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Octane levels

Posted By Rusty_S85 5 Years Ago
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Tedster
Posted 5 Years Ago
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I don't have fuel chemistry smarts but Ethanol was used to replace stuff called MTBE, whose purpose was to meet a federal mandate for oxygenated fuels. MTBE was banned however due to groundwater contamination issues, it's nasty stuff once it percolates into the water table, and it is persistent. So ethanol sort of makes sense as far as that goes, and it also increases octane. But it runs leaner and has other well known problems. I wonder what the percentage of ethanol is really needed to meet those requirements compared to what they are actually using. It's a very noticeable fuel economy decline even at 10%.
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FORD DEARBORN (1/16/2019)
There is only one non-alcohol fuel retailer near me but it costs about a whopping 70 cents more/gal in my area.  I have tried it in all my vehicles including my modern daily drivers and small engine appliances. Every engine loves it. Like, engines will give you a big hug for feeding them that stuff.  Several years ago I tested it for alcohol and found none, at that time. As far as what it is?  I'm guessing it may use av-gas as its base stock with out the lead, of course. I remember very well what 100LL smells like from my aviation days and the non-alcohol fuel has a hint of that "sweet" smell like av gas. Non-alcohol fuel doesn't have that nasty smell and the exhaust smell is much better. Since refineries are still producing av gas for piston engine aircraft, it would make sense to possibly use that stock for non-alcohol fuel IMHO.  If it were reasonably priced and available more places, we and our Y-blocks would have it made in the shade.  

Bunch of stations listed here that sells ethanol free fuel.  Problem is though city is quite large and I don't know if I want to drive that far just to get some ethanol free gas.

There is a Exxon, Conoco, and a Phillips fairly close to me that is listed as having ethanol free gas.  But still its at least a 3 mile drive one way to get to those stations for me.

Correction only one in the city that has it and they sell it by 5 gallon pails as they only sell race fuel.  The ones coming up were popping up just cause they are gas stations not because they were ethanol free.


1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

Rusty_S85
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Tedster (1/16/2019)
I don't have fuel chemistry smarts but Ethanol was used to replace stuff called MTBE, whose purpose was to meet a federal mandate for oxygenated fuels. MTBE was banned however due to groundwater contamination issues, it's nasty stuff once it percolates into the water table, and it is persistent. So ethanol sort of makes sense as far as that goes, and it also increases octane. But it runs leaner and has other well known problems. I wonder what the percentage of ethanol is really needed to meet those requirements compared to what they are actually using. It's a very noticeable fuel economy decline even at 10%.


Its a considerable economy decrease, around here we have stickers saying contain up to 15% ethanol and my economy in my old truck went from 15 city to 12 city after they made the switch here.

Closest ethanol free station to me would be the buccees in Katy and I am not going to drive nearly 20 miles one way to that station to buy ethanol free.  I will just buy the 93 to see if I can get the knocking to go away and if not then I might need to play with jetting.  I don't think I need to how ever considering this carb is listed as for a 312 which I was told by the guy that restores these holley 4000`s that they are jetting bigger than the holley 4000 listed for the 292.


1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

Tedster
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I'm no expert, but I've read - not sure about this - but a carburetor is jetted for a certain flow or fuel curve and as such would not need rejetting when installed on a different size engine. So you might be right. On the other hand, looking at the charts the manufacturers jetted what appears to be the same size carburetor with quite a spread of jet size over the years depending on application. A wideband O2 sensor is interesting to use and experiment with jetting and carburetor tuning. Even with modern equipment though the plugs need to be looked at very carefully.
ian57tbird
Posted 5 Years Ago
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We don't subsidise the corn farmers over here in Australia so thankfully we don't have the alcohol in our fuel.
Getting back to the original question about detonation. I have a 1989 Landcruiser with original untouched engine that I have owned for about 18 years. It ran fine on regular unleaded in the early days, but over the years started to develop detonation under load, especially with the higher temperatures. I am now running high octane unleaded equal to your 93. I have checked mixture under load and advance curve. About the only thing left in my mind is carbon build up. Not looking forward to pulling the head.
miker
Posted 5 Years Ago
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Ian, back in the day of 10 and 11 to 1 stock motors, and 105-110 octane at some pumps we had that carbon build up problem. I was a teenager in those days (and knew a lot more than I do now), but IIRC, the local mechanic used to dribble water down the carb at high idle, maybe more than idle, maybe 2000 rpm or so. He said the steam broke the carbon loose and it didn’t hurt anything, just blew it out. My Dad’s partner had a 1/2 ton pickup with a Corvette 396 in it (what’s known as a COPO car now), and that’s what I was told they did with it. Hopefully someone with some hands on experience will chime in before you pull the heads.


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Pete 55Tbird
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miker (1/16/2019)
Ian, back in the day of 10 and 11 to 1 stock motors, and 105-110 octane at some pumps we had that carbon build up problem. I was a teenager in those days (and knew a lot more than I do now), but IIRC, the local mechanic used to dribble water down the carb at high idle, maybe more than idle, maybe 2000 rpm or so. He said the steam broke the carbon loose and it didn’t hurt anything, just blew it out. My Dad’s partner had a 1/2 ton pickup with a Corvette 396 in it (what’s known as a COPO car now), and that’s what I was told they did with it. Hopefully someone with some hands on experience will chime in before you pull the heads.

Miker, your post rings a bell with me. We did dribble water into the carb at fast idle  to de carbon our engines. Clouds of smoke would come out
not unlike an add for SEA FOAM. It did work, as the engine that this was done on did not ping as much and if a head was pulled you could
see how clean it was. Best part was the cost, FREE. Pete
Rusty_S85
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At work we do ATF but that is mostly done to try and get rings unstuck.  weve also used that AC Delco top end cleaner in concentrate form and pour it down the intake as well then stall the engine out with it and let it sit in the cylinders for a bit.  Problem is not sure how you would do something like that with a HOlley 4000 with the primary barrels shrouded by the choke assembly and fuel bowl.   Guess you could dump it down the secondaries.


1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

Florida_Phil
Posted 5 Years Ago
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On this subject, here's an interesting side note.  When I put the 1957 G heads on my motor, I took them to my machine shop.  These people do a lot of work for local racers and they have been around for a long time.  I asked the machinist if I needed to install hardened valve seats in my heads.  He told me the alcohol in the today's fuel makes this unnecessary.  My car is only driven slightly, so I did not pursue this any further.  Anyone have an opinion on this?


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FORD DEARBORN
Posted 5 Years Ago
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Florida_Phil (1/17/2019)
On this subject, here's an interesting side note.  When I put the 1957 G heads on my motor, I took them to my machine shop.  These people do a lot of work for local racers and they have been around for a long time.  I asked the machinist if I needed to install hardened valve seats in my heads.  He told me the alcohol in the today's fuel makes this unnecessary.  My car is only driven slightly, so I did not pursue this any further.  Anyone have an opinion on this?

IMO, you will not have issues with the valves/seats. The engine will not be under long time high stress such as constant heavy load/stress as might be the case with heavy truck duty of racing. Twenty some years on a mild 289 build I just couldn't see cutting away the original pristine seats in these particular heads. There has been no reported issues. An added benefit is the exhaust valves should run a little cooler due to better heat transfer through the integral seat, for what that's worth.  Again, just my opinion, JEFF........................


64F100 57FAIRLANE500


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