woodscrews

Hi guys, any info is greatly appreciated. Just swapped a rebuilt 1407 edelbrock carb on my rebuilt but (factory specs) 66 Chrysler 440 with stock iron 4 hole intake. Can't seem to tune the shake out at idle. Also below 1500 rpms the engine seems to surge slightly on the tach in a no load situation. Engine runs great otherwise, pulls hard from a dead stop through the gears with no hesitation. Checked timing over and over again. Makes 14" vacumn at idle but when the engine has a hick up or shake ideling the vacumn gauge bounced around at same time. Only noticed this prob after removing the original carter afb carb. 440 ran smooth as glass with the carter, just took it off because it looked worn and unknown age of rebuild. 1431 carter 575 cfm rating. The 1407 edelbrock really woke up performance all around. I had a 1" spacer open style under the edelbrock when first installed but I removed because the carb company said the open style spacer would cause turbulence with the 4 hole intake. After I removed and put carb right on the intake it did smooth out the idle some but still nowhere as smooth as the carter was. I did also swap a mopar electronic ignition in at same time with orange box when I did carb. Had timing at 35, 36, 37, and 38 deg total advance and the more t retarded timing the worse the stumble became. Engine runs best at 38 total coming in at about 2400 rpms. No pinging what so ever and runs cool all day. Thanks, I hope I gave enough info Tim

RacerHog

Re Check it for vacuum leaks..... The lower vacuum kind of bothers me...
But for the most part. I would say it's overly lean at idle being the problem.

Just my 2 cents.

woodscrews

it seems that if I richen idle screws much more I get rich smelling exhaust. I have them at 2 turns out each. I've tried 1.5 turns out as well. The other day while adj the mech choke I bumped the secondaries lever a little and it seemed to smooth it out just increased idle rpm. I snapped the throttle and operation went back to previous. Also I was checking vacumn at carb, should I use intake or does that matter? Thanks again Tim

RacerHog

Take the screws out 4 turns and see if it smooths out...
Not to sure where your taking the vacuum read... But unplug the PCV hose and check it at that port and see if the vacuum is better there....
I'm not sure if your fighting a larger cam or maybe late timing or possibly a mechanical issue to give you the low vacuum...?????
Will keep hunting it with you...

woodscrews

ive been taking the vacumn reading from the constant vacumn port off of the right side of carb. My vacumn advance is plugged in on the ported left side of carb. I will def try taking the idle screws out that far today and see what happens. I believe it's a stock cam, idled smooth as glass with the carter, I noticed the problem immediately after firing up the 440 with the different carb and electronic ignition. I hope it's nothing mechanical that would be a weird coincidence that something mechanical failed at the same time as carb and distributor swap. I really appreciate all the info. I'm kinda stumped

woodscrews

i did adj idle mixture screws out 3-4 turns but that made the engine start to lope like it has a big cam, stumble was still present at idle too of course. I put both mix screws back down to 2.5 turns out. It quit loping and started running clean again, but still has a skip. I tried unplugging wires one by one but that makes it miss dramatically. Everything in ignition system is brand new. About ready to put points back in and carter carb. It ran great before I messed with things

RacerHog

Ok... Humm... Ok on the Idle air mixture screws.... Will revisit those later..


Double check the wiring for the new Dist. Sometime the wires get crossed with the two coming out of the Dist. and it will cause the engine to run funny. Normally this only effect the upper part of the RPM, But you never know.


Also, Just try the old Cater first and see if that fix's the problem and then if that dose not.. Then try going back to the points....


Let see if you can find out just what one is causing the problem.


What I'm saying is... It might be one or the other, and you will not know by doing both at the same time.


Keep us posted....

woodscrews

i sure will. I sent off the carter to be rebuilt for piece of mind. I'll put it back on when it comes back. When I got home today I changed all the plugs. They were only a week old but were black and carboned up. They looked worse then the plugs I removed in the first place. Installed standard champion replacement and gaped to .035 Noticed an improvement at idle immediately. Should I try a warmer plug? Sprayed intake and carb area with choke cleaner, didn't find any vacumn leaks. Plugged off all vacumn ports to make sure I didn't have bad hose or pvc valve. Really notice the stumble right off idle. If I idle it up to 1000 rpm the stumble is at its worst. Completely smooths out if you idle it up any higher. Still 14" vacumn at idle. If I idle it up slightly vacumn goes up to almost 20" on my gauge and is rock solid, no fluttering

RacerHog

Look down the carb when its running and see if it is pulling fuel from the ventures at Idle?
Also look to see if the carb primary plates are in the transfer slot or are actually down working off the Idle Circuit? Might have to take the carb off and turn it upside down to tell.


Plugs should not have been black....


The stumble might be a accelerator pump adjustment. But I don't think I would touch it until some of this other stuff gets sorted out.


What I'm looking for is some of these carbs come with the Float level way out of whack.. Might give that a check over. Some times to high.