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Edelbrock carb question
I have 1406 edelbrock 600 carb and I want to go back to the original sdc fuel lines. Mine has rubber lines to a plastic filter into the carb. The fuel return is blocked off. Will this carb function well with the fuel return hooked up properly?
Im about to change the intake, install wooden spacer as I have a warm weather perculating fuel problem and a rich burn through the carb as I have a lot of carbon on the tail pipes and rear of the car.
I was thinking of replacng the fuel line if this carb will work that way and after its all together see what the PO has for jets and rods. Its going on a 72 lt1 motor and the original intake is BUBBA d so Im replacing the intake regardless.
Thanks
Last edited by Rescue Rogers; Mar 24, 2016 at 10:59 PM.
Not to derail your thread, but I want to mention that those carbs really need a pressure regulator to work well. Edelbrock says 5.5 psi is OK, but that must be the point at which the needle is practically pushed off the seat. Pulses from a mechanical pump will get past it. Use something like the Holley 12-803 set near minimum and you'll see much better mileage and driveability. Google "edelbrock 600 cfm flooding" if you want to see posts from people who didn't do this.
I have the same carb on a 400 HP smallblock, no problems whatsoever. I don't have a fuel return line, and I don't have a fuel pressure regulator using a factory style replacement mechanical pump. I don't have a thermal spacer under the carb, just the gasket. I do have the factory issued metering rods in it and it's not dirtying up the back of the car. You should check the sparkplugz for deposits, that will tell you much more than examining tailpipe soot. The motor might be burning oil, timing might be off, etc.
What evidence do you see of fuel percolating? Have you experienced the mythical vapor lock?
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Originally Posted by 454Luvr
Not to derail your thread, but I want to mention that those carbs really need a pressure regulator to work well. Edelbrock says 5.5 psi is OK, but that must be the point at which the needle is practically pushed off the seat. Pulses from a mechanical pump will get past it. Use something like the Holley 12-803 set near minimum and you'll see much better mileage and driveability. Google "edelbrock 600 cfm flooding" if you want to see posts from people who didn't do this.
I'm looking at the holly regulator that allow a for fuel return. I guess I need to look at braided lines too
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Originally Posted by SH-60B
I have the same carb on a 400 HP smallblock, no problems whatsoever. I don't have a fuel return line, and I don't have a fuel pressure regulator using a factory style replacement mechanical pump. I don't have a thermal spacer under the carb, just the gasket. I do have the factory issued metering rods in it and it's not dirtying up the back of the car. You should check the sparkplugz for deposits, that will tell you much more than examining tailpipe soot. The motor might be burning oil, timing might be off, etc.
What evidence do you see of fuel percolating? Have you experienced the mythical vapor lock?
When the weather was cold it would start fine weather the motor was cold or hot. When the ambient air temp was 60 it started fine cold but acted flooded when it sat after getting gas or just stopping for a 10 minutes or more. I have to hold the peddle to the floor to start it at that point. No blue smoke or black smoke. No smoke or puffs at starting so I done believe it's burning oil
The return line requires a pump with the return spigot on it......nothing to do with the carb at all.....
I have heard a million times about the Edelbrock 5.5 lbs. pressure deal and all I can say is after owning and installing about 100 of them....I never ran a regulator....
My 66' Coupe had a 1406 on it and it ran perfect in all weather...all of the time after it was metered properly.....
Use this to help with your plumbing.....put a push-loc style -6 fitting on the filter and bend your own line off the pump...use a small piece of Parker hose to tie them together, or look for the correct -6 to flare fitting...they are out there.
When the weather was cold it would start fine weather the motor was cold or hot. When the ambient air temp was 60 it started fine cold but acted flooded when it sat after getting gas or just stopping for a 10 minutes or more. I have to hold the peddle to the floor to start it at that point. No blue smoke or black smoke. No smoke or puffs at starting so I done believe it's burning oil
Mine does the exact same thing, minus a dirty rear end I almost always have to hold the throttle open to re-start a warm motor condition. A thermal barrier might help, but the carb is still sitting over a hot motor.
Read the plugs, check the timing before going any further.
IIRC, the factory return line was plumbed into the fuel filter, but I'm not sure on that.
The return line requires a pump with the return spigot on it......nothing to do with the carb at all.....
I have heard a million times about the Edelbrock 5.5 lbs. pressure deal and all I can say is after owning and installing about 100 of them....I never ran a regulator....
My 66' Coupe had a 1406 on it and it ran perfect in all weather...all of the time after it was metered properly.....
Use this to help with your plumbing.....put a push-loc style -6 fitting on the filter and bend your own line off the pump...use a small piece of Parker hose to tie them together, or look for the correct -6 to flare fitting...they are out there.
Good luck...
Jebby
The return set up on many C3's did not use an additional line on the pump. The fuel filter in addition to the 3/8 inlet and outlet had a 1/4 fitting that connected to the return line with a combination of short rubber hoses and a steel line. See the image of the L46 fuel filter set up in this link. https://www.corvetteforum.com/forums...-1969-l46.html
The return set up on many C3's did not use an additional line on the pump. The fuel filter in addition to the 3/8 inlet and outlet had a 1/4 fitting that connected to the return line with a combination of short rubber hoses and a steel line. See the image of the L46 fuel filter set up in this link. https://www.corvetteforum.com/forums...-1969-l46.html
Thank you for correcting.....I know the later ones were at the pump...such as my 72' was. Although this achieved the same thing....a controlled bleed. Not a bad idea really for longitivity.
Anyway the later pump could be used in lieu of the correct filter.
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Thanks everyone for the replys. Im wanting to use the stock metal ac filter with the return from that. I have a 68 with the LT1 motor so the return lne is still on the frame, just blocked off. I'm planning on running a holley regulator and a Summit pressure gauge use ng braided stainless lines.
Can someones explain the -6 and -8 lines. I don't know what those numbers relate too. And what type of connectors work wth those lines. I'm loading up my shoppng cart at Summit. I just want to do a big order instead of alot of small ones
Thanks Scott
Just to be clear about the regulator issue, it's possible that not everyone who uses this carb without one will actually know there's a problem. The 1406 I had was on my T-bucket using a mechanical pump. Plugs looked good, power was good, but I could tell something wasn't right. For one thing, fuel mileage was way below par. The car weighs 1,800 lbs., has a 2.79 rear and a mildly tuned 350. Mileage was in the mid-teens. It also started hard when hot. Rebuilding the carb didn't help, so after researching the subject a little more, I decided to add a regulator. Both of those symptoms disappeared right away, with fuel mileage up about 25%. Hope this is helpful, good luck with everything!
Thanks everyone for the replys. Im wanting to use the stock metal ac filter with the return from that. I have a 68 with the LT1 motor so the return lne is still on the frame, just blocked off. I'm planning on running a holley regulator and a Summit pressure gauge use ng braided stainless lines.
Can someones explain the -6 and -8 lines. I don't know what those numbers relate too. And what type of connectors work wth those lines. I'm loading up my shoppng cart at Summit. I just want to do a big order instead of alot of small ones
Thanks Scott
A -6 line is approximately 3/8" and a -8 line is approximately 1/2". I have a 69 with a 70 LT-1. Only difference with mine is a Holley carburetor. I have -6 line coming off the fuel pump going to the fuel filter with a 1/4" return connected to the factory steel line going back to the line on the frame. The outlet on the filter also has -6 going to the feed block for the carburetor. The type of connectors you use will be determined by what you have on the fuel pump, the connection on the fuel filter, and finally the connection on the carburetor. All these connectors should be for -6 since -8 is overkill unless you are racing.
Thanks everyone for the replys. Im wanting to use the stock metal ac filter with the return from that. I have a 68 with the LT1 motor so the return lne is still on the frame, just blocked off. I'm planning on running a holley regulator and a Summit pressure gauge use ng braided stainless lines.
Can someones explain the -6 and -8 lines. I don't know what those numbers relate too. And what type of connectors work wth those lines. I'm loading up my shoppng cart at Summit. I just want to do a big order instead of alot of small ones
Thanks Scott
The -6 and -8 refer to the size of the line. -6 is 3/8" and -8 is 1/2". I'm pretty sure you only need -6 (3/8). This is what I used and it is working good.
Jim
fitting and elbow coming from the fuel pump
elbow at top and fuel filter
fitting at carb, also showing 'heater hose' added where it is laying on the valve cover
I 've used Edelbrock carbs on quite a few builds with no problems whatsoever. Most of the carbs I have used are the AVS Thunder series and never before needed a regulator with a mechanical pump. Now in saying that after putting the Edlebrock on the Vette it has ben a nuisance. From fuel percolating out after shut off, dieseling and just poor performance.
I did a bunch of tuning, moving and isolating fuel lines to keep things away from heat the best I could. Yep tried the regulator. It still was hard to start and at times. You could smell like it was running fat at times (you could smell the fuel from the side pipes).Finally I bought the L88 hood added a 1.0 phenolic spacer and fixed it.
The hood I put on is a functional L88 with an air box so the air cleaner is sealed in the hood. Even though that what not the fix alone but I needed that to install the spacer under the carb.
Hopefully you wont need to go to this extent LOL
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Originally Posted by jkippin
I 've used Edelbrock carbs on quite a few builds with no problems whatsoever. Most of the carbs I have used are the AVS Thunder series and never before needed a regulator with a mechanical pump. Now in saying that after putting the Edlebrock on the Vette it has been a nuisance. From fuel percolating out after shut off, dieseling and just poor performance.
I did a bunch of tuning, moving and isolating fuel lines to keep things away from heat the best I could. Yep tried the regulator. It still was hard to start and at times. You could smell like it was running fat at times (you could smell the fuel from the side pipes).Finally I bought the L88 hood added a 1.0 phenolic spacer and fixed it.
The hood I put on is a functional L88 with an air box so the air cleaner is sealed in the hood. Even though that what not the fix alone but I needed that to install the spacer under the carb.
Hopefully you wont need to go to this extent LOL
Luckily with the LT1 intake, the PO has to put on a L88 hood so I won't have the clearance issues. The Edelbrock carb came with the car so instead of starting over with a new carb, I am using a Performer AirGap intake with a 1/2" wood phenolic spacer. I think this will solve my problems but I want to toughen up the fuel line since fire and fiberglass dont mix. There's no such thing as a small corvette fire.
So I want to return to the stock fuel return system and while I'm at it, put in the regulator. Plastic filters and rubber lines may be okay, I have used them on all my past muscle cars, but better safe than huddled in a corner sobbing uncontrollably while clutching my plush corvette toy
Last edited by Rescue Rogers; Mar 25, 2016 at 06:15 PM.
I have 1406 edelbrock 600 carb and I want to go back to the original sdc fuel lines. Mine has rubber lines to a plastic filter into the carb. The fuel return is blocked off. Will this carb function well with the fuel return hooked up properly?
Im about to change the intake, install wooden spacer as I have a warm weather perculating fuel problem and a rich burn through the carb as I have a lot of carbon on the tail pipes and rear of the car.
I was thinking of replacng the fuel line if this carb will work that way and after its all together see what the PO has for jets and rods. Its going on a 72 lt1 motor and the original intake is BUBBA d so Im replacing the intake regardless.
Thanks
With all the "Bubba" you've shared in the past, it may be wise to rebuild that 1406.
I did mine last week and found the accelerator pump discharge check ball missing, one of the venturi booster gaskets missing, and the floats were way out of adjustment. Additionally, it looked like my PO installed the top of the carburetor with the step up rods already installed, bending both of them.
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Good advice thanks, I ordered the jet and rod kit and the gaskets for changing them. I will check the float levels when I have it apart. If I have to, I will definitely rebuild it. I think I can get the rebuild kit easily locally.
From: Las Vegas - Just stop perpetuating myths please.
I think u will find that once u can recirc all the way from the carb u will keep fresh fuel in the carb bowl and the percolation may go away. Also many owners overlook the bowl inlet fitting on the other side of carb that gets plugged/capped. It will need an tiny orifice to reduce return flow and of course a banjo fitting to connect but it could become a fast fix to install a return all the way from the carb bowl.
As for line I like to use cheap brake line and bend my own. May take a few tries to get something u like but brakeline and double flaring tools are cheap.
BTW those AFB style carb are very easy to change jetting and work on. Have u considered an air/fuel monitor for nailing your tune? They are cheaper than ever any w/o a cat u can just put the sensor in the tail pipe with a temporary clamp.
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Originally Posted by cardo0
I think u will find that once u can recirc all the way from the carb u will keep fresh fuel in the carb bowl and the percolation may go away. Also many owners overlook the bowl inlet fitting on the other side of carb that gets plugged/capped. It will need an tiny orifice to reduce return flow and of course a banjo fitting to connect but it could become a fast fix to install a return all the way from the carb bowl.
As for line I like to use cheap brake line and bend my own. May take a few tries to get something u like but brakeline and double flaring tools are cheap.
BTW those AFB style carb are very easy to change jetting and work on. Have u considered an air/fuel monitor for nailing your tune? They are cheaper than ever any w/o a cat u can just put the sensor in the tail pipe with a temporary clamp.
Hope this helps.
Thanks!
I already ordered the stock stainless fuel line and filter from corvette central along with a lot of other stuff. Summit just got a handfull of my cash as well for braided hose and fittings. Should last for my lifetime. I'll be starting the replacement tomorrow.
I noticed today that when I started it, it smelled of gas and on the highway at WOT it was choppy. It just didnt feel like a steady throttle at 80.
Had plenty of extra power down around 70-75. Im guessing the jets have been messed with because the gas mileage is crap too.
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I found a diagram of the 1406 carb and they were using timed vacuum, not manifold vacuum, as I dont have any emmission controls I used mainfold vacuum and my car now has better power off the line. Before it had a big stumble under power
Edelbrock carb question
