Flat spot

[octanejunkie]

Ok, after a long restoration and layup, my Charger was rolled out in the sun today for a shakedown run. I had it set up last year by a local chap, who did the timing and idle etc.
It ran better but still not perfect. Then i noticed one of the vacuum hoses was in the wrong place. It ran better still with this remedied, but again, still not right.
Car starts up hot or cold no problem.
When driving, as soon as you go to put your foot down, or want a bit of power, from anything other than light throttle, the car car bogs down before picking up once again. It improves slightly as the car warms up, and becomes just an elongated flat spot.
Its a 73 model 318 with a standard 2 barrel Carter. No smog stuff, just the charcoal canister. No vacuum leaks or inlet leaks.
Does this just sound like it needs a bit more timing?

Also, can somebody explain to me about needle heights on this carb and how they work, as there is quite a bit of adjustability there too, though i don't know what the consequences of this are??

Please help, it really put a downer on my day

[GJUK]

I would start with checking for an air leak - check everything is tight, all the outlets blocked off if not in use.
I had this issue with my Dart, many weeks of swearing found that the base of the carb was wonky and letting in air. It used to spit and bang something terrible under load.

Next I'd check to make sure you are getting good constant sparks - all the plugs and consistent.

Anyone local to you that could pop over and help you out?

[ScottyDave]

When driving, as soon as you go to put your foot down, or want a bit of power, from anything other than light throttle, the car car bogs down before picking up once again

mmmm I'm interested in knowing how this goes also, mine also used to do exactly the same when last on the road, never knew what it was as all basics checked out.

[octanejunkie]

My thoughts are timing. The carb is new, as is the gasket. Definitely got no leaks at the carb. All intake bolts are tight, and no signs of leaks from there...

[octanejunkie]

Plugs/ignition system all new..

[ScottyDave]

Is it timed to "factory specs" by any chance? I believe our old motors need to be advanced to run on modern fuel..

[GJUK]

Do you get a good spark if you pull the HT leads from the engine and try to turn it over?

[MilesnMiles]

Easy to advance the timing. Small block, warm engine up, loosen dizzy hold down clamp and rotate dizzy anti clockwise. You should hear it pick up revs.
Turn it off. Leave three minutes and try to start. Does it drag the starter down or fire up? If the latter, road test it and see if it has improved but do check for engine pinking.
If starter is dragging down or its pinks you've gone too far advanced.
Just need a half inch spanner and screwdriver to adjust carb.
Old school tech, but easy to try.

[octanejunkie]

Easy to advance the timing. Small block, warm engine up, loosen dizzy hold down clamp and rotate dizzy anti clockwise. You should hear it pick up revs.
Turn it off. Leave three minutes and try to start. Does it drag the starter down or fire up? If the latter, road test it and see if it has improved but do check for engine pinking.
If starter is dragging down or its pinks you've gone too far advanced.
Just need a half inch spanner and screwdriver to adjust carb.
Old school tech, but easy to try.

This will be my job for tomorrow...

[MilesnMiles]

Do make sure motor is fully warmed up first. If it's too far advanced (go easy) a hot motor will pull the starter down more than a cold one. Will sound like a tired battery.

When engine warm, turn the dizzy until engine revs rise and then turn back just a touch before testing and then report back.

If your mate/mechanic timed it to factory spec it will run badly. All Mopars like more advance..as much as the motor can tolerate.

[MattH]

Agree, timing. I'm 318 2 barrel too and had this. Factory settings won't work on modern fuel.

[MilesnMiles]

Not sure why you guys have 2 barrels, but that's another story!
Out of interest, my old 2 barrel Dodge truck did 12mpg, my 340 Runner with a Speed Demon 4 barrel runs me 16mpg.just sayin.

[MattH]

21 mpg to Le Mans and back!!

I have a 4 barrel manifold to go on, but whilst it still runs I leave well alone.

I do have a bad flat spot which I hope to cure with an electric fuel pump, but no time to fit it yet.

[octanejunkie]

Not sure why you guys have 2 barrels, but that's another story!
Out of interest, my old 2 barrel Dodge truck did 12mpg, my 340 Runner with a Speed Demon 4 barrel runs me 16mpg.just sayin.

Its a question of priorities at the moment. I'd love to slap a 4 barrel set up on there, but with all the other restoration work, the performance stuff will have to take a back seat for now. I had been telling myself that it would be more economical to keep the 2 barrel.
My Buick had a high compression 455 in it, so i'd like to think a 2 barrel s/b will be a bit better!

Yeah, a truck will always turn in pants MPG compared to a car.

[ScottyDave]

Not sure why you guys have 2 barrels, but that's another story!
Out of interest, my old 2 barrel Dodge truck did 12mpg, my 340 Runner with a Speed Demon 4 barrel runs me 16mpg.just sayin.

Its a question of priorities at the moment. I'd love to slap a 4 barrel set up on there, but with all the other restoration work, the performance stuff will have to take a back seat for now.

Same for me, get it back on the road and home to the Midlands first then add some goodies