Timing issue?

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70DUSTER/74SCAMP

Sold the scamp ....still got the duster tho
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Ok where do i start. So the issue i have been having is when i start my car from cold let it run and idle it seems fine. once it has warmed up some i will drive it and it runs really well . especially with my new summit 600 cfm carb . after a hard drive it once to peeter out and idle ruff on me then barely makes it home. once home in the drive way it starts to idle rough and die at normal operating temp for me is 190. So yesterdays project was i removed the electirc fuel pump and pressure regulator and went back to stock cam driven oem pump . seemed to help bc i thought it was gettting to much gas at the carb . like i said new holly style carb on it now . and trying to get used to it still. not sure how to adjust the back float either that sight glass is plum full front sight glass is half where i think it should be . also says there should be a high idle screw on pass side of carb near choke i cant find that any place trust me looked all over. so just working of adjusting curb idle. It is around 10 degrees BTDC but fluctuates between that and 8 . when i set my timing i made sure the balancer lined up with 0 but what to i need to do exactly to get it to coincide with blowing my finger off at cylinder one and getting the balancer dead at 0 ?? bc i have not been able to achieve that. so to recap runs great cold i go drive it runs awesome when it warms up it runs like hell then idles and dies very frustrating! thrown every damn part at it new and still can not get it to just run. i know. enough about it to obviously get my self in trouble between youtube and beer cant figure it out and im at my damn wits end on this car . its a 74 scamp 318 AT. any help please will be appreciated. for everyones info these are new on the car with in the last month or few.

Distributor OEM. blaster 2 coil. alternator . ballast resistor. battery . alternator plugs cap rotor wires . summit racing carb and spacer. ignition box blue one . radiator water pump belts gas tank fuel pump ( mechanical)

im wondering like i said did i not time it right ? or is my chain stretched and wont hold time. idk. obviously thats a fun gamble take half the front of the engine off either its good or stretched. i know its a 34 dollar part at carquest but what do ya do lol

thanks for looking and appreciate any help.
 
Original gas tank in the car yet?

There is a fine screen sock on the pickup tube in the tank that can plug off once you start driving and stirring up the sediment in the old tank.

Pour out and cut open your fuel filter. If there is rusty brown sediment in it, then there is your problem.

Need to have clean fuel and an unrestricted supply to begin with.
 
I would get that ^^^ corrected first.

I adjusted the front float to middle level of the sight glass . used a 5/8 wrench and went clockwise to lower the float. i did that on the rear and it just bottomed out no more adjustment and sight glass is plum full in secondary. using a stock pump mechanical. i get how techinically just dont know why it wouldnt lower the float. front went down just fine like i said it just bottoms out no more adjustment to give.
 
Original gas tank in the car yet?

There is a fine screen sock on the pickup tube in the tank that can plug off once you start driving and stirring up the sediment in the old tank.

Pour out and cut open your fuel filter. If there is rusty brown sediment in it, then there is your problem.

Need to have clean fuel and an unrestricted supply to begin with.


Definately got clean gas i drained 3 gallons out yesterday removing the electric fuel pump off frame went back to factory style. tank is new with in last few months new line new filter yesterday even with new pump. so i know the has is clean running 91 octane.
 
i did that on the rear and it just bottomed out no more adjustment and sight glass is plum full in secondary. using a stock pump mechanical. i get how techinically just dont know why it wouldnt lower the float. front went down just fine like i said it just bottoms out no more adjustment to give.

Sounds like you will need to pull that end and check the float. Either it's stuck, or it has a pin hole, filled up and sunk.
 
Sounds like you will need to pull that end and check the float. Either it's stuck, or it has a pin hole, filled up and sunk.

i would hope not considering it was new out of the box 2 days ago lol. from summit like i mentioned. but thank u for the info i may check that out. got the primary float set just fine its just the back is full at idle.
 
The way to check your timing mark is NOT with your finger. All this does is to tell you what 'stroke" of the firing cycle you are on. To accuratly check the timing mark, buy or make a piston stop

I made this one and have had it since the early SEVENTIES

stop2-jpg-jpg.jpg


To use, remove no1 plug and make sure (stick/ flashlight, etc) that the piston is down a ways, remove battery ground, and screw the sop into no1

Wrench the engine around gently until the engine stops against the device. Make a temporary mark onto the balancer directly under TDC. Rotate engine backwards until it again stops, make a second mark

Your true TDC witll be halfway between the two temporary marks, and if the original mark is correct that is where it will be
 
However, it it runs pretty good some of the time, it is likely not timing, unless, say, the advance mechanism in the dist. is rusted up and for some reason sticking when it gets warm. Remove the dist cap and twist and release the rotor CW. It should have spring pressure, when released should snap back to original position, and move freely.

Is it possible you are experiencing fuel boil/ vapor lock? Is any of the fuel system close to exhaust, or moved from stock location? Is it possible the tank is not venting or that the tank pickup screen ("sock") is plugged
 
However, it it runs pretty good some of the time, it is likely not timing, unless, say, the advance mechanism in the dist. is rusted up and for some reason sticking when it gets warm. Remove the dist cap and twist and release the rotor CW. It should have spring pressure, when released should snap back to original position, and move freely.

Is it possible you are experiencing fuel boil/ vapor lock? Is any of the fuel system close to exhaust, or moved from stock location? Is it possible the tank is not venting or that the tank pickup screen ("sock") is plugged

distributor is new and no vapor lock. i routed lines away from heat and tank is vented. with a one inch carb spacer. so not getting any heat soak or vapor lockage.
 
I'd be surprised if the problem persists after the float levels have been dialed in.
If it does, IMO, the best way to sort this out, is to do a fuel volume test, immediately when the problem manifests.
 
so to recap runs great cold i go drive it runs awesome when it warms up it runs like hell then idles and dies very frustrating!
So... When the choke is closed (cold engine) the engine runs fine, when the choke is open (engine warms up) it doesn't.

Except for the rear float issue, sounds like a vacuum leak to me.
 
Check to see if it's running rich at a hot idle. If so, I suspect one or more of the carb bowls is flooding due to a bad valve, float, or setting. What do the plugs look like? Does adding more fuel down the carb intake from a dribble can make it better or worse? Does opening a vacuum port on the intake manifold make it better or worse?
 
Re-reading the post here, '74, 318 guessing it is stock with a 4 bbl set up.

You are saying it is a new 600 cfm summit racing carb. What is the actual carb?

Do you have access to an Edlebrock 1406 600 cfm electric choke carb? Beg, borrow or steal from a friend or local car guy. Those carbs are pretty much fool proof, bolt on and go. No rejetting needed, run nice right out of the box. Just set the 2 idle mixture screws at the front of the carb and good to go. They just run nice . . .

Here:
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Here:
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Here:
Resized_20200712_194110_8421.jpeg


Here: Stock 1967 383
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4 bbl upgrade '69 Satellite Stock 318
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They all have the 1406 Edelbrocks, they all run great. Simple, works well.
 
A quick swap out of the carb will tell you a whole lot.

Here is the 1406 Edelbrock on a fresh run in of a stock '91 318 roller engine, with the 4 bbl conversion. Was a factory TBI engine.

 
It ain't your timing chain, and not the timing either. Pull some plugs and let them explain it to you.

plugs looked decent they only have a few hrs on them. not fouled out seem like they look ok even for NGK i know i need to use champions but the damn oreily didnt have any and i needed some i will be switching them to champions. i rep lace the edelbrock 1406 600 CFM carb that was on it that was rebuilt by someone. i still have the carb. but the new summit carb 600 cfm electric choke. summit brand was doing the same dang thing the edelbrock was doing. what little vacuum hoses i have are new and not leaking. could the intake manifold gasket be causing this maybe once the engine warms up gasket may leak but runs decent when its cold or just started? gasket looks a little ruff maybe in places it is an edelbrock performer rpm foro a thermo quad but im running new square bore gaskets and a summit one inch carb spacer all new on it. no leaks on that part
 
Check to see if it's running rich at a hot idle. If so, I suspect one or more of the carb bowls is flooding due to a bad valve, float, or setting. What do the plugs look like? Does adding more fuel down the carb intake from a dribble can make it better or worse? Does opening a vacuum port on the intake manifold make it better or worse?


i have not tried to open an intake manifold vacuum port on the intake no . wouldnt that make it leak and ruff worse?
 
So... When the choke is closed (cold engine) the engine runs fine, when the choke is open (engine warms up) it doesn't.

Except for the rear float issue, sounds like a vacuum leak to me.


not sure what i have to do to fix the issue of the rear float sight glass filling up to full other than take a new carb apart which i shouldnt have to if summit got things right it should be fine id say maybe i need to contact them about the issue bc the float screw is maxed out that pushed the float level down . that trick worked fine on the primary bowl it brought it down middle level of sight glass
 
i would hope not considering it was new out of the box 2 days ago lol. from summit like i mentioned. but thank u for the info i may check that out. got the primary float set just fine its just the back is full at idle.

You can’t adjust a float on the secondary side if it’s already full.

Your not using fuel out of the secondaries sitting at idle and that’s why you see no change when you screw the adjustment down.
Loosen the bowl and drain it.
Then screw you adjuster clock wise until it lightly stops.
Start the motor and start backing out the needle and seat adjustment as you watch for the fuel to come up to the level.
Tighten down the locking nut.
 
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Coil gets hot and starts to missfire. Swap the other coil on from your other A body and give it a try. Have had coils go bad like that.
 
What does out the tailpipe look like?
Black ?

White ???
 
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Once it warms up and starts to miss and stumble at idle, spray some starting fluid down the carb and see if it comes out of the stumble.

This will tell us if it is ruining out of fuel after it warms up.

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Same thing when it warms up and starts to miss, start closing off the choke plate and see if it comes around or just dies. ☆☆☆
 
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