440 six pack high idle

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Always adjust timing before the carb(s). It sounds like a carb issue for sure. Disconnect the outboards and I’d suggest taking a flat blade screwdriver and go down past the boosters on the outboards and tap the throttle plates to verify they’re closed. Then tune just off the center to get the idle you want. Once that’s set you can look at the outboards. I’ve had the gaskets hang one outboard open and the engine will run off just that.
 
Thanks! I have a couple days off coming up, so I’ll be able to spend some time on it. I backed the timing off to about 12 initial just to make it drivable while repositioning it, and that seemed to help quite a bit. I anticipate needing to give it some more advance later down the road, but that’s not my focus at the moment.
 
Well, I started looking at the basics, beginning with the float bowls just to make sure I'm starting at square one. The outboards seemed to be adjusted properly, but the primary was bottomed out - empty. After some trial and error, I was able to get it set correctly. Reset the idle mixture screws to 1.5 turns out. I tried to visualize the throttle plates, and from what I could see they all looked closed.

I gave the engine a little more timing advance, initial is now at 15 - seems much happier, although the idle is high. With a vacuum gauge connected to manifold vacuum, I took a reading of 17 mmHg. Couldn't seem to get any effect on vacuum by adjusting the idle mixture screws, so I moved on to the idle speed screw. I tried lowering the RPM by adjusting it, but the engine would slowly sound like it was being choked out at anything below 15-16 mmHg, and then die.

The high RPM issue pretty much only surfaces after the engine is at operating temp, so I'm trying to think of what it could be that changes or opens as the engine warms up. I think today I'm going to look everywhere I can to make sure there's not a vacuum leak.
 
Always adjust timing before the carb(s). It sounds like a carb issue for sure. Disconnect the outboards and I’d suggest taking a flat blade screwdriver and go down past the boosters on the outboards and tap the throttle plates to verify they’re closed. Then tune just off the center to get the idle you want. Once that’s set you can look at the outboards. I’ve had the gaskets hang one outboard open and the engine will run off just that.
I actually forgot about the suggestion to disconnect the outboards, so I'll try that today. Obviously there are a lot of moving parts and many different things to try, so I hope nobody thinks I'm ignoring any advice given...
 
I actually chased a very similar problem with my six pack. In my case the major culprit was actually the distributor. A pair of weak advance springs were not drawing the mechanical advance back down and when I was timing it I noticed it. Eventually it would settle down and the idle would come back down. I wish sure it was some kind of vacuum leak and did all of the standard tests to no prevail. The distributor had a couple small other issues so I just replaced it now my idle is a beautiful thing. Most likely not your problem but something you may look into.
 
Thanks K.O., I can't rule anything out at this point. Engines are crazy...so many "little" things that make a HUGE difference.
 
It does have the solenoid, however it's not wired up. Should it be? I don't have any experience with them. Also, please excuse the dirt...10 years in storage and I'm getting to it one piece at a time, haha.
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Leave that disconnected. with the advance - if you shut it off, the weights should return to “o”. Very light springs will make it idle high but it should still shut off if the throttle closes.
 
Copy, I'll leave it disconnected.

Also, I suspect this is related, but I've also noticed some dieseling when I shut the engine off. Throttle plate hanging open??
 
Six packs are a labor of love and have quite a large learning curve. I have tried to glean as much information as possible through books and articles and internet. Really it's a somewhat limited source specially in tuning .
Leave that disconnected. with the advance - if you shut it off, the weights should return to “o”. Very light springs will make it idle high but it should still shut off if the throttle closes.
This statement is absolutely correct but I think it just held the RPMs up at a high enough level that it began to slightly engage the outboard circuits all I could make out of it.
 
Six packs are a labor of love and have quite a large learning curve. I have tried to glean as much information as possible through books and articles and internet. Really it's a somewhat limited source specially in tuning .
That makes me feel a lot better. I got a book in the mail the other day on six packs, seems pretty informative. Unfortunately I left it at work, so I don't have it on hand at the moment.

And having been someone else's project that I know nothing about, I've got plenty to look at. For example, when I replaced the plugs before starting it, I simply asked for an equivalent to what was already in the car. I pulled one yesterday to inspect it, and it's got a .025 gap. Not even close to .035-.045 as recommended.

Have you downloaded a FSM?
What are the carbs you are working with lists and dates? That can tell you what year manual to follow up with.
Crap! I knew I was forgetting to do something. I found a FSM for a 73, couldn't seem to find one for a 74 on the website I was on and must have gotten distracted because I never got around to it. I also meant to have a look at the list dates as suggested before, I'll do that when I get off my butt this morning.
 
Copy, I'll leave it disconnected.

Also, I suspect this is related, but I've also noticed some dieseling when I shut the engine off. Throttle plate hanging open??
That is EXACTLY what that idle solenoid is for--anti diesel. It simply connects to "ignition run" so is energized "with the key." It does not have enough "pull" to pop the throttle open, you have to bump the gas to get it "up." You set the "curb idle" on the solenoid, and then when you kill the key, the throttle blades close a bit more. This was done especially with the slow curve/ retarded timing "back then." You can "lessen" this if you run a fair amount of initial timing advance.

Also, I'd download the 70 and 72 manuals as well and read through the "6 pak" stuff there might be a little different info through several years
 
The issue with manuals is they refer to correct for the year/model parts. Your car is a hodge podge so you need to know all bits outside of the manual.

on the 6bbl it’s easy. It’s basically a vacuum secondary 4bbl. The center are the primaries. The outboards are the secondaries. Isolate the primary, make sure the secondaries are closed fully, and work with that. Once that is up and running right (you can actually drive it just B on that one) then worry about the outboards.

Edit- the dieseling only happens because there’s an air leak somewhere.
 
This Dieseling points to a vacuum leak, or a carb hanging open and letting in air. Like an outboard. I really think this is your problem.
Engine off, disconnect choke and have center carb at idle. Remove one outboard linkage. Manually open and close that outboard carb. Make sure it opens and closed without sticking. Coles that carb. Now that linkage should slip in the lever on that carb, if not turn it to adjust length. Do the other one the same way.

when it works right you don’t need that solenoid.

yes Weak dist advance springs Can do this. Do you have a stock dist to put in for a test. What coil is on it? Swap on another for a test.

The next problem is you could have a cracked intake. The aluminum ones will do that. Seen many for sale that are welded up in the heat crossover. Not common, but possible on aluminum intakes.
 
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I have also heard of warped bases on these carburetors mainly being caused from over tightening be careful of that. When problems like this arise tendency are to continue to tighten things resist that urge! Chasing a problem like this can lead to someone making more changes that are just things that need to be corrected later. Take your time. As suggested before when outboard carbs are in the closed position and return linkage is connected you should be able to tap the linkage rods with your finger and they should wiggle freely in the hole with no resistance of pushing or pulling
 
I couldn't find any vacuum leaks, but that still doesn't mean there isn't one. I was watching it idle and pulled back the linkage on the rear outboard, and there was some travel left after the throttle was let off. So I extended that part of the linkage to "push" it closed, and shortened the front to "pull" it closed. I think that may have been a big part of the problem, because while the car still idles a little high, it's at least down to maybe 1200. (I really need to get that damn tach hooked up....) I'm going to keep playing with it, but since there's so much more to do to make it roadworthy - like rebuilding brakes - I might put this on the shelf and come back to it.

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To answer your question @413 , I don't have a stock distributor to use, and I'm running an MSD Blaster 2 coil. I out that on after running the stock coil it came with (same RPM issue).

I have also heard of warped bases on these carburetors mainly being caused from over tightening be careful of that. When problems like this arise tendency are to continue to tighten things resist that urge!
Yes! I've made that mistake before...
 
Another thought looking at the picture...
I'm fairly sure that's a std v8 throttle cable bracket and kickdown setup. It's not set up right for it to operate... not the throttle or the transmission. So you may want to either modify that bracket and kickdown to get things in line, or buy the correct LA 6bbl throttle bracket and make the kickdown work with it.
 
Thanks for pointing that out! The throttle has felt weird since I brought it home - was on the list of to-dos. I have a Lokar setup on the Scamp and I love it. I know some people say to stick with the factory linkage, but I think especially when working with cars with modified or aftermarket setups, factory linkage no longer applies.
 
I couldn't find any vacuum leaks, but that still doesn't mean there isn't one. I was watching it idle and pulled back the linkage on the rear outboard, and there was some travel left after the throttle was let off. So I extended that part of the linkage to "push" it closed, and shortened the front to "pull" it closed. I think that may have been a big part of the problem, because while the car still idles a little high, it's at least down to maybe 1200. (I really need to get that damn tach hooked up....) I'm going to keep playing with it, but since there's so much more to do to make it roadworthy - like rebuilding brakes - I might put this on the shelf and come back to it.

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To answer your question @413 , I don't have a stock distributor to use, and I'm running an MSD Blaster 2 coil. I out that on after running the stock coil it came with (same RPM issue).


Yes! I've made that mistake before...
I think u have the wrong kick down linkage. Unhook it and see if it idles down. Also make sure the throttle cable is adjusted properly. Kim
 
Do u see how ur kd is hanging down and laying dii or wn on the throttle bracket. Take the bolt and nut out of it and pull it ahead. It will lift it up off the throttle bracket. There should be a spring holding the linkage ahead and then it will be in place. U still may have the wrong bracket and lower rod as well as the top slider rod. I may have the right stuff for u if what u have doesn’t work out. Kim
 
I was going to attempt a Lokar setup today, but I couldn't find a location to mount the kickdown cable on the carb. So, I corrected the angle on the linkage. Wouldn't ya know, the KD linkage wasn't even connected at the trans. I fixed that and added 1.5 quarts of tranny fluid, also manipulated the return spring so it would close the outboards a little tighter -- drives much better! Still has a slightly high idle when put into park, but I'm okay with that for now.

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I ordered a correct throttle bracket, but I'm not quite sure how that will relate to the kickdown linkage. So @oldkimmer I might be interested in seeing what you've got.
 
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