I have a 1967 Dodge Dart 225 slant 6; need a little help with tune up specs as the internet is extremely unhelpful. Just need to know what the spark plug gap should be and plug wire placement on the distributor cap.
Another issue I've been having is that when I get the Dart started, it runs ok for about 20 minutes then starts to hiccup and acts like it's running out of fuel and tries to quit. I've revved it up and it's kept going until lately, when I've had to really put the foot to the floor and/or pump the pedal to keep it going; but now quits after only a short time. I'm smelling fuel, so suspect the fuel pump which I am replacing. My confusion is: if the fuel pump was going out, why would it start acting up after so long a period of running?
My third question is: my other half says that (when it is in good running condition anyway) to pump the gas pedal once or twice then hold halfway down for first time of the day start. Is he full of it, or is that the way a slant 6 is? Thanks!

Spark plugs are gaped at .035 inch. And yes that is how you start a carburetor car. When cold/first start of the day you push the gas pedal down about half way and then start the engine. Not like a modern fuel injected engine at all.

_________________
50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

IT sounds like you may have a vacuum leak that shows up after the choke warms up. Check for leaks around the intake manifold and carb-use a spay can of carb cleaner around gaskets/head/carb.

_________________
50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

ive got a 67 dart gt, welcome to the boards, found this with a quick search online, cant remember if its right, my books are in the garage, others who have more experience may be able to chime in if its accurate or not. as for the hiccuping etc, has it been sitting for a while? my dart had sat for 9 years when i got it, and had lots of issues due to it sitting that long with half a tank of gas! mine was more immediate than yours, but would get it up to about 35-40 and it would cut out and lose power due to junk in the system

The trick is to be systematic. Replacing parts to diagnose a problem is not the best way to go about it. It would be really helpful to have a factory service manual about your car, CD's of it are cheap on ebay.
The suggestion made by 4speed is a good, inexpensive way to begin to look for the problem. As he said, spray some carb cleaner, or even penetrating oil around the intake manifold and carb. If the car runs better (increased RPM), you can locate a possible vacuum leak. Also spray the throttle shaft bushing on the carb, often a leaky area. If that doesn't work, someone will have a suggestion for the next step.

As quickly as you can, get the three books described in this thread. Tune-up parts and technique suggestions in this thread. The engine is probably overdue for a valve adjustment. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

My beloved Dart had been a daily driver until these issues cropped up. Prior to this the exhaust pipe separated about 1/2 inch inside the exhaust manifold so I couldn't match it back up to the pipe properly and now sounds like a tractor. I can't afford another manifold right now. Being as this is so close to the carb etc., could that be a contributing factor, and what can I do until I can get another manifold?

Welcome aboard Nancy’s67,

Proper method of starting a carbureted engine equipped with an automatic choke first start of the day; is to depress the accelerator fully to the floor quickly releasing it, and then depressing the accelerator about a quarter of an inch, holding it there and at the same time crank over the engine. It should start right up and settle in at a high idle if all is adjusted properly, at which point one can remove their foot from the accelerator.

What just took place under the hood is the following:
Once the throttle plates are full opened, a bi metal spring housed in the manifold closes the choke plate fully with a bit of tightness, and the idle adjustment gets repositioned to the high spot on the high idle cam producing a higher rpm say around mid teens. At the same time a shot of raw fuel is ejected into the manifold. When depressing the accelerator peddle a quarter of an inch prior to starting, a second partial shot of fuel is sprayed just as the engine cranks over. As soon as the engine catches, the choke plate opens a pre determined amount, about a 3/16 to ¼ inch depending on carburetor used, to allow enough air in for a rich mixture which a cold engine needs for its first few moments of operation. As the engine warms up, the choke will automatically pull off, idle will reduce as throttle is opened and closed, reducing the mixture and idle to normal.

On a hot engine, all that is needed is to depress the accelerator about a quarter of an inch at the moment of cranking to get that little squirt of fuel for an instant momentary rich mixture, and the engine should start right up without a lot of cranking of the starter, and than settle down to its curb idle speed.

If none, or only some of these phases of choke operation are taking place, than you need to clean & inspect the choke linkage making sure it is freely moving, and choke is full closing with authority on a stone cold (first start of the day) engine.

Once you acquire the manuals that Dan recommended, you will be equipped to tackle most any project, and converse with authority regarding a problem with others here on this site.

As for your exhaust / manifold problem, without seeing it in person, it is hard to say if that exhaust leak is causing a carburetor problem. What I can say is; that such an exhaust leak is a life & death situation. You should not be driving this car until that leak is repaired, and do not transport any kids in this vehicle until fixed. Carbon monoxide poison will kill you, and at the other end of the spectrum, give one a damn good headache with diminished reasoning abilities and response.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Question-are you running the stock points dist or has it been converted to electronic ignition? The manifold problem might be because the heat riser valve is stuck. It is in the exhaust and the counter weight sticks out the side and should move freely. If it is stuck it may over heat a local area and cause a crack to form. It should not cause running problems except for cold running/drivability.

_________________
50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

Thanks Bill, I appreciate your mentioning the carbon monoxide danger if only to warn others; I am fully aware of this, I had to drive the car because I had no choice to get to work, and whenever I did, opened the driver's side and rear windows about a 1/2 inch to keep fresh air flowing through the interior

Plug Gap: .035
Dwell: 42 Degrees (use a meter)
Point Gap: .020
Timing: 5 Degrees Before Top Dead Center
Idle (Neutral) 550 RPM
Valve Lash: .010 Intake, .020 Exhaust (Fully warmed Engine)

_________________
50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

[quote]Thanks Bill, I appreciate your mentioning the carbon monoxide danger if only to warn others; I am fully aware of this, I had to drive the car because I had no choice to get to work, and whenever I did, opened the driver's side and rear windows about a 1/2 inch to keep fresh air flowing through the interior[/quote]

Nancy I want to reiterate my CO warning by a personal experience from the late sixties:

Forty years ago I occasionally drove a step van for a commercial laundry where I worked part time after school. This van was referred to as “The Spareâ€￾, in other words, the oldest POS in the fleet still running, one state inspection from the junk yard…

I was sent to pick up an account’s dirty laundry down on the coast some 30 miles away from the plant. Off I went, side window wide open, puttering along 45 mph or so all the way so there was a lot of fresh air entering the vehicle. What I didn’t know, the exhaust system was not working as it should, and or the rear door's seal wasn't sealing. When I neared my destination an intersection with a stop sign in my path had to be negotiated with a car stopped in line in front of me. I applied the brakes way too late, brakes were less than marginal at best on this heap, with all my strength and managed a damage free bumper tap with that car.

Exiting my van, I became light headed, disorientated, felt weak, and apologized to my victim for hitting his car. I recall him being rather skeptical of my driving, but he let it drop, and I was on my way for my pick-up wondering why I was so out of it.

On the return trip to the plant, the side door was wide open, after 60 miles under my belt, the old noggin was pounding, I didn’t feel too well, it was punch-out time, and I went home.

Later the next day, feeling better and thinking clearer, I realized that I had a dose of CO poisoning the day before. I also realized that having a window, or a door slid wide open won’t prevent CO from polluting one’s brain.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC