Edelbrock 1406 problems??

[jacill]

I have a 70 chevy 4x4 with a built 350. Nothing crazy just an rv cam, aluminum intake and it is bored .030 over. I am running 4.10 gears with a 350 turbo tranny. The truck seems to run alright when there is no load, but as soon as I hook up to my 19' camp trailer and it has no low end pulling power. When I go up hills I can smell it running rich. Would the carb have that much effect on the power? What kind of setup are you guys running with the 1406. Any ideas would be great. Thanks

[tomatocity]

Originally Posted by jacill

I have a 70 chevy 4x4 with a built 350. Nothing crazy just an rv cam, aluminum intake and it is bored .030 over. I am running 4.10 gears with a 350 turbo tranny. The truck seems to run alright when there is no load, but as soon as I hook up to my 19' camp trailer and it has no low end pulling power. When I go up hills I can smell it running rich. Would the carb have that much effect on the power? What kind of setup are you guys running with the 1406. Any ideas would be great. Thanks

Check to see if there is trash from your gas tank in the carb. Check for vacuum leaks. Use a squirt bottle of water and run the water over the usual places with the engine running 1200-1500. If it increases in RPM you have a vacuum leak. Check the metering rods. What do your sparks plugs look like when not towing? They should be a choclate color.

[pjmoreland]

When I moved from California to Colorado a few years ago, the altitude change of 6000 feet totally messed up the perfomance of my carburetor. I spent a lot of time playing with the metering rods, jets and metering rod springs to get the carburetor back to normal. I would suggest getting your hands on the owner's manual for your carburetor. It contains a lot of helpful information on how to select the correct combination of jets, metering rods and springs.

[jacill]

I will check all of those things out. I live about 3200 feet, and when I go to the mountains at around 6000 to 8000 feet it really runs like crap. What should I jet it for in those conditions to get the best all around performance. Thanks

[CPNE]

1406 Manual

This should help you

[chickenwing]

Welcome to the board! I am no tuning guru and have had my share of 1406 woes. http://67-72chevytrucks.com/vboard/s....php3?t=127083 This is a good link for carb spacers (helped me out a lot): http://67-72chevytrucks.com/vboard/s....php3?t=122462 There was another really good one about the spacers but could not find it.

[shortbed70]

Not trying to hyjack post but my truck has a lean problem part to full throttle. What should I change to solve?JACILL i'm runnin a 1406 5" tall air cleaner carbspacer to addapt to spreadbore intake 355 with compcams 280H flat top pistons 3.73 rear. I got most of the stumble out of mine but now it goes real lean at 4500rpms. So lean its like it floats the valves. I think I need to go up two sizes but I'm no carb guy.

[pjmoreland]

There's a graph in that 1406 manual that shows what combinations of jets and metering rods to use based on what change you want to see. There are also some suggestions in there for high altitude. If I remember correctly, I used setup #24 on the 1406 chart for 6000 ft, and it works great. Of course if I ever go down in altitude, I get a bunch of valve knock. Personally I would recommend tuning the carburetor for the lowest altitude you drive at on a regular basis.

[meathead95]

check your timing i had that problem when i pulled my trailer timing was off

[Green Machine]

Carbs tend to run richer as altitude increases, Might want to wean it out a bit, maybe leave the fat part of the rod alone and fatten up the skinny end as that is the power or enrichment end that you may be using when pulling hills. JMHO.

[SweetandLong68]

Guys guys guys....3 words...Fuel Pressure Regulator. With the Edelbrock carbs you HAVE to run a FPR with them. Unlike holley/q-jet carbs that like 6-8 psi fuel pressure, Edelbrock carbs only like 4-5 psi. Trust me on this. You will be suprised what a difference it will make. Probably solve most of the problems that you guys are having with the Edelbrock carbs.

lata
CHRIS

[pjmoreland]

The 1406 manual recommends using the Edelbrock #8190 fuel pressure regulator if the pressure is over 6 psi. I think I'll get one of these. Unfortunately it costs about $50 for one.

[chickenwing]

I agree that is required. Had one from the get go.

My problems were mainly fuel contamination, and a spread bore wood spacer, that caused major vacume leaks. Pitched the contaminated tank and got a phenolic 4-hole 2"spacer. Most of my problems went away. Only thing left is a slight stumble on part throttle acceration. I've went this long... I'll get to it. I had a suggestion of going to a stronger step-up spring and/or moving the pump linkage. I might try the linkage since I can SEE it. The springs.... I'm scared I'll screw something up.

[laplander]

I agree with Meathead, check your timing first. My 72 was freshly built, with new carb other goodies and it ran great and sounded Bad A$$. But when I hooked up to my tiltbed trailer it would slow to a crawl going up a hill. After chasing a supposed carb problem it turned out to be the dizzy all along. AAaaarrggghh.

Nik

[jacill]

I have checked the timing and it is about 10 degrees. It wouldn't change with a heavier load on it would it? I am going to get one of those regulators. Thanks keep the info coming.

[jacill]

I took everyones advise and fixed a couple vacuum leaks, put on the regulator and it is set at 5psi, put all new plugs gapped at 40 in and it is running a lot better so far. It still seems to be boggy on the bottom end. In the high r's it runs really good. Just wondering how to get more snap out of the hole. Thanks

[SweetandLong68]

Try playing around with the FPR a little bit...Take it down a 1/2 psi or 1 psi and try it again.

Also might want to check on the timing again. Maybe the advance is off a bit.

lata
CHRIS

[jacill]

What is a good average setting on the timing for these things. Or just keep playing with it?

[oldsub86]

Just bumping this up as I want to know if it worked out in the end. The fuel pressure regulator that is. I have a similar problem.

[SweetandLong68]

Originally Posted by jacill

What is a good average setting on the timing for these things. Or just keep playing with it?

Most of my motors I at least start at 32 degree total advance and work it up a couple degrees at a time until you see detonation. Of course this is with some good plugs and 93 octane and a modified motor. Stock setting I am not so sure about. I dont have any stock motors anymore...Thank goodness You get the timing and the fuel just right you will know it...SOTP meter will be happy But timing is something thath you have to find what is best for your motor. Keep trying different settings until you find the one that is perfect for you setup.

lata
CHRIS

[70GMC_BOB]

how much pressure does the mechanical fuel pumps produce? I thought they produced 5 psi? does it produce a constant pressure, or does the pressure icrease with engine rpm? Would a pressuure regulator help me get better gas milage out of my truck?

[jacill]

I have a stock fuel pump on my truck and it was pushing about 8psi. And yes the regulator helped out a bunch so far it looks like. Now I 'm just playing with the timing.

Hey sweetandlong what do you mean about the 32 total advance. Mine is set at about 12 degrees right now with the vacuum advance off. Thanks

[70GMC_BOB]

I will be putting one in my truck soon

[SweetandLong68]

I am telling you guys A FPR is a must have on the Edelbrock carb...No matter what. Just make sure you get one with some sort of gauge so you know what fuel pressure you have. If it was a Holley or a Q-jet I would say not to worry about it. But it can't hurt in any situation no matter the carb. It is just that Edelbrock carbs dont function to their maximum with too much fuel pressure. 4-5psi is all they need.

lata
CHRIS

[oldsub86]

I put a Holley fuel pressure regulator on to see if it would help my problem. It may have helped a bit but I think the engine is still running rich. The exhaust smells rich to me.
I put a "T" in temporarily and a guage on to see what the pressure was after the regulator. It was about 5# so I adjusted it down to about 3# and the engine still seems to run about the same. No starving for fuel. I have noticed that the pressure builds to about 5# after I shut the engine off. I assume this is due to heat. I am uncertain as to what I can do about that. One of my problems is that the engine is hard to start once it is warm. I have to hold the gas pedal down in order to start it. That leads me to believe that fuel is getting into the manifold while the engine is off. Anyone have ideas on how to stop that?