Gas Tank Insulation

[Carl Stouffer]

I touched on this a little in a previous thread concerning vapor lock and boiling gas, but I would like to hear opinions and actual experience on this
subject.

I have taken down the insulated sheet metal panels off of the bottom of my tanks in order to change out some hoses and to clean up a mess that the
Pack Rats made under there, and I'm debating whether to patch up the insulation and re-install them, or leave them off.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member

 

[MikeB]

Hey Carl
I don’t have any experience with this but I’m in the middle of dropping my tanks. My guess is the heat comes from the street, exhaust, two
in-tank pumps and return line. I think what I’m going to do is use Lizard Skin on the bottom of my tanks. I have sheet metal pieces next to
exhaust pipe where it runs by the tanks and one in front of the forward tank. The PO installed them. They look like the ones sold by Applied. I’ll
be spraying Lizard skin on the tank side of those heat shields. . I’m hoping leaving the top of the tank bare will allow heat to escape.

Not sure how much this will help but since I have them down anyway... I’m also not sure how well the LS will hold up but I’ll surely find out.
--
M Beam
75’ Avion
TBI EBL , 3.70 LSD and other stuff
Zuki Sidekick,
Dozier Al

 

[lw8000]

After having lots of vapor lock issues myself I thought about doing this but did not get around to taking on such a project. I can't remember the
name of the person that did the study that I found a couple years back, but it was extensive and he concluded that it did help prevent vapor lock and
also helped the tanks from building up excessive pressure. I thought Jim Bounds did the Lizard Skin test and concluded that it didn't help much.
Just passing along what I remember reading.

Chris
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan

 

[jim kanomata1]

I understand the draw back of insulating the tank, but the heat that it
faces from the hot pavement is tremendous at slow speeds.
What I try to do is to top off the tank when I fill up and also park where
it has some shade as I fill up. Never go less tha half full on hot days.
Exhaust shields by the tank was installed on later models at the factory.

> Hey Carl
> I don’t have any experience with this but I’m in the middle of dropping my
> tanks. My guess is the heat comes from the street, exhaust, two
> in-tank pumps and return line. I think what I’m going to do is use Lizard
> Skin on the bottom of my tanks. I have sheet metal pieces next to
> exhaust pipe where it runs by the tanks and one in front of the forward
> tank. The PO installed them. They look like the ones sold by Applied. I’ll
> be spraying Lizard skin on the tank side of those heat shields. . I’m
> hoping leaving the top of the tank bare will allow heat to escape.
>
> Not sure how much this will help but since I have them down anyway... I’m
> also not sure how well the LS will hold up but I’ll surely find out.
> --
> M Beam
> 75’ Avion
> TBI EBL , 3.70 LSD and other stuff
> Zuki Sidekick,
> Dozier Al
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[Carl Stouffer]

Good advice on running off the top of the tanks. I generally allow them to get down to 10 - 15 gallons before I fill up. I will try to make that
more like 1/2 a tank during hot weather.

So, here's what I decided to do:

I eliminated two restrictions in my gas hoses (removed a redundant in line filter and a splice in the other hose).

I patched up the insulation that was damaged by the pack rat (2300 degree fireplace insulation blanket), and painted the bottoms of the sheet metal
shields white, and I am re-installing them.

Hopefully some of that will give me the results I am looking for.

My Carter 4070 pump is only three years old and has about 20,000 miles on it. If I still have issues, I will assume it has weakened somewhat, and
replace it. I do replace fuel filters on a regular basis and they always seem to be very clean and restriction free. The tank selector valve was
replaced at the same time as the Carter was installed, and the gas lines relocated to the outside of the frame.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member