Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. I have largely eliminated this problem with all fuel system components rebuilt, and an electric fuel pump but will get occasional stumble with a hot (after say, an hour run) engine idling or in traffic if it is say, 80 or hotter out. Yes the light elements will still be in there. What we call gasoline - as Rusty showed; is blended today - and the various chemicals blended into it for the various regions and state laws make it a special product where you BUY it. I wanted to upload the map, but at 2.73mb, it was too big. . You can do a Google search for it, though. So they started putting more of the low grade gas, or high grade kerosene into the gas. To keep it on simple terms, several people have confirmed that adding some kerosene, diesel fuel or stove oil will reduce the tendency to vapor lock and will NOT hurt an older model, low compression engine. Holley Fuel Pressure Regulators 12-803 HLY-12-803. Check "Reid Vapor Pressure" in Wikipedia, or similar. Please use a different way to share. However I would welcome you advice on the following. I suspect as the article suggests even with all these steps you can still get the crap gas to boil if it is hot enough under the hood. A: Log In / Register Order Status. See Standard conditions for temperature and pressure - Wikipedia, the free encyclopedia. Mounting Bracket Included. You set it to the exact fuel pressure you want. MFG. It IS variable and a result of the various fuel blend components. If the carbs are drawing fuel and you lower the pressure at the reg, it should show on the gauge. Please try again later. As Raywith pointed out, you need to let the pressure go somewhere. Driving on a warm day in heavy stop start traffic it started vapor locking on a climb - using 10% ethanol fuel with no additive . THE SECOND ISSUE - the vapor system on the Packard is going to be a problem no matter what today. Now my equipment sits idle while I wait for a response from the vendor. Refining of oil is basically heating it into vapors and then capturing those vapors various degrees of cooling - at the top is "propane" - at the bottom is "pitch" or "road or roof tar". My bypass line has a shut-off valve that I can use to manually adjust the pressure, but when air bubbles develop within the input fuel line, this valve requires adjustment to maintain the fuel pressure. Of course you may already have this setup - that is the first issue. I turned into a side street and opened the hood. Two Port Use with standard pump only - not recommended for maximum pressure pumps. Yes, you will need to buy the type of connection you want to use such as hose barb, compre. If I could get 75-85 octane, non-ethanol, Regular gasoline that vaporized at above 180 deg F, I think my car would run fine all the time. I do not have a pressure regulating valve to reduce the pressure from the pump but it works fine with no flooding under normal conditions and I have fitted a modern soft seat to the float cut off needle. Holley 12-804 Holley Fuel Pressure Regulators JEGS 41040 JEGS Fuel Pressure Gauges Now you need fittings. Copyright 2008-2023 OReilly The thinner, lighter products are at the light end of the scale the thicker heavier products are at heavy end. If so how? Reviewed in the United States on June 5, 2022. P/N 12-803, 12-803BP, & 12-804 Installation Instructions 199R7914-3 NOTE: 12-803BP IS NOT TO BE USED WITH MECHANICAL FUEL PUMPS! A long time ago it was in use in the oil business. In theory the vapor carburetor was the way to go in that day - with lower flash point fuels like poor grade fuels that all pretty much resembled the weight of kerosene in that early day of motor fuels. Going to check my VW bus fuel pump pressure. In this document is a chart for Seasonal Gasoline Specifications. Fuel pressure regulators are used to adjust for fuel pressure requirements of various carburetors. . Show details I have a electric pump at the tank to try and speed up the fuel cooling process but if you have a 100 deg F day you may have fuel near 100 deg F in the tank. My car runs and idles fine with no flooding when running with the electric pump, the flooding only occurred once when it vapor locked. The fuel pressure is at 1 - 3 psig since the pump is not running. All kinds of remedies were tried. Putting kerosene into gasoline - while both are hydrocarbons - and they will blend - the lighter oil nature of the kerosene to the solvent of gasoline; in an amount of 5% is not enough to change the STP vapor point of the gasoline, but it will weaken the octane rating of the gasoline enough to feel it under acceleration AND under pressure will raise the vapor point enough to perhaps prevent vapor lock depending on the ambient and under hood temperatures of where one is located. A by-pass style regulator has the fuel coming in the same side of the check ball as where the fuel comes out to the carb. I have used kerosene to avoid vapor lock and there is no doubt it helps, the more the better up to 20% in a low compression 1920's car. Wont be good for a finicky carb. We currently do not have an estimate when this item will ship. Once the fuel fills up the float bowls in the carburetor and the needles and seats shut, it starts to build pressure, pushing the diaphragm against the adjustment spring under the adjustment screw and allowing the ball to go "up" against the seat, effectively shutting off fuel flow to the carb. 1996-2023, Amazon.com, Inc. or its affiliates, Select a location to see product availability, Holley HOL 12-804 12-804 Fuel Pressure Regulator. This approach is not recommended for higher compression cars made from the mid fifties onwards. should be one inlet in two outlets out, i've seen very smart mechanically inclined people hook the carb to one outlet and the pressure in to the other, it's easy to do, not saying anything bad but could be a a possibility. bowls after each run, just to see exactly at what temperature the problems become apparent. Two 3/8" nipples/hose connections and a 3/8" to 1/8" reducer. Some Holley 12-803 4.5-9 psi and 12-804 1-4 psi regulators mislabeled from factory. I feel I am 95% there, and a slight improvement would be all I need - for now, that is unless the ethanal mix changes (your tax dollars at work). In fractional distillation (the refining of oil) - what we call "mineral spirits", "paint thinner", "kerosene" and "diesel fuel" all ALL "heavier" hydrocarbons (pretty much in that order) than what we call gasoline - in that they occur lower in the distillation tower and condense at lower temperatures back into liquid before what we call "gasoline" does. (Maybe this arrangement was intentional to assist in vaporising the fuels of the day but it is all bad in hot weather with today's fuels). But the heavier elements will raise the boiling point of the mixture. Then, we got what was loosely described as winter gas, all year round, with RFG. For over a century Holley has driven the cutting edge of fuel-system design. I had a chrome dial regulator, which leaked gas everywhere but luckily didn't actually burn down my ride. Had to reset to Zero. I have just this Spring started taking temp. The 12-804 is made from durable aluminum and has a satin chrome finish that is extremely resilient to corrosion and abrasive chemicals. Some parts are not legal for use in California or other states with similar regulations. 12-804) is a Low Pressure (1-4 PSI) regulator. Did not like having to reset to zerobut I did. Gasoline was so light if you left the cap off a gallon can it would all evaporate in a few days. Easy to read. The lower I can get with this pressure is 3.5 psi (at max adjustment). 2-Port Carbureted Fuel Pressure Regulator (12-804) by Holley. . readings of the carb. LASTLY on your first issue of understanding vapor lock and boiling point. Error posting question. In the fuel use map in the Exxon or Mobil gasoline websites, there are a few places where the Reid Vapor Pressure spec is varied from other fuels. I can only say acetone will lower flash point (light easier) but also lower auto-ignition temperature and thus create knock into too much of a quantity - while a very little bit will raise octane but not lower auto-ignition - so if you go TOO low with kerosene or diesel you can bring back some kick to the fuel with SMALL amounts of acetone. For more information go to www.P65Warnings.ca.gov/passenger-vehicle, WARNING: This product can expose you to chemicals including Styrene which is known to the State of California to cause cancer. #2. . Vapor lock was just a fact of life for the Fords. [{"displayPrice":"$58.17","priceAmount":58.17,"currencySymbol":"$","integerValue":"58","decimalSeparator":".","fractionalValue":"17","symbolPosition":"left","hasSpace":false,"showFractionalPartIfEmpty":true,"offerListingId":"UhTnfcw7IZxaNntXlJwDKCZdMn2swwW9Qa8PxzrWBz%2By8RC0ilxVsHIj8toGUO%2FPmmF8b2HD1iNYooZ7n4ER0XuKiQsQQvJG86lgqsni6KYZs%2FdLcIOIE0Ukulbz%2BJYBuUOC820ciUZxU2UEL9sUjtoq8gdk8bOPIZ3QChg8zpgyIZxlTaXQEA%3D%3D","locale":"en-US","buyingOptionType":"NEW"}]. This item can be returned in its original condition for a full refund or replacement within 30 days of receipt. There was a problem adding this item to Cart. The Holley 12-804 is one of the most popular low fuel pressure regulators that works perfectly for setups that require 1 to 4 PSI. I installed this on my Onan 7000 generator as part of a project to resolve vapor lock issues in hot weather and high altitudes. Second, you adjust this regulator by turning the hex screw on top - does anyone happen to know how many pounds one or more full turns would produce etc? I commented that it was already vented by the clearance around where the float needle projects through the top but he advised that this was not enough and the vent needed to be at least a 1/4" tube and that he could see it venting vapor. . Gasoline vaporizes according to fuel system pressure. the fuel pressure gage needs to be in the line going to carbs. Adding some additives can raise the AVERGE boiling point but cannot remove the lower-boiling components, so regardless of what higher ends are present, the initial boiling point will remain that of the most volatile components. Too much fuel pressure for a given needle and seat assembly can overload the needle and seat and may cause flooding or drivability problems. This regulator is used to adjust to fuel pressure requirements of various carburetors and supplies the proper pressure to the needle and seat valve to prevent flooding or drivability problems. Like many others, I have been considering what to do recently. Sorry, you're using a web browser that is no longer supported. neglect, accident, improper installation or adjustment, dirt or other contaminants, water, corrosion or faulty repair, or used in applications other than . Could you explain a little more about how you would run the bypass? GENUINE Holley 12-804 CHROME 1-4 PSI Adjustable Fuel Pressure Regulator Kit $49.99 Free shipping Holley 12-804 Carbureted Fuel Pressure Regulator $37.07 +$14.99 shipping Holley 12-804 Chrome Street Strip Fuel Pressure Regulator 1-4 PSI $54.53 Free shipping Holley Performance 12-804 Fuel Pressure Regulator $54.53 Free shipping Holley 12-804 $55.86 ${cardName} unavailable for quantities greater than ${maxQuantity}. Volatility is a measure of the gasolines tendency to vaporize under a given set of conditions. To add the following enhancements to your purchase, choose a different seller. I take this to mean that the separate boiling points of the constituents occur at atmospheric pressure but at higher pressure the resulting mix has a single boiling point. Adjustable fuel regulation from 1 to 4 psi, 1965 and older U.S. manufactured California Certified vehicles, 1967 and older U.S. manufactured Federally Certified vehicles, 1967 and older Foreign manufactured vehicle, 1966 and newer U.S. manufactured California Certified vehicles, 1968 and newer U.S. manufactured Federally Certified vehicles, 1968 and newer Foreign manufactured vehicle. He finally achieved significant improvement by fitting a vent to the carburettor top (which is routed away and under the car for safety). What Rusty writes IS correct. By the way, I had an excellent service from this seller (5 stars!). I remember when I was a teen in the 50's and everyone had a flathead Ford V8 or a Chevy stovebolt 6. The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles: WARNING: It is against the law to install this part on an Emissions Controlled Vehicle. The 12-803 4.5-9 psi spring is plain, (just the gold colored plating) the spring is accessible and replacable The cheap dial units are terrible. order To see our price, add these items to your cart. . If this is true, how come adding antifreeze to water raises the boiling point? ***The inlet pressure limitation is 7 psi. 03-28-2012, 03:04 AM. Q: From propelling the LS-, Coyote-, and Gen 3 Hemi-swap trends, to continuously innovating late-model and vintage vehicle performance, Holleys commitment to its customers and their cars is at the core of everything we do. Boy am I glad to have happened on this thread. Applications. Some of these items ship sooner than the others. Amazon has encountered an error. If you put in too much you can return the fuel to some "kick" without knock with a small amount of acetone. So - you cannot just say whether it will work or not. I will be trying one of these but am curious what is the active ingredient(s). Any thoughts on this? $41.19. The summer gasoline vaporizes in the line and the heat soak is quicker and longer on hot day's. In those days before 1905 kerosene had a strong piercing odor and coal oil lamps sometimes exploded. Holley HOL 12-804 12-804 Fuel Pressure Regulator; ; Customer reviews . Does this need to be mounted upright or is it ok on its side? What I would do, is with the car off, (or electric pump off), turn the screw a good ways out. I did, works great & looks beautiful. It is not all the same. Adding heavier weight hydrocarbons WILL raise the vapor point under pressure - usually enough to keep the fuel from vaporizing in the line or boiling off in the carburetor bowl while flowing. In refining crude oil they distill it to separate out the different products. So in an open cup the boiling points would also appear the same as water but under pressure the boiling point is different. If youre looking to dial it in accurately its not going to do it. Adjustable from 1 to 4 PSI. Unfortunately, this fuel pressure regulator does not even come close to regulating the pressure and keeping the pressure down. Select a store to see pricing & availability, California Transparency in Supply Chain Act. Pre-set at 2.8 PSI Octane is an actual chemical which would be at the light end of the scale for gas, kerosene would be at the heavy end. A larger tank might need two quarts. Purchased the regulator from Baxter, unit arrived in 4 days.. [endif]-->,