take it out again. The American way. Any unleaded gas sold at the pumps today will run the Model A nicely. To a point. One problem I experienced on my trip last summer was that as the ambient temperature climbed, especially at altitudes over 4000', I had trouble maintaining any speed. Chug, chug. After going through the entire fuel system and finding no plugs or trash I finally discovered my problem. I rapidly ruled out vapor lock and that left only the fuel.The new gas (reformulated as in CA and coming to AZ) is so light (I noticed that two gallons evaporated from a 5 gallon bucket in less than 12 hours) that I believe when ambient temp goes up the new gas boils in the carb float bowl. I did some parking lot experimentation with boiling point of the gas at 4000' elevation and although I can't remember exactly the temp the gas boiled at it was much lower than I would have thought. With the ambient temp at 90 I once again tried to climb the hill that had been giving me trouble. Again no cigar. Returning to the bottom I pulled into a Texaco and added 1 gal of diesel fuel to the gas and climbed the hill like a stripped --- ape. I deduced that by adding the heavy fuel to the lighter I mixed a concoction that would not boil in the carb. Remember the A carb is bolted almost directly to the exhaust manifold so it can get mucho caliente.
Switching from diesel to Marvel Mystery Oil and adding roughly a quart to 10 gallons whenever needed I had no more trouble.
In Phoenix, Arizona when the temp can go to 110 in the shade if you can find any shade this is a real problem when you want to drive in the heat.
Food for thought.
Mike Flanagan, The Model A Fool.

Follow Ups:
Re: Recommended Gas Bob Johnson June 12, 1997 at 09:42:21(1)
Re: Recommended Gas Mike Flanagan June 12, 1997 at 15:01:47(0)
Re: Recommended Gas Dave Rinearson June 11, 1997 at 17:14:04(1)
Re: Recommended Gas Mike Flanagan June 12, 1997 at 00:41:26(0)
Re: Recommended Gas Al Wood June 10, 1997 at 13:55:10(1)
Re: Recommended Gas Mike Flanagan June 10, 1997 at 15:53:21(0)

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