edelbrock 1406 help please !

[c10sob]

I have first gen chevy 350 with 1406 electric choke carb. I live at 2700 altituded and of course have some problems setting it . I know i need to change the metering rods and springs, does anybody know a good combonation ? I am unsure if i am reading the edelbrock guide right and need some opionions .

[geezer#99]

Actually, you need to leave your carb alone until you get your timing perfect.

What's your initial timing?

[63 Spud]

I'm running the same thing at the same altitude and mine seems to run good. I believe Edelbrock calibrates those to make a mild 350 run decent right out of the box. The altitude of 2700 feet should not make a drastic difference. What is it doing that you don't like? I live close by if you need some help. Just send a PM.

[c10sob]

As soon as it got cold started to get some poping in the exhaust pipe and the carb has just seemed to be alittle out of wack . i did the tuning with a vacuum gauge and was running good in the warmer weather but as soon as the weather changed it did to.

[c10sob]

My timing is around 10 btdc

[GASoline71]

Advance it to 12 or 14.

Also, are you using a fuel pressure regulator? Edelbrock carbs do not like anything over 5.5 psi. Some stock pumps can put out more than that.

gary

[c10sob]

I have a edelbrock fuel pump on the engine .

[Marv D]

Edelbrock fuel pumps put out 6-9psi. You need a fuel pressure regulator (or a new carb) or you will never get it in tune. Isn't it nice of Edelbrock to not tell you that!! Look on page (IIRC) page 7 or 14 of the manual where it says use a regulator to get the pressure to NO MORE THAN 5psi. They seem to work good around 4-4.5. There is also some tweeks to the accelerator pump rod and plunger height that will help the off idle stumble.

The Edelbrock carbs come out of the factory calibrated for normal fuel delivery at sea level. That way as you install it at higher density altitude there is LESS free O2 and the thing runs rich (not lean with engine destroying detonation,,, keeps carb manufacturers out of law suits) They are roughly 14.x to 15:1 at idle and light throttle cruise mode, and 12.8ish in power mode.

Issue IS....
Every engine will deliver a different signal strength to the venturi. Poor intake charge speed will cause fuel to drop out of suspension,,, means the fuel may fall to the plenium floor and what goes in the cylinder is a lean charge. Or a extremely high vacuum signal may fool the carb into thinking it should be in high rpm 'power mode' and go rich at a low rpm.

Where I'm going is what works for one engine / guy is probably DEAD WRONG for your combination. And reading plugs is simply a joke. You can not tell what the plug saw 20 seconds ago if you made a HARD WOT pass then idled or drove slowly back to your house (pit) AND unless you have a FRESH CLEAN plug,,, and a lighted viewer,,, your simply guessing what your looking at anyways.

If you want to tune it RIGHT for idle, cruise and power mode. FIRST get a fuel pressure regulator,, cause your never gonna get it right with it pushing fuel past the seat and screwing with fuel level in the well.
Then get a WIDE BAND O2 and some way to data log so you can see what the heck it was doing,, and when!

I'm not saying you can't get it somewhere in the ball park reading plugs IF YOUR EXPERIENCED in plug reading,, just that you will NEVER have it 'ideal' for your motor.

Whatever you do don't think dumping more fuel at it is going to make more power. In fact on the edge of detonation will make best power,,, but step just a little over that edge and things get expensive in a hurry

[c10sob]

Thank Marv D , ill give it a try .

[Marshy]

SO, Im getting ready to put a 1406 on my vortec motor I'm assembling and this thread is helpful because I will have to use an electric fuel pump and was wondering if I can get a pump with low enough PSI so that I didnt need a regulator. It looks like I will need a pump with 4-5 psi output if possible. I dont mean to hyjack but I've been looking at this pump.
http://www.summitracing.com/parts/atx-e84070/overview/

[geezer#99]

Try it!!
You'll know soon enough. Just look in the carb.
You can add a reg later, if needed. Use one with a return system though. Electric pumps can heat up and quit with too much back pressure.
Make sure you insulate that pump well. Put a piece of rubber between it and the frame. Hook a ground wire up from the pump to the frame.
Otherwise the droning will drive you nuts!!

[Marshy]

Honestly, the reason I wanted to avoid the pressure regulator was because I didnt want to install a return.

Here's another pump made by Holly.

http://www.summitracing.com/parts/hly-12-426/overview/

[geezer#99]

I here you!!
The less plumbing the better!!
Try that holley. It's set less at 4 psi.
Cheaper too!!
Some might think that's too low of a pressure.
But I've run 3 psi with a dual quad and never ran out of fuel.

[70's luvr]

What is a good low pressure reg to use in this application? I'd prefer one with a gauge included.

[im4darush]

My experience with the edelbrock (carter) carbs....

First thing..they are VERY likely to heat soak. I live in the tampa area and nothing I did could make that condition go away. All the spacers in the world (even the ones they make) did not solve it. The design of the carb boils today's fuel. Very annoying problem to have. I pulled my 1406, replaced with a holley style carb and issue was gone. Holley carbs have the float bowl hanging off the sides and thus the fuel does not get as hot in there. This is not a holley commercial, dont worry. Just stating the facts. I am now running a quadrajet on that same car and it also is much better than the 1406. Only under really HOT conditions will it exhibit a hot start. And even then it is nowhere near as bad as the 1406 was. As stated above, the 1406 is an out of the box carb for the masses. It will never be right, but for most people, they will never know it. I will also tell you that my 1406 had a vacuum leak at the secondary throttle shaft. I sent it back to them for a rebuild and it came back the same. Seems you can not replace the bushings on these. It is now a big paper weight. Probably one year since new. I am guessing I was lucky enough to get a flawed carb. A quadrajet is an excellent carb, and once you get to know it, is not at all hard to calibrate. Secondary side a monkey can do. Primary requires you take it apart, but its not bad. These carbs run great and offer the best fuel economy you can get aside from EFI. And elevation will not really change things much.

[cadillac_al]

GM has a good option too. Some places have it listed cheaper but it doesn't seem to come with the handy mounting bracket. Pace shows it with the bracket but it is $10 more.

http://paceperformance.com/i-6485833...6-9-p-s-i.html

[70's luvr]

Originally Posted by im4darush

My experience with the edelbrock (carter) carbs....

First thing..they are VERY likely to heat soak. I live in the tampa area and nothing I did could make that condition go away. All the spacers in the world (even the ones they make) did not solve it. The design of the carb boils today's fuel. Very annoying problem to have. I pulled my 1406, replaced with a holley style carb and issue was gone. Holley carbs have the float bowl hanging off the sides and thus the fuel does not get as hot in there. This is not a holley commercial, dont worry. Just stating the facts. I am now running a quadrajet on that same car and it also is much better than the 1406. Only under really HOT conditions will it exhibit a hot start. And even then it is nowhere near as bad as the 1406 was. As stated above, the 1406 is an out of the box carb for the masses. It will never be right, but for most people, they will never know it. I will also tell you that my 1406 had a vacuum leak at the secondary throttle shaft. I sent it back to them for a rebuild and it came back the same. Seems you can not replace the bushings on these. It is now a big paper weight. Probably one year since new. I am guessing I was lucky enough to get a flawed carb. A quadrajet is an excellent carb, and once you get to know it, is not at all hard to calibrate. Secondary side a monkey can do. Primary requires you take it apart, but its not bad. These carbs run great and offer the best fuel economy you can get aside from EFI. And elevation will not really change things much.

Interesting info! The other day I got the truck nice and heat soaked sitting in traffic in Tampa and it started to act like it was loading up at idle while in drive. First time I've put it(1406) in that situation since I got it on the road so I figured it was pushing unregulated fuel past the float needle, but maybe it was the fuel boiling instead. I'm running a 1" spacer.