Guess who's back!?! Atl-atl's K5 Blazer + Four Wheel Camper "The Crawlin Cabin" documentation thread!
- Thread starter Atl-atl
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nitro_rat
Lunchbox Lockers
Nice job on the hard line for the carb! If you continue to have an issue with vapor lock you could wrap it with an insulated sleeve like this one:
They're usually commonly available at auto parts stores where the Chinese chrome valve covers and fuzzy dice are.
Also insulate anywhere along the frame that the exhaust is close to the fuel line. A heat shield on the exhaust pipe is another way to skin that cat.
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They're usually commonly available at auto parts stores where the Chinese chrome valve covers and fuzzy dice are.
Also insulate anywhere along the frame that the exhaust is close to the fuel line. A heat shield on the exhaust pipe is another way to skin that cat.
nitro_rat
Lunchbox Lockers
The reason for the vapor lock is that the fuel is actually boiling (reaching its vapor point) inside the fuel line or in the carburetor itself. The action of the mechanical fuel pump actually exacerbates the situation as it "sucks" the fuel from the tank.
It's common knowledge that the pressure cap on your radiator raises the boiling point of the water in the cooling system and gelps prevent steam pockets from forming in the engine block and heads. The same applies to your fuel system!
The mechanical fuel pump puts a vacuum on the fuel line coming from the tank which lowers the boiling point of the fuel. The mechanical pump can't suck vapor, so in many cases when the engine is stalling due to vapor lock, the vapor is in the line between the tank and the pump.
An electric pump mounted near the tank is fed by siphon and all of the column of fuel between it and the needle and seat in the carb is under pressure. This pressure raises the vapor point of the fuel and in most cases cures the vapor lock entirely.
At some point Chevy went to a return line mounted on the mechanical fuel pump. It is normally effective as it keeps the fuel in circulation even when the demand from the carb is low. This solution is nearly as good as the bypass filter that Tony talked about in the video I linked earlier because the vapor problem is usually in the line between the tank and the pump.
Even with a mechanical pump, the fuel between the pump and the needle and seat is under pressure and less prone to vapor lock as long as the supply to the pump itself is vapor free!
The last issue that can rear its head in the vaopr lock equation is the fuel vaporizing in the carb body itself. This is the reason that Carter came out with the Thermoquad with its phenolic float bowl section. There are a variety of heat shields and phenolic spacers that are available to mount between your intake manifold and the carb to help resolve this issue.
Sorry for the long post but I think that it gives enough background on the causes of vapor lock that you can figure out your own solution for your application if it continues to occur after the repairs you just made!
It's common knowledge that the pressure cap on your radiator raises the boiling point of the water in the cooling system and gelps prevent steam pockets from forming in the engine block and heads. The same applies to your fuel system!
The mechanical fuel pump puts a vacuum on the fuel line coming from the tank which lowers the boiling point of the fuel. The mechanical pump can't suck vapor, so in many cases when the engine is stalling due to vapor lock, the vapor is in the line between the tank and the pump.
An electric pump mounted near the tank is fed by siphon and all of the column of fuel between it and the needle and seat in the carb is under pressure. This pressure raises the vapor point of the fuel and in most cases cures the vapor lock entirely.
At some point Chevy went to a return line mounted on the mechanical fuel pump. It is normally effective as it keeps the fuel in circulation even when the demand from the carb is low. This solution is nearly as good as the bypass filter that Tony talked about in the video I linked earlier because the vapor problem is usually in the line between the tank and the pump.
Even with a mechanical pump, the fuel between the pump and the needle and seat is under pressure and less prone to vapor lock as long as the supply to the pump itself is vapor free!
The last issue that can rear its head in the vaopr lock equation is the fuel vaporizing in the carb body itself. This is the reason that Carter came out with the Thermoquad with its phenolic float bowl section. There are a variety of heat shields and phenolic spacers that are available to mount between your intake manifold and the carb to help resolve this issue.
Sorry for the long post but I think that it gives enough background on the causes of vapor lock that you can figure out your own solution for your application if it continues to occur after the repairs you just made!
Buddha.
Finally in expo white.
I'm getting flashbacks. A friend of mine had a '85 blazer with that rear mounted gas tank. There had been a custom made skid plate for it that got packed full of mud and rotted out the tank. That was the biggest pita to change. Had to drop the skid plate, the receiver hitch, and then finally the tank. Every bolt was seized and snapped. I didn't like that truck at all. It was nice shiny paint over tons of bondo, the rear hatch took three guys to close because the rear quarter panels (bedsides?) would flex like crazy. It was lifted 6" on 35's. It was odd being that high off the ground in a truck with that short of a wheelbase.
nitro_rat
Lunchbox Lockers
There was a factory skid for the blazer tank. Same skid for 25 and 35 gallon tank. If you had the big tank it fit tight to the skid. If you had the 25 gallon tank the skid hung down below the tank and was prone to packing with mud in that area!
A friend of mine had a K5 that was 6" suspension and 3" body on 38.5's. It wasn't nearly as sketchy as another friend's short bed K-10 with 12" suspension, 3" body and 44's! He eventually rolled that one...
A friend of mine had a K5 that was 6" suspension and 3" body on 38.5's. It wasn't nearly as sketchy as another friend's short bed K-10 with 12" suspension, 3" body and 44's! He eventually rolled that one...
zoomad75
K5 Camper guy
I've got the skid for the fuel tank to install on mine. It's a heavy chunk. However it really only prevents punctures to the tank. On my old '75 I actually got hung up on the fuel tank skid. Rear wheels hanging in the air total stuck. The skid supported the entire weight of the truck, but naturally it did bend some and cave in the tank a little. I used to be able to put 30 gallons in it with the gauge at or below "E", after the most I could force in was 27 gallons.
That was due to me trying to navigate a boulder field with a truck that had no business going into it. The peace of mind you get from the protection point of view is worth it even if you don't plan to do anything stupid like I did.
That was due to me trying to navigate a boulder field with a truck that had no business going into it. The peace of mind you get from the protection point of view is worth it even if you don't plan to do anything stupid like I did.
Hillbilly Heaven
Explorer
Here in South Carolina a plate like that is only for limited use vehicles. I live in a rather small community and if I was spotted passing thru town several days in a row, it would be questioned. Not any 1979 Fullsize Broncos roaming the streets around here.
zoomad75
K5 Camper guy
The curtains came out great. I'd get to tinting the camper windows pronto if you want them to stay looking like that. My sisters made me some out of red/black plaid like the Woolrich models get now and the sun over the last year has started to bleach them. You get just as much sun down there in AZ as we do here in Southern CO so it's only a matter of time. I just tinted mine finally a couple of weeks ago. I may do it again because I went with 35% and should have gone 15-25% at least.
Buddha.
Finally in expo white.
Did you give any though to using a gas heater instead of a propane furnace?
expeditionportal.com
$200 5KW Portable Diesel Air Heater
( E-cigarette above, unit not smoking :ylsmoke: ) ( Hot air out is metal flange ) ---- Parts $200 eBay 5kw diesel air heater $38 Dewalt DS300 tool box $7 Spectre 8148 3" duct mounting plate (for the cool side) $15 Spectre 81413 3" maf sensor plate (metal, for the hot side) $0 Metal plate...
expeditionportal.com
nitro_rat
Lunchbox Lockers
Nice progress! Make a round plastic or stainless ring to trim out around the faucet and it will probably be good enough to delay the countertop replacement!
Zoomad75 has some good info on replacing the rotten structure. I would definitely be looking for a donor fiberglass top to kill for the front flange!
Zoomad75 has some good info on replacing the rotten structure. I would definitely be looking for a donor fiberglass top to kill for the front flange!
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