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Messages - Drew Pojedinec

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The Lounge / Re: Holley 1848
« on: June 24, 2020, 03:26:19 PM »
Installing carbs backwards and setting to the plug messes up the timing.
Having a carb without sight plugs should not be too odd, anyone here that runs Lemans bowls should be familiar with the concept.

No apologies needed, no offense taken, nor did I ever think they was an intention.

The questions will be repeated below:
(The participation is in your own mind... I provide setup for you to answer your own question)

The Lounge / Re: Holley 1848
« on: June 24, 2020, 10:23:46 AM »
You asked a question.
I explained the answer in detail which required participation....
Your participation would have answered your future questions.

Perhaps I wasted my time explaining this.

The Lounge / Re: Holley 1848
« on: June 23, 2020, 10:36:09 PM »
Iíve done hundreds of 2x4 carbs, I donít think Iíve ever opened the sight plug.

The Lounge / Re: Holley 1848
« on: June 23, 2020, 08:24:18 PM »
Ok, I will answer, but it isnít free, you have to think on it and answer it yourself, Iíll just set it up.

Look at it a different way.... why not?

Putting float level high on primary does what?
Makes fuel easier to pull from booster since it doesnít need to lift as far.
What is the negative? Well hard acceleration and fuel will spill from booster.... but under hard acceleration the boosters are online anyway, so no biggie. Might argue that itís beneficial.
Ok, now secondaries, why are they low?
Low fuel level makes it less likely to spill?  When would it spill? Hard braking.... the EXACT time you do not want excess fuel in the intake.

Alright, so that is technically the answer.... now for the work around!

Ok, so fuel is harder to pull from secondaries due to lower float level. Greater pressure differential is required to pull fuel. How is this dealt with?

Ok so lets look at basic calibration of a common carb an 1850.
In the primaries we have:
So we have a large idle air bleed at .067
Idle feed restriction for fuel is .026
We have a high speed air bleed at .031
So looking at high speed, what does .031 feed?  It puts emulsion air into air well. This bleed air enters high into the emulsion tube via. .026 passage. Tube has 4, .025 holes right at float level.
Std emulsion from air well to main well is 2@.028
What does this do and why?
Why does putting air in right at float level matter? What dies it accomplish?

Moving onto, the secondaries:
Idle air bleed is .028
Idle feed restriction is .031
Ok.... how is this idle circuit different than the primary?  Why?
Secondary High speed bleed is .025

How does a .031 hsab act differently than a .025?
Explain in detail and it all becomes clear.

Another work around, angle channel primary vs secondary metering block, different angle for same reason.
Now lets toss the wrench into the gears... you check float level via this plug right?
A minor angle is present in how level the carb is fore and aft.
Now mount two carbs backwards 😆

Please remember each carb was designed for a specific engine. Float requirements are different for different carbs. Thus some float bowls have different sight hole locations. All part of the overall system.

The Lounge / Re: Holley 1848
« on: June 23, 2020, 04:35:03 PM »
They are all like that. It is normal.

Float level effects circuit timing. Also lower secondary prevents fuel spillage on hard braking.

1967 Shelby GT350/500 / Re: 3259-1 comparisons
« on: June 22, 2020, 01:45:34 PM »
I donít have all of the data and history....
Just figured I had a bunch of these in at one time, so be handy to note some external differences.
Seeing as how the two look similar but one is worth 3x what the other is makes it worthwhile to see them both.

Dan, One question that maybe you can answer.
3259ís and 3259-1ís have a pretty much exact calibration fir the most part through time. Air bleeds etc are pretty much the same.
For some reason about half of the 3259-1ís in 1967 have a massive idle feed restriction.
Typical is .069 idle air bleed, .031 idle feed restriction.
On about half of the 67 dated ones you have a .069 idle air bleed and a .040 idle feed restriction.
At first I thought it came from a few over enthusiastic racers.... but Iíve now found a dozen just like that. Exactly .040, too common to be a fluke.
Any idea how, or why they would be so oversized?


1967 Shelby GT350/500 / Re: 3259-1 comparisons
« on: June 21, 2020, 08:23:44 PM »
Original choke and throttle shafts had a distinct pattern where the die attached the levers.
Later is blockier.

1967 Shelby GT350/500 / Re: 3259-1 comparisons
« on: June 21, 2020, 08:22:07 PM »
Not always, but many later baseplates are fatter where secondary shaft is housed.
Pump spring and bolt are different on original vs later

Early throttle plates had smaller numbers stamped

1967 Shelby GT350/500 / Re: 3259-1 comparisons
« on: June 21, 2020, 08:20:22 PM »
Metering blocks are double stamped on later versions.

1967 Shelby GT350/500 / 3259-1 comparisons
« on: June 21, 2020, 08:19:15 PM »
Since the subject of carb parts came up recently.....

I still had these pics on my phone, I had 7, 3259 variants in my shop last month.
I compared two from forum members.

In this collection we see the three vs four digit date code.
Also the thickness of the choke horn casting.
Note the secondary squirter boss

1967 Shelby GT350/500 / Re: 67 carb question
« on: June 21, 2020, 03:23:43 PM »
Dang, thanks for the info.

Catch me at home sometime and I can show better pics. This is just what is on my phone.
Most photos are on my laptop, at the shop I have a ton of the carbs around, seems a good idea to detail everything as they come in. Currently have 500 or so files on factory carbs. Trying to triple/quadruple verify them all.

1967 Shelby GT350/500 / Re: 67 carb question
« on: June 21, 2020, 03:03:58 PM »
Other fun photo
67 dated 3259-1 with later over the counter 3259-1

I did a highly detailed comparison on my afs page last month.

1967 Shelby GT350/500 / Re: 67 carb question
« on: June 21, 2020, 02:56:33 PM »
Bent choke plate. Bent plate with cutout, flat plate.

Choke rods:
Nearly straight, very bent, and one that needs cotter pins to retain

This is just Ford stuff, there are more variations with chevy stuff. More still when you get out of the 60ís. Blah blah blah

1967 Shelby GT350/500 / Re: 67 carb question
« on: June 21, 2020, 02:52:46 PM »
Um yes it is hot. Boat is running loads in the gulf.
My engineroom is 122 degrees at the moment.
Day 4 of 42.

Pictures below which detail some of the stuff

The second photo is a 1963 dated list 2919 with bent flap and cutout.

1967 Shelby GT350/500 / Re: 67 carb question
« on: June 20, 2020, 12:10:06 PM »
On early factory carbs there are 3 different choke flaps, 4 different rods, all shafts are dimensionally the same, but there are many distinguishing features.

I often show these comparisons on my AirFuelSpark page.
If you ever want pictures of all the differences of something, just ask and Iíll collect the images.

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