Carburetor wizard part 2

[Geoff 2]

And I said to drill only after checking the T slot position.

 

[Geoff 2]

This engine has been rebuilt with non-original parts [ Source heads, RPM intake, headers etc ].
It may have a hotter than original cam in it as well. That would explain a lot of the tuning problems.

 

[Geoff 2]

Cheap,
Unless you follow basic steps, you will never get the carb running properly & bog free.
Those steps are:
- bolt on carb after checking float level & get it running.
- adjust idle mixture & speed to get as best idle as possible.
- now you dial in idle timing before doing any more to the carb.
- with idle timing correct, re-adjust idle mixture screws & speed for best idle.
- remove carb to check T slot position; correct if needed as I described earlier.

The T slot position is absolutely critical. If too much is exposed at idle [ most common problem ], not enough slot is left for the transition [ that is what the T stands for: transfer or transition ] to the main system. Result is flat spot &/or lean spot. You do not fix that, & you will not fix that, with jets & rods.

Here is a quote from David Vizard, in Stock Car Racing magazine, Nov 06, page 64.
He has written over 30 books, at least two on carbs.
" As much as it seems divorced from carb calibration, ign timing can have a lot to do with how responsive an engine transitions onto the main cct. ....At idle a hot street with vac adv may require as much as 50* of ign advance, with 45* being common. If this is what the engine wants, it will idle at a lower rpm with less throttle opening than if it had only 10-14* of ign advance. WITH THE BUTTERFLIES CLOSED MORE, MORE OF THE TRANITION SLOT IS AVAILABLE [ to transition onto the main cct ]".

 

[Cheapsunglasses]

This engine has been rebuilt with non-original parts [ Source heads, RPM intake, headers etc ].
It may have a hotter than original cam in it as well. That would explain a lot of the tuning problems.

It has the factory cam, factory hp manifolds, and it’s the regular performer intake.

 

[Some Car Guy]

Some Car Guy.
Try reading what the OP has written. I know about, & have used hot idle compensators for added air, probably before you were born.
The trouble is....Edel carbs [ the OP is using one ] do not have them.

I did. You have not. He has a rich carb all through the range with a small cam and overall mild build. Some normal tweaks will resolve this.

 

[Ceedawg]

One thing more, did you check to see if BOTH rods stay down when running? If one is stuck up it will run rich

 

[Geoff 2]

Post #65. Normal tweaks are not resolving the problem, are they?

 

[Geoff 2]

Post #10. 15" of idle vacuum. The factory 350 hp cam would have at least 17" of vacuum. Maybe the cam has more duration than thought, has been installed in a retarded position or has some other problem. Like lobes going south....

 

[Cheapsunglasses]

Post #10. 15" of idle vacuum. The factory 350 hp cam would have at least 17" of vacuum. Maybe the cam has more duration than thought, has been installed in a retarded position or has some other problem. Like lobes going south....

Hope it’s not the lobes going south, cams aren’t cheap

 

[Cheapsunglasses]

One thing more, did you check to see if BOTH rods stay down when running? If one is stuck up it will run rich

Yes both rods are down

 

[Geoff 2]

According to my Motors Manual, the 350 HP idle speed is 500 rpm for auto or man trans.
If it doesn't idle well @ 500, that is another indication that the cam is not a 350 hp duplicate.

 

[Cheapsunglasses]

According to my Motors Manual, the 350 HP idle speed is 500 rpm for auto or man trans.
If it doesn't idle well @ 500, that is another indication that the cam is not a 350 hp duplicate.

I pulled the engine out of a low miles 1 owner Newport, I changed the timing chain, looked the timing cover has never been off. That’s all I know

 

[Cheapsunglasses]

Black autolite 3924s, which means it’s running rich, kinda like what the afr gauge indicates. Funny thing is it doesn’t burn your eyes while it’s idling line something running rich normally does.

My transfer slots are at .022, so that’s in spec too.

 

[KingCapt]

They don't look bad to me...

 

[furious70]

Plugs are getting coked up already? How many hours or miles on them?
You changed the timing chain and made super sure you kept the same time?

 

[Cheapsunglasses]

Plugs are getting coked up already? How many hours or miles on them?
You changed the timing chain and made super sure you kept the same time?

Yes

 

[furious70]

What was the health of the engine before you upgraded heads, did it run? Compression check? Now wanting to make sure the engine is sound

 

[Cheapsunglasses]

Furious, The engine had 34,000 miles, I ran it with iron heads, an offenhauser single plane, and a 71 440 avs. I never did a compression test, and other then pinging no matter what fuel and timing I had, it ran like a sad 440. It would go down the road ok, but wouldn’t do anything great. So I through the heads on, and the cylinder walls still had cross hatching and everything looked ok. After the head change it was stupid lean, and I tried a 67 440 AFB, and it was stupid rich. So I bit the bullet and bought the AVS2 because it sounded like it was better then the regular performer, I was a little afraid of the 800cfm being too much, but better rich then lean. I also wanted to ditch the intake, and go with a dual plane. And now other then being rich, this car is the happiest it’s ever been. It feels like a stump pulling street terror.

 

[Cheapsunglasses]

Just as a refresher, I was in tune 4, 101 jet, 65/52 rod. Then tried my own made up tune based off that, 101, with a 68-57 rod. That leaned it out too much at wot throttle. Then today I added a little timing, and after looking for the millionth time I saw a rod I didn’t see before, a 68/52. I tried it out, with my little bump in timing, I’m running the accelerator pump in the closest hole, and I’m running the orange springs. It now idles at 13:1, and cruising at that range, but in the mid range it dips to 15:1, but at wide open throttle it’s at 10.7-11:1. It also does pretty good burnouts, and is able to stop a 4 year old from playing with his Tonka trucks in the yard, and compliment my car.

 

[Some Car Guy]

Post #65. Normal tweaks are not resolving the problem, are they?

yes, the tweaks are working as expected. The carb is getting leaner with thicker rods. not sure what else anybody would expect.

There is no need to cloud the matter with long posts and data dump style information.