In Canada, we can basically get 3 types of premium gas, 91 Octane (Shell), 93 Octane (Esso) and 94 Octane (Petro Canada).  The Shell 91, has NO Ethanol in it, but both the higher octane fuels have as much as 10% ethanol in them.
Now my question is this: I have recently run into head gasket problems due to detonation taking out the fire rings in my motor. This was caused by my distributor and has since been cured by a new MSD distributor. However, my engine guy recommends the higher octane, since I am at 10.5 to 1 compression. My concern is when I ran ethanol based gas in the past, I ran into carb problems (float sticking). Not sure if this is still an issue as I have switched to a new Holley Avenger (2 years ago)?  Thoughts.........anyone?

I love the smell of burning rubber in the morning!

With 10.5 to 1 and iron heads I would run the 94 octane. We have 90 octane no ethanol and I can't run it with my 10.4 to 1 aluminum heads so I run 93 BP or Shell with ethanol and no pinging with 36 degrees all in timing. Don't let the car set months at a time with out cranking because of the ethanol which can lead to problems.


-Gary Burnette-

Doesn't Stabil have a product to help with the problems associated with today's fuel?

Durham Missouri

Regarding the Issue with Float sticking. Was it a case of the Needle sticking due to the "soft" Tip? Change to all Steel Needle and Seat used for alternative Fuels. I changed the Ones on my Holley to all Steel.

  

Gary,
You may be right. I am running a full 36 deg. in for timing (no vacuum advance) and the ethanol may actually help keep the iron heads a littler cooler??? No sure if  you know anything about Avenger carbs (as OldCarmark said, I had a problem with my original Holley's needle valve sticking) does the Avengers have steel seats or are they still neoprene?  That carb works great and I really don't want to tear into it if I don't have too.
Thanks.


I love the smell of burning rubber in the morning!

62Bigwindow, not sure about that, I know I could run Boost 104 but that gets pretty expensive.

I love the smell of burning rubber in the morning!

I have an Avenger, and no problems at all with the gas. Down here it is opposite, though.  The lower grades have more ethanol than the higher grades.

Most octane boost does practically nothing.  If you read the bottle, the recommended amount boosts the octane a minuscule amount, usually not even to the next grade.  Don't waste money on that stuff.



Lawrenceville, GA

Charlie,
We are the same in Canada, the lower grades do have more Ethanol, as much as 20 % I believe. Premium fuel is regulated to not have any more than 10 %.  Do you run a premium gas in your engine?

I love the smell of burning rubber in the morning!

Yes, I use premium.



Lawrenceville, GA

Slightly off topic due to different head designs but my iron head non-y-block daily runs a 327 with an honest 10.4 to1 and seems to love standard old 92 octane(i belive it's 10%ethonol out here). It's all old style mostly 350hp vette stuff so it isnt like some modern setup.

Number one is TIMING, you may have been better off just dialing in a different curve (or having it done) for far less than the cost of a new distributor, you could have had your old one recurved to whatever you need(linder techincal service pops into my head as a guy that could have done it) Also it is good especially in a heavy car to have a vacumn advance, if you are full centrifugal you are only adjusting timing by rpms and not load like it should be. The vacumn compensates for load on the engine which is when you are going to detonate.

Also plug heat ranges and designs matter. I was going AC r54s 's which were the same heat range as r45 's but the S has a longer electrode, well i found every couple hundred miles of abuse i blew the porcelain off the end of the plugs when running the S's but i still havent damaged a standard. (Blowing the end of plugs off is a sign of detonation, also it creates even more detonation)

Mabey run slightly rich? I run a 600 double pumper so under acceleration the extra pump of gas helps it run cooler under acceleration

Lastly, listen to your engine, if you are having head gasket problems then it was giving you signs a long time ago.