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New worry, Having put just a few miles on a new motor(45) this comes up. Here in coastal N.C. we have straight unleaded,no vodka added. At present I'm using mid grade with a bit of Marvel Mystery oil added. Valves etc are original. Should I use a lead substite like I do in my original 57 chev? Floats! I know Cottens are the best but here is a question. I just went thru readjusing mine and wonder what it is. It's a white material,almost looks like styrfoam, definitely not brass or copper and not just a plastic hollow tube. Well I say white,probably was somewhere in the past. Chris
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Chris -
With your low compression (no matter the heads), I would recommend 87 octane with the bare minimum of MMO. 87 will ignite better in your engine. Also, when you have run at a sustained speed for more than a few minutes (assuming you are still in break-in), snap the throttle closed, every once in a while, running in high gear. No more than a second or so is necessary. Then, back open and up to speed. You will draw oil up into the exhaust guides, even though your MMO will be giving some top end lube. Your intake guides are under constant vacuum, so they always have a bit of oil being pulled up through them. The exhaust is always under pressure, forcing any lube back down. Later on when you are out running at higher sustained speeds, snap the throttle closed every hour or so.
Jack -
Fuel
Thanks Jack. Had read about snapping the throttle shut in one of my service manuals but had no idea as to why. Makes sense now. Had to curtail my breakin runs till my generator gets back from repair since I don't have a way to plug the hole to keep sand out. ChrisComment
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Re: Fuel
Originally posted by Chris Lastinger
New worry, Having put just a few miles on a new motor(45) this comes up. Here in coastal N.C. we have straight unleaded,no vodka added. At present I'm using mid grade with a bit of Marvel Mystery oil added. Valves etc are original. Should I use a lead substite like I do in my original 57 chev? Floats! I know Cottens are the best but here is a question. I just went thru readjusing mine and wonder what it is. It's a white material,almost looks like styrfoam, definitely not brass or copper and not just a plastic hollow tube. Well I say white,probably was somewhere in the past. Chris
chris, i just changed the float in my 41 u ,i put in one of cottens , works great!when i took out my old cork float it was white also .through the years i had always resealed an iffy float with plain old shellac,but i think now the new fuels have an additive that has a reaction with the shellac.the cork float i took out was shellacd(sic) just last fall and in a matter of months the shellac job was ruined. has me wonderin about all my other bikes as they all have cork in them ,mabey cotten has a bulk rate on his floats as i need 6 moreComment
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chris..
Your float is probably an "Armstrong", and as long as the original sealer/coating hasn't been eaten away by modern fuel additives it should still be serviceable. Those 45's were originally designed to run on very low octane fuel, the military called it "MOGAS", so 87 or 89 should be fine.
Something Cotten has never mentioned in all his discussions about floats and fuels is that today's fuel is much less dense and far more volitile than the leaded fuels of yesterday. He is absolutely correct about the digestive properties of modern fuel but the big impact of trying to use modern gas in yesterday's carbs is that the specific gravity of the fuel that comes out of the pumps these days will not float anything as high as the "heavy" gas we used to buy. I'd like to see some comparative specs on 1965 leaded regular verses 2007 no-lead with 10% alcohol regarding specific gravity. What this means to us is that we have to set the float at something more than the 1/4" factory setting in order to get the needle to seat tightly. I've got an Armstrong still floating in one of mine but it is set a "hair" more than 5/16", no drips.
motorhead mikeComment
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"Armstrongs" were molded black foam, although I have encountered dark red ones.
I suspect that Chris's is one of the modern molded floats marketed by Tedd as "Armstrong".
The real irony is the originals were not made by "Armstrong" either!
If Chris's cream-colored float didn't turn into a dumpling in fifteen minutes, then indeed his local fuels do not have the digestive additives of other regions, and very well may have close to the same volumetric efficiency as the good old days.
Minus the tetraethyl lead of course.
I can fill and average a few volumetric flasks full of the horrible Midwestern P4gas (10% ETOH) if we need a true density to compare with.
Finding the density of 1965 gas would be a little harder.
Please remember also when opening jets that flow increases geometrically with increase of diameter of the hole.
...CottenComment
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Fuel
Cotten, Are you saying that odds are good my float is a knock off Armstrong and as such will turn to jello not if but when I finally go somewhere that has P4 type gas.? I've seen that stuff up in Virginia and out West, for sure my shovel runs funny on it. I'd rather bite the bullet and replace it than take a chance on it melting. It's definitely not cork. ChrisComment
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The odds are much better than "good".
It's a sure thing if it is the Tedd "Armstrong"; The catalog even warns that it is not compatible with oxygenated fuels.
Even original OEM black molded floats eventually swell in P4gas to where they not only rub the bowl, they cannot be removed!
....CottenComment
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Today I measured the densities of Shell Premium with ETOH ("P4gas"), and Casey's General Stores Regular gasoline (unblended).
To my surprise, the blend was heavier:
P4gas = 75.5g / 100 ml for a sp.gr. of .755
Straight petrol = 73.6 g/100 ml
That's only one and one third of a percent difference: hard to believe we should even tickle our needles for that.
I then poured the 100ml samples into tared watch glasses (pyrex casserole lids, actually) and evaporated them upon a slab of pooltable slate in the sunshine, with a surface temperature averaging 130 F.
The P4 "tracked" on the dish like wine on the side of a glass, and 'bloomed' its surface with convection.
The gasoline kept a mirror reflection upon it.
By three and one-half hours time, both had reduced to an oily residue, however the P4 was remarkably thicker and darker.
Both stunk like varnish.
Continued baking for another ninety minutes reduced the weight of the residues only a few tenths of a gram: A final total of .75g for the P4, and .90g for the straight gasoline.
The difference barely exceeds the accuracy of the triple-beam scale.
So about one percent of either fuel doesn't vaporize at 130F.
The P4 also displayed more debris, and a noteable skift of white precipitate settling out.
If the stuff doesn't vaporize, what the hell is it, and why is it in our fuel?
A comparison of drops 'flash' evaporating directly upon the slate is attached, petrol on the left, P4 on the right. Photos were taken roughly every ten seconds.
I could not detect a difference.
6-15-07 Addendum:
After another twelve hours at ~ 70's F room temperature, the straight petrol still showed some liquidity, while the P4 was literally as thick as mollasses.
Both residues weighed ~ .9g +/- .05g.
After another eight hours at 80+ F, both had lost all liquidity to leave ~.5g of a sticky varnish.
Thus a final non-volatile residue at that point of a half a percent.
....CottenComment
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AWSOME analysis Tom!
Looks like something from an episode of CSI or Numbers: "The suspect had an oily residue and white precipitate on his left boot and traces of EtOH on his left pants leg, we think he is riding a Harley WL with a faulty float and missing J-slot cover and stopped at the Shell station to refuel. Check the premium pump nozzle for prints."
And you thought those college chemistry classes were a waste of time. I taught chemistry at the Univ of WI before private industry lured me away, the students always complained that the practical exercises were not very practical. I wish I had a classroom now, I'd put 'em all to work on this project.
I have some old CRC handbooks stashed away somewhere, from the "good gas" era. I'll see if I can dig up some comparative data regarding specific gravity, volatility and flash point.
Anyway, it looks like my density theory is shot to hell based on your excellent research, which leaves us with the unanswered question: what exactly is the non-volitile component and why are they putting it in our gas?
mikeComment
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Fuel
Mike, You and Tom need to keep this going! It's of interest to guys like me that have just enough knowledge to be dangerous. Just before you suggested going to 5/16 I'd done it and a bit more because I was using mineral spirits to check things out in stead of gas( I smoke and ...well better a slow fire than KABOM!) Took chemistry back in the 60's when the periodic chart still had lots of " holes" in it. Heck I still have a Quagliano(spelling) chem book from back then. I can't say it any simpler than I really love the way Tom went to just the basics to evaporate and see just whats left. ChrisComment
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Sorry about my pedantic language, but juggling testubes for the Federal government taught me to never use a big word when a diminuative synonym would do.
Meanwhile, I have plenty of notes and pics on these observations that I shall not bore anyone with unless they become topic, or downright sensational.
For instance!:
I realize there are few O-rings on Flattys, however the fuel's effect upon V-TWIN OHV manifold o-rings in either fuel produced dramatic swelling within 24 hours (see attachment)
Similar immersion tests concluded that Liberty's signature cosmetic coatings, sealer, and float material are still impervious to the digestive action of a noteably agressive ethanol-blend.
Now I can get back to cutting floats,.. unless the roof comes down, finally.
....CottenComment
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Cotten..
pe·dan·tic /–adjective 1. ostentatious in one's learning.
2. overly concerned with minute details or formalisms, esp. in teaching.
I don't think you can be too "pedantic" when teaching anything, those that already knew the minute details are merely reminded of them once again, and those that never knew them have now learned.
Keep it coming buddy
I noticed that the swollen O-Rings showed up over on Hydra-Glide, I think you should put the same caution here about not getting too aggressive with the clamps. I've seen guys put exhaust clamps on those intakes and crank 'em down 'til it hurt. About all you accomplish there is distorting the manifold or spigots, or both.
mike
p.s. now I have to go look up "ostentatious"Comment
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June 17, '07 addendum to above post:
(Board format refuses to let me post further edits)
Although the final non-volatiles were the same measurable weight, the appearances were not the same. The relative volume and coloring of the dried varnishes appeared much like they did at three hours, as shown in the attachment: The blend was noticeably darker and of greater volume.
Curiously, the tacky-dry petrol residue showed some 'tracking' at its last stage of evaporation.
With an eyeloupe, the precipitate in the P4 appeared as uniform long grains, perhaps crystalline.
(Anyone manage to hook a digicam on a stereoscope?)
....CottenComment
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Cotten
The uniform long grains are more than likely crystalline as you noted. My guess is Napthalene, which is usually present in a mix of distilled liquid hydrocarbons anyway. When you concentrate the solution by evaporating the solvent the crystals form naturally.
Your approach and scientific method are textbook, the only part you left out was a check for suspended solids. We should hope that what remains in the nonvolitile residue was not there in solid form when it came out of the pump. Did you **** any of the samples through a tared piece of filter paper?
The third possibility is that some chemistry occurred during evaporation. The affects of heat, sunlight, and exposure to atmospheric gasses, noteably oxygen, nitrogen and hydrogen, along with atmospheric moisture have caused a reaction which created some new compounds. The scariest possibility is that some polymerization took place. If it happens in open air then what happens under extreme pressure and temperature conditions (like on top of your pistons)? The deposits in our combustion chambers are probably not simple carbon like they used to be.
Which brings us back to Napthalene, more commonly known as moth balls. I remember that back in the 60's, even when you could buy 100+ Octane pump fuels, that some of the drag racing motorheads used to dump moth balls in the tank to give their fuel a little more kick. It may have been "hoodoo" but it actually makes sense. Napthalene is a double benzine ring and I think I saw something that Perry Rueter posted from an old Super-X owner's manual that suggested a drug store concoction of 50% benzine for optimum performance.
I don't know how many moth balls per tank would be the correct ratio but it doesn't matter anymore, I think the Feds put a stop to pure napthalene moth balls because of fire and health hazards. I think modern moth balls are dichlorobenzine or something like that, you wouldn't want that in your tank.
This is starting to sound like "Wierd Science", better hide all the Barbie Dolls and jumper cables.....
mikeComment
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