Carb Heat Soak

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Maybe it's so cal gas or Colorado gas but I have never had the problem.
 
S'cuder said:
In 50 years I never had it happen until last summer. Hot day, AC on, when I shut the engine off it sounded like popcorn popping under the hood. Lousy gas is certainly a contributor. A Edelbrock insulator gasket was available at the local AutoZone. That seems to have quick fixed it, but a comprehensive solution would also include blocking manifold heat and installing a vapor return.
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Will a Vapor Return cause a Loss of Fuel Pressure to the Carb from a Mechanical Pump?
 
eekvonzipper said:
Will a Vapor Return cause a Loss of Fuel Pressure to the Carb from a Mechanical Pump?
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If it's too big it can. I've read about folks putting restrictors in the return line to keep the pressure from falling too much.
 
S'cuder said:
If it's too big it can. I've read about folks putting restrictors in the return line to keep the pressure from falling too much.
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He said vapor return, not fuel return. Vapor return cannot cause a drop in fuel pressure. All it does is vent the float bowl. Now a solid fuel return is a different story. But properly set up using the fuel pressure regulator as the return orifice, the pressure won't drop, as long as there's enough pump for it. In my case though, there's not an HP mechanical pump for the slant 6 that I know of, so if I run a good return system, I'll have to go electric......which I despise. lol
 
I'm in Manitoba Canada at about the 50th parallel, at ~930ft elevation, and the hottest days of summer here, rarely get past the mid-90s, but most days in July, are in the mid- Eighties.
>My engine has been running just fine on 87E10, since 1999.
Ok sure, after a week of sitting, the leaky front pump has partially drained the front bowl. Sometimes I prefil the front bowl, and Sometimes I get lazy and just stomp the double-pumper a couple of times.
>After she's warm, on any restart, she'll usually fire up on the first revolution, often on the first or second cylinder that comes up.
Well, to be honest,
>I have a couple of secret weapons, namely; 180psi plus CCP, a 750DP on an AirGap, fresh cool air from above the hood, a well-synced transfer slot, and a shady North-side carport, that stays relatively cool.
>The thing is this; fresh 87E10 begs to lite off. At 80*F, the VOCS are anxious for a spark. After a week in a vented fuel tank..... not so much..... unless it's been "stabil"-ized, lol.
I've been running that cheap skunk-pee since 1999, and everything on my yard has been tuned to run on it, cuz it's the only gas sold in my town.

>Op is in Florida; what's the elevation there?, and how hot does it get ?
Wiki says the highest point is 345ft and and the summer temps are maybe a tad higher there as here, namely upper 80s. Thus my engine would be right at home in Florida.

I understand that some of you guys have trouble with percolation down there; I get it.
And I get that the gas companies have reformulated their fuels for EFI closed systems, which can create starting issues for carbed engines; I get that too.
What I don't get, is your aversion towards alcoholized gas, when it clearly is a winning recipe, when you work within it's limits. Sooner or later it's gonna be all you can get, so you might as well tune for it now.
 
AJ/FormS said:
I'm in Manitoba Canada at about the 50th parallel, at ~930ft elevation, and the hottest days of summer here, rarely get past the mid-90s, but most days in July, are in the mid- Eighties.
>My engine has been running just fine on 87E10, since 1999.
Ok sure, after a week of sitting, the leaky front pump has partially drained the front bowl. Sometimes I prefil the front bowl, and Sometimes I get lazy and just stomp the double-pumper a couple of times.
>After she's warm, on any restart, she'll usually fire up on the first revolution, often on the first or second cylinder that comes up.
Well, to be honest,
>I have a couple of secret weapons, namely; 180psi plus CCP, a 750DP on an AirGap, fresh cool air from above the hood, a well-synced transfer slot, and a shady North-side carport, that stays relatively cool.
>The thing is this; fresh 87E10 begs to lite off. At 80*F, the VOCS are anxious for a spark. After a week in a vented fuel tank..... not so much..... unless it's been "stabil"-ized, lol.
I've been running that cheap skunk-pee since 1999, and everything on my yard has been tuned to run on it, cuz it's the only gas sold in my town.

>Op is in Florida; what's the elevation there?, and how hot does it get ?
Wiki says the highest point is 345ft and and the summer temps are maybe a tad higher there as here, namely upper 80s. Thus my engine would be right at home in Florida.

I understand that some of you guys have trouble with percolation down there; I get it.
And I get that the gas companies have reformulated their fuels for EFI closed systems, which can create starting issues for carbed engines; I get that too.
What I don't get, is your aversion towards alcoholized gas, when it clearly is a winning recipe, when you work within it's limits. Sooner or later it's gonna be all you can get, so you might as well tune for it now.
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But this ain't about "you" and "your engine". Let that sink in.
 
RustyRatRod said:
You "think" you run non ethanol. I've done some testing on it around here and there's still some in it.
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I watched a video recently where a lady showed how many gas pumps use the same pump lines for the filler hose. If a guy fills his car with regular ethanol 87 and another guy comes after him and fills his 1 gallon gas can with non-ethanol 91; he will likely get 1/2 to 3/4 gallon of the E87 because the lines are still full of the old stuff. Only pumps with dedicated nozzle for non-ethanol would be exempt from this. Was an enlightening video.
 
Dana67Dart said:
Then pedal to the floor and crank.

I have never in 30 years of driving carborated cars had that problem.

How did our parents ever drive these cars daily 50 years ago. It must have been miserable :poke:

:rofl:
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Wast the same fuel. Things change.
 
Rat Bastid said:
I think you can buy small kits to test it or you buy a hygrometer and use that.

It’s a PITA to do it at the station. Easier to do at home.
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A hygrometer measures moisture in the air. I could see Rusty using that to test. :poke: :lol: Hydrometer may be?
 
AJ/FormS said:
What I don't get, is your aversion towards alcoholized gas, when it clearly is a winning recipe, when you work within it's limits. Sooner or later it's gonna be all you can get, so you might as well tune for it now.
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It depends where you live. Filling stations selling E-0 are all around me here on the southern shore of Lake Ontario. There are more now than anytime in the last 15+ years, with more stations taking it on all the time. Many have dedicated systems with separate tanks, plumbing, pumps and hoses. Before this, I used Stabil Marine.

It's a fact that ethanol gas can make a mess out of a carburetor. It's happened to me on outdoor power equipment and it ruined beyond repair a rare carb on my brother in law's Corvette. So if there are alternatives, why mess with it?
 
toolmanmike said:
How do you test it?
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Pour some in a glass and let it sit a day or so. Anything "not" gas will separate. Ethanol is lighter than gas and ends up at the top. You can really smell it when it separates. Based on what I've seen in a glass like that, I'd estimate probably 2 or 3% in the supposed "non" ethanol gas around here. I know it's not scientific, but that's the only way "I" can do it.
 
toolmanmike said:
A hygrometer measures moisture in the air. I could see Rusty using that to test. :poke: :lol: Hydrometer may be?
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You can do that. You can also use an old optical anti freeze tester. When was the last time you saw one of those?
 
Ricks70Duster340 said:
I watched a video recently where a lady showed how many gas pumps use the same pump lines for the filler hose. If a guy fills his car with regular ethanol 87 and another guy comes after him and fills his 1 gallon gas can with non-ethanol 91; he will likely get 1/2 to 3/4 gallon of the E87 because the lines are still full of the old stuff. Only pumps with dedicated nozzle for non-ethanol would be exempt from this. Was an enlightening video.
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That's a big problem too! We're gettin fleeced, there's no doubt about it!
 
Here's the thing though. Ethanol ain't your enemy really. As long as you actually DRIVE your cars and don't let them just sit like a dang old man ethanol is arguably a good thing. It has less resistance to detonation, because it has better octane qualities. I use 93 super with ethanol in Vixen and she likes it. Since we drive her literally all the time, I don't worry about it. I'm gettin ready to put her down to finally do the transmission and rear end swap before too much longer and I'll probably add some sta-bil to the tank then. But all in all ethanol ain't your enemy.
 
www.delphiautoparts.com

How to test the alcohol content of gasoline

Here’s a safe, fast and easy way to check the alcohol content of gasoline using a graduated cylinder.
www.delphiautoparts.com

I have a few hydrometers and a couple refractometers. I need to do some testing I see.
 
@Dana67Dart I've had minor issues with gas percolating in my carbs here in northern CO, not enough of a big deal to warrant paying extra for ethanol-free gas but it's still there. I run a phenolic-body Street Demon on the 360 in my Duster with a 1/2" wood-fiber spacer and it still gives slight symptoms of fuel evaporating and the vapors collecting in the carb venturis/intake plenum (have to hold the throttle open a tad and crank for a few seconds before it'll fire on warm starts). I still usually pop my hood partially open once I park and my engine is fully warmed up to let the heat flow out of the engine bay instead of just collecting around the carb. Same goes for the Edelbrock 1406 on the 360 in my truck. The Duster's engine has Edelbrock heads so no exhaust crossover to speak of but I rarely miss it unless I try to drive the car in 20-degree or lower weather which is rare. The D200 has a regular Performer intake on factory iron heads but I blocked off the exhaust crossover on that. I've thought about installing a factory dual-snorkel air cleaner with a functional heat riser and warm-air intake tube on the truck as it can be a bit finicky the first few minutes in cold weather but I'm about to move to Georgia where it rarely gets below 60 degrees in the coldest months.

Exhaust crossover IMO just shouldn't be used with aluminum intake manifolds in about 90% of cases. They just get way too hot too quickly (speaking from experience). Warm air induction with some type of valve to switch to "cold" (non-heated) air when fully warmed up is much more effective. Since aluminum transfers heat much faster than cast iron an aluminum intake manifold gets warmed up to the same temp as the rest of the engine after 5-10 minutes of run time especially if it's a non-Air Gap type which I generally don't run anymore on street-going vehicles if I can.

I think after I move I will be upgrading the fuel system on the Duster to have a fuel return line with pressure regulator and an electric pump as I have a feeling once I jet up to compensate for the lower altitude the increased fuel demand will be too much for the current setup which is basically factory 5/16" line with stock-type mechanical fuel pump dead-headed to the carb with no regulator.
 
Interesting.

My car was a So Cal car, no issues there then I brought it to FC and I figured I should lean it a bit at 5000 ft.

It ran like crap, ended up with a lean misfire. Put the stock jets back in and no issues here at elevation.

I don't run any spacers between carb and cast iron intake, the crossover is intact but the manifold valve is not functional so it is open to flow out vs crossover.

I have not had any trouble starting or restarting my car here. I even drove it when it was -10 late last year. Ran like a champ. Restarted fine.


When it's in the high 90s starts and restarts fine as well. I have the OEM called for thermostat, standard not high flow, and the rad is a HO / AC but the standard cooling rad worked the same.

I don't pay too much attention to the temp, as long as it's between normal and not too high I'm good.


I did switch to alcohol free gas after battling a stall issue on hot days with a hot engine. But not starting or restarting related. I Have not had the issue again.
 
Rat Bastid said:
LOL…when I bought my hydrometer I’m pretty sure it said you can’t use the ones for drinking alcohol on non drinking alcohol…just sayin…don’t mix up your fuel and your booze.
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It's all ethanol. :thumbsup: :rofl:
 
Installing the heat insulator gasket this week to see if it helps. Another question for everyone, has anyone ever wrapped their fuel lines in the engine with heat insulator? Does it help? I want to exhaust all easy routes before doing a vapor return line if all else fails.
 
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