440 owners - a question

[Todd Peterson]

I'm going to make this post more general than specific to my car, because I've ruled out the entire fuel system in mine... For those of you that have the 440 engine, do any of you find that, in spite of everything you try, your engine LOVES to run rich, to the point of occasional misfires?

I've already addressed the whole fuel system, including brand new carburetor. Everything is lean as it can go without running rough, but still runs rich.

I'm kinda looking at the possibility of ignition, since I have a 1967 440 that some fool in past converted over to a 1970 electronic ignition system, but - with timing within spec, can ignition really make it run rich?

The only other anomaly is that the same fool that did the ignition in past also put dual straight pipes on it with just glasspack mufflers. I am pondering if it could be the near complete lack of back pressure in the exhaust.

Again speaking in general, and not to my vehicle specifically, anyone have similar "always run rich" experience with their 440?

Update: I am redacting the back pressure comment. I'm actually trying to undo the work of the fool that tried to make my poor car a drag strip queen, including the air shocks and drop shackles in the back. Fortunately my car never made it to the drag strip. The car is way too pristine to abominate in such a way. In the case of my car, no back pressure = WAY too $%^& LOUD.

 

[Big_John]

Try advancing the timing a couple degrees at a time. If it runs better or the same, advance it a couple more. If it runs worse (I bet it won't) retard it a couple degrees. The outer ring on the balancer can slip and give you false timing readings.

The "back pressure" is a myth. If anything, the car would be lean from a less restrictive exhaust.... But really, glass pack mufflers aren't any less restrictive, just louder.

 

[Boydsdodge]

Your engine may need more initial timing as John pointed out. By increasing timing your idle rpm will increase, allowing you to back off on carb idle screw. Then you should adjust your mixture screws with vacuum gauge and tach.
With the distributor being a swap to electronic, you can check how quick your advance is with a dial back timing light.
So many words can be typed to try and help, when none will be helpful without full info on your engine settings, components your skill level and tools available.

 

[413]

To answer your question, NO not always rich at all

What fuel and how old? Old gas sucks, and ethanol gas gets old way to quickly.

what carburetor? Does the choke open all the way when warm?

But it could be anything, ot nothing. what is the compression ratio of your engine? If somone put open charmed heads and thick gaskets where closed chamber heads were that's bad. If 8:1 that's bad, also a retarded cam timing due to a bad timing chain or skipped timing. If the rings are carboned up that's bad.

 

[Mbaird]

What makes you think its running rich ? Smell ? O2 sensor ? Plugs ?

 

[CBODY67]

(Not a 440-vehicle owner, just 383s).

If the air bleeds on the top side of the primaries are closed down, even a little bit as they are that sensitive, it shifts the whole fuel calibration to the rich side of things. Some deposits are hard deposits and do not come out with a carb cleaner soak, so they have to be removed mechanically.

The ignition system can be electronic and still produce a weak spark, although the engine seems to run good.

On a Holley 4150/4160-family carburetor, if the power valve is defective (or has been blown by an engine backfire or two), then the carb is producing "power mixture" all of the time, which is "rich", on the MAIN SYSTEM of the carb. Primary fuel bowl removal required.

ALL of these things are not engine-size-specific.

My only 440 is hanging on the engine stand,
CBODY67

 

[Mbaird]

(Not a 440-vehicle owner, just 383s).

If the air bleeds on the top side of the primaries are closed down, even a little bit as they are that sensitive, it shifts the whole fuel calibration to the rich side of things. Some deposits are hard deposits and do not come out with a carb cleaner soak, so they have to be removed mechanically.

The ignition system can be electronic and still produce a weak spark, although the engine seems to run good.

On a Holley 4150/4160-family carburetor, if the power valve is defective (or has been blown by an engine backfire or two), then the carb is producing "power mixture" all of the time, which is "rich", on the MAIN SYSTEM of the carb. Primary fuel bowl removal required.

ALL of these things are not engine-size-specific.

My only 440 is hanging on the engine stand,
CBODY67

Did 67s come with Holleys or Carters? I think you are on the right track. Carb may have been replaced at some point with wrong specs .

 

[CBODY67]

1967 C-body cars with 440/350 non-CAP cars came with a Holley 4bbl from the factory. Which is what I thought I remembered from back then, which the '67 Chrysler parts book verifies. 440HP cars came with Carter AFBs.

CBODY67

 

[USSMOPAR]

My crystal ball is broken, you have not given enough information to determine if the problem is with the mechanic/the car or perhaps both. Today's gasoline requires a completely different engine tune than 1967. There is nothing wrong with chrysler electronic ignition at all, again, proper installation and tune up. As i am not getting compensated to troubleshoot the problem this is as far as i can go.

 

[Timothy]

I'm going to make this post more general than specific to my car, because I've ruled out the entire fuel system in mine... For those of you that have the 440 engine, do any of you find that, in spite of everything you try, your engine LOVES to run rich, to the point of occasional misfires?

I've already addressed the whole fuel system, including brand new carburetor. Everything is lean as it can go without running rough, but still runs rich.

I'm kinda looking at the possibility of ignition, since I have a 1967 440 that some fool in past converted over to a 1970 electronic ignition system, but - with timing within spec, can ignition really make it run rich?

The only other anomaly is that the same fool that did the ignition in past also put dual straight pipes on it with just glasspack mufflers. I am pondering if it could be the near complete lack of back pressure in the exhaust.

Again speaking in general, and not to my vehicle specifically, anyone have similar "always run rich" experience with their 440?

 

[Timothy]

Hi,
I have had 440's and 383's most with electronic ignition systems and two of those I installed and one that was factory installed. As mentioned earlier in a post in general the Chrysler electronic ignition system runs good.

If you are thinking your issue has to do with the electronic ignition system temporary go back to a points ignition to rule out the electronic system.

Hoping you find the issue.

 

[Jengel451]

exactly what carb are you using and what settings and jets are in your carb? when at idle what vacuum are you pullling?

One note. Backpressure is a bad thing, I don't care what you think, engines don't like it. it's an air pump. and to add to that, if you have remove backpressure (restriction) of that pump you will in fact lean out your mixture since the engine becomes more efficient at drawing air through the carb.

The 100% sure way of figuring out your AFR is by installing a wideband, it's not hard to do and you can mount the gauge out of the way, but that's the only way you will be able to really dial in your AFR at different throttle/Load and circuits.

Also, be sure you know what your fuel pressure is and float settings, too high of float settings will lead to rich, too much pressure will lead to rich. if the carb floats were never checked out of the box they are probably wrong.

 

[CBODY67]

If the spark plugs are sooty, that's too rich. If the porcelain of the spark plugs is tannish, that's fine, usually indicating the "design" 14.7 to 1 air/fuel ratio (with leaded gasoline we had back then). If the plug porcelains are white, but not smooth white (as new), the mixture is too lean. No wideband required.

If the porcelain is heavily-tannish-deposited, that might mean a new air filter element is needed, from my experiences.

Instruments for some diagnostics is fine, but we got along just fine without them in the 1960s and later. IF one knew what they were looking at. The engine is telling you things, you just need to know what things it is telling you. All a part of a learning curve on such things, without instruments. FWIW A good dwell-tach, timing light, and maybe vac gauge will get you a very long way by themselves.

Just some thoughts,
CBODY67

 

[Todd Peterson]

Did 67s come with Holleys or Carters? I think you are on the right track. Carb may have been replaced at some point with wrong specs .

I changed it back to a brand-new 600 CFM Holley 4160. They had a 775 CFM double pumper on it. Mistake.

 

[Todd Peterson]

To answer your question, NO not always rich at all

What fuel and how old? Old gas sucks, and ethanol gas gets old way to quickly.

what carburetor? Does the choke open all the way when warm?

But it could be anything, ot nothing. what is the compression ratio of your engine? If somone put open charmed heads and thick gaskets where closed chamber heads were that's bad. If 8:1 that's bad, also a retarded cam timing due to a bad timing chain or skipped timing. If the rings are carboned up that's bad.

Thankfully the engine itself is unmodified - stock heads, intake and all. I did a bore scope on #1 cylinder and it looked really good. I am using non-ethanol 93 octane which fortunately I can obtain locally.

 

[Todd Peterson]

If the spark plugs are sooty, that's too rich. If the porcelain of the spark plugs is tannish, that's fine, usually indicating the "design" 14.7 to 1 air/fuel ratio (with leaded gasoline we had back then). If the plug porcelains are white, but not smooth white (as new), the mixture is too lean. No wideband required.

If the porcelain is heavily-tannish-deposited, that might mean a new air filter element is needed, from my experiences.

Instruments for some diagnostics is fine, but we got along just fine without them in the 1960s and later. IF one knew what they were looking at. The engine is telling you things, you just need to know what things it is telling you. All a part of a learning curve on such things, without instruments. FWIW A good dwell-tach, timing light, and maybe vac gauge will get you a very long way by themselves.

Just some thoughts,
CBODY67

I've replaced the plugs, gapped to spec. After running a while they get wet, black and smell of gasoline, even after running with choke fully open and idle trims dialed back. Ignition timing plus or minus seems to have no effect on the richness. Only thing I haven't verified is whether or not the float level in the brand-new out of box Holley is out of spec.

 

[Todd Peterson]

Try advancing the timing a couple degrees at a time. If it runs better or the same, advance it a couple more. If it runs worse (I bet it won't) retard it a couple degrees. The outer ring on the balancer can slip and give you false timing readings.

The "back pressure" is a myth. If anything, the car would be lean from a less restrictive exhaust.... But really, glass pack mufflers aren't any less restrictive, just louder.

Agreed on the "just louder" part. This thing is TOO loud. LOL

 

[Todd Peterson]

My crystal ball is broken, you have not given enough information to determine if the problem is with the mechanic/the car or perhaps both. Today's gasoline requires a completely different engine tune than 1967. There is nothing wrong with chrysler electronic ignition at all, again, proper installation and tune up. As i am not getting compensated to troubleshoot the problem this is as far as i can go.

I'm OK with that being as far as you can go. I am not looking for a diagnosis, really was just trying to see if others have had issues with the 440, not mine in particular.

 

[Todd Peterson]

To answer your question, NO not always rich at all

What fuel and how old? Old gas sucks, and ethanol gas gets old way to quickly.

what carburetor? Does the choke open all the way when warm?

But it could be anything, ot nothing. what is the compression ratio of your engine? If somone put open charmed heads and thick gaskets where closed chamber heads were that's bad. If 8:1 that's bad, also a retarded cam timing due to a bad timing chain or skipped timing. If the rings are carboned up that's bad.

It has fresh, ethanol-free 93 in it. It has a brand new Holley 4160 in it, and I have adjusted the choke to open fully quickly (electric choke).

 

[Todd Peterson]

I would like to thank everyone for their input on my post. I've gotten out of the post as much as I can, and will quit monitoring it now. Thanks again and have a great day!