Carburetor wizard part 2

[Ceedawg]

One thing, the secondary jet controls wot reading

 

[Some Car Guy]

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.

View attachment 1352833

What is your wot number with the 68/57 rod?

 

[Cheapsunglasses]

What is your wot number with the 68/57 rod?

high 14s-mid 15s

 

[Bee1971]

That plug looks terrible

No base color - Clean
No timing mark - Just fouled

How about the other plugs

Do they smell like gas or oil washed

Like furious said , a compression test on all eight will answer some questions

Then it’s on to different spark plugs

 

[Ceedawg]

This is where your slots should be, also a pic of my chart showing the jet sizes. Primary and secondary are same jets stock sec is 401 but can go up to 404-407-410 and so on. See what you have in there now. I’ll take some pics

 

[Ceedawg]

If you close the throttle blades more just open up air screws for more air in idle circuit. In pic right one is primary left or back one is secondary

 

[Cheapsunglasses]

This is where your slots should be, also a pic of my chart showing the jet sizes. Primary and secondary are same jets stock sec is 401 but can go up to 404-407-410 and so on. See what you have in there now. I’ll take some pics

View attachment 1352872

View attachment 1352873

View attachment 1352874

What you’re saying about the slots is different then what others are saying. Are you saying my slots aren’t open enough which is causing a problem?

Because that sounds like the opposite of what another member said.

 

[Cheapsunglasses]

If you close the throttle blades more just open up air screws for more air in idle circuit. In pic right one is primary left or back one is secondary

View attachment 1352877

I understand the parts of of the Carter/Edelbrock, I’ve cleaned and had a few apart. It’s the tuning part I haven’t done, other than idle screws. Trying to figure out the rod, spring, jet combination is the tricky part.

 

[Ceedawg]

What you’re saying about the slots is different then what others are saying. Are you saying my slots aren’t open enough which is causing a problem?

Because that sounds like the opposite of what another member said.

Those slots is where your idle FUEL comes from. Somewhere in the middle is right. Once you’re out of those slots (reason they’re called transition slots) the fuel starts flowing out the Venturi. Not good at idle, 750 rpm is too high in my book about 5-600 is right. If you have to close the blades a lot you got a vacuum leak. Get some carb cleaner then spray around manifold at the head anywhere air could seep in. If engine speeds up there’s your vacuum leak. Old time trick

 

[Cheapsunglasses]

Those slots is where your idle FUEL comes from. Somewhere in the middle is right. Once you’re out of those slots (reason they’re called transition slots) the fuel starts flowing out the Venturi. Not good at idle, 750 rpm is too high in my book about 5-600 is right. If you have to close the blades a lot you got a vacuum leak. Get some carb cleaner then spray around manifold at the head anywhere air could seep in. If engine speeds up there’s your vacuum leak. Old time trick

Yes I understand how the slots work, it’s one person saying they should be “small” and you saying they should be “bigger” that’s confusing. One person saying one thing, another saying another, and sometimes an argument between.

If my engine is too rich, then how can I have a vacuum leak? A vacuum leak is uncontrollable air that causes a lean condition.

 

[Ceedawg]

Yes I understand how the slots work, it’s one person saying they should be “small” and you saying they should be “bigger” that’s confusing. One person saying one thing, another saying another, and sometimes an argument between.

If my engine is too rich, then how can I have a vacuum leak? A vacuum leak is uncontrollable air that causes a lean condition.

Is it rich at idle, I don’t want to go back thru all the posts. If rich the jets-rods have zero effect, they are the main circuit, look at the diagram in that book you have. See this pipe and hole, idle air bleeds, make sure they’re open.
When idling is any fuel dripping out of the Venturi?

 

[Cheapsunglasses]

Right now I have it 13:1 at idle and cruise depending on speed is high 12s low 13s, at part throttle it’s 15:1, and at wot throttle it’s in the high 11s.

It seems I might have fixed my idle, made my wot better, but in between I’ve done something wrong

 

[Ceedawg]

What’s the vacuum reading at each of those spots?

 

[Ceedawg]

15 is great, move throttle and vacuum drops, rods come up making it richer @ 12-13 sounds ok to me. Any change in that area would be working with the springs

 

[Cheapsunglasses]

What’s the vacuum reading at each of those spots?

15 is great, move throttle and vacuum drops, rods come up making it richer @ 12-13 sounds ok to me. Any change in that area would be working with the springs

I know at idle it’s 16in, I was kinda paying more attention to the afr gauge.

I always thought 15:1 afr was bad, but that chart says otherwise.

Sorry if this sounds dumb, but by springs you mean the metering rod springs?

 

[furious70]

Right now I have it 13:1 at idle and cruise depending on speed is high 12s low 13s, at part throttle it’s 15:1, and at wot throttle it’s in the high 11s.

It seems I might have fixed my idle, made my wot better, but in between I’ve done something wrong

This post sounds like you're getting closer. My experience with today's gas is you can't run 14.7 anymore, on my fury with efi I'm 13.8-14:1 in the map to keep full timing and no pinging. Your aluminum heads should help you.

 

[Ceedawg]

I know at idle it’s 16in, I was kinda paying more attention to the afr gauge.

I always thought 15:1 afr was bad, but that chart says otherwise.

Sorry if this sounds dumb, but by springs you mean the metering rod springs?

Yes

 

[Cheapsunglasses]

Yes

That’s what I thought, thanks.

 

[Some Car Guy]

I would go back to the 68/57 rod, and change to one size bigger on secondary jet. That chart that was posted about the ratios should be helpful.

you can calculate surface area of a given jet and rod combo, but as close as you are that’s what I’d do. I think your numbers look good other than wot. 12.5-13 would be nice at wot, but just see where it goes with one step.

from there you can play with air door, springs, and pump shot. Check for vacuum leaks as the one guy posted. Toss in some new plugs of the proper heat range and you’ve got this.

 

[Some Car Guy]

Building in that, with that much idle vacuum you’d be looking at the silver springs that are rated 8 pounds. Air door is a feel thing. You’ll want it drivable without a bog. A guy I’ve followed for years said he did extensive testing at the track and the best quarter mile time setting resulted in a noticeable bog on the street. So just get it where it works best for you driving wise.

I’ve never seemed to have any luck changing from the middle hole in pump shot. You might. Who knows.

good luck