Carb tuning: Bog off idle.

[Jonas Nordstrom]

How do the plugs look? Have you checked your TDC and confirmed your timing?

Havent checked plugs from coming to a stop after cruise, though AFR is between 13.5-14 both idle and cruise now.
(Removed plug to check TDC and it was dark brown, but that was from idling in the garage for 30 min.)

I have checked TDC and confirmed the timing.

 

[Jonas Nordstrom]

It seems like you are expecting alot out of your carburetor. They are not perfect. Its hard to expect a carb to just take off when you floor the accelerator pedal, without a hesitation. In my experience, you have to work the gas pedal a little on a hot rod car. Fuel injection would probably work better for 0 to WOT, without any bog or hesitation. Just my opinion again. Im not a super tuner...

I do expect a lot from my carb and it sure delivers, it smokes the tires from stand-still, it takes off hard when flooring it from cruise and it gives lots of power up top. No hesitation when pulling away.

The thing is, there is no hesitation/bog when pressing down on the pedal, the hesitation/bog/engine stalling is when you give a little gas standing still and then quickly let go.
- Standing still in drive, make a quick blip to the throttle and the engine dies.

I think I need to write a list of what I have done through the pages. Lots to read.

 

[4speed68rt]

It sounds like you almost have it where you want it. I guess I misunderstood the problem. Keep after it, something will make a difference. I will keep reading to find out how it goes. I have learned alot from this thread. Thanks

 

[Jonas Nordstrom]

It sounds like you almost have it where you want it. I guess I misunderstood the problem. Keep after it, something will make a difference. I will keep reading to find out how it goes. I have learned alot from this thread. Thanks

Thanks for your tips. I have also learned a lot from this thread and going through everything on my car.

Yes, yesterday I decided to tune in the car to where I want it but still continue to look for the stalling issue.
Car meets are coming up.

 

[Runner71]

Havent checked plugs from coming to a stop after cruise, though AFR is between 13.5-14 both idle and cruise now.
(Removed plug to check TDC and it was dark brown, but that was from idling in the garage for 30 min.)

I have checked TDC and confirmed the timing.

Okay - read the thread and u done quite the work on the carb already - hope u find the issue and as u said, car meets coming up and its a short season atleast here in Sweden!

 

[Jonas Nordstrom]

Okay - read the thread and u done quite the work on the carb already - hope u find the issue and as u said, car meets coming up and its a short season atleast here in Sweden!

Where you at Runner71? Im in Uppsala.

 

[AR67GTX]

If you nail the throttle from a stop and don’t let off - it doesn’t stumble?

With what sounds like a very mild engine, maybe the secondaries need to be closed down more and the primaries opened a little more for curb idle, so they can’t snap as far shut when you let off the throttle.

 

[Runner71]

Where you at Runner71? Im in Uppsala.

Pretty close then, Im in Västerås

 

[Jonas Nordstrom]

If you nail the throttle from a stop and don’t let off - it doesn’t stumble?

With what sounds like a very mild engine, maybe the secondaries need to be closed down more and the primaries opened a little more for curb idle, so they can’t snap as far shut when you let off the throttle.

Nope no stumble, nail the throttle from a dead stop and dont let off and the car rips the tires and keeps going strong.

Hm, my secondaries are fully closed.

Digged into my Distributor, a bit dirty but looked ok.

 

[AR67GTX]

If secondaries closed then ignore - it was a bit of a wild guess. Another wild guess would be a real tight torque converter - but I’m sure you could goose stock 318/383 auto engines in drive all day long and they wouldn’t stall, so . . .

Another wild one is the springs in your distributor. If real light so that the swing way out on the goosing of the throttle and the as the revs start to fall, they suddenly snap back in and kill all the centrifugal advance, then maybe that could contribute to stalling. That’s one reason that I like springs that don’t advance until at least 2 or 3 hundred rpm above curb idle.

Maybe someone has already covered this.

Good luck.

 

[Runner71]

Have you checked fuel pressure and changed fuel filter, cut the old one up on the inlet side to see if it's any dirt inside blocking the fuel

 

[Jonas Nordstrom]

If secondaries closed then ignore - it was a bit of a wild guess. Another wild guess would be a real tight torque converter - but I’m sure you could goose stock 318/383 auto engines in drive all day long and they wouldn’t stall, so . . .

Another wild one is the springs in your distributor. If real light so that the ways swing way out on the goosing of the throttle and the as the revs start to fall, they suddenly snap back in and kill all the centrifugal advance, then maybe that could contribute to stalling. That’s one reason that I like springs that don’t advance until at least 2 or 3 hundred rpm above curb idle.

Maybe someone has already covered this.
Good luck.

Thanks, it is a Summit Dist with original springs.
Yeah, torque conv could be a thing, I have the one that came with the car, so dont know the specs.

Have you checked fuel pressure and changed fuel filter, cut the old one up on the inlet side to see if it's any dirt inside blocking the fuel

Yep, checked fuel pressure and the filter is new.
For the throttle blip I think the Holley has enough fuel to play with.


Out today setting baseline timing/idle and testing carb spacers.

 

[hunt2elk]

View attachment 1287546

You really have the front end sitting low. How does it handle like that?

 

[Jonas Nordstrom]

You really have the front end sitting low. How does it handle like that?

It looks very low in that pic, a bit more balanced irl.

The car has a FF st3 box with sector support, solid adjusting sleeves, hotchkis sways front and rear, hotchkis upper arms and struts, Eddys ias shocks, New rt leafs from eaton, poly bushings all around (Except front lower arm and front leaf eye that has rubber.) Boxed lower arms and sub frame connectors.

Car handles like a go-cart, more fun to drive than all modern cars Ive driven and takes corners like on rails.
I think it handles too good for my own safety.

 

[hunt2elk]

Sounds like you have the suspension and steering sorted out just fine. Hope you can get this bog figured out. Car looks great by the way.

 

[Jonas Nordstrom]

Sounds like you have the suspension and steering sorted out just fine. Hope you can get this bog figured out. Car looks great by the way.

Thanks!
Up close the paint job is rough with scratches, though this is a RT survivor without rust and very straight, so keeping it like that.

About the bog/stalling, last week I took off the intake. Mostly cos its so fun on the RB, dry and off in a couple of minutes.
I had some oil at the lower edges of the intake. So cleaned everything up, put some The right stuff on all sides and also added a paper gasket between pan and intake. Bolted back together it seals fine.

Now I found another thing by mistake that could be something......will do some more tests.

 

[KENTON]

If secondaries closed then ignore - it was a bit of a wild guess. Another wild guess would be a real tight torque converter - but I’m sure you could goose stock 318/383 auto engines in drive all day long and they wouldn’t stall, so . . .

Another wild one is the springs in your distributor. If real light so that the ways swing way out on the goosing of the throttle and the as the revs start to fall, they suddenly snap back in and kill all the centrifugal advance, then maybe that could contribute to stalling. That’s one reason that I like springs that don’t advance until at least 2 or 3 hundred rpm above curb idle.

Maybe someone has already covered this.

Good luck.

I was also wondering if the springs might be too lite.

 

[Jonas Nordstrom]

I was also wondering if the springs might be too lite.

You and AR67GTX could be on something here, the springs looks ok but I found some other suspicious behavior in the Distributor.
Got a new one on the way home, fingers crossed....

 

[Runner71]

You and AR67GTX could be on something here, the springs looks ok but I found some other suspicious behavior in the Distributor.
Got a new one on the way home, fingers crossed....

Hope you sort it out! You know theres a Mopar meet @ Brostugan/sthlm every last friday of the month between may - aug. This friday is the first one if the weather is good!

 

[Jonas Nordstrom]

Hope you sort it out! You know theres a Mopar meet @ Brostugan/sthlm every last friday of the month between may - aug. This friday is the first one if the weather is good!

Thanks.
Yeah, dont think I will make it to this friday but I am aiming for the next meet.