Help needed with 318 (timing, ruff starts)

[70DUSTER/74SCAMP]

hello i have a 74 plymouth scamp and i just changed the distributor back to the oem style bc ebay sold me a junk msd knock off..any way timed it best i could by ear waiting on timing light from amazon to get here. just need some help where this should be timed correctly at what degree and what not. stock engine besides 600 edelbrock and alumimum intake...also since i have had the car it always cranks and cranks and cranks before it finally fires off and runs rough till it warms up, seems like i have always had to adjust the damn idle every new time it runs. . these are the new parts i have installed on the car

new gas tank, new fuel pump(electric) new sending unit , new lines, new alternator new external voltage regulator, new igniton control box(blue one) plugs , wires cap rotor , radiator , water pump, fuel pressure regulator, filter, air cleaner, battery .....alot of new stuff just frustration setting in bc i cant get it to run correctly , runs and drives just need some advice to see where i need to look. also noticed my after market tach needle has been jumping around and it never has done that( yes wires are all hooked up correctly) but the engine doesnt rev up up and down like the tach . any help would be appreciated..thank u

 

[318willrun]

If the OE distributor is really OE, then start with about 6* BTDC at about 700 rpm's idle and no vacuum advance. That will get it running and in ball park.

• If the tach is jumping around but the engine isn't following those RPM's, then maybe a faulty tach.... Or a loose wire, etc.

 

[70DUSTER/74SCAMP]

thank you sir i appreciate i will try that and see if it helps out. could be the tach...still trying to iron out the rough starts carb was rebuilt professionally locally so i know and or think thats good lol

 

[318willrun]

thank you sir i appreciate i will try that and see if it helps out. could be the tach...still trying to iron out the rough starts carb was rebuilt professionally locally so i know and or think thats good lol

Rough starts could be just a simple choke setting.

 

[dano]

Buy a vacuum gauge too.

Define rough start more?

 

[Alaskan_TA]

Have you checked for timing chain slop yet?

A worn timing chain can cause the timing to jump all over.

 

[70DUSTER/74SCAMP]

choke is electronic it is set and does work......i have not checked the chain yet have not wanted to open that can of worms yet... as far as rough start it cranks over like it has no fuel or spark but i know it has to or should be getting both i know im getting 6.5 psi of gas at the carb . seems like it just cranks and doesnt hit like it should hell my slant 6 in the duster 2 pedal pumps bam starts every time, then i get in the scamp and have to fight it to start . just frustrating with all the new parts ive thrown at it. but yes i will get a vacuum gauge. what are the settings for that on the carb?

 

[318willrun]

choke is electronic it is set and does work......

Doesn't matter if it's electronic and "works". Is it working properly??? You have adjustments and settings on the choke.

 

[67Dart273]

The thing is "it ain't simple" although "it" is comprised of lots of simple pitfalls

1....What is your feel for the general engine mileage and condition? "In other words" does it use oil, and run a compression / leak down test

2...Fuel boil/ vapor lock is a constant source of irritation now that we have this "new improved" fuel.

3...You can NOT effectively set timing by ear. PERIOD. Yes I can get it to run, and sometimes pretty well. But I stand by this.

4...Along the way there are usual "other" troubles, fuel/ carb/ or poor components in your igntion system, such as ratty wires, bad coil wire, worn plugs/ and worn/ dirty/ wet cap and rotor.

5...Sometimes old coils can limp along damaged and "run ok" but not be up to full output. At some point there is a "tipping point." Either the coil gets worse, or the weather gets wetter and colder, and the "lines cross."

 

[Mattax]

If the OE distributor is really OE, then start with about 6* BTDC at about 700 rpm's idle and no vacuum advance.

Understanding this will help you understand why its very difficult to set timing "by ear".
Look at the posts and graph here Large RPM and Vacuum drop when shifting from park to gear

was rebuilt professionally locally so i know and or think thats good lol

Yup. Paying someone doesn't always mean it was done, done well, or done correctly.

Rough starts could be just a simple choke setting.

choke is electronic it is set and does work

Will has already responded but I'll add this. It's not electronic. It's an electric assisted mechanical device. As the bi-metal coil gets heated, it acts like a spring on the choke linkage.
There are several settings:
a. Initial (this is the position when the engine is cold and turning at less than a couple hundred rpm)
b. Qualified (this is the position the choke plate moves to when the engine fires. Manifold vacuum is used to open the choke to the 'qualified position')
c. relation to fast idle (there's usually some method of adjusting this)
Those are the most important ones.

new fuel pump(electric)

i know im getting 6.5 psi of gas at the carb

A carb doesn't work on pressure in the fuel line. In fact 6.5 psi very well may be too much pressure and can cause the bowl to overflow.
The fuel pump is just to supply fuel into the bowl. The bowl is open to atmosphere. The pressure in the bowl is essentially atmospheric pressure.
The vacuum under the throttle plate sucks the fuel from the bowl.
One analogy for the fuel bowl is a toilet tank. LOL If that helps you picture how it works, then its a useful one.
More here: Won’t start

just frustrating with all the new parts ive thrown at it. but yes i will get a vacuum gauge. what are the settings for that on the carb?

OK. So stop that and don't buy the vacuum gage unless you really want to.
A vacuum gage is a useful tool, but not essential and I hate to see you throwing more money at a problem. Now if you like to have tools, its not a bad one to have and you probably will find occassions to use it.
There is no setting that uses a vacuum gage. In a situation like this it can be used to see if a small change in fuel mixture screws improves the engine's pull (higher vacuum). it can also indicate some problems. For example a broken valve spring will show up a jump in the gage every time that cylinder fires. You may need some vacuum tees and adapters to hook it up to a port or an existing hose line.

What you definately need with the timing light is a tachometer. As you can see in the graph I posted in the linked thread, a difference in 50 or 100 rpm can cause a big change in timing. Some digital timing lights have one built in, traditional ones do not.

If you don't get the vacuum gage, use the tach to confirm to confirm when fine adjustments create more power.
With an automatic transmission, the test for power and torque at idle is when you put the car in gear.

 

[toolmanmike]

Yes, 4.5-5# of fuel pressure is more than enough for a Carter/Edelbrock carb.

 

[pt70]

When the engine is cold [under 100*] in the morning open the hood, remove the air cleaner, the choke should be 1/4 closed. Move the throttle about half way. The choke plate should slam shut. Open the choke plate and look down into the the carb. Hit the throttle. You should see two squirts of gas. Then start the car. The choke plate should open to ~3/4 closed. There is a dimension for this adjustment or you can move the plate manually to get it to the right adjustment. This may take a few tries.

 

[70DUSTER/74SCAMP]

Thank you all for you help and information....just a few things coil is new, carb rebuilt by smith built carbs with power plate add on ( thompson performance) . only thing i did to the choke with the engine cold was move the coil cover to the right enough so that a debit card would clear between the flap and the carb. it seems to open up ok when engine warms up. . as far as the psi goes i can bump it down if i am putting to much fuel to the carb (1406) i am going to time it more correctly when my light arrives. yes i did it by ear last nite got me in the park enough to drive it, did 60 mph few pops and spark knocks still but not bad . it is an older 318 seems to have miles on it sure its not original. does smoke alot of blue smoke. doesnt use much oil tho.....id bet the timing chain is stressed but not ready to dive into that