87 Octane

[1929]

I always use 87 octane in my regular car, and my Model A. Someone I know who owns more then a few old cars ,and Hot Rods, says I should only use in my Model A, High Octane, and add high octane booster due to the fact that there is Ethanol in are gas, and that my motor was newly rebuilt. Is that excessive?

[marc hildebrant]

That is a waste of money to use high octane in a low compression motor.

I have talked to more than one person who does not understand that high octane does not mean that the gas is higher quality.

Marc

[Sunnybrook Farm]

I would think that it wouldn't explode at the same time as 87 and would throw off the timing and may even be less efficient in a low compression type of engine.

[Dodge]

I use the mid range in my Model A and Model T. In the A it keeps it from pinging with a high compression head, and the T won't start on the hand crank when it's hot on the 87 but will star no problem on the 89 octane. This was on the recommendation of a BP tech when I called with the starting problem.
My two cents.

[Patrick L.]

I think corn should be in our food supply, not fuel.
But, I don't see a problem using it [87] in an 'A'. Mine burns anything including all my old stale fuel from the small engines [ but I usually have 90 non-ethanal in them]. But, this corn crap does spoil pretty quickly.

Some folks don't seem to understand gasoline. Low octane burns quickly and contains more BTUs, high octane burns slower.

[BILL WILLIAMSON]

Sponsored Links (Register now to hide all advertisements)

OH, for the days of STANDARD & CHEVRON Super Ethyl, in the WHITE pump. I know a Guy who calls his WIFE, "SUPER ETHEL"--She LOVES it & she never "PINGS"--LOL
Bill Alone

[Dodge]

Bill that's one of your better ones, I'll remember that one. I guess he must have like to pump Ethel.

[Scottio57]

I hope 87 isn't bad for my engine. I've been using it in my T with a Z head and my A with a B (police) head for many years now. I use 87 in everything except the V-10 motor home that requires mid grade.

[1929]

Originally Posted by Scottio57

I hope 87 isn't bad for my engine. I've been using it in my T with a Z head and my A with a B (police) head for many years now. I use 87 in everything except the V-10 motor home that requires mid grade.

Some are telling me, if you have a stock motor its ok, but if your engine has upgrades with higher compression, no. I can only say one thing I know, with my back pack Redmax blower I only use 89, because the store I bought it at says they will void the warranty if you use 87.

[RawhideKid]

Personally, I go to the Arco station and buy the cheap stuff, pour in 4oz of MMO and happily drive around with a few more coins jingling around in my pocket.

My modern gets the same treatment.

[Simonpie]

The plus of the Model A is the low compression, so detonation is rare. The minus is the gigantic combustion chamber, with a spark plug miles from the far edge of the chamber. This promotes detonation. I'd say- rule of thumb - that a stock compression engine is fine on low octane and a high compression engine would need higher octane. I haven't heard detonation in mine, but most cast iron engines are pretty audible. If it sounds good, don't worry about it.

[Y-Blockhead]

As with oil, todays gasoline is miles ahead of anything available ~87 years ago. Find something else to worry about.

And yes, corn alcohol is not a new additive in gas...

[marty in Ohio]

Since I can't find gas without corn in it, except at the marina, I did a little checking. Around home Marathon gas has the lowest amount of alcohol in it, about 7%. I use that in my Model A with about 4 oz. of MMO per tank. Runs great.
Marty

[holdover]

Marty and others find a gas station close, might have to drive a bit.. https://www.pure-gas.org/index.jsp?stateprov=OH I'm luck I have three where I live. All issues with alky gas have ended years ago and all small engines and the 4 As run great.

[Dick Steinkamp]

Originally Posted by 1929

I always use 87 octane in my regular car, and my Model A. Someone I know who owns more then a few old cars ,and Hot Rods, says I should only use in my Model A, High Octane, and add high octane booster due to the fact that there is Ethanol in are gas, and that my motor was newly rebuilt. Is that excessive?

I think you're safe with 87

"By the early 1930s, automobile gasoline had an octane reading of 40 and aviation gasoline of 75-80."

http://www.newworldencyclopedia.org/entry/Gasoline

[Y-Blockhead]

Originally Posted by 1929

I always use 87 octane in my regular car, and my Model A. Someone I know who owns more then a few old cars ,and Hot Rods, says I should only use in my Model A, High Octane, and add high octane booster due to the fact that there is Ethanol in are gas, and that my motor was newly rebuilt. Is that excessive?

Ethanol actually has a rather high octane rating. Chevron in the 30's actually added ethanol to gasoline to raise the octane level. Unfortunately ethanol doesn't have as high Energy Content (BTU's) as gasoline so you have to burn more.

[Keith True]

I've never understood the concern about the gas either.The 29-30 automotive journals said gas was running up to about 67 at the time.Phillips was so proud of their gas they even used the octane rating in their name,Phillips 66.Lead was being developed for use in gas,and it wasn't in widespread use at that time either.I just don't seem to notice any difference in the A's with alcohol gas.If I forget to stabilize the cars in the fall when I park them I just start them up in the spring and drive off.A small engine place near me says he is having a lot of trouble with people using av gas in lawn equipment.When he told me that we didn't have time to go into it,but he is getting stuck on warrenty work from trouble the high octane gas is causing.

[1crosscut]

1929

High octane fuel is more difficult to burn. It is used on high compression engines to help prevent pre-ignition / pinging.
In a high compression engine fuel will want to ignite prematurely due to compression sort of like a diesel engine ignites fuel from pressure.
Using high octane fuel that is more difficult to ignite solves this issue.
Stock Model A's do not have this problem and will run better on the lower octane fuels.
Has anyone had troubles with pre-ignition / pinging with a high compression head on their Model A?

[1929]

Originally Posted by 1crosscut

1929

High octane fuel is more difficult to burn. It is used on high compression engines to help prevent pre-ignition / pinging.
In a high compression engine fuel will want to ignite prematurely due to compression sort of like a diesel engine ignites fuel from pressure.
Using high octane fuel that is more difficult to ignite solves this issue.
Stock Model A's do not have this problem and will run better on the lower octane fuels.
Has anyone had troubles with pre-ignition / pinging with a high compression head on their Model A?

I have a 6-1 Head

[Mike V. Florida]

You have read it here but there will still be those that refuse to believe that octane is added to fuel to SLOW burning.

http://bestride.com/research/buyers-...e-premium-fuel