Spark Plugs turned Green??

[ABMax24]

Funny thing is everyone compares Avgas to VP C111, ever notice how VP C111 is the same shade of blue as Avgas? My understanding is VP buys AvGas to blend their C111, being the reason it is the cheapest out of their product line. Also someone mentioned lead content, most VP fuels contain over double the lead of Avgas. So go ahead and pay twice as much for your "superior" race fuel, I've tried many of them and noticed no significant difference, I'll continue to just burn cheap Avgas.

 

[JMCX]

Av gas is high quailty, high octane gasoline with lead. Simple as that. Just because airplane engines don't generally rev high doesn't mean they engineered a special fuel that falls on it's face at high RPM. As for the designed for high altitude thing, how do planes get off the ground at sea level? Take off requires the most power.

I would say the OP's green plug is a symptom of something else wrong not the cause.

Cut and paste from a google search:

Real info on Race Gas/Av Gas...

My experience comes from 7 years as the western states representative for 76 Race Fuel, Unocals 40 hours Advanced Products course, Working personally with Tim Wusz (senior performance products Rep for Unocal, Tim was responsible for Unocals race fuel development for 30+ years). I have also met and discussed fuels/motors with just about every engine builder in every facet of racing in the western United States. I also conducted Educational Seminars at the Fred L. Hartley Institute in Brea in which we would invite Engine Builders for a tour of Unocals testing facilities and do live octane tests on any gasoline they would choose to bring to the seminar. Included in the training we would demonstrate live tests how Distillation curve, Reid Vapor Pressure, Specific Gravity, Octane Rating, F;ashpoint, etc are conducted and the importance of these numbers. Some of you will remember me from contingency with my 76 Racing Gasoline hospitality trailer in the 1990's.

Through the 50's, 60's, 70's and 80's Av gas was the base product used for most racing "gasoline". VP, f&L, Turbo Blue, and Trick all used AV gas as the base product. They would buy a tanker (8000 gallons of Av Gas) than add other hydrocarbons/TetraEthylLead (TEL) to the base, drive around the block stopping and accelerating the truck/trailer until they felt the product was mixed well. Obviously this was not science, but it worked for most racers only because most racers use a higher rated octane than they actually need.

In the mid to late 1990's VP graduated to buying there own base product and do there blending of products in a much better fashion. Turbo Blue and Trick have since been bought Sunoco and are blended by Sonoco. Trick was purchased by Phillips 66 and has continued to be blended by Phillips 66.

The only two companies I am aware of who "cracked" there own base product is Sunoco and 76. And as we all know, 76 race fuel is no longer available, leaving only one true manufacturer of Racing Gasoline....Sunoco.

AV Gas has a MOR (motor octane rating) of 96, R+M/2 rating of 100, and ROM (Research Octane Rating) of 106.

AV Gas is lighter than racing gasoline thus more fuel/larger jetting is required. Jetted correctly you should not experience a lean burn at WOT.

I would not use AV Gas as a cleaner. The amount of TEL (2 grams/gallon) and other hydrocarbons makes it extremely carcinogenic. Same goes for all other racing gasolines.

Shelf life is NOT better. The reason pump gas won't last as long is because street gas has extremely lightend hydrocarbons to help your car start and idle. Racing Gasoline does not have these light end hydrocarbons needed for idle and starting, hence the reason race motors start and idle poorly.

Av Gas is NOT designed for low RPM motors. AV Gas is designed to not detonate/preignite causing detination. This would be the same design as race fuel. If you compare the "distillation curve" of AV Gas to Race Gas, you will find they are almost identical. The "distillation curve" controls the speed of burn across the combustion chamber.

You will only "spit" gas out the exhaust pipes if you run to rich or include a supercharger/turbocharger on your engine and "overdrive" the blower. Example would be the bitchin flames you see at the starting line of a drag race on normally aspirated engines and the long flames you see on all "blown" engines.

The LEAD (TEL) added to AV Gas is to increase the octane rating only. All heads these days have harden valve seats. There is no need for lubrication of the valve seats. All engines have come with harden seats since the late 60's.

AV Gas is not formulated for High Altitude. and will have very little, if not any performance differences vs racing gasoline. On the other hand, commercial grade fuels (87, 89, 92) will definitely enhance your performance due to the commercial fuel being oxygenated. The Oxygen enhancers added to commercial fuel is only for California Smog laws.

Advancing timing on your motor will definitely help with AV Gas and Race Gas due to its slow burn characteristics. On the other hand, be careful if your running commercial grade gasoline, more timing can cause detonation/preignition quit quickly.

AV Gas does not go BAD faster. It is extremely consistent. The MOR is only 96, whereas Sunoco Purple or VP C12 is 104. A rating of 96 is good for up to 10:1 on Steel heads and 12:1 on Aluminum heads with water cooling. Air cooled motors run much hotter.

Buying a higher octane for a $20-50K motor is the cheapest insurance available.

Remember this...OCTANE is a measure of a fuels ability to resist detonation/preignition. The higher the Octane number, the slower the fuel burns. Technically speaking 87 Octane fuel will develop more power than 118 Octane fuel. With this said, you should see gains in throttle response and HP by mixing commercial fuel and AV Gas/Race Gas. You now have some light end Hydrocarbons for throttle response and heavy hydrocarbons/TEL for detonation resistance.

Bottom line... use the most consistent fuel you can find and create horsepower by moving as much air as possible though the combustion chamber.

I have no reason to be bias here as I have moved on to much greener pastures. See you on the race course.

Good Luck,
Steve Poole

 

[cedarpoint]

jmcx you hit the nail perfect . I put 5500 miles on a 860 never missed a beat 100ll is good fuel

 

[Lund]

Lots of guy's run AV fuel with no problem or at least that is what they say. There is alot of info on this subject with alot of controversy in all power sport's about AV fuel vs race fuel, its an old argument.
Its easy to search the web and copy and past info.
I could easily find info. to contradict the info. posted, but why. My suggestion to the OP. Try it, put in new plug's and run some race fuel for a while then switch back to AV fuel. Let him come to a conclusion.
I think your conclusion might be surprising to some but maybe not.

 

[DRD]

Av gas has been beat to death on this and other forums. Everyone who says it works good has/is using it, everyone who says it doesn't work good is going off anecdotal evidence it seems.

 

[overkill131313]

I love avgas....I found race fuel in the apex cracked headers.....avgas did not.....cheap...I just detuned the triple mod sled so I don't have to run anything fancy now......Im just going to sled with my kid and have fun now!

 

[Keith Brown]

Talk to an AME (aircraft maintaince engineer) who services piston engine airplanes. You wil find that when aviation fuels were changed from two grades two the now available 100 Low Lead that it necessitated increasing the spark plug cleaning/replacement intervals on most engine that burnt the lower grade fuel prior to the changes. In fact many operators of these low performance engines applied to Transport Canada for STC (standard type conversation) to burn "mogas"(automobile gas) which eliminates the fouling problem. 100 Low Lead in a misnomer and is full of lead to accommodate air cooled aviation engines and there tendency to heat on taxi and take off. This being said it seems reasonable to assume that those with high performance sleds that ride hard will get along fine with 100LL and those with lower performance sleds that ride easier may have fouling problems. It is also reasonable to assume that if deposits are accumulating excessively on the plugs that the combustion chamber is looking pretty ugly to.

 

[Modman]

before you guys start a raging debate about av vs race.....oh wait that already started.....anyway, lets see some pics of these "green" plugs because I want to see how green they really are. I ran 100LL av gas in my sled and nothing turned green. There might be slight colour change but I think some folks here are thinking your plugs are the colour of the Hulk. Either dye from the fuel or maybe something else is causing it (oil?)