High test gas

[Dave Rumbel]

Hi I'm a newbe with a question. Hope this is the right place for it. This pertains to my 49 Pan and my 02 Roadking. I know Harley calls for high test gas in there bikes, and I always did use it, but with rising costs of gas it makes me hesitate to buy it, not becouse of the cost but I always wonder how long that gas was setting in there underground tanks. On one ocasion the gas station pump for high test was broken and I had to run regular, and the Roadking ran fine with it, no pings or knocks. So I wonder about running it full time just for the sake of fresh fuel. And I was always leary about gas tank additives, so many oil additives were found to do more harm than good. Any inputs? Thanks for your time, and what a GREAT forum. I found so many usefull tips here.

One other nagging question. On the 49 it has a relay not a voltage regulator, Does this system need to be polorized, or flashed as they call it?
Thanks
Dave

[Bill Huth]

Dave, This is a common question. I've seen it on several threads on different forums. There is always 2 sides, so I'm pretty sure someone will tell you how wrong I am. I always argue that you don't need it, that you are throwing your money away for a street vehicle. A modern vehicle with computer controlled ignition can automatically adjust the timing to compensate for variations in available octanes. You proved this by putting regular in your '02. Fuel detonates when the pressure of the compression stroke creates enough heat to ignite the mixture before it is supposed to. So before the spark. Regular gas actually has more "power" in the fuel. Higher octane = more additives and less power. It is a more diluted fuel. The advantage of high octane is it can be compressed without detonating, so it is smoother burning at high compression. But if the ignition can compensate, why bother? For your Pan, you may have to manually adjust the spark a little bit. You don't want to run it with any pinging. You won't notice performance difference in regular street use. If you are out there on the drag strip, yeah, you are going to take a hundredth of a second or something off your time. As far as age of the fuel, I've heard that modern gas starts to get unstable and break down in as short as 30 days. But I'm really guessing here. Logically, with low temps, like something in ground storage, should be more stable. I don't know how the stations check for "freshness" of their gas. Maybe someone can chime in on this. Good luck!

Oh and a PS to the high octane gas... I'm riding with a group of antique riders and one of the guys asked me why I don't give my flathead, with 5.5: 1 compression, a "treat" of high octane gas! There are a lot of misconceptions about high octane, that it is just "better" gas (like giving a low compression bike a treat), "needed", or just better in all cases, which just isn't true.

[koanes]

I run the premium fuel in all my machines, not because they need it, but in my area it is the only the only fuel available that does not have 10-11% ethanol added.

[Sargehere]

Depends on where you live. Gasoline additives and ethanol content, I mean. The Florida Legislature, in the spirit of our all-knowing Congress mandating 1.5 gallon flush toilets and toxic, mercury-filled mini-fluorescent lightbulbs all over our houses, mandated a couple of years ago, here, that ALL motor gasoline sold in Flah was to contain 10% ethanol. All that did was ruin the fuel and make the price of food-corn go through the roof for everyone, but that's another story.

I pulled my UL sidecar combination in to a Shell station the last week. (I almost never buy Shell, usually a few cents more expensive than other brands, and almost all Arab oil, anyway) but I was about on "fumes," and so filled up both tanks and 2 1-gallon emergency cans I keep behind the sidecar seat. Filled up with Premium. The low-compression old Sidevalve just seems to run better on the slower-burning hi-test. Five gallons for twenty bucks.

Well, we pulled out of the station (only a little under two miles from home) and got about a half-mile; the contents of my Linkert's float bowl, and the engine flat quit. Roadside checks revealed nothing wrong. I unscrewed the OEM fuel filter under the Linkert, in case it was clogged with sand, or something, and out gushed, basically water! It ran on the footboard extension, where I could see the water beading up amid the "flat" gasoline, and it even "smelled weak." Almost no gasoline smell to speak of. That old Flathead shore wouldn't run!

I ended up calling the station on my cellphone, then pushing the rig down the sidewalk back to the station, like I said, about a half-a-mile. A strapping young high school sophomore walking the other direction turned around and helped me to push it about half the way, for which I thanked him profusely.

The girl behind the counter at the convenience store was sympathetic, but the store's area manager that the Shell was being sold at, called up by the girl, insisted that the tanks in the ground had just been filled that morning and "tested clean", and that she filled her modern car and went 20 miles to the next store on Premium from the same pump with no ill effects. And she'd never before had a complaint of "water in the gas." I told her I was looking at water, and tanker driver "tests" are mostly pro-forma, anyway. Who's going to condemn an entire load of gasoline if it did test for content of water? He's not crazy.

I showed the girl working at the store how the water beads collected in gas I let out of my tanks. I'd been prescient enuf to ask the girl for a printed receipt for my $20 worth of Premium gas when I got back to the store. Finally, I started pushing the rig back the way I'd come, towards home. An angel (also a biker) in a pickup truck, with a long nylon strap, pulled over and he towed me two miles to home. Turns out he'd just gotten over a terrible accident of a 6-ton dump truck pulling in front of him on his Twinkie. He didn't even hit the brakes. More proof that "Sometimes you need an angel, and sometimes you are one." There really are angels among us, and we are them, called upon for assignments when we least expect.

When I got home, I emptied the tanks and float bowl and put my lawnmower gas in it, and the UL started right up! Next morning, on her usual rounds, I met the area manager at the store and went through it all again. The manager insisted there was nothing wrong, but gave me my $20 back. I read in a pamphlet on the counter at a mower repair shop right down the street from that station, that was to go with some "additive" for ethanol-diluted gas, that the ethanol is 'anhydraullic" like brake fluid, and absorbs water from the atmosphere. Of course, their few ounces of miracle additive was supposed to correct that in 48 gallons of gas. I didn't buy the additive, but I drained the gas and ended up pouring it in my F150 pickup. That'll eat anything I pour in it, unlike my 73 year old vee twin. Never had so much trouble just getting a fill up of gas. And I'll go back to avoiding Shell gasoline like the plague.

[sirhrmechanic]

The biggest problem with ethanol and old vehicles is not dirt in the fuel... it's likely the dirt that's already in your tanks!

Over the years/decades, most older vehicles have accumulated some amount of varnish, scale and rust in the tanks, bowls and even lines. With 'pure' gas, that varnish will reside there happily ad infinitum. The gas won't dissolve the varnish which will simply cling to the tanks, etc.

Add ethanol (which is essentially Gumout or solvent) and the old varnish and scale that has resided in your tank goes into solution, contaminating your new gas. At the same time, the dirt, sand, rust particles, etc. that were entombed in/by the varnish come loose as well. The crud plugs up the filters and jets in the system... the varnish gums up everything else. Run for a while, it puts what I term a 'candy apple coating' all over the intake and intake valves and can create nasty carbon in the cylinders.

The only solution is proper and full cleaning of your tanks. Ideally, they should be sealed at the same time. We see these issues in 100 percent of the vintage cars that come through our facility. If the tank hasn't been cleaned/sealed in recent memory, it's gummed up and odds are the engine is seeing issues from the varnish. And this is on cars that have run fine for decades with 'dirty' tanks.

Here are some pictures:


gas3.jpg

Gas tank. Scale and varnish visible.

Ghost carb.jpg

This is air valve showing the molasses like coating

2025 carb 1.jpg

Bottom of carb showing crud in jet tube areas

2025 carb parts.jpg

Fuel filter screen holder.

All this is the result of cars run with dirty tanks and clean... ethanol fuel!

I would also add that while ethanol will have no effect on metal and brass parts, it can wreak havoc on plastic and some types of rubber. I have heard horror stories about '70's bikes having carbs, etc. getting really messed up by ethanol.

As far as octane... my experience is with pre-1939 vehicles... so I'll let postwar folks talk more about your 'Pan. In my pan, I run low grade... it's a 1964 FLF. But for others who are interested... unless you have high compression engines or racing machines running crazy compression ratios, your older vehicle should be fine on the lowest grade gas.

The gas, further, will have no issues from being underground and virtually every underground tank today is polymer... so won't have rust/dirt in it.

Also, as it often comes up in discussions like this, tetra-ethyl-lead wasn't added to fuel until well into the 1930's (and it really became prevalent c. WWII.) So there is no need for leaded fuel for early bikes/cars, either. They weren't built for it. Yes, you will get valve seat recession over time. But w.out hardened seats, that's going to happen anyway.

One thing that we are seeing a need for is ZDDP additive in oil. This is especially necessary in vehicles with a flat tappet (ie not a roller tappet) engine. Flat tappet engines deprived of ZDDP show rapid wear and damage. Musclecars and vehicles from the performance era are really suffering from what I understand. In my world, the PII's are getting destroyed as are the early postwar Six's. Note, however, that while ZDDP in proper amounts is good... too much and it will attack yellow metal (Brass/bronze, etc.) That can include wrist pin bushes, gears, bearing cages, etc. which are found in early vehicles.

Anyway, hope this hasn't fuzzified the muddification too much.

Cheers,

Sirhr

[fillibuster]

This discussion could go on forever.
Today's cars and fuels are matched to what can be accepted by the greatest volume of users, and again, old motorcycles fall into the category of the "one-percent-ers", or certainly less than that. Complete burn of the fuel requires higher compression and higher temperature running, and while flatheads can only increase compression just so much (any 9:1 strokers out there? you are -.01%!), higher temperature smells like trouble. Further, hard-seating a sport scout intake port is next to impossible, Chief intakes nearly that. Modern fuels were not designed to extend the lives of dinosaurs. Oils, as Sirhr has reported, are similarly designed for modern machinery. Meantime, it is prudent to make serious study of our compromises for use in those gems in our temporary care, custody and concern.

I haven't experienced ethanol complications since softening a rubber-tipped float needle some 20 years ago. But Minnesota is now a 15% ethanol blend state, and I'd have to defer to those riders for comment.

Sarge, in SD we catch bad blenders cuz they have nowhere to hide amongst high population (like in Flawda), and we castigate (should say castrate, but then the city-slickers would say "duh") them. .. sucks to be you that day, huh? 's-okay, I'd have pulled you in too.

Off-the-wall, .. how many members of congress could pull a spark plug and tell you anything about it?

[D.A.Bagin]

If you need ZDDP in your four or other flat tappet motor what I do is get the appropriate wt non-detergent oil and use 2oz Comp Cams engine break-in additive per qt. Gives the proper ratio. Not for use with cat converters tho.

[duffeycycles]

sarge -just because you got water with your tank of gas doesnt mean anything about the tank filled before or afterwards.water will be in big bubbles in a tank and does not blend with the fuel,like the bubbles on flat gas you described. As a gas attendant in high school I was lucky enough to send a 3 gallon bubble into my arch rivals tank.he blamed me for pouring in water while he sat in car!we drained and refilled for no charge.he wanted to sue for a new motor stating the damage from water,until he was told about water injection systems!

[Chris Haynes]

I have been told by old timers that burning hi octane fuel in a sidevalve engine can damage the valves.

[Sargehere]

Chris, Old timers may have been talkin' about old-time gasoline. Tetra-ethyl lead used to just help lubricate valve stems and guides and seats, that I know of. I've noticed that modern hi-test seems to make it run a little smoother, but it's just a personal preference. As far as oil, it's the only thing I buy at the Harley Stealership: I splurge on overpriced straight 60 wt. on the excuse that at least it was made for Harley air-cooled engines. Long ago, I ran Pennzoil aircraft 70 wt. oil, also for air-cooled boxer Lycomings and Continentals and such.

That old leaded gas has very little resemblence to the junk we're forced to use today. I know there's no rust or any other contaminants in my Harley's tanks-- I regularly run them, rt. side until dry, then the left one past reserve, and the stock micro-mesh fuel filter remains clean. That thing was designed to bar sugar and sand and anything else an a**hole might introduce into your tank when you're not looking.

Duffey, that's what I was thinking: that the water was just accumulated in the tank in the ground regardless of whether it was just filled or not. But I seem to have gotten "the bubble," or a good part of it. Most seemed to be in the first tank i filled, the rt. one, almost "all" water, and more gas than water in the left one. Hell, it doesn't bother the F150, but Tex refused to fire. Emptied the float bowl, got some good gas, and it fired right up.

[Dave Rumbel]

WOW lots of opinions, thanks. What I'm gathering is its ok to use regular just watch for pinging or such. I'm not TOO worried about ethanol becouse I have uncoated repop tanks on her and a fresh rebuilt carb I picked up at Oley last year that works great. But I still worry about the freshness (or condensation water) in high test gas, just becouse its setting so long in there tanks. Imagine what you would get if you select the mid grade gas (do you know of ANYONE that uses that stuff?) but again thanks for the input.
Dave

[Sargehere]

I think tanker trucks only carry two grades today, and "mid-grade" goes through a mixing valve, combining the other two in a specific blend. At least, I know that's how it used to be in the old "Sunoco," that mixed about 6 or 7 grades to come out of the pump. Now you're dating me. Old, blue and yellow pumps, dial on the side. Sixties?
So "mid-grade" would be a simple mixture of the other two. You pays yer money and you takes yer choice.

[Dave Rumbel]

I remember them well, as a kid I worked at one my uncle owned for spending money

[cdndewey]

I worked at one in high school. We had regular that was called 180 and premium that was called 240 and a range in between in multiples of tens. And then two higher octanes, 250 and 260. I remember one day running out of 180 and only having 260. I had to explain that all other grades were a blend and 260 was all we had. Some people used it and others were a little to freaked out to.

[T. Cotten]

Back to modern reality, folks,..

Pre-detonation is not always audible.

...Cotten