Fuel line insulation

[Normspeed]

Well, first warm weather here, I'd changed to a 180 thermostat for the winter, added a heater box that cuts down on engine compartment air circulation near the intake and exhaust manifolds. Sure enough, I started getting fuel percolating in the line near the front exhaust downtube. Park it while hot, come out later to a flooded engine and it reeks of raw gas. Shopped around for some header wrap, but ended up with some stuff from a local hot boat/speed shop. The stuff is called Fire Shield. You just slip it over the steel fuel line. Pretty easy if you have compression ferrule connections.

It's some kinda space age high tech stuff, seems pretty indestructible. Has a fiberglass matrix inside a rubberized insulating layer. It won't win any beauty contests but might help. I need to work on some heat shields too. And go back to the 160 stat. Gets pretty hot here in the summer.

[greg g]

Some one on the truck board discovered door insulation from the wood stove store works in the same fashion. While you are fooing around with the lines, I suggest you adjust you float level so that the float bowl doesn't fill all the way to factory spec. Setting it a bit lower give you some more room for expasion of the gas when its hot.

[Normspeed]

Thanks Greg. My floats are already set lower than normal, but I think I need to take 'em down another notch.

BTW, I found a little info about the product. Turns out it's not a fiberglass matrix, it's asbestos. I found that there's a little stretch built into the outer layer. If I were to do this over again I'd use longer pieces and cover the brass compression fittings as well as the steel lines. It would still be ugly though.

[bob westphal]

I have been using clothes pins clipped onto the fuel line for years with good results. Gets lots of smiles because it's an old trick that actually works. All the old timers know what it's about!

[1940Mopar]

are we talking about vapor lock or.... or heated gas. Or are the two one in the same. I'd like to anticipate any problems I may have with my new intake before it gets too hot here in Nashville, TN. Last year we had a bunch of days over 100 degrees with high humidity.

I Probably won't drive the car much when the temps are like that but maybe on a weekend for a quick run to a cruise in or something.

[Normspeed]

With mine, it's heated (boiling) gas. Currently the fuel line from the pump runs very close to the front exhaust downtube. Since I raised the operating temp 20 degrees with a thermostat change and added a heater box that restricts air circulation on the passenger side of the engine compartment, on a hot day, if I'm idling at something like a drive-thru, the car will start to surge and sputter, and it clears right up once I'm underway. If I park it hot and open the hood I can see bubbles coming up through the clear fuel filter above the pump like a percolater. I'll be going back to the 160 degree stat. Car is not overheating, just too much heat near the steel fuel line.

[1940Mopar]

Thanks for the info. That's is definitely something for me to think about when i route my fuel lines for my custom intake.

[Don Coatney]

I routed my fuel lines as pictured below. I have never had any vapor lock or boiling gas trouble

and I have driven my car on the hottest days where my engine temperature goes above

200 if sitting at a stop light or in a traffic jam. Although there is a heat shield in the pictures below

I never installed it in the car. I no longer have it as I sold it on the bay a couple years ago.

[Normspeed]

Yeah Don, my problem area is right near the pump. I took an outward turn and the line is within an inch or two of the downpipe. You can see the proximity way down there in the photo. I Shoulda looked more closely at your photos before I started bending lines, it was my first try at making up hard lines.

I could re do that line but I plan to convert to all flexible lines and a fuel block soon. I just need to get some thread repair done on the fuel block. One hole will be for the fuel pressure gauge.

Greg, I rechecked the rear carb float level, that's the one that floods. It was on the weak side of 7/32". Stock is I believe 5/32". The needle is nearly new and looks perfect under a magnifier. I'm getting tired of smelling gas after parking, so I gave 'er a good tweak, probably now more like 9 or 10/32. I'll give it a good test drive today to make sure that isn't too low.

Jeez, life would be so simple if only I had chosen another hobby, like collecting toy cars...

[stevenelle]

Referring back to Bob's post, what exactly do the closthspins do? Are you talking about regular wooden clothspens? Thanks.

[Normspeed]

I've seen the clothespin trick a few times too. The wooden ones. I guess they somehow draw off a bit of heat from the steel lines. You just clip them on the line here and there. People say they help with vapor lock.