leaded or not gas

Mon Nov 27, 2006 7:20 pm

reading all the interesting oil change'stuff',i have a ??does anyone add lead substitute to 'unleaded gas??have been doing that in the last few yrs.,but am out of the''lead''..is it a moot point?an old timer told me unleaded burns hotter..p.s.i love this forum thanks...

Mon Nov 27, 2006 7:22 pm

I believe there are a few who do but I do not and I think most do not. Modern day additives make it un-necessary.

Mon Nov 27, 2006 8:17 pm

Additives provide benefits for those who make and sell them. Unless a specific short-term problem is identified that could be helped by a one-time use of a specific additive, I consider them to be absolutely unnecessary.

Mon Nov 27, 2006 9:34 pm

I believe BD was referring to the adititves put in by fuel manufacturers, not after market ones.

Mon Nov 27, 2006 9:36 pm

And you would be correct! :D

Mon Nov 27, 2006 10:05 pm

The Cub was designed to run on 80 octane gasoline, that's the original unleaded stuff. Compression isn't high enough to warrent using lead or lead substitutes because the low compression engines aren't prone to detonation.

Unleaded gas doesn't run hotter, the new engines that must use unleaded have a leaner air to fuel ratio that makes the combustion temperatures hotter. Detroit had to make the exhaust valves and seats harder to resist the hotter exhaust temperatures, thus creating the myth that unleaded gas burns hotter and lead is a valve lubricant.

Mon Nov 27, 2006 10:20 pm

Lurker Carl wrote:The Cub was designed to run on 80 octane gasoline, that's the original unleaded stuff. Compression isn't high enough to warrent using lead or lead substitutes because the low compression engines aren't prone to detonation.

Unleaded gas doesn't run hotter, the new engines that must use unleaded have a leaner air to fuel ratio that makes the combustion temperatures hotter. Detroit had to make the exhaust valves and seats harder to resist the hotter exhaust temperatures, thus creating the myth that unleaded gas burns hotter and lead is a valve lubricant.


Cool, Carl.. and here I was thinking :oops: :idea: :wink: :D .. additives were just another way for the oil companies to take more of our cash... sheeesh.. shame on me huh :roll: :oops: :roll: :oops: :roll: :!: Image

Mon Nov 27, 2006 10:31 pm

I run high test (92) in all my power equipment. I also use two stroke chainsaw oil in my 4 stroke engines on all my power equipment too. Just a little will do. Its the same as using an upper lube for the valves.

I built my own log splitter using the cheapest 8hp briggs motor aluminum cast cylinder. The dealer told me it wouldn't last one year. It lasted over 20 years by adding the two stroke gas to it every once in a while. The motor is on a second splitter still running wide open today with its second owner. I know when i see the blue colored gas in the fuel bowel its right. Just a little will do so you don't foul the plugs.

This newer gas is raising hell with the older fuel lines too. The gas hoses melted on my older husky chainsaws and they had to be replaced. The dealer is my buddy and he said its the new gas thats the problem with the older rubber hoses.

Tue Nov 28, 2006 8:53 am

BigBill,

You're wasting your money on "hi-test" gas. It's of no better quality than regular, and octane is not a replacement for lead. In fact, the octane does nothing for low-compression engines like that 8HP Brigges, or the ones on our Cubs... Hi-test gas is only necessary in some high-compression, high-performance engines in expensive cars.

Tue Nov 28, 2006 9:00 am

I never really understood octane, my Camaro SS says to run premium, I always run the 87 octane. When you get on it the valves rattle, if you run the good gas in it, it doesn't do it. Cheap gas makes you think you need to adjust the valves. Why is that? I can understand needing it for the higher compression but why do the valves rattle? :D Brandon

Tue Nov 28, 2006 9:09 am

thanks all,its just a matter of opinion,so i'll keep it simple..just was wondering.. 8)

Tue Nov 28, 2006 9:54 am

Brandon Webb silverta16 wrote:I never really understood octane, my Camaro SS says to run premium, I always run the 87 octane. When you get on it the valves rattle, if you run the good gas in it, it doesn't do it. Cheap gas makes you think you need to adjust the valves. Why is that? I can understand needing it for the higher compression but why do the valves rattle? :D Brandon


I believe that sound is called "knocking or pinging" this occurs when too low of an octane is used. From what I have learned Octane is just the resistance the fuel has to igniting. So when too low an octane is used, as the piston travels up the cylinder the pressure builds and the mixture ignites before the sparkplug fires. This is the sound you hear, I have heard it discribed as marbles in a can. If this is allowed to continue it can cause severe engine damage. I think I saw a piston with a hole blown through the top of it! :shock:

Tue Nov 28, 2006 10:28 am

Brandon Webb silverta16 wrote:I never really understood octane, my Camaro SS says to run premium, I always run the 87 octane. When you get on it the valves rattle, if you run the good gas in it, it doesn't do it. Cheap gas makes you think you need to adjust the valves. Why is that? I can understand needing it for the higher compression but why do the valves rattle? :D Brandon


Brandon,

What you hear has nothing at all to do with the valves. It's the pre-ignition hammering the beJesus out of your piston tops. It can and will destroy your engine if allowed to continue.

Those who understand octane don't waste their money paying extra for higher octane than needed in a low compression engine, nor be penny wise and pound foolish when buying gas for an engine that really needs the higher octane.

Tue Nov 28, 2006 11:13 am

Well I guess I'll be buying the good stuff now. :? Thanks Glad I know now. Brandon. :)

Tue Nov 28, 2006 12:45 pm

Depending on the year model, the Camaro SS would have had a fairly high compression motor as compared to todays engines. Yours probably needs higher octane fuel. 8)