Thread: "anti-vapor lockification mechanism"

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I had problems with vapor lock when I switched to braided AN lines that soak up the heat. My solution was a bypass regulator/return line. Rather than fuel dead heading at the carb it is constantly flowing so doesn't have time to get hot in the first place. Insulating the line and regulator did no good and heat sinking the fuel rail I do not think will be significant benefit. Cool cans are good but I don't know how good for street application...

Shawnlee28 said it first and in my experience bypass/return is the best solution to the problem

two cents

-Chris

The trans cooler will heat the fuel more.

Skids72; I ran a cool can on the Streets in Las Vegas for years.
But the ice didn't last long driving around during the day with 120 temps out there.
Mostly just good when you are going to be racing and have access to a big ice chest.
You guys realy hit on a good subject here and making me re - think my fuel line run.
I am not running a bypass right now, but you guys have convinced me that I should be.
Though I am running a big steel line from a mech pump, I'll be changing it now to electric
back in the tank. Still gonna run the big steel line though so I can get plenty of fuel in a hurry. Thanks for the tips guys. Kurt

Although the original post is getting close to 2 years old I think we are going to find especially on carbureted vehicles that vapor lock and heat soak after the vehicle is shut down is going to be an ongoing issue especially as the fuel boiling point is lowered with the addition of ethanol mandated by the eco-Nazis. I know 3 of my cars that have never had a problem before did last summer when the area I’m in started running 10% ethanol on a year around basis. I also noted that the EPA has recommended raising the allowable limit of ethanol to the 15-20% area.

Besides the obvious of routing the fuel lines away from heat sources and Phenolic carb spacer (to prevent heat soak) the best methods I have found to prevent vapor lock and heat soak are increasing fuel line pressure (but only so much can be done in this area without overwhelming the needle and seat) building a bypass/fuel return system.

The solution I’ve come up with for my 500 Caddy may not be the prettiest thing in the world but should be effective. I’m bypassing the fuel right at the needle and seat area to eliminate any areas that can heat soak all the way to the carb, as opposed to using a fuel pump or fuel filter with a built in return line provision or an aftermarket by pass regulator which wold still leave some sections of line to absorb heat.

The amount of fuel by passed and pressure retained at the carb is controlled by a changeable fixed restrictor located in the pipe leading to the return line. Like I said not necessarily pretty but it should be effective (and with the air cleaner on not to noticeable).

I personally like this because it's cheap (cheap is GOOD ) and as there are no moving parts or diaphragm .....ever wonder why they sell rebuild kits for a lot of the fuel pressure regulators on the market?........there is nothing to fail.

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Put it in a new thread.

I used to work for a travel/adventure program that traveled 7500 mile through the western US. every summer for 4 years. We had two almost identical Dodge Ram 15 passenger vans. Every year when we were in the high desert of Utah one van would get vapor lock, the other van functioned flawlessly. We ended up at a Dodge dealership who mounted a second fuel pump(electric) to solve the problem, but alas the next year we experienced vapor lock again, and having to sit on the side of the road to wait for it to cool enough to get going again. Only to limp 20 miles at most before vapor lock stopped it again. The third summer I worked for MHL Adventures, I called Dodge's engineering tech line and explained what was happening. I really was tired of dealing with this every year, and wanted to nip it in the bud. What really stumped us was the two vans were near identical, one being slightly more posh(and the problem van) the other working fine? It turned out the fancier one had a slightly smaller gas tank, and a longer fuel line run(the combination causing the problem). The Dodge boys suggested when filling the gas tank(in the high desert areas) to add a quart of transmission oil which would raise the vapor point of gas, thus preventing vapor lock. I was worried this would screw up the engine some how, but he assured me, all it would do is add lubrication, and not damage anything, or void their warranty. So I figured what the hay, and when traveling through Utah that summer, every time we fueled up, we added a quart of tranny fluid to both vans. The wild thing is it worked great. Also as far as I know, the vans never incurred any damage related to this. Mind you it was in the late 1980's but seemed an easy solution to the problem that left 15 teenagers baking on the side of the road every summer for a few days.

Use an electric fuel pump mounted back near the tank. Running a return line allows the fuel to return and the fuel in the tank doesn't heat to the point of vapor-or-ization and helps.

Thanks, i suppose i should have updated this.... I already installed a electric fuel pump a good while back, I mounted it just a couple feet from the fuel tank. I also re-routed my fuel lines further away from my motor using fuel injection hose. I did run into a problem with the fuel pumps burning up which was quickly resolved by re-wiring the pump to run off a relay instead of a fused circuit straight from the battery..