Race Fuel? Use as suplement?
Hey guys, I have a 67 L79 Smog car. All original. I had the 3814 original carb rebuilt (not restored) by Phil Cancilla out of NJ. He did my 3811 for my maroon car. Nice job on both. I took the silver car (L79) out for a spin after the rebuild on a warm day down here in South Florida and when I got home and turned her off, gas was leaking from what appeared to be under the front metering block. I called Phil and he said he's getting a TON of similar complaints from his other customers. He said it's heat soak from the boiling point in the ethanol gas along with the warmer temps/summer time. Sounds plausible but want other thoughts. He recommended race fuel/Sunoco 100 unleaded octane. I can get it locally, so that's not a problem. I know that race fuel keep cooler than conventional gas, but should I use it? Any other ideas? As always, I appreciate any input from you guys.....Regards....ARA
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Re: Race Fuel? Use as suplement?
Ara, If it's boiling, evaporating, how can it be leaking onto the manifold? It could be the accelerator pump gasket or the metering block and bowl gaskets. You could try snugging up the 4 screws on the fuel bowls a little. Remember if it doesn't leak it isn't a Holley
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Re: Race Fuel? Use as suplement?
Not looking to get into any more arguments regarding whether ethanol casues problems, so if somene reading this doesn't have any problems when using 10% ethanol fuel, great, I'm happy for you, this commet is for those of us who do:
Pure, no-ethanol gasoline is available at many gas stations and marinas throughout the U.S. There is a web site, "Pure-gas.org" to help you find these stations. Usually, it is sold as unleaeded 90 or 91 octane premim with "no ethanol". Its also called "recreational fuel". It's a bit more expensive than 10% ethanol pump gas, but you'll get better mileage with it. Some cars (not all) need slightly more octane than 90 octane fuel offers. If you get knocking, I suggest you add a gallon of 110 octane, no-ethanol racing fuel per tank.
Good luckMike
1965 Black Ext / Silver Int. Coupe, L84 Duntov, French Lick, 2023 - Triple Diamond
1965 Red Ext / White & Red Int. Conv. - 327/250 AC Regional Top Flight.Comment
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Re: Race Fuel? Use as suplement?
I run normal ethanol blend unleaded CAL gas in my rebuilt 2818-1 Holley and it's not leaking, in hot weather, or hotter weather. I don't think the unleaded corn blend gas is making your carb leak. If Phil is getting a ton of complaints about leaking carbs from his customers, I think he should consider a different rebuilt kit.Comment
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Re: Race Fuel? Use as suplement?
I agree with Don Hooper, unlikely the weather, no problem here in Texas with any temps, including those 100+ degrees. good luck with whatever solution you find.Michael
70 Mulsanne Blue LT-1
03 Electron Blue Z06Comment
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Re: Race Fuel? Use as suplement?
Thanks guys. Keep the comments coming. I have 5 gallons of ethanol gas in the tank already. I am going to put 5 gallons of race fuel in and take Her out for a spin and see what happens. Can't hurt right? Odd that my 3811 doesn't leak, but then again I don't drive her very much at all...AraComment
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Re: Race Fuel? Use as suplement?
Florida seems to be the epicenter of ethanol related fuel problems. Owners there seems to see problems that (almost) don't exist anywhere else. No idea why.
This case sounds like percolation, possibly pure gas might help.Comment
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Re: Race Fuel? Use as suplement?
Ara, I live in the Northeast and I have seen many fuel related problems even here on hot days. I can tell you what I Do to help with the gas boiling over onto your throttle blades and leaking onto manifold( BIG FIRE HAZARD), Take the float level that the factory says and lower it by 2 to 3 /32ths. this will however still not cure the hot restart problems the accompany ethanol. which is long cranking times. just a note to others with no problems with the hot weather, NO TWO CARBURETORS ARE THE SAME AS NO TWO ENGINES ARE THE SAME. Horse power will sometime equate to higher engine exhaust temp's. as we know corvettes with heated cross overs and heat risers create more heat. to boil the ethanol fuels. Do as many here have wire open the heat risers and plug up the heated cross overs if you have them.New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.Comment
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Re: Race Fuel? Use as suplement?
Regarding Sunoco unleaded race fuel..keep in mind that many of those blends include ethanol. Details can be found at http://www.racegas.com/fuel/index select fuel type then technical detailsComment
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Re: Race Fuel? Use as suplement?
Living here in central Florida, I too have had to deal with the Ethanol laced fuel problem. One reason more of us in Florida post about the problem is because there are more of us old white haired members who actually drive our cars year around down here to experience this situation. Many of us, being old back yard mechanics from "back in the day", have learned to deal with it one way or another. I went the non-ethanol fuel route and added some Maxlead-2000 to deal with the high compression of my 63 L-76. I run an aggressive advance curve and rarely see my temp gauge go above 180. I get very good hot soak re-starts and no longer have any "post nasal drip". I use a 3/8" phenolic spacer with 2 gaskets and a fuel hose from my filter to the carb, as well as an electric choke controlled by a thermal sensor (all of which can be returned back to stock very easily).
About rebuilt/restored carbs, my experience has been that one is better off restoring your original carburetor. I had to search for a long time to find a correct model AFB for my car (my original was stolen). I bought one finally from one of our good members. He had it for a 63 that he sold, but I suspect he tried to run it on the car and found it wanting. It was restored by someone in NJ, and I disassembled it for inspection before putting it on my car. I first noticed it had an incorrect top plate w/SS vent tubes instead of brass. After removing the top plate, I found one incorrect Venturi cluster, an inoperative hot idle valve, no override spring on the accelerator pump and the leather was doubled over on one side. There also were some after market floats which weigh in at a gram less than stock. It appeared to me that some one just put a bunch of parts together out of a bin with no concern as to whether they were the correct ones or not. This particular model draws a big buck as it is exclusive to 63's, with the added caveat of finding a correctly dated unit. Once I got all the correct parts, I installed it on my car (that was in 2011). Since then I have had it on and off my car at least a dozen times due to a lean surge condition. I finally gave up on it and put it asside for about six months. Recently, I did one last thing and that was to re-bush the primary shaft. On close inspection, even though it didn't show any vacuum leaking, the throttle plates did not seem to have equal exposure of the transition slots. The shaft was that sloppy. I re-installed it again just today and so far it seems to adjust and work very well. Tomorrow I will do a test drive to confirm whether I finally got the lean surge out.
About Holley carbs, I recently rebuilt a tri-power set for my son's 69 L-89 due to a leaking condition. On re-installation, I ran into a condition where I could not get the idle speed down. This turned out to be that the rear carb was being held open slightly by the throttle return linkage. Then when the engine was fully warmed up, I went to adjust the float levels and found that if I just slightly loosened the set screw, fuel would leak out even though the level in the bowl was close to correct. I set all the float levels "below" the sight plug opening by about 3/32". The car runs very well; no leaks and good hot soak re-starts. We had already changed his fuel over to non-ethanol with a boost for octane like my 63.
Sorry for the long winded post, but maybe someone else can learn from our experience.
Stu FoxComment
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Re: Race Fuel? Use as suplement?
If the engine has AIR, then it's probably got ported vacuum advance, which generates a lot more internal heat and higher EGT than full time vacuum advance.
Switch to full time vacuum advance, install a B26 VAC, and wire the heat riser valve open, and the percolation should be significantly mitigated, but percolation doesn't really result in an external fuel leak, so you may have other issues.
DukeComment
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Re: Race Fuel? Use as suplement?
I heard all the hoopla about avgas 100 LL (100 octane Low Lead) and always said it was BS. Boy was I wrong. I have converted all my older cars to if and there is a remarkable difference. My 1960 270 HP always poured out black smoke at idle because the carbs are designed to run rich and on 93 ethanol or non ethanol -- it did. After conversion to 100LL no smoke --- what a difference. I also have a 600 HP 65 resto mod and it always took 10 minutes of throttle manipulation to get it to idle. After conversion --- less than 30 seconds (no choke on an ARE carb by the way) No more that I drive these cars the difference between $ 5.50 a gallon and $ 3.89 makes no difference. It is a pain to get becauce you cant pull up to a pump but the pain is well worth the effort in my book BTW the side pipes on the 65 are turning white again!!! My 2 cents worth !!Founder - Carolinas Chapter NCRSComment
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Re: Race Fuel? Use as suplement?
I'm not too familiar with Holley models used as production equipment on 64 and up Corvettes (primarily because I have avoided them by choice), but the tri-power I recently worked on had a throttle linkage controlled vent valve on the top of the fuel bowl of the center carb. This vent is open during normal full warm idle or hot soak shut down, and could easily be the source of external fuel leakage during fuel percolation. Other than that, it appears to me that the other weak points on Holleys where external fuel leakage might occur would be the O-rings at the fuel bowl mounting screws and perhaps the accelerator pump diaphragm. The seals between the fuel bowl and metering block, and metering block to the main body seal fairly well (even though they have a lot of sealing surface below the fuel level). One will spend a lot of rebuild time scraping these gaskets off which will prove this point. I can't imagine the bowl or metering block can warp enough to cause a leak during normal service.
I also recall my experience with a Holley 4165 spread bore that I had on my 72 Nova SS. It had a fuel transfer tube from the front bowl to the rear which liked to move in the transfer holes to the point that the sealing O-rings would leak.
Stu FoxComment
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Re: Race Fuel? Use as suplement?
Wouldn't you expect to see a Holley 3810 on a 67 L79 ?Comment
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