1? 2? 4?

Ken B · Jan 3, 2022

I have the ravajet 2 setup on my 6.

SirRobyn0 · Jan 3, 2022

Ellie Niner said:
Yeah. I've seen those EFE heaters in some parts lists, and my only takeaway was that they look like they might restrict airflow quite a bit... I wonder if those were used in all applications, as it seems like it would be easier to just route an exhaust passage under the intake manifold on something like a 2.8 V6, and operate it in a conventional fashion. The EFE setup on my 1986 uses a Thermal Vacuum Switch on the thermostat housing which operates a vacuum motor on the heat riser valve, instead of the old school bimetallic spring. FWIW- It still works great. The EFE setup on my 1975 GMC back in Montana went away when we put headers on it many years ago, and yep... It could be pretty miserable for a few miles after a cold start.

But yeah... I just looked at some prices, and those electric EFE heaters are pretty damn expensive.

My 84 Celebrity with the carb'ed 2.8L had an EFE heater, I did have to replace it once. I think the preferred thing about the EFE heater was that the computer could control it better than even a vacuum operated heat riser and it may have heated faster than even a thermac could. I wonder if a EFE heater could be adapted to help folks with cold weather drivability issues on carb'ed vortec's?

AuroraGirl · Jan 3, 2022

SirRobyn0 said:
My 84 Celebrity with the carb'ed 2.8L had an EFE heater, I did have to replace it once. I think the preferred thing about the EFE heater was that the computer could control it better than even a vacuum operated heat riser and it may have heated faster than even a thermac could. I wonder if a EFE heater could be adapted to help folks with cold weather drivability issues on carb'ed vortec's?

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I heard on a forum that if you can control it right, it would, helps get the temp of the intake there for air atomizing to where it should be. but without a diagnostic system like newer vehicles, it not working would not be obvious till it ***** you

SirRobyn0 · Jan 3, 2022

AuroraGirl said:
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I heard on a forum that if you can control it right, it would, helps get the temp of the intake there for air atomizing to where it should be. but without a diagnostic system like newer vehicles, it not working would not be obvious till it ***** you

Well there are two maybe three ways I can think to hook this up on a non-computerized carbureted. #1. To a coolant switch via relay so once the engine is warmed up the EFE turns off. #2. To an air intake temp switch so if the air intake temp is below a certain temp it comes on. #3. Hooked to coolant temp switch so it normally runs when the engine is cold + an air intake switch so it'll also stay on for the duration if the air temp is low, and if you wanted a manual override switch to keep it on.

Dang I wonder what a guy like @77 K20 would think about this idea.

AuroraGirl · Jan 3, 2022

SirRobyn0 said:
Well there are two maybe three ways I can think to hook this up on a non-computerized carbureted. #1. To a coolant switch via relay so once the engine is warmed up the EFE turns off. #2. To an air intake temp switch so if the air intake temp is below a certain temp it comes on. #3. Hooked to coolant temp switch so it normally runs when the engine is cold + an air intake switch so it'll also stay on for the duration if the air temp is low, and if you wanted a manual override switch to keep it on.

Dang I wonder what a guy like @77 K20 would think about this idea.

I think once I get back to a qjet on my square I will be trying to use or setup the EFE heater and also use a Thermac. I dont think i will be using the old exhaust mounted butterfly system tho.
I may also put back on an old cast manifold because 1) my broken intake bolts will be easier to back out and fix the threads and use new bolts 2) I could check what I did for my intake gaskets. I found out after a long time that its common to put plates on the heat crossovers from the intake gasket kits and I dont recall metal plates so I may have too much or too little heat depending on if they were on the gaskets, 3) I could paint one of my cast manifolds while its off

4) fix small coolant leak from the broken bolt heads

But since I want to use the truck for plowing duty, an EFE heater and thermac should help low speed and low temp low throttle use use

Ellie Niner · Jan 4, 2022

Something else just crossed my mind regarding blocking off the exhaust passage through the intake... If you're running one of the old school divorced automatic chokes with the bimetallic spring mounted atop the intake, it will also cease functioning worth a sh¡t if you disable the heat riser. Another problem I've encountered occasionally is the intake exhaust crossover getting completely blocked with crap... usually on engines that are tired and burn oil. Didn't the trucks switch to an electric choke around 1979?

The Thermac system on my 1986 isn't working right now, as I haven't gotten around to replacing the dead thermostat in the air cleaner. I think the main purpose of that system is to prevent carburetor icing in cold weather, though it probably plays a small part with emissions too. Had an old Datsun pickup that was missing the foil hose between the exhaust manifold and air cleaner, and the primary venturi would freeze up on it any time the temperature was around 40 degrees and the humidity was high. Would have to sit on the side of the road and let everything heat soak for about 5 minutes whenever it happened, so I fixed it pretty quickly. Have only had that happen maybe once on my '86, but it's still on my list of things to do.

AuroraGirl said:
you by chance know any Monsanskys out in montana? My gpa is from there and he brought with him, to wisconsin, his 75 GMC and thats the one that now sits in my dads driveway with a hole in the TH350

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I don't. What part of the state do they live in?

AuroraGirl · Jan 4, 2022

Ellie Niner said:
Something else just crossed my mind regarding blocking off the exhaust passage through the intake... If you're running one of the old school divorced automatic chokes with the bimetallic spring mounted atop the intake, it will also cease functioning worth a sh¡t if you disable the heat riser. Another problem I've encountered occasionally is the intake exhaust crossover getting completely blocked with crap... usually on engines that are tired and burn oil. Didn't the trucks switch to an electric choke around 1979?

The Thermac system on my 1986 isn't working right now, as I haven't gotten around to replacing the dead thermostat in the air cleaner. I think the main purpose of that system is to prevent carburetor icing in cold weather, though it probably plays a small part with emissions too. Had an old Datsun pickup that was missing the foil hose between the exhaust manifold and air cleaner, and the primary venturi would freeze up on it any time the temperature was around 40 degrees and the humidity was high. Would have to sit on the side of the road and let everything heat soak for about 5 minutes whenever it happened, so I fixed it pretty quickly. Have only had that happen maybe once on my '86, but it's still on my list of things to do.

I don't. What part of the state do they live in?

im not sure, his family like daughter and son still live there but Ive never met them. hes been here in wisconsin since the 90s. Just fancy collision of you saying montana and 75 square which just happens to be a relevant 2 pronged thing in my life lol

SirRobyn0 · Jan 4, 2022

Ellie Niner said:
Something else just crossed my mind regarding blocking off the exhaust passage through the intake... If you're running one of the old school divorced automatic chokes with the bimetallic spring mounted atop the intake, it will also cease functioning worth a sh¡t if you disable the heat riser. Another problem I've encountered occasionally is the intake exhaust crossover getting completely blocked with crap... usually on engines that are tired and burn oil. Didn't the trucks switch to an electric choke around 1979?

The Thermac system on my 1986 isn't working right now, as I haven't gotten around to replacing the dead thermostat in the air cleaner. I think the main purpose of that system is to prevent carburetor icing in cold weather, though it probably plays a small part with emissions too. Had an old Datsun pickup that was missing the foil hose between the exhaust manifold and air cleaner, and the primary venturi would freeze up on it any time the temperature was around 40 degrees and the humidity was high. Would have to sit on the side of the road and let everything heat soak for about 5 minutes whenever it happened, so I fixed it pretty quickly. Have only had that happen maybe once on my '86, but it's still on my list of things to do.

I don't. What part of the state do they live in?

I had a 1977 Class C motorhome on a the Dodge Chassis that had a terrible time with percolation and vapor lock. I installed on of those fuel filters with the built in return line and ran a return to the tank as it did not have a factory return and I blocked off the intake crossover as well. It was a divorced choke Holley 2 barrel, I could not come up with an electric choke setup without changing carbs so I ended up going with a manual choke, however having the crossover blocked did effect cold drivability in cooler weather for sure. That is my only experience with a blocked off crossover. I did have a working thermac, so it seemed like once that kicked heat in it was ok.

On the freeze up note, I once had a 77 Toyota pickup with the 20R and weber 32/36, in below freezing temps the carb would ice up and it would run ruff, I never had it stalled and basically just lived with it.

mikeoverland · Jan 4, 2022

auroragirl is correct. pictures would make things a ton easier. ask and ye shal receive so:

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these are the carb while still on the intake manifold but WHT are the next two pictures? the intake IS a 2bbl and this carb fits on the intake without that metal? piece.

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i fugured out where the air leak was coming from the first base plate gasket is hashed! since the carb is off of the manifold and looks like death warmed over i'm either going to rebuild it or replace it (leaning towards replace since all of the vacuume pots are sketchy the float is sketchy and it ould be less money to get a new one than it would be to fix this paperweight)

mikeoverland · Jan 4, 2022

amost forgot...... while removing the carb those vacuume check valves "accidentally" fell off. I also find it funny that the carb has isc motor on it considering that the vehicle doesn't have ac. i don't think that the isc has ever been hooked up and it's fried to begin with so........ weight reduction........ (expertly filed)

mike

SirRobyn0 · Jan 4, 2022

@mikeoverland That's all stock. That's a Rochester 2SE carb, and that sheet metal thing is a heat shield, because the exhaust manifold is below the intake. They wanted some heat to get into the intake manifold to help fuel vaporization but to much in the carb will boil the gas and is hard on all the rubber lines. So all that stuff looks factory to me. Those are actually really good carbs, and I'd suggest rebuilding it would be worthwhile.

mikeoverland · Jan 4, 2022

SirRobyn0 said:
@mikeoverland That's all stock. That's a Rochester 2SE carb, and that sheet metal thing is a heat shield, because the exhaust manifold is below the intake. They wanted some heat to get into the intake manifold to help fuel vaporization but to much in the carb will boil the gas and is hard on all the rubber lines. So all that stuff looks factory to me. Those are actually really good carbs, and I'd suggest rebuilding it would be worthwhile.

heat shield..... that makes a ton of sense! thanks for the info and i'll see if i can find a rebuild kit and float.

Turbo4whl · Jan 4, 2022

mikeoverland said:
auroragirl is correct. pictures would make things a ton easier. ask and ye shal receive so:
You must be registered for see images attach

You must be registered for see images attach

these are the carb while still on the intake manifold but WHT are the next two pictures? the intake IS a 2bbl and this carb fits on the intake without that metal? piece.

You must be registered for see images attach

You must be registered for see images attach

i fugured out where the air leak was coming from the first base plate gasket is hashed! since the carb is off of the manifold and looks like death warmed over i'm either going to rebuild it or replace it (leaning towards replace since all of the vacuume pots are sketchy the float is sketchy and it ould be less money to get a new one than it would be to fix this paperweight)

Yes, as Sir Robyn stated, all looks stock

1? 2? 4?

Ken B

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SirRobyn0

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AuroraGirl

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SirRobyn0

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AuroraGirl

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Ellie Niner

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AuroraGirl

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SirRobyn0

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mikeoverland

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