Something I was wondering about recently

Had a really nice day in NY today and took the Maverick around town. When I was filling it up I was wondering about how much of a difference gas may be today from the days when these cars were new.

I usually always put in 87 in my Mav and never gave it much thought. The car moved afterall and it never once complained. but today I was wondering, is 87 the best gas for these old engines? Or does it not even matter anymore?

 

It probably doesn really matter, but if I am not mistaken, the octane in leaded fuel was higher than our 87 regular unleaded. But if it doesn't ping, don't worry about it.

Does your 74 have a catalytic converter? I think 74 is the pivotal year where some have it and some dont. If it does, then it was built for unleaded 87 octane.

 

i have bought the GOOD gas a few times before i go to the track but i have not noticed any diff in power

 

Just what's your definition of "the good gas" ?

 

93 octane pump gas

 

you can make adjustments in the timing to run the 87 octane in your maverick but I know at least for the 1972 Maverick IIRC the Owner's manual that I have it says you are supposed to run like 97(?) octane.
But anyway I have my timing retarded just a tad to keep both of my engines 72, 200-I6 and 73, 302-V8 from pinging (detonating) when running low 87 - 89 octane gas and they both run just fine. but they do run better on 93/94 octane

 

my new... AFR headed 347...runs on 87...

... ...

 

You're correct about adjusting timing, but you're incorrect about the 97 octane part. It was 91 octane back in the day. That's what regular leaded gas was rated at.

 

There are two different ways to measure the octane level of the gas we buy. Back when these cars were new they used the one that gave the highest number. Today the numbers at the pump are an average between the two numbers. So what is 87 today was probably close to 90 back in the day. With the 8.5 compression in our engines you should have no reason to use anything more than our 87 octane unleaded. Higher octane fuels do not make the engine run any better unless the compression is high enough to get it close to the detonation point. Higher octane fuels will burn faster and can cause problems with LOWER power in a low compression engine. That has been shown in dyno tests many times in the last 40 years.

 

Sure seemed like the gas was stronger when I was a kid. Back then if you poured some of that great smelling red gas on the ground and tossed a cig. in it it would ignite in a big way. These days you pour this watery looking gas on the ground a match might not set it off. lol
clint

 

:16suspect That's what happens when you buy cheap gas. Buy the good stuff, just don't talk on your cell phone while pumping it.

 

Don't forget as well that back in those days the fuel was leaded which resulted in acting as a lubricant as well as boosting octane. Once the EPA's regulations came along coupled with catalytic converters becoming required lead was removed.

I was fortunate in that when I bought my car, the head had been re-done with hardened valves and seats that are better compatable with unleaded fuel.

And, since ethanol is found in practically every fuel now, I rarely fill my tank more than the amount of fuel I'll burn in two months because of it becoming "stale". 87 works just fine in my setup.

 

Gasoline really varies from station to station. When I fill my bike up, I'm much more sensitive to it, because I guess I get more direct contact with the fuel. At the marathon down the road, the gas is oily and has a diesel smell to it. It's still gas, just at the very low end of being able to be classified as gasoline. The Shell station smells the way I remember gasoline smelling, seems to have much better additives in it, and just seems "better". They both burn the same, so I think the only real difference is how much "gunk" the marathon station leaves in my carbs. I fill up at the shell to be on the safe side. The extra $.50 per tank is worth it I guess.

When the floats stuck open on my bike, it dumped a bunch of gasoline on the road by my house. It was that marathon gas and stained the road for months. I don't think gasoline is supposed to do that...lol...

 

I agree with that Adam. I use the Exxon down the road. It is the closest. I don't use much gas anyway. It smells like alcohol and say on the tank that it has that in it. That started about 6 months ago but of course the price didn't change any. My low compression 460 in my truck could probably burn kerosene and not spark knock. lol
Once in a while I will stop at a Shell station if I get far enough from the house. Their gas sure does smell alot more like what I remember as a kid. Can't say it runs any better but I bet you are right about it leaving less gunk in the carbs
clint