What Is Octane Creep?
 

Does your street-driven car ping now when it didn't use to ?

Street Car Octane Creep Is The Need For Better Gas To Prevent Spark Knock Due To Deposit Buildup On Piston Tops And Combustion-Chamber Surfaces That Causes Spark Knock.

https://www.hotrod.com/articles/what...0engine%20life.


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I can't see the article, it won't load for me. But one thing I've used for decades to help fight the build up of carbon and deposits is 2 cycle engine oil with TCW3.

It's a good cleaning agent that isn't harsh like some chemicals sold today, and it also adds lubricity to the fuel that's been missing since lead was removed. Great for the top end, valve seats, valves, and tops of pistons with no negative affect.

I just mix 1 ounce per 5 gallons of gas. Been using this stuff since the mid 90's on various vehicles and happy to say that on tear down I've had very little if any carbon build up issues.

Marvel Mystery Oil or ATF in small quantities works as well. Also keeps the leather-cupped accelerator pump seals supple in old Carter carbs. Seems to help with heat soak boil off, too.

I Googled "What Is Octane Creep?" for the link. It is from the new issue of Hot Rod magazine.



https://www.hotrod.com/articles/what...0engine%20life.


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Adding Marvel Mystery oil, ATF, and 2-cycle oil to your gasoline decreases the fuel's octane rating slightly. Doesn't mean it won't help some conditions however. It also lowers the fuel's vapor pressure, which is generally a good idea for engines with carburetors. And it lubricates. One of those deals where if it works for your particular situation, why not use it. Octane creep from deposits can be effectively reduced with a huge variety of fuel cleaning additives and top engine cleaners. Half of every AutoZone, Oreily's, and Pep Boys is all this type of stuff.

In 35 years of this business I have never heard of the term octane creep. Never. If you get some sort of build up on pistons it does not usually increase compression ratio enough to require higher octane fuel. Never heard of that either. Carbon build up if begins to glow red hot can cause detonation and pre ignition. But increasing the octane rating won't make pre ignition go away. Adding oil to fuel will itself cause detonation and will cause a build up of carbon that will also cause detonation and pre ignition. Marvel mystery oil being the worst offender. It's waste motor oil, transmission fluid and unrecyclable cooking oil. Octane creep? Never heard of the term.

Oh that explains it. I cancelled all my subscriptions when they stopped distributing the magazines. They wanted me to pay the same amount to have just internet reading and I said no thanks, keep it.

So apparently that stuff doesn't load for me anymore.

I can comment on that with a couple dozen years of experience using it.

Never once have I had the oil content mixed into the fuel cause any detonation. Mixing one ounce per 5 gallons isn't much at all. Think about that amount for a minute.

As an example, on one of our cars I'm running 11:1 compression with iron heads and 91 octane fuel. Pushing beyond the limits some might say.
Been daily driving it for over 30k miles now for the last 3 1/2 years. Using the 2 cycle oil formula I mentioned above. There is no sign of any detonation or pre ignition. Would have found that issue instantly years ago if it were present.

In fact, most every car here we drive pushes the compression and octane level to what most here consider too much, and I have years and thousands of miles on these setups, using 2 cycle oil. It's basically the same thing that Lucas Oil has been selling for a fuel additive for decades. It's just a thin oil with a cleaning package. It's a gentle cleaning package that needs to be used over a prolonged period of time for good results. 2 cycle with TCW3 does the exact same thing for 1/4th the cost. It also acts as a lubricant that is good for valve seats, guides, seals, cylinder walls etc...while at the same time keeping things clean.

If you're worried about detonation, it starts with the build as there are many other factors inside the engine that are a much bigger player with detonation than having 4 ounces of oil in a 20 gallon tank of fuel.

On the other chemicals offered by the chain stores, like Sea Foam for instance. Of course that type of stuff has cleaning abilities too but almost all of them are extremely harsh, hard on seals and gaskets, and not something I want in my engine. They work fast, usually meant as a maintenance procedure that an individual can knock out quickly. May as well pour lacquer thinner down the carb. It does nothing to add any lubricity to the fuel either. I avoid the harsh chemicals.

That's another advantage to adding the oil to the fuel. Lubricity in the fuel is a good thing.

A long time ago, HRM had a "tech" article on Corvette Carter dual quads.

The "hot set-up" was to replace the vacuum springs in the WCFB's with the return spring from a Papermate ball-point pen.

I quit reading HRM with that issue.

If the article were true, how many points octane would my 300 CID six increase with 440,000 miles and the cylinder head never removed? 87 worked very well.

Jon.

where do you purchase this 2 cycle oil?

I buy it at Walmart in the blue 1 gallon jugs. The stuff that has the TCW3 package. It's about $13 for a gallon and at the mix ratio I use it treats about 640 gallons of fuel, so it goes a long way.

You can see why it's much cheaper than the Lucas fuel treatment that does the same thing. Plus I use it for the 2 stroke lawn equipment too.