Edelbrock Carbs and Ethanol

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TrailBeast

TrailBeast

AKA Mopars4us on Youtube
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I was talking with another member about an issue I have when it's hot out and he told me he has the exact same problem, and the same carb.
This is it.
Edelbrock 1506 600cfm runs and starts well all the time exept when it's hot out.
His car does not have the thermal gasket between the carb and manifold (But he has a hood scoop)
My car does not have a scoop but has the eddie thermal gasket.
So it seems to be a wash
(His gets more heat to the carb but has better ventilation and mine has no extra ventilation but has the thermal barrier)

This is what we found out about the problem from chking and searching websites like hotrodders.com as well as quite a few other sites.

Eddie carbs are more susceptible to heat for some reason than most other carbs, but more so with ethanol mixed fuels because ethanol boils at a lower temp than non ethanol gas. (Eddies are more prone to heating the fuel, and ethanol makes it worse)

If I pull into a store or whatever, and come back out in a half hour or so the car does not like to start normally and acts like it's a little flooded.
Once it does start it acts like it's flooding as if the float was stuck and I can smell raw fuel and have to keep my foot in it for about 60 seconds or so till it clears up and runs just fine again. (Revving it clears it up sooner)
What we decided was that the fuel inside the carb itself was trying to boil. (when new fuel was introduced to the carb bowls the problems cleared up) leading us to determin that the fuel that was actually inside the carb was the problem.

Next I started more research.
Why Edelbrock, why is fuel boiling when it's 90 degrees out?
That's when the answers started coming in.

One of the searches turned up a page in the Eddie manual that states "Methanol mixed fuels of 10% or more are not recommended in these carbs as the methanol will deteriorate the rubber parts and also corrode the metals. (I guess I missed that before this)
I guess I'll have to pay more attention to what the mixtures are at the satation.

This is directly copied from the manual:
Blended Fuels​
Typically, two types of blended fuels are available: Gasohol and Gasahol. Gasohol is a blend of not more than 10% ethanol and gasoline. As long as there is no more than 10% ethanol
mixed with the gasoline your carburetor will function properly. As the percentage of ethanol climbs above10%, a richer A/F ratio will be required. Also, because gasohol is more volatile than
gasoline, hard hot starting and poor hot weather driveability may result.
Gasahol can be a blend of either ethanol, methanol or other alcohol with gasoline. Methanol blended fuel should not be used in your Edelbrock Performer Series carburetor as it will cause
corrosion of the fuel system components. It can also cause rapid failure of seals, gaskets, diaphragms and pump plungers.​
Always check to see if you are using a blended fuel. Although the pump may not indicate the fuel is blended, it is always advisable to verify the type of fuel the station carries.
A little beside the point of this post but good to know, so now where do we go from here?


Ok then, now what do we do about the heat issue?

There is a company called Coolcarb and the website is www.coolcarb.com that sells a product that claims to solve this issue.
If you watch the first video on the page it does explain how the product works and they seem to prove it with a thermal gun.

Does anyone have realtime experience with this product?
It's about 50 bucks so I would like some real info from real users before I order one.
 
methanol and ethanol...methanol highly corosive...ethanol not highly corosive
 
There's also this style thats been around for years.... about $30
 

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70aarcuda said:
methanol and ethanol...methanol highly corosive...ethanol not highly corosive
Click to expand...

Exactly.

TrailBeast said:
I was talking with another member about an issue I have when it's hot out and he told me he has the exact same problem, and the same carb.
This is it.
Edelbrock 1506 600cfm runs and starts well all the time exept when it's hot out.
His car does not have the thermal gasket between the carb and manifold (But he has a hood scoop)
My car does not have a scoop but has the eddie thermal gasket.
So it seems to be a wash
(His gets more heat to the carb but has better ventilation and mine has no extra ventilation but has the thermal barrier)

This is what we found out about the problem from chking and searching websites like hotrodders.com as well as quite a few other sites.

Eddie carbs are more susceptible to heat for some reason than most other carbs, but more so with ethanol mixed fuels because ethanol boils at a lower temp than non ethanol gas. (Eddies are more prone to heating the fuel, and ethanol makes it worse)

If I pull into a store or whatever, and come back out in a half hour or so the car does not like to start normally and acts like it's a little flooded.
Once it does start it acts like it's flooding as if the float was stuck and I can smell raw fuel and have to keep my foot in it for about 60 seconds or so till it clears up and runs just fine again. (Revving it clears it up sooner)
What we decided was that the fuel inside the carb itself was trying to boil. (when new fuel was introduced to the carb bowls the problems cleared up) leading us to determin that the fuel that was actually inside the carb was the problem.

Next I started more research.
Why Edelbrock, why is fuel boiling when it's 90 degrees out?
That's when the answers started coming in.

One of the searches turned up a page in the Eddie manual that states "Methanol mixed fuels of 10% or more are not recommended in these carbs as the methanol will deteriorate the rubber parts and also corrode the metals. (I guess I missed that before this)
I guess I'll have to pay more attention to what the mixtures are at the satation.

This is directly copied from the manual:
Blended Fuels
Typically, two types of blended fuels are available: Gasohol and Gasahol. Gasohol is a blend of not more than 10% ethanol and gasoline. As long as there is no more than 10% ethanol
mixed with the gasoline your carburetor will function properly. As the percentage of ethanol climbs above10%, a richer A/F ratio will be required. Also, because gasohol is more volatile than
gasoline, hard hot starting and poor hot weather driveability may result.
Gasahol can be a blend of either ethanol, methanol or other alcohol with gasoline. Methanol blended fuel should not be used in your Edelbrock Performer Series carburetor as it will cause
corrosion of the fuel system components. It can also cause rapid failure of seals, gaskets, diaphragms and pump plungers.​

Always check to see if you are using a blended fuel. Although the pump may not indicate the fuel is blended, it is always advisable to verify the type of fuel the station carries.

A little beside the point of this post but good to know, so now where do we go from here?


Ok then, now what do we do about the heat issue?

There is a company called Coolcarb and the website is www.coolcarb.com that sells a product that claims to solve this issue.
If you watch the first video on the page it does explain how the product works and they seem to prove it with a thermal gun.

Does anyone have realtime experience with this product?
It's about 50 bucks so I would like some real info from real users before I order one.
Click to expand...
 
TrailBeast said:
Do you know if that is just a plain plate, or is it layered with something?
Click to expand...

You mean the one in the video link???? don't know anything about it, but if the engine's been sitting 20 minutes with the hood up, in a nice shaded cool shop, it's going to be cooler than the 180* or higher under your hood out on the street.

You can also just block off the exhaust X-over port in the intake manifold. That'll help immensely, but the engine won't run very well in cold weather because of no carb base heating.
 
I was asking about the one in the pic you posted.
The one I posted is a layered design with poly between two sheets of aluminum.
They showed in the video a pretty big difference in carb temp after the plate was installed.

I thought about blocking the crossover also, but don't really want to do the whole intake all over again.
 
TrailBeast said:
I was asking about the one in the pic you posted.
The one I posted is a layered design with poly between two sheets of aluminum.
They showed in the video a pretty big difference in carb temp after the plate was installed.

I thought about blocking the crossover also, but don't really want to do the whole intake all over again.
Click to expand...

i am curious as well, i might add that my crossover is already blocked off
 
A heat shield is definitely the next step. It may well solve the problem completely. Buy ready-made or make your own. Coat the underside of the plate with thermal-barrier coating. Also thoroughly insulate your pump-to-carb fuel line and make sure there's no heat transfer to it directly from the engine via heat-conducting steel clips and clamps, and retrofit a vapour return: It uses a 3-nipple fuel filter (Wix 33054 or NAPA Gold 3054, Purolator F20030); the 3rd is ¼" and has an 0.060" orifice to prevent bleeding off useful fuel pressure. You run a new vapour hose from that 3rd fitting all the way back to the fuel tank (usually easiest to add a nipple for it to the sender plate).
 
Good advIce Dan. I also had the Same problem and wrapped uP my fuel line as well as a thick gasket under the carb. No heat cross over.
 
TrailBeast said:
I was asking about the one in the pic you posted.
The one I posted is a layered design with poly between two sheets of aluminum.
They showed in the video a pretty big difference in carb temp after the plate was installed.

I thought about blocking the crossover also, but don't really want to do the whole intake all over again.
Click to expand...

The one I posted is a layed design as well...2 sheet-aluminum pieces interspersed with 3 gaskets, and a larger sheet of aluminum on top.

Someone also makes a 1" plywood spacer plate which would be a good heat insulator as well.
 
Ethanol is a problem. I have seen returnless EFI systems having problems here in the heat.

The Reid Vapor Pressure of gasoline was always the standard, and was adjusted for seasonal use - especially with carburetor equipped engines. RVP numbers are stated as "PSI" but they actually mean PSIA. They roughly compare to the measured vapor pressure at 100f

When the EPA mandated oxygenates, the oil companies chose MTBE. It does not adversely affect the vapor pressure when mixed with gasoline. It could be added at the refinery, and went through the extensive underground distribution system in the USA just fine.
But the corn ethanol industry wanted a piece of the action... And we got stuck with ethanol.

Ethanol jacks the RVP around. Rather than deal with the issue, the gasoline companies got a waiver from the EPA to let the RVP change from the requirements. Since ethanol would pick up water from underground piping systems, it can't be added at the refinery. So it is put in the gasoline with a less effective blending process near the point of use. Percentages are not as well controlled, this is why you see labels that say "up to10% Ethanol" on a pump.

Now, about the Edelbrock / Weber boiling fuel. Yes, it is somewhat more prone to on a hot soak. The carb body is well connected to the bowls, and has a short heat transfer path to the fuel. I run the Edelbrock #2732 steel plate that they tell you to use on Mopar applications with a standard gasket on both sides. It seems to work well here in the summer. I only have trouble on hot restart in a steep driveway at a friend's house. Obviously float level issues can make this carb much worse in the heat.

Holley carbs have a poor heat path to the bowls. The two gaskets on the metering blocks keep the fuel from picking up heat quickly on shutdown. They do eventually get just as hot as the engine, so the fuel can still boil, it just takes longer.

.
 
this is why after drive the dart and plan on driving soon i shut the electric pump off when i pull into the lot or the light before...
 
I thought about that too, but kind of a PIA.

And /6 Dan's solution while effective as it would be, I just aint into it THAT much. :D
Sorry Dan

So I'll ask again.
Does anyone have any experience with the Coolcarb insulators?



805moparkid said:
this is why after drive the dart and plan on driving soon i shut the electric pump off when i pull into the lot or the light before...
Click to expand...
 
TrailBeast said:
I thought about that too, but kind of a PIA.

And /6 Dan's solution while effective as it would be, I just aint into it THAT much. :D
Sorry Dan

So I'll ask again.
Does anyone have any experience with the Coolcarb insulators?
Click to expand...

i also run a 2" phenolic spacer...
 
Back in the day i always ran the shield 65val showed earlier. One consideration i haven't seen addressed as far as the heat issue is large low profile air cleaners that some use. Almost like putting a large metal heat soaking blanket over top the whole shootin' match.
 
I have an Air-Gap intake, and I run a fresh-air duct that feeds under the carb plenum. Sitting in traffic will still warm the carb but it's not in intimate contact with engine heat and slow-traffic speed moves enough air to keep it cooler.
 
I had the same issies untill I put a 1" phenolic spacer, that fixed my issues I have a 650cfm Edelbrock Thunder series on an Airgap, and I am wondering what the heat riser plays into this since there is not any provision for it (it's blocked off ) on my airgap. or are you tallking about the oem manifolds?? and as far as cold starting, I push my pedal to the floor once turn the key and mine started every 2 weeks all winter long up here in Green Bay and it gets REAL cold up here in winter. just my .02
 
we are running 2176 edelbrock performer intakes and 1406 carbs. i have my heat cross over blocked off with the intake gaskets. we are looking for someone who has tried the coolcarbs insulator and their results.
 
i bought the cool carb insulator pkg. last year at mopar nats , replaced the edelbrock insulator gasket no difference at all dont waste your money and the substance inbetween the metal plates has started oozing out !
 
cudarudy said:
i bought the cool carb insulator pkg. last year at mopar nats , replaced the edelbrock insulator gasket no difference at all dont waste your money and the substance inbetween the metal plates has started oozing out !
Click to expand...

I bought the coolcarb at the NATS last year but never installed it. It looked like a well made piece and the demo the guy gave was pretty convincing I guess.

I have a Carter 625 (EDEL 1406) on an aluminum Weiand intake. Last time I had the intake off, I blocked the heat crossover using SS sheet. That seemed to help. The fuel line is routed from the fender area and does not come up the front of the engine like the stock line. I have the MP cast aluminum air cleaner and it is right up against the hood with the spool mounts so I have zero room for a thicker insulator. The car definitely takes more cranking and fuel to start when it soaks for awhile, but it always starts.

But...over the last couple weeks when the temps were in the mid-90's, I was still cruising w/o any issues. Pretty sad when only about 10-20% of the normal cruise crowd stays home because of the hot weather. I always planned on running a return line to the tank with an electric pump or trying a ThermoQuad if it became worse. Gee, is it any wonder that it was Carter that developed the plastic carb body?
 
This is NOT what I wanted to hear.
Even the part about the filler material, because I wondered about how poly was going to stand up to the heat over time.

Guess I may have to muster all my materials knowledge at once and come up with something that works.
I told 73ABODEE that we may be the first to end up with our carbs and aircleaners on TOP of the hood.

I also planned on using the current Eddie insulator AND the Coolcarb plate.
I stll may, just to see how it does.
It happened again yesterday.
Went to the grocery store and came out a half hour later.
Hard starting and ran like **** for a couple of min. then cleared up.

cudarudy said:
i bought the cool carb insulator pkg. last year at mopar nats , replaced the edelbrock insulator gasket no difference at all dont waste your money and the substance inbetween the metal plates has started oozing out !
Click to expand...
 
That sounds good, but the "Inspect and replace often" sucks.
I might try the pheonolic though.
 
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