100ll av gas vs 10 percent ethanol

[David K.]

Re: 100ll av gas vs 10 percent ethanol

I only use my Corvette for racing or getting parts on the farm.

[Stuart F.]

Re: 100ll av gas vs 10 percent ethanol

David;

If I can't get mine to run a little better on crap gas, it to will become a racer on the farm!

[Tom H.]

Re: 100ll av gas vs 10 percent ethanol

"Back in the day" when leaded gas was the norm, all my Porsche buds were searching out the closest AMOCO station to fill their mounts. Seems the VW derivative 4 bangers didn't like leaded fuel as it quickly fouled their plugs. I don't recall any of their engines or valve trains failing. Food for thought.........

[David K.]

[Joe L.]

Re: 100ll av gas vs 10 percent ethanol

All-----


I've said it before and I'll say it again: the late John Lingenfelter, a Corvette expert of some repute, once said that unleaded gas was the best thing that ever happened for performance. I agreed with that then, I agree with that now, and I'll agree with that in the future.

I'll also repeat something else I've said before (and attributable only to me): lead in gas is good for octane rating and good for exhaust valve seat protection. It's BAD for everything else. Period. There are other ways to get the required octane and most engines, even vintage Corvette engines, don't really need the exhaust valve seat protection that lead offers.

[David K.]

Re: 100ll av gas vs 10 percent ethanol

Good statements and I can agree. I just like the way AV gas does not leave a residue that regular pump gas will. Nor,will it vapor lock like pump gas. I do know it is low lead, but what the lead is in it, I have no idea. I wouldn't care of it had no lead in it. I just like the way it behaves.

[Duke W.]

Re: 100ll av gas vs 10 percent ethanol

The prospect of "leaving the city" is exactly the reason I chose to go with the Max 2000. I can take as many quarts with me as necessary, and my engine loves it.

As for whether my original 63 L-76 engine needs it, I prefer to believe that it might. It has been stated by several learned NCRS members that this engine doesn't have the advertised 11.25 to 1 compression ratio, rather that they were double gasketed at the factory and check in more like 10.5 to 1. Not wanting to remove a head to verify this, I was advised I could check with a simple feeler gauge at various places around the head to block mating joint. It was stated that the original head gaskets were .016", and that given the use of two, initial "pre-crush" would be .032". It was not stated what the "crush" dimension would be (lets assume .003" to .005" each), but I should probably see at least a .022" to .026" gap. Well, the best measurment I can come up with is .015", and that is in the right front stamp pad area. Noting this, I've decided to stick with what works for me.

Stu Fox

No, it was stated that the OE gasket is .018", and a double installation should measure .036" with a feeler gage between the block and head. Further, steel shim gaskets only crush in the formed area, so measuring the stock thickness in an unformed area of this type of gasket is the compressed thickness, and this is also the thickness you will measure using a feeler gage between the block and head on an assembled engine.

This double gasketing of SHP/FI engines began as a running change in 1962 and is discussed in a service bulletin. It continued at least through the end of the '63 model year. My mid production L-76 was double gasketed by Flint, which I did not realize until I took it apart for a rebuild.

I assembled my engine with double .017" stainless steel gaskets that were available through GMPP years ago, and they measure .034" with a feeler gage on the assembled engine.

Duke

[Joe L.]

Re: 100ll av gas vs 10 percent ethanol

Good statements and I can agree. I just like the way AV gas does not leave a residue that regular pump gas will. Nor,will it vapor lock like pump gas. I do know it is low lead, but what the lead is in it, I have no idea. I wouldn't care of it had no lead in it. I just like the way it behaves.

Dave-----


Yes, there may be other qualities of avgas that some folks might find beneficial. However, there's no way to get the avgas without the lead and the lead is, overall, a detriment. So, to me, that offsets whatever beneficial qualities there may be. The lead content of 100 "Low Lead" aviation gas is actually quite high. The "Low Lead" is only a distinction from the old 100 octane (green) avgas which had an even higher lead content.

I've never had any problems that I know of with normal pump gas, except for problems associated with leaded gas in the old days. Folks complained mightily about fuel system problems when MTBE was the more-or-less ubiquitous oxygenate. I never had one iota of problems with it, though. Now, since MTBE is gone, folks claim to have the same sort of problems related to the ethanol that replaced it. I've never had one iota of problem, though.

One other thing: I think some folks just don't like the idea of anything being "added" to their gasoline (except, maybe, tetraethyl lead because they think that's "good" because it was used in the "old day"). The fact is that gasoline is now and always was a MIXTURE of volatile hydrocarbons and NEVER a single chemical compound. For years the mixture has varied both regionally and seasonally. So, if you travel 100 miles from home the gasoline you buy may very well be different than that you buy where you live. It may vary from refiner to refiner, too. It's not as if the only difference in fuel is whether it has ethanol added to it.

As a matter of fact, if there's anything that's brought better consistency and quality to the fuel market it's air quality regulations. There's a much narrower and well-controlled range of acceptable gasoline formulations today than there was in the "old days". Plus, there are even minimum standards for detergency so even "cheap gas" of today is a more consistent and quality product than it used to be.

I try to stick with brands that guarantee to provide "Top Tier" spec fuel. The majority of gasoline out there does not guarantee "Top Tier" spec fuel. However, I'll be the first to admit that our older, carbureted cars are far less sensitive to low quality fuel than more modern cars. For my 1992 Corvette, though, I've always used "Top Tier" gasoline; I've never even used a DROP of anything else. And, in 15 years I've never had a fuel-related problem with it.