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Re: Carburetor junk
pockets #734837 April 07th 2018 5:34 pm
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Awesome. Thanks for everything Reed. I'll have to see if I can spare the funds. Take care and best wishes.

Re: Carburetor junk
pockets #734839 April 07th 2018 6:13 pm
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One last thing-

I dug around in my garage and found that I have FOUR 1945 carbs. Unfortunately, none of them are suitable for your use.

I had another thought- the 1945 carburetor was used from the mid 70s to the late 80s on the slant six. This meant that the carb was introduced when the only computer in the engine bay was the ignition conytrol unit but lasted until the days of computerized EFI and computer controlled transmissions. This carb was used duting the time when Chrysler was introducing the "lean-burn" engine control systems, and 1945 carbs were made for lean burn systems where the lean burn computer controlled the timing BUT NOT the carb! This is important because the carburetors used on timing-control-only lean burn systems look externally exactly like an older 1945 carb, but have some important differences that would not be noticed by nearly all commercial rebuilders of carbs.

The main difference I am talking about, and the difference I think might be causing your problem, is the difference in the vacuum signal for the distributor vacuum advance. 1945 carbs built for use in lean burn systems where the computer controlled only the ignition have all the same exterior vacuum ports in all the same positions as the older non-computer related 1945s, but the carbs built for use with a lean burn system give full manifold vacuum at the vacuum advance port all the time instead of no vacuum at idle and full vacuum off idle. The main difference was the port for the vacuum signal on the non computer carbs was above the throttle plate at idle but the port was below the throttle plate at idle on the computer related carbs.

Here are some pictures to explain. These pictures ae of two 1945 carbs. One is a late model carb where the carb was not computer controlled but it was designed for use with a computer that controlled the ignition system. The other is an older 1945 that is designed for use with a fully mechanically controlled distributor that uses trafitional vacuum advance. The pictures are taken with the carbs upside down and the throttles fully closed, except the third picture where the throttle on the old 1945 is slightly open.

The first picture is of a late 1945 carb that was intended for use with a lean burn system. You can clearly see the idle mixture screw port, the transfer slot, and the vacuum advance port in the throat of the carb. All of these are clearly below the throttle plate at idle and therefore receiving full manifold vacuum. This carb was intended to be used with a lean burn computer that required full manifold vacuum at all times to control the vacuum advance.

The second two pictures are of the older carb. You can see all the same landmarks in the pictures, but the main difference is that the vacuum advance signal is ABOVE the throttle plate so it has a vacuum signal only AFTER the throttle is opened beyond curb idle. The vacuum port on this carb is a thin rectangle rather than a round hole, but it is in the same place as the late 1945, just above the throttle plate.

Why does this matter? I suspect you may have a situation where the distributor vacuum advance port is seeing a vacuum signal at all times because it was intended for use with a lean burn system and not with a vacuum advance distributor.

Try unplugging the vacuum advance hose from the carb and capping the fitting on the carb. See if that changes how the engine runs. If my suspicion is correct, then your cold running problem will improve.

Attached Files LATE1945.JPGOLD1945CLOSED.JPGOLD1945OPEN.jpg
Last edited by Reed; April 07th 2018 6:15 pm.

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Re: Carburetor junk
pockets #734849 April 08th 2018 9:17 am
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That's a lot of info right there. Thanks. I will have to look at the carb itself to see how the slots are. I know when at idle I am getting no vac at the distributor. But I will double and triple check that with a guage. My van originally came with the lean burn box of crap that only controlled the timing and not the carb. I should have kept it but I have a habit of throwing stuff out that I don't use after a bit. I'll check it with a guage today and get back to ya.

Re: Carburetor junk
pockets #734852 April 08th 2018 1:51 pm
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Well, if you have no vacuum at the distributor port then you are fine. It was just a thought. I think if you can't get the idling problems to go away after a full disassembly, soaking in carb cleaner for a few ours, and blowing out all the passages with compressed air, then you should try a different carb.


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Re: Carburetor junk
pockets #734855 April 08th 2018 2:03 pm
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Ya. I'm gonna hit it with a cleaner again and see how it goes. Some carb are just unwilling to cooperate. But that's what we deal with when you deal with older vehicles. Now if I could find a 2 barrel setup then there is a whole world of options, but that's a different story there. Thanks again for your help.

Re: Carburetor junk
pockets #734856 April 08th 2018 2:12 pm
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If you offer me enough, I might have a two barrel intake and a 318 Carter BBD carb that I would be willing to sell. Of course, shipping a cast iron manifold from Washington state to New jersey would be pretty pricey. There are some very active slant six clubs in New Jersey and New York. Someone out there will have a spare Super Six intake kicking around. The most difficult part will be getting an air cleaner that will clear the doghouse. I guarantee you likely won't find the rare factory van-specific Super Six air cleaner, but you can modify your stock one barrel air cleaner to work.


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Re: Carburetor junk
pockets #734860 April 08th 2018 3:49 pm
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I'll have to keep that in mind should I have the funds. The shipping would be quite pricy. I'll have to see what clubs are around me too. I'm not worried that much about the air box. I could do some metel work and weld up a custom box. I'll see what's around me.

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