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We have been suggesting this patch for maybe 25 years. We have heard back from literally hundreds of customer after the patch was installed. Believe me, it DOES work!

This link to our website troubleshooting section explains it better:

http://www.thecarburetorshop.com/Troubleshooting.htm#Fuelleak

Jon.

thank you for the link after driving (sturgling) over the rockies in my 1940 buick I will now know y

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  • 6 years later...
On 9/3/2014 at 7:57 PM, Wheelnut said:

I used to have hard starting problems on my MGB roadster after shutting it down on hot days. I had just converted it to the earlier dual carb setup but didn't have the heat shield that goes between the carbs and the engine. The heat shield is just a flattish piece of sheetmetal. I added a home-made heat shield made from a thin piece of shiny aluminum and that cured the problem. It worked by just blocking the radiant heat from the engine and exhaust manifold.

A simple reflective heat insulator sleeve slipped over the fuel line will do a lot to keep it cooler. A reflective heat shield under the base of the carb, combined with the phenolic carb spacer, will reduce carb temperatures significantly. Not very original looking, but effectve.

Two summers ago my mgb started having problems. After driving it then shutting it off it wouldn't start again until the motor cooled down. I started replacing parts,points,condensor,fuel pump,coil,made sure the tank was clean.It has a Weber carb.with an electric choke.I removed the gas cap thinking the tank wasn't venting.I then installed a phenolic spacer under the carb and am using only ethanol free gas. It seems a little better but the other day after a drive it died on me just as I was putting it back in the shed.Again I had to wait until it cooled down to start again. I thought of installing a hotter coil.Very frustating! Maybe it still is a fuel issue. 74 mgb.

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In recent years refiners have had a surplus of butane.  Butane is a relatively low value byproduct of refining.  In fact, as refiners process heavier and cheaper crudes, those processes produce more butane.  

 

Refiners have discovered that they can blend butane into gasoline up to meeting a seasonal vapor pressure specification usually established by a city or region.  Essentially they can sell butane at gasoline prices.  
 

The octane bump that they get from ethanol helps facilitate this blending.  Butane is volatile and it will flash at elevated temps and cause vaporization in our fuel lines.  High pressure and low temperature are the enemies of this vaporization.  
 

Gasoline has changed significantly in just the last 15 years.  Also I have heard that in the US there are as many as 94 different “boutique” gasoline blends because of the many air quality regs and regions.  Boy do I have stories that can’t be told!

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41 minutes ago, JoelsBuicks said:

Also I have heard that in the US there are as many as 94 different “boutique” gasoline blends because of the many air quality regs and regions.  

 

Last time I heard, it was about 54, but that was maybe 20 years ago.  Every city and individual thinks "they're special".  And people wonder why the price of gas is as high as it is.  It would be cheaper if there was only one non-leaded fuel for the whole country.  It could be shipped anywhere it was needed and the refinery would not need to be changing over to a different "special" blend.  Just IMO

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23 hours ago, Larry Schramm said:

 

Last time I heard, it was about 54, but that was maybe 20 years ago.  Every city and individual thinks "they're special".  And people wonder why the price of gas is as high as it is.  It would be cheaper if there was only one non-leaded fuel for the whole country.  It could be shipped anywhere it was needed and the refinery would not need to be changing over to a different "special" blend.  Just IMO

Larry, you are right.  I did some searching and found that the reformulated gas is far fewer.  But the map did not include seasonal blends.  Two major changes that are now several years old are the benzene reduction and sulfur reduction. 
 

I recall a time when refiners were crying foul about ethanol reducing gasoline demand.  Then, almost in a moment’s time, refiners realized they could leverage ethanol producers due to over production thereby buying it cheap and selling it at gasoline prices. Big profit!  Then they started making subgrade unleaded and blending with ethanol to get octane.  Big profit again because it allowed them to sell their iso-octane (2,2,4 trimethyl pentane) to the aviation gasoline market instead of downgrading it to unleaded.  Big profit!  Think about it, when was the last time you heard an oil major complain about ethanol?

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Seasonal blends have been around since at least 1963, when Texaco advertised "customized blends" for regions and times of the year.  I suspect that other main brands did similar, just that Texaco tried to capitalize on it back then.

 

In the back of the websites of both Chevron (circa 1990) and Mobil (circa 2000s), there used to be some great information on the then-upcoming (RFG in Chevron's case) and USA maps (Mobil's website) with the many ozone non-attainment areas and their related fuel blends.  Doing a recent Google search for the maps came up with the same or updated maps on the www.aaa.com website.  In some cases, the only major change (by comparison) was in Reid Vapor Pressure specs.  I suspect that most of these non-attainment areas also had E10 in their available fuel products.

 

Outside of these non-attainment areas, E10 is apparently optional, BUT if the main fuel terminals (splash blending, usually) do most of their volume in E10, the "reach" of E10 most probably extends well beyond that particular metro area, by observation.  Probably for the entire state.  

 

In the www.fuel-kits.com website and others, I beleive that you can find non-E10 fuel sellers.  Brand of the fuel and octane rating are listed too.  Not sure how up-to-date the listings are, so probably best to not rely upon them completely.  Many are located at lake/river/coastal marinas, by observation, but some are in more remote locations of their regions.

 

What has been interesting is that E0 has been resurfacing in major fuel markets, at places like WalMart (when they'd remodel the Murphy USA fuel stations.  All in the basic "regular" grade and about 35cent/gallon more expensive than their similar-octane E10 fuel.

 

Reid Vapor Pressure is a function of the total fuel, whether it has ethanol in it or not!  Although ethanol might be a component of the fuels which are more volatile and "easier to evaporate" (as "winter gas" used to be in comparison to "summer gas").  Obviously, modern fuels are normally much more "winter gas" even during the warmer months of the year.  In any fuel, ethanol'd of not, there are "higher aromatic" components which will evaporate first, which usually can be related to the octane level of the fuel (and any improvements in octane from the base fuel in the blend, at the time that batch was blended).  Which means there is a basic-spec unleaded gasoline to which each brand has their particular additive package(s) added at the fuel terminal to result in their possibly unique gasoline in their branded gas station pumps.  This is the "splash blending" orientation, unlike when each of the fuel brands had their own fleet of trucks, operating from their own tank farms, into which THEIR fuels were delivered via pipeline or railroad tank cars, then distributed to their branded local fuel distributors and the local gas stations they served.  That way, you KNEW the brand of fuel you were getting, which some cars might like better than other brands, by observation.

 

In prior times, it was the basic lead level which could increase fuel octane, but now it's more related to other chemical compounds (usually related to alcohol-type components) added to the basic spec/open market supplied gasoline.  Various components which will allow the fuel/air mixture to completely ignite in a millisecond or so, which is needed for the newer Gasoline Direct Injection engines of today.  Consider, it used to be that the fuel was mixed with air by the carburetor.  This mixture had a length of time (in the intake manifold and cyl head ports) to more fully vaporize before it got into the cylinders, where a spark would ignite it.  Now, with the fuel being directly-injected into the cylinder (as it is in a diesel engine!), all of this must happen in just a few degrees of crankshaft rotation!  Add a small turbocharger and new dynamics are introduced into the mix!  An orchestrated "dance" that needs powerful computer capabilities for it to work at least as well as it does.  Everything must be tightly-controlled as to what happens when and in what sequences.  Which also relates to a whole new set of operational issues (over time) with these GDI engines, by observation!!!

 

Don't look for E10 fuels to "go away" any time soon.  Why?  E10 usually results in a 6% loss in fuel economy, which means more base crude oil is needed (in addition to the original %5 increase to build unleaded fuel rather than leaded fuel).  So, that means MORE gallons of gasoline sold in the USA.  More gallons means more state and federal "gasoline tax", which relates to state revenues.  Analysis of the financial impact on the states (for things like locally-funded roads!) would decrease, which has stopped any move to outlaw ethanol'd fuels in any state where such legislation had been considered (including Texas).  But, with our generally more affluent society (and related residential building), I suspect the greater availability of the E0 fuels has been the result of the vast expansion of lawn service industries in these locations.  The early and initial outcry of "watercraft owners" when the E10 started to melt the fiberglass fuel tanks in their expensive boats was more "niche" in nature, but with the great expansion of lawn service (lawn mower and weed eater users), E0 suddenly saw a much larger market across the nation.

 

So, I suspect that any driveability issues related to modern fuels is NOT specifically related to ethanol'd fuel blends, but to the greater impact of fuels needed to make the modern fuel injection systems and engine designs work better to meet increasingly-tighter emission control strategies.  Which include the necessity of quick vaporization in these electronic fuel-injected cars.  Which can make life a bit more trying for drivers of older carbureted vehicles.  Just something else to deal with, just as we had to adjust to unleaded gasoline and lower-zddp motor oils.

 

Just some thoughts and observations,

NTX5467

Edited by NTX5467 (see edit history)
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In the case of the Chevron website's information on RFG (ReFormulated Gas), which was when MTBE was initially used as an oxygenate to gasoline, it mentioned "increased crank time to start" when compared to the then-existing fuels they sold.  As if that would be a noticable change in this area, from their extensive testing of the new and old fuels.  A slight fuel economy loss was noted too. 

 

At that time, I was driving a 1970 Skylark Custom 350 2bbl CA emissions car in which I documented a 3% fuel economy loss from non-RFG Chevron gasoline (Chevron's information pamphlet stated "3.2%", as I recall).  "Crank time" was not significantly longer with this car, as in maybe one more engine revolution before it started (although I seem to recall that Chevron claimed it could be up to 10% longer?).  This was the first major national foray into "oxygenate-extended" fuels.  Which was extended when a total of 10% oxygenate content was advocated for the benefits of air quality AND to help reduce foreign crude oil purchase quantities.  In that later 10% orientation, the oxygenates were MTBE and ethanol, in right at a 50-50 split.  Later, when  the carcinogenic MTBE started to appear (in trace amounts) in many municipal water supply sources,  MTBE use was stopped and ethanol became the sole oxygenate (but only up to the mandated total 10% level).

 

By observation, crank time after a "hot soak" situation can relate to many things.  Especially air circulation under the hood, I suspect.  Even back in the 1960s, some car brands/engines had these issues BACK THEN while others were not affected nearly so much, by observation.  Under hood temps, carb design, mass of the intake manifold, and other factors all figured into that mix.  BUT, as all cars were generally unique (compared to others outside of their particular OEM family), starting technique (i.e., accel pedal input/position) could be important factors in getting the engine to start as quickly as possible in these conditions.  "Learning to drive the car", which was in addition to learning its responses to steering and braking system activities/responses.  Be that as it may/was.

 

In more modern times, the "heat soak start" might be affected by several factors.  Some of which would not have been a consideration, but now are.  As in cooling system condition (related to internal accumulations of "debris" in the rear cylinder areas of the cylinder block).  More materials to hold heat and radiate it into the engine compartment with no fan-induced air flow across the engine.

 

The ignition system would need to be in "better than when it was designed" condition.  Meaning that the breaker lobes that run the points open and closed are not worn very much, which relates to point gap and point dwell, and the ultimate "spark" that gets to the spark plugs.  

 

In the case of spark plugs, what used to be "good" might now be "sub-optimal".  But some of this can be improved upon by looking at modern/OEM plug designs.  Most OEM designs now have a .040" "fine wire" center electrode and a narrower ground electrode, to allow for greater exposure of the spark to the air/fuel mix in the cylinder.  Several YouTube videos show the differences in how much better these designs work, which is significant in both ignitability of the mixture and engine run time (on a specific amount of fuel).

 

The first evolution of these newer/different spark plug gap designs started in the 1990s, as an OEM effort to have a more efficient combustion cycle and related better fuel economy and decreased exhaust emissions.  Accel and Denso had their U-Groove spark plugs, which tended to move the main spark-jump points to the edges of the electrodes.  NGK also had their V-Power plugs, which had a distinct "V-shape" cut into the center electrode with sharp edges (unlike the flat edges on the Denso plugs).  Plus the cut-back ground electrode (covering only 1/2 of the center electrode's area), or as Champion called it on their 1960s-era "race plugs", "J-Gap".

 

ACDelco "Rapid-Fire" plugs, by observation, used all of the tricks at that time.  A center electrode with small vertical splines around its circumference (possibly more air disturbance) with a ground electrod that would only cover 1/2 of the center electrode's area, plus having angle-cuts to make a more pointed ground electrode.

 

NOW, IF you might desire to run the OEM spec plugs, you can modify them to be more like the modern plugs (with the modifications being hidden while the plugs are screwed into the cylinder head).  First thing to do is to find a "point file" and a smaller pair of diagonal cutters.  Use the cutters to bend the ground electrod more open so it's easier to do the modifications and not harm the ceramic insulator of the spark plug, AFTER first determining how much shorter that ground electrode needs to be to only cover 1/2 of the center electrode.  From that observation, you can either choos to file it wih the point file and then dress it flat and square before re-bending it down for the final gap adjustment (more time-consuming) or you can snip it with the cutters and then dress it flat for the final gap adjustment.  When done, the ground electrode should be centered over the center electrode, but only covering 1/2 of its surface, leaving the other 1/2 uncovered.  Resulting in the "J-Gap" situation.  End result, when the spark ignites the mixture, the flame kernal is not shrouded by the ground electrode.

 

After I discovered the NGK V-electrode plugs, it was in a NGK/Toyota spark plug brochure.  Touting its possibility to fire leaner mixtures.  I found Toyota applicaiton of that plug and then crossed it into a Champion plug, which just happened to fit the 1980 Chrysler 360 I was driving at the time.  The Autolites in the Chrysler (when I bought the car) were burning fine with a white ceramic electrode coloring, no operational issues at all, BUT when I put the NGK plugs in it, there was an immediate difference in its sound and throttle response with the NGK V-electrode plugs.  No increase in fuel economy that I could discern, but the engine sounded happier and more responsive.  Later, the same NGK plugs appeared as their then-new "V-Power" line of aftermarket spark plugs, so I put them in everything I had.  It seemed that the more "open" the combustion chambers were, the greater improvement they made, but with the more wedge-shaped chambers (as on my '77 Camaro 305), their combustion efficiency was noticed on cold starts, especially as I like to have the automatic choke set as lean as possible, consistent with good driveability for the first mile or two of driving.

 

During the time all of this was taking place, the newer "fine wire" center electrode plugs were starting to appear, as were platinum-tip spark plugs on the OEM and aftermarket levels.  The initial platinum plugs had a thin layer of platinum laser-welded to the ground electrode's spark contact area.  Later "double-platinum" plugs had a similar piece of platinum laser-welded to the center electrode's spark area, for even longer-than-50K mile durability.  These designs later gave way to the fine-wire Iridium electrode plugs used by almost every OEM in modern engines.  One of the first GM applications of these fine-wire Iridium plugs was in the Buick 3800 Supercharged V-6 (with ACDelco numbers and markings on the outer ceramic insulator and NGK stampings just under the socker "hex" on the metal of the plug).

 

Another trick I've used on my lawn mower spark plugs is to gap the plug, then use a pair of pliers to gently rotate the ground electrode such that it covers only 1/2 of the center electrode.  Getting most of the same affect as all of the filing and such, which might be just enough to work well.  A point of note is that the Champion "Easy-Start" lawn mower spark plugs have been observed to be of the .040" Fine Wire electrode design, whether Iridium or not.

 

So, efficient-firing spark plugs, powered by a good ignition coil, working through minimally-restrictive spark plug wires for the application, with a properly-timed spark (from a good set of points, gapped correctly to spec, with appropriate lube on their rubbing block, sliding against a non-worn breaker cam, with the basic ignition timing set to spec/what works best) in concert with a good fuel system might help things to work better with more driving enjoyment.

 

As for what happens "pre-carburetor" in the fuel system, that can be variable with regard to the particular vehicle, with respect to in-use vapor lock and such.  How such things are engineered and executed can be related to just how stock-appearing the owenr might desire the vehicle to be (i.e., how well these things might be hidden from normal view).  As in a simple, low-pressure, "pusher" electric pump mounted near the fuel tank, switchable for when it might be needed, for example.  Or a slight re-routing of the fuel line away from head-producing areas and/or into safe spaces with more exposure to air flow, for example.  Or possible heat shielding of the fuel line?

 

Enjoy!

NTX5467    

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