Author Topic: Octane question  (Read 1392 times)

Offline jst

  • Posts: 200
  • Name: Joe Tortorice
Octane question
« on: May 10, 2012, 05:08:16 AM »
Hi
I've been trying to find out what octane gas was recommended for use in the 1953 Cadillac  331 engine, without any luck. Does anyone know ? Thanks  Joe T

PS I am using straight unleaded with a lead additive. Does anyone use or recommend an octane booster ?
CLC #27640
USMC  63-68
1953 Cadillac series 62 COUPE

Offline Dave Shepherd

  • Posts: 1748
Re: Octane question
« Reply #1 on: May 10, 2012, 06:42:28 AM »
Today's 87 will do fine ( 8.5:1), remember that engine does not have hardened exhaust valve seats so if you drive the car hard or for long trips some lead additive should used.

Offline Richardonly

  • Posts: 524
  • 1948 Cadillac Fleetwood
  • Name: Richard V. Pattison
Re: Octane question
« Reply #2 on: May 10, 2012, 07:00:46 AM »
According to the owner's manual for 1948, the 346 ci flathead required a minimum of 80 (yes 80) octane for that year.  It may have gone up some with the "newer" overhead valve engines in 1953.  I would think that 87 octane is enough.

Richard
1948 Cadillac Fleetwood 60S
1995 Lincoln Towncar, Signature Series
1995 Jaguar XJ6
2001 Chrysler Sebring Convertible
1986 Yamaha 700 Maxim X motorcycle

Offline Art Gardner CLC 23021

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Re: Octane question
« Reply #3 on: May 10, 2012, 11:01:34 AM »
The lowest grade of fuel now offered is the correct one for your 53 and will perform better (with  less tendency to vapor lock) than the higher octane (which has more ethanol in it).  So run the cheap stuff and be happy to do so!
Art Gardner


1954 S62 Sedan
1955 60S

Offline waterzap

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  • Name: Waldo Du Toit
Re: Octane question
« Reply #4 on: May 10, 2012, 12:26:18 PM »
Does 93 have more ethanol in it than 87?
Charlotte, NC
-1978 Eldorado Coupe

Offline Jay Friedman

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Re: Octane question
« Reply #5 on: May 10, 2012, 01:01:26 PM »
A friend who works for a firm that services oil company facilities told me that you must remember that the signs on gasoline pumps say "Up To X Percent of Ethanol" is blended into the fuel.  I forget his exact words but the underlying meaning of this statement is that ethanol is delivered by truck because it can't be transported in pipelines and is "dumped in" at some point along the way between the pipeline and the retail outlet.  The result is that some tankfuls of fuel in the underground storage tanks at the gas station will have a greater percentage of ethanol and some will  have less.  I don't think you can assume that premium gasoline has more (or less!) ethanol in it than regular or the mid-grade.  Apparently, it's all over the map.
1949 Cadillac 6107

Offline jst

  • Posts: 200
  • Name: Joe Tortorice
Re: Octane question
« Reply #6 on: May 11, 2012, 05:38:20 AM »
Thanks for the feedback. There is a site on the net that will tell you where you can purchase alcohol free gas. These places are few and far between.  I try to stay away from alcohol. Well, most of it .
Joe T      http://pure-gas.org/
CLC #27640
USMC  63-68
1953 Cadillac series 62 COUPE

Offline R Sotardi #11719

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Re: Octane question
« Reply #7 on: May 15, 2012, 12:17:04 PM »
Never heard that higher octane contained more ethanol. A few months ago I got ambitious and wanted to see just how much ethanol was in a gallon of Shell regular unleaded. Up to 10% was on the pump. Ethanol( alcohol) will absorb water. Took a glass of fuel added some water after marking the levels. The result was an increase of 8%  in displacement level. Therefore 8% ethanol, 92% gasoline. I got the tip on line. Incidently, in a clear glass the fuel will rise to the top, and the water will remain below. You can see the color differance.  I could not ignite it when the gas was sperated. So... fuel starvation can be attibuted to water absorbtion from the ethanol, not the ethanol itself. Ron

Re: Octane question
« Reply #8 on: May 17, 2012, 07:20:24 AM »
FYI,  From Sheets on how they blend.

 
This is from Sheets explaining how they blend. 




As you likely know, due to the EPA’s Renewable Fuels program and related subsidies; for better or worse, ethanol is now a part of America’s fuel mix.

We would love to be able to offer you pure conventional gasoline; however, there are a number of factors preventing us from doing so:

The majority of gasoline now entering the state is an 83 octane blendstock that requires ethanol to be added to make a saleable 87 octane product
Brining in segregated batches or importing pure conventional gasoline would raise the cost of the finished product; as would not receiving the 4.5 cent per gallon ethanol subsidy. This would result in a product that is significantly more expensive than the 10% blend we are currently offering. While some customers like yourself may be willing to pay extra to get pure gasoline, most would not.
Since we do not have the tankage to offer both products in many locations, we would have to choose one or the other."

I then asked how the 89 and 92 octane gases were made:

"Finished premium is created using a variety of blend ratios, depending on the area.

In PA, we use a 91 octane product, mixed with 10% ethanol (which increases octane above 92) as well as the 83 octane product (to bring the octane back down to 92 or 93)


Pure 93 octane premium is still being shipped on some southern pipelines (NC, VA, MD), but due to the second two bullet points below, ethanol is still added (taking the octane way up), then even more of the 83 octane product is mixed in to bring it back down to 92 or 93 octane." 
 
     

Offline R Sotardi #11719

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Re: Octane question
« Reply #9 on: May 18, 2012, 06:49:41 PM »
Interesting, Thanks Wayne. So, regarding fuel starvation/ vapor lock issues, is a lower octane less likely to cause drivability issues in our old cars? Ron

Offline Fred Zwicker #23106

  • Posts: 589
  • 1930 LaSalle Conv. Coupe - Restored
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  • Name: Fred Zwicker
Re: Octane question
« Reply #10 on: May 19, 2012, 06:59:35 PM »
Just wondering - with all of our regulations, does "lead additive" contain lead?   Fred
1930 LaSalle Convertible Coupe, CCCA Senior
1939 LaSalle 2-Dr. Conv.  CLC Senior in 2008
1966 Cadillac DeVille Conv. Restored - Red
See Pictures at www.tpcarcollection.com

Offline TJ Hopland

  • Posts: 4145
Re: Octane question
« Reply #11 on: May 20, 2012, 07:24:28 AM »
I think in the 1990's most of the lead additives did not contain any actual lead.  Notice that most are called 'lead substitute'.   When you could still buy it either as an additive or even at a pump it contained just a trace amount that was no where even close to what was in the gas in say the 50's or 60's.   A pilot friend told me that they have even cut it way back in the av gas in recent years and 'they' are working on trying to remove it from batteries.
StPaul/Mpls, MN USA

73 Eldo convert w/aftermarket EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline Fred Zwicker #23106

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  • Name: Fred Zwicker
Re: Octane question
« Reply #12 on: May 20, 2012, 08:58:27 AM »
Aviation fuel at our local airport is 100 Octane LL (low lead - but does contain lead).  I guess there are still a lot of older planes that need the lead. Also aviation fuel does not contain Ethanol, according to my understanding.

Fred
1930 LaSalle Convertible Coupe, CCCA Senior
1939 LaSalle 2-Dr. Conv.  CLC Senior in 2008
1966 Cadillac DeVille Conv. Restored - Red
See Pictures at www.tpcarcollection.com

Offline D.Yaros

  • '55 Coupe de Ville
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  • Name: Dave Yaros
Re: Octane question
« Reply #13 on: May 20, 2012, 02:08:44 PM »
Aviation fuel does not contain Ethanol, according to my understanding.

Fred
That understanding is correct.  It is against federal law for av gas to have any ethanol.  That it may not says quite alot about the undesireability of ethanol as a fuel additive? 
Dave Yaros
CLC #25195
55 Coupe de Ville
92 Allante
62 Olds  

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Offline Fred Zwicker #23106

  • Posts: 589
  • 1930 LaSalle Conv. Coupe - Restored
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  • Name: Fred Zwicker
Re: Octane question
« Reply #14 on: May 20, 2012, 02:43:24 PM »
For many years we bought and used Amoco White Gas, which supposedly had no lead.  I ran it in many cars without a problem, but never could understand that if fuel without lead causes valve seat problems, how did we survive using the Amoco White Gas?  It was a premium grade and a little more expensive than other brands as I can recall.

In NE Ohio it is no longer necessary to post Ethanol content on the pumps (at least I don't see any such information).  They publish lists on the Internet of Ethanol Free Gas Stations and one is about 1/2 mile from my home.  I asked the manager if their fuel contained Ethanol and received a definite "Yes".  Others claim that premium fuel contains no Ethanol, but other information posted on this and other forums say otherwise.  Either way, the Ethanol destroys rubber hoses and components in our older cars, as they were not designed for this type of fuel.  We have a car museum and have been gradually replacing all rubber fuel hoses with SAE 30R9 fuel injection hose, which is recommended for Ethanol fuel.  There are also rubber components in fuel pumps and carburetors, so we have a long way to go.

Here is a quote from another forum.  Google "Amoco White Gas" for more information.

"Back in the '60s, when most gas was leaded, Amoco had this special super premium which was not leaded and was therefore safe for some uses where leaded was not, and it also was much less likely to foul plugs in motors which had a severe plug fouling problem, such as the early Porsche 911 (I had a late '66 for a while in the '70s) and Ferrari V12 motors of the pre-smog control era, so it was much sought after by owners of high-performance machinery, including modified American "super" cars. I doubt that it would be any different from the current 93 octane unleaded in practical applications, if it were still on the market, except that some of the other additives that Amoco used instead of lead have now been banned, too.

Addendum: Amoco's early unleaded premium is NOT the same as the "white gas" meant for lanterns, camp stoves, and torches, which was a form of light distillate, similar to the cheap fuel sold for specially equipped farm tractors during the Depression and WWII years. It was almost as dangerous to use the Amoco premium for those purposes as any other gasoline because of the explosion danger and the other additives. "

End of quote.

Fred
1930 LaSalle Convertible Coupe, CCCA Senior
1939 LaSalle 2-Dr. Conv.  CLC Senior in 2008
1966 Cadillac DeVille Conv. Restored - Red
See Pictures at www.tpcarcollection.com

 



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