When we bought our C3 it came with this carb, I had some friends with them and I heard great reviews. After having the engine rebuilt I put the old cab back on and had nothing but trouble when the car gets hot, after driving a while and especially if it is extremely hot out. So I bought a brand new 1406 last spring and ran it most of the year with similar issues with the heat, but not nearly as bad. This year though has been a nightmare and we are just out of the gate.

Last year I had a hard fuel line fabricated so the rubber fuel line wasn't touching the engine. I thought I was boiling the fuel before it got to the carb. That didn't cure the issue. Last week it was an extreme heat wave here and while driving the vette it just bogged down and died mid drive.

Edlebrock suggests a laminated wood spacer, I believe I have the room. We are using the performer 2102 intake and I believe I have an inch clearance. the spacer is 1/2". The tech at Edlebrock says I am percolating the fuel because of the heat.

The car starts fine cold and runs flawless in cooler temps, Higher temps it has starting issues and can stall sometimes at red lights.

Has anyone had this issue and used the recommended spacer?

 

The fuel probably isn't what it used to be. Alcohol has been added and whom knows what else. I would agree intake manifold heat needs to be reduced if you want that carb to run right on today's gas.

If you block the intake manifold heat riser passage it should help. You will need to wire the exhaust flapper in the open position and it might take a few more minutes to warm up but no biggie. Add a thin piece of stainless steel sheet metal between the center intake bolts. Do it on the side away from the choke stove if you still use it. This will prevent hot exhaust gas from flowing thru the intake manifold under the carb base.

 

This is what I did and actually took it all off this spring to put on the original intake and tried 3 carbs until I went back to it. What is your motor status (stock, slightly above, mild cam, hot cam.....?) What is your heads and exhaust setup.


with the Edelbrock 600 1406 with the 1405 jetting (but am now into a 750)

I installed a low pressure fuel pressure regulator to keep the pressure down to 4 psi

I installed an Performer Air Gap intake which worked great with the stock LT1 heads and hooker comp headers and 2 inch pipes. Wanting a RPM now for this motor with the edelbrock 750 electric choke, World Product heads, McJack headers and 2.5 sweet thunder pipes. Huge breathing increase

I installed a 1/2 wood spacer originally which worked on the performer air gap intake but am now using a 1" spacer to increase velocity. I have plenty of room with the L88 hood

I bought braided steel line and used Russel ends to fabricate a solid fuel line.

All of these together stopped the problem but the biggest thing that changed my problem was the Air Gap intake. I removed it and all the other changes prevented bad driving but it would flood as the engine cooled so it would contaminate my oil and made it hard starting in the morning. And that was with the ambient air temp in the 60s and low 70s. It would get worse as it gets hotter outside

My suggestion would be the Air Gap first. Then and try that. Then go to a small wood spacer. If it still persists get a regulator that keeps the pressure below 6 psi (1-8 psi would be the best range so your desired pressure is near the middle and not on the end of the range) or get an edelbrock fuel pump which is designed for their carbs.

LT1 intake and still having flooding issues



these are of the AirGap

 

I have the same Edelbrock 2101 aluminum manifold with a new Edelbrock 1406 carb that I installed a month ago. I am using a one half inch spacer under the carb and have had no problems with the setup at all. It runs good both cold and hot with no stumbles or hesitation. We have just had 98 degree temperatures here in Florida the past few days and the car runs flawlessly. I don't think you should have to do anything else to the engine to get the setup to work for you.

 

It could be the fuel regionally as well. Not everyone has the same fuel and Altitude either. My buddy has a 400+HP 350 with an edelbrock 750/ RPM intake and no problems, but he mixes some race fuel in his

 

do you still have the fuel pump return line hooked up?
are you using a 180 or 160 thermostat?

 

I have the return with a 180* stat and its still an issue. the engine is usually below 200* on the highway at 80mph at 3500rpm.

My cabin doesnt even get that hot. My feet never feel like theyre on fire, in fact the steering column doesnt get hot, but the shift lever did last year.
Edelbrock carbs are just pressure and heat sensitive, the upside is theyre super easy to tune and arent backfire damage susceptible. The only thing that can fail is the accelerator pump rubber ripping.

Does anyone use a 160* stat. I havent tried that

 

Actually the question was for the OP who hasnt responded to any of our posts

 

RR said "All of these together stopped the problem but the biggest thing that changed my problem was the Air Gap intake"


Did the air gap intake decrease your carb to hood clearance? I have a fuel boiling problem when my 68 bb car is turned off when hot and then re-started. The fuel literally boils dry in the fuel bowls, even with an insulating carb spacer. I can get the car started without grinding the starter by letting my electric fuel pump operate about ten seconds before hitting the key to engage the starter. This fills up the fuel bowls, but it is still annoying. I'd like to try the air gap intake (just installed a new Weiand Stealth) but I have only about 1/4 inch clearance from the air cleaner wing nut to the hood. (aftermarket L88 long type hood)

 

You should definitely get the Woodfiber Laminate spacer. Full disclosure: my company makes those for Edelbrock, so take that for what it's worth.

 

Sorry if the thread got Hijacked but I was just trying to get some info out there
There isn't much info out there on this subject and I've been looking for info about this and other Edelbrock questions across the web or a while and sharing my experiences only seems fair

 

I don't know the hood clearance on a Big Block vs a Small Block in general. With the Performer Air Gap the height was lower vs the stock LT1 intake which has been described as being similar to the regular RPM intake. There was a slight height difference but I have enough clearance with my L88 hood as long as the breather bolt was screwed all the way in. I probably have a 1/4 inch or so to the bolt on the LT1 intake as well until I modified it.. I have a cold air intake and a modified drop base air cleaner so the bolt is no longer close. I want to upgrade to a RPM Air Gap and If its close I can use a smaller wood spacer.

Heres Edelbrocks dimensions and how to measure them
http://www.edelbrock.com/automotive/...mensions.shtml
RPM Air Gap page with dimensions
http://www.edelbrock.com/automotive/...r-gap-sb.shtml

 

Very sorry to all that replied, I hadn't been getting emails tell me there were replies and I have been swamped at work. Ill try to reply.

Roger I remember you, we met in Billerica last year at the Vettes for Vets. I specifically remember your set up and when I got home I sent my car over to the engine builders. He tested my fuel pressure and said it was 6 lbs. so I did not need the regulator, I had actually bought the whole set up. He made a steel fuel line for me to get the fuel line off of the manifold.

I am going to order the spacer this week as I do have the room, it's pretty cheap of a remedy, if that doesn't work I will have to look into a new intake.

 

I also will check on the return line on the fuel pump. I'm still at work so tomorrow is a new day

 

Good to hear from you!!! If theres anything I can do to help out let me know. I have an extra 1/2 inch spacer if you want to try it out. I can get it to you tomorrow night after work. Its the 4 hole design

 

Roger that would be awesome, let me see if the studs I currently have will fit another 1/2 inch. I'll check in the morning.

 

Roger I don't have the room for that spacer on the current studs I'll order it from Summit, it comes with the studs and gaskets, thank you for the offer though.

I'm questioning the room still, may have to look for a low profile wing nut for the air cleaner

 

i have studs too, i replaced mine to go to the 1" spacer. let me know if you want them.

Take a sheet of tin foil and make a tube and join/wrap it around the stud then tap the stud so it doesnt move, it should stick up above the stud an inch to an inch and a half. the tin foil is soft enough that when you gently lower the hood it should compress, giving you the distance without sticking or rebounding giving a false length

 

Damn, I have a crazy day at work and didn't see this post. I ordered the parts from summit yesterday. I do appreciate the offer, I ordered a low profile wing nut as well. Yesterday morning I noticed the wing nut I had made an impression in the hood insulation. It's going to be tight but it has to be done. Roger thanks agin, we should connect this summe for a nice cruise

 

so you have had this trouble with 2 different carbs on a rebuilt motor.

what makes you think it is a carb issue? lots of reasons a motor runs poor when it gets hot. timing, vacuum leak, etc. are your intake manifold heat passages blocked off when it was rebuilt? float set correct, mixture correct?

I've posted info before if you want to search, but pressurized fuel in the line rarely boils, and recirculating setups keep it cool as well.

if you think it is boiling out of the carb, hit the bowls with a IR temp gun and see. but if it is running fine on the highway, there is plenty of fuel in the bowls. if it runs rough at a stop light, where there is minimal need for fuel, I doubt that is the case. I would be putting on a vacuum guage and looking for leaks when hot before I ran out and bought a bunch of snake oil parts.