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Duraspark conversion.

Shran

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That ballast resistor should be fine. You just want like 8-9v at a round coil... 12v will make them go into meltdown mode.

How did you set the timing? Top dead center on #1, compression stroke... stab distributor with rotor pointing towards #1 spark plug wire connector on the cap, fire it up and let it warm up, then adjust to 10° BTC?

What adjustments did you do on the carb and is the choke opening all the way? How many turns out are you on the idle screws? I would first verify that your choke is opening all the way when it's warmed up, then hook up your vacuum gauge and adjust both of those screws equally so that you get the highest possible vacuum reading. Then adjust the idle speed screw. Should be pretty close to perfect at that point assuming the carb is functioning as it should.
 


Bronco648

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That ballast resistor should be fine. You just want like 8-9v at a round coil... 12v will make them go into meltdown mode.
(y)
How did you set the timing? Top dead center on #1, compression stroke... stab distributor with rotor pointing towards #1 spark plug wire connector on the cap, fire it up and let it warm up, then adjust to 10° BTC?
This is what's confusing me. There are two "pointers" bolted to the timing gear cover; one is clearly a pointer, the other is like a tunnel sight on a rifle barrel. I marked 12* BTDC on the harmonic balancer and tried to set the distributor so that the mark on the balancer lined up with the pointer. The engine died every time I approached that mark. So, I used the 'tunnel' as the timing mark. It's running very rich so I know it's incorrect but don't know what to do to fix that.
What adjustments did you do on the carb and is the choke opening all the way? How many turns out are you on the idle screws? I would first verify that your choke is opening all the way when it's warmed up, then hook up your vacuum gauge and adjust both of those screws equally so that you get the highest possible vacuum reading. Then adjust the idle speed screw. Should be pretty close to perfect at that point assuming the carb is functioning as it should.
The carb came set up from Carburetors & More in Texas. They ran the carb on an engine stand on a V8. I asked if the settings would translate to a 2.8 V6 and they said they would. I have not messed with the carb settings at all. They told me to set the timing to 30* BTDC at 3000 RPM. I don't have an external tach so I'm not sure how I'm going to do that.

The choke is electric, is wired to the alternator and is working/open all the way.
 

Shran

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I will let someone else chime in about the timing marks. It has been 10 years or more since I've messed with timing on a 2.8.

As far as the carb goes......................... what size venturis does it have? What jets do you have in it? I am just sort of questioning whether it's grossly oversized for a V6 if they have it set up for a V8. That would explain why it's running rich... those Motorcraft 2bbls were used on pretty much everything up to big engines like the 429. The adjustment screws on the carb will only control the engine at idle so if you have those dialed in correctly and it's still rich while driving around, there is another problem.

I have also seen some damaged when people overtighten the idle screws, it breaks the fuel passages and dumps huge amounts of fuel into the engine. Only found this when the carb was disassembled and I took a close look through the throat where the idle needles come out... pretty obvious chunks missing...
 

Bronco648

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I will let someone else chime in about the timing marks. It has been 10 years or more since I've messed with timing on a 2.8.
Fair enough.
As far as the carb goes......................... what size venturis does it have? What jets do you have in it? I am just sort of questioning whether it's grossly oversized for a V6 if they have it set up for a V8. That would explain why it's running rich... those Motorcraft 2bbls were used on pretty much everything up to big engines like the 429. The adjustment screws on the carb will only control the engine at idle so if you have those dialed in correctly and it's still rich while driving around, there is another problem.
It has the 1.08 Venturis but I do not know the size of the jets. I can ask. Do you know what jets it should have in it?
I have also seen some damaged when people overtighten the idle screws, it breaks the fuel passages and dumps huge amounts of fuel into the engine. Only found this when the carb was disassembled and I took a close look through the throat where the idle needles come out... pretty obvious chunks missing...
I do know that it does not have chunks missing near the pointed end of the idle screws. I definitely would have noticed that (cracks on the other hand....).
 

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You need a ballast resistor if you run the round cannister coil, not necessary with the TFI coil though.
The above is not exactly correct. True, the square coil does not need a resistor when used with it's original TFI ignition module, or a HEI module. But if you are using a Duraspark ignition box, you have to run a resistor no matter what coil you decide to use. Some people do use the square coil with a resistor and the duraspark II ignition box, but with the failure rates associated with the dursapark II box, I think you are safer running the round duraspark II coil. It's the one that does not have threaded connections, but has pins on it and requires a special horseshoe connector the stores sell.
 

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...a special horseshoe connector the stores sell.
Any chance you know what auto parts stores refer to this as? The only one I find is the one from Painless and it's $86.

Never mind: Dorman Electrical Wire Connector 85848 ~$12

 
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Shran

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The above is not exactly correct. True, the square coil does not need a resistor when used with it's original TFI ignition module, or a HEI module. But if you are using a Duraspark ignition box, you have to run a resistor no matter what coil you decide to use. Some people do use the square coil with a resistor and the duraspark II ignition box, but with the failure rates associated with the dursapark II box, I think you are safer running the round duraspark II coil. It's the one that does not have threaded connections, but has pins on it and requires a special horseshoe connector the stores sell.
Oh yes, you are right, I guess I should have specified that it is not necessary with the HEI conversion and the GM ignition module.

It has the 1.08 Venturis but I do not know the size of the jets. I can ask. Do you know what jets it should have in it?
1.08 venturis sounds right, I do not recall the jet size exactly. #51 or 52 seems to pop into my head but again it's been a lot of years.
 

Bronco648

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1.08 venturis sounds right, I do not recall the jet size exactly. #51 or 52 seems to pop into my head but again it's been a lot of years.
Hmm, OK.

The carb rebuilder says he checked it with an Air-Fuel-Ratio gauge and it registered at 13:1.

Optimal for a vehicle with a cat is 14.7:1 and a little leaner is supposed to be best for fuel economy. However, it also results in higher engine temps and higher NOx emissions.
 

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Just for reference purposes, I bought a carb just like the one in this link


And it has been working fine for the last 3 years on my 2.8. I did have a few problems in the beginning, I did end up swapping the float and the power valve out of my old original computer controlled carb into this new carb. It ran great the first test drive, but was doing some bucking in the 2nd test drive. I wasn't sure if the float was acting up so I changed it, and I didn't like the look of the power valve they had in there so I changed it also. The problem went away. I then had a minor leak around the top of the carb, their gasket was not cut accurately and fuel was leaking around the top in one corner. So I stole the gasket off the old carb and everything has been good since. Typical made in China stuff.

But I am confirming that a carb made for a v8 will work fine on the v6, jetting and all. I did not change the jets. This carb says the venturi are 1.16, I think mine were 1.21. The only thing I notice about it is I can't lug the engine as well as before. In other words, when in town if I am below 45mph in overdrive I need to shift when I didn't before. I noticed on the sunvisor the shifting instructions do tell you to shift out of overdrive below 45, so I guess it's not a big deal but it did run better below 45mph when in overdrive with the original smaller carb.
 

Bronco648

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I had someone that knows carbs better than I take a look. He made some adjustments, to lean it out, that has it running pretty nicely now. He also told me to remove the cap on the float bowl vent (and plumb it into the air cleaner). :)

He's also going to check into the vacuum issue. He says there's plenty of vacuum and isn't sure why the brake booster and tranny don't seem to want to work properly. :unsure:

Also a little pissed at O'Reilly Auto Parts. They advertise that you can get parts "next day" if you order by a certain time. But no, you can't. It must be their feeble attempt to compete with Amazon. Supposedly, I have a Duraspark II coil and wiring adapter being delivered to my local store. We'll see...... :mad:
 

Bronco648

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OK an update: Got the carb dialed in (I think) and the vacuum and transmission issues are fixed. There was never a proper lack of vacuum (my bad) and the modulator, that I received from the PO, was wrong. So, the tranny now shifts properly.

The remaining issue seems to be the ignition system:

The engine will run for a short time and then performance starts degrading, pretty rapidly, until it quits running and will not re-start. All of the electronics are new; distributor, Duraspark coil, ignition box & battery. I thought it might have been a fuel issue but the tank is 3/4 full, I can see fuel in a clear, in-line filter that's down by the steering box (before the fuel pump) and the fuel pump is new.

I'm not saying that new parts are beyond reproach but even a local shop seems a bit stumped. I picked up the truck from the transmission shop and drove it about 2 miles before it started to idle roughly, at a traffic light, and then just died. Switching coils had no effect and it seemed not to have any spark. I rented a tow dolly and took it back to the local shop. The shop called a few days later and said "it started right up, what's the issue?". However, after they drove it around it apparently exhibited the same issue(s) as I encountered.

So, what am I missing here? Anyone have any thoughts?
 

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Does it still have an EGR and if so, is it sticking open and causing the problem?
A 2150 with 1.08 is around 289 cfm, with 1.12 is about 351 cfm, and the one from a 429 2 barrel( I don't know how they were marked) flowed 500 cfm. The 1.08 is what you'd want, I've seen them on 2.8 Mustang II's and 79 Mustang 302's.
You should be using the pointer to set the timing but first I'd verify the marks on the balancer are correct. The outer ring on the balancer can turn if the elastomer between it and the hub degrades. I would pull out the #1 spark plug, turn the engine over until #1 is at TDC, and stick a screw driver in the plug hole to feel the top of the piston, Then put a breaker bar on the balancer bolt and slowly rock the engine back and forth to find where TDC actually is. The marks on the balancer of the 390 I built this summer had moved 15 degrees retarded and the owner said it was a dog. I'm sure he was right.
 

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The front pulley is a one piece casting, so you don’t have to worry about the numbers moving.

I’d be looking at the pickup in the distributor.
 

Bronco648

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Does it still have an EGR and if so, is it sticking open and causing the problem?
A 2150 with 1.08 is around 289 cfm, with 1.12 is about 351 cfm, and the one from a 429 2 barrel( I don't know how they were marked) flowed 500 cfm. The 1.08 is what you'd want, I've seen them on 2.8 Mustang II's and 79 Mustang 302's.
You should be using the pointer to set the timing but first I'd verify the marks on the balancer are correct. The outer ring on the balancer can turn if the elastomer between it and the hub degrades. I would pull out the #1 spark plug, turn the engine over until #1 is at TDC, and stick a screw driver in the plug hole to feel the top of the piston, Then put a breaker bar on the balancer bolt and slowly rock the engine back and forth to find where TDC actually is. The marks on the balancer of the 390 I built this summer had moved 15 degrees retarded and the owner said it was a dog. I'm sure he was right.
No EGR anymore. Carb is 1.08. Pointer was at TDC when I inserted the distributor and I verified that by checking that the piston was up and the valves were closed.
The front pulley is a one piece casting, so you don’t have to worry about the numbers moving.
Correct.
I’d be looking at the pickup in the distributor.
That's kinda the conclusion I was coming to. If true, that would be a bummer because the distributor is new and they seem to be unobtainium now. Maybe the pick-up is something more common?
 

19Walt93

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Good luck finding a good one. I bought a Chinese Napa distributor for my 351 and had to replace the stator the first summer. I had a Ford one but I used it in my old boss's Mustang, figuring I'd just order another one. Then I found out it had been obsolete for years. The Ford part number is D4PZ-12A112-A, if you're lucky enough to find one, my son and I spent 2 days in the Carlisle swap meet this spring and didn't find one. If you find more than one I'd love to buy one from you.
 

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