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Messages - Drew Pojedinec

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1
1968 Shelby GT350/500/500KR / Re: Intake hot spots, can't be good
« on: August 09, 2020, 04:55:00 PM »
I cut a small piece of sheet metal, knock it in with a punch. Cover with epoxy.
I live in the deep south, exhaust crossovers are not very useful here.

2
Most of the stuff has been covered....

I wrote this a few years ago for when customers had heat soak issues.
It is certainly not the end all but it was meant to point folks in a direction, so a cut and past from my files.


Starting to get warm out around here. In prep for summer driving, a small primer on how to avoid fuel boiling in the carburetor on shut down. My "fuel percolation issues checklist"

I had this problem a lot in Southern GA. Part of the issue is me running whatever pump gas is available. Most of this is 10% Etoh junk. Sure sure people can say "well just buy pure gasoline." But I want my cars to be real street vehicles, I drive them everywhere. The only vehicles I own are carbureted, so it isn't an option to seek out special fuel, especially on 5-6 hour trips.

-Carb spacers. Edelbrock makes a 1/4inch spacer that is good. If you can go bigger, use the phenolic wood resin types, they are the best.

-exhaust crossover blocking. It isn't hard, just get some steel sheet jb welded in the exhaust crossover.

-try to shield the accelerator pump. If fuel in it expands it will push out the accelerator pump nozzle. I think in the 80's Ford addressed this issue by drilling a tiny tiny hole in the accelerator pump channel in the metering block which pushed the fuel back into the bowls. If you look at the location of the pump, it's pretty much a wide open heat sink on shut down. In my Galaxie, I run 2, 600cfm Holleys.... twice the fun! Would be just as bad with a double pumper.
This is less of an issue with the check ball type of pump and more a problem with the later umbrella seal style.

-Keep your timing as far advanced as feasible. Limit mechanical to your max and push the initial a lil further if you can. I regularly run 18 initial and 38 total on a "stockish" engine, my HP engine runs 22 initial, 32total, and it helps keep it cooler.

-Fuel line insulation and isolation, keep it away from anything hot. Best is for it to enter the engine bay and go directly to the carburetor.

-Electric fuel pumps. Insulating the fuel lines doesn't matter if the fuel goes into an engine mounted fuel pump. Have you ever felt how hot the fuel pump gets while the engine is running? Hot oil is splashing on the inside.... just trust me, it gets hot. This also makes fuel routing easier as you can keep it away from anything hot. I run -8 SS braided hose and it stays decently warm through all scenarios.

-Fuel regulation and control. With modern fuels, the are designed for sealed fuel injection, so being exposed isn't an issue. Of course we run carbs, they are wide open. This fuel expands and contracts, and I do not have the data to back it up, but I think the specific gravity is different than it used to be. On side hung floats I regulate to 4.5psi With center hung floats I regulate to 5.5psi. I have also found that the .097 needle valves are better at keeping control than the .110 that most new carbs come with. Now some folks might say this isn't appropriate for performance usage. Everyone knows fuel in a carb is about flow not pressure. Use a larger pump and hoses than needed and have a good regulator.... no problems. I'm in the under 600hp crowd and the Carter HP 4600 works great as a lift pump, very quiet and seems very sturdy. I use a QFT regulator with an Aeromotive gauge. (30-1803QFT and
Aeromotive Fuel Pressure Gauges 15632).

-Some folks suggest a return line. I have never used one, so I cannot comment. Thus far I haven't required one.


3
1967 Shelby GT350/500 / Re: BJ/BK Carbs Will Not Idle Down
« on: August 04, 2020, 09:20:08 AM »
Leaking PV would slow idle.

Yes I think you have a vac leak.
Vacuum leak check.
Most folks spray fluid or use a torch, etc.
I never do that, If you have no vacuum leaks, you should be able to shut the engine off by putting your hand over the choke horn.

If your choke air inlet drawing air?

4
1967 Shelby GT350/500 / Re: BJ/BK Carbs Will Not Idle Down
« on: August 03, 2020, 05:39:27 PM »
If nothing else, that reply was entertaining :P

5
1967 Shelby GT350/500 / Re: BJ/BK Carbs Will Not Idle Down
« on: August 03, 2020, 09:58:23 AM »
Cuz it looks cool 😂

Personally for smaller engines I really think the 3x2ís are more fun.
427+ and 2, 600ís make a ton more sense.

Odd you have so many needle/seat issues. You claimed I use a mallet, but honestly I really just donít have a problem there.
I have two really good fuel filters and a high end regulator set at 5psi. No problems.

Royce is 100% correct about factory settings on factory engines.
Of course once you throw a 250@.050 cam at the car, you do whatcha gotta go to make it all work.
My car is pretty fussy if I asked it to idle below 800 in gear. You can get it tuned to do it, and I often do a ďlow idle checkĒ  but itís a lit more forgiving with 100rpm more.

6
1967 Shelby GT350/500 / Re: BJ/BK Carbs Will Not Idle Down
« on: August 02, 2020, 10:39:16 AM »
I toss the stock screws for secondary venturi. Replace with 8-32 or 10-32 set screw so it can be adjusted with carbs installed.


Dry setting:

Open primary venturi both carbs until t slot is visible. Close slowly while holding baseplate up to light. Stop closing when t slot is not visible but you can see itís location via the light.
Do this both carbs.

Secondaries, open until you can view t slot. Close to hide t slot. Do this both carbs.

This will result in a 900-950rpm no load on almost all engines.
If cam is mild and you prefer a slower rpm, close secondary venturi on both carbs.
If cam is large and you prefer a faster idle, open the primary venturi on the primary carb.

I prefer to not expose slot on secondary carb, here is my reason:
With moderate cam in the 240-250 @.050 kinda duration that is common with performance engines you see 8-10 inch of vac at idle.
If idle settings are adding fuel to keep proper a/f no load they will provide excessive richness at cruise when vac is high.
Yes you can tune around it, but better to keep it simple and bot have to chase your tail.

Iím sure there are several methods to reach the same endgoal, this is just mine.

7
Stick a fork in it.Please

Canít we talk about something not decisive like religion or politics?

8
Wanted to Buy / Re: WTB Holley C8OF-9510-AA, would consider AB
« on: July 22, 2020, 07:21:55 PM »
I have -AB core I could restore if needed.

9
Up For Auction / Re: rare 63 dated holley nos Lemans
« on: July 11, 2020, 10:25:16 AM »
Seems a lot of those popping up recently. I bought two this year 

10
Doug, I get nonstick black gaskets that are on the level with the blue ones.

Nylon bowl screws are cool.... sadly I would say with 1960ís carbs Iíd get maybe 1 out if every ten that would stay wet with the hard gaskets.

11
Yes, there are balance tubes on the reproductions.

Do not confuse transfer tube with balance tube on 4160ís.

12
A note about the kit Royce linked.
Youíll need to cut the fuel bowl gasket a tiny bit for the brass balance tube.
With some small scissors or razor blade it is not hard at all.

13
There are some specific parts that doesnít contain.

I honestly do not recall what as it has been years since I bought any sort of generic kit.
I have a company make me kits to my own specs for that reason.

14
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)

15
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.

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