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'39 120 vapor lock after shut down, suggestions?


ak

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Hi, after shutting down after a run, it simply wont start. I have a glass bowl just alongside the carb and I can see bubbles being injected into it while the engine is turned over. Is the fuel pump overheating? the fuel line is routed outside the frame. Any suggestions for a fix would be appreciated. Thanks in advance.

John

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Guest PackardV8

U'll get plenty of suggestions on how to fix it. Easiest one to try first is to hold the accelerator pedal althe way to the foor while cranking until it starts.

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That is the usual suggestion, and it works, for percolation. (Of course I did try this, to no avail.). This is not percolation from the carb. This appears to be vapor lock at the pump. Hopefully there is a practical solution other than dousing it with water after a short sit.

John

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Guest John_Lawrence

Try adding a gallon of diesel fuel to a tank of gas. The diesel in the gasoline has helped to eliminate vapor lock in my 1947 Custom Clipper.

(o{}o)

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Yes, excellent advice from Jon that works well. Unfortunately I have to relearn the steps each season!! :)

Another thought - set the float as high as you can, although the stock setting is pretty much kissing the top of the carb body on the '39 120 EE 16 carb.

Electric pump has a few advantages, first you can fill the bowl form a cold start reducing cranking, second you can hit it when needed for that extra nudge and finally you can set your carb float without the engine running - a huge advantage in terms of safety, IMHO. I mounted mine on section of frame under the fender about 12" to 18" behind the wheel - you will see holes already there which is why I chose that area. Plus is is relatively easy to get to there. I understand closer to the tank is more efficient but for the limited use I need it seems to work just fine. Forget the brand but you can get it right at NAPA, inline or flow through use so you do not need elaborate plumbing, or a duel feed if you will between that and the stock pump. Very easy to do.

These fuels are just not the greatest, and when you do stop, at least initially, the temp will rise before dropping, on hot days I pop my hood as well.

Is the stock pump rebuilt? Dirty but straightforward enough task, I would be sure to do that as well.

Good luck with it. The only other thing I have yet to do is fabricate a heat shield, but the steps I have taken seem to address for the most part.

Edited by Steve_Mack_CT
added info (see edit history)
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Guest Packardman

See if you can find some gas without ethanol in your area. This will solve 90-100% of your problem. It will also keep your fuel tank from rusting out when your car sets in the winter. Ethanol is a very bad thing for our old cars.

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Guest PackardV8

Also check the needle in the carburetor. If it has a 'rubber' tip (of incorrect 'rubber' compound) it will sweel and cause a lean condition. A lean condition that will not be evident until SUSTAINED higher engine rpms are reached (say 60 mph). Nonetheless, it causes diminished fuel reserve in the bowl of carb which will allow it to boil faster at ANY speeds.

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Thanks a lot, fellas. That is some of the best stuff I have read. I understand it now. (don't know if I have a real solution but I get it) Thanks especially for all of your time, and thanks for that great link to the Packard site.

John

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Guest olcrow

ok now someone educate me on my 39 jr. 6 cyl. the carb has a small "container" on the outlet side of the carb. looks like an air chamber of some sort. what is the purpose???

b.

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Hi Olcrow, was waiting to see if any 6 owners piped up. Packard went to an auto choke in '39 - at least on the 120 models. I am guessing your carb has a simillar set up. Does a tube go into it?

Can you post a picture - or are you going to make me dig up the shop manual? :)

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  • 2 weeks later...

I started a thread in general discussion area on unusual old timer type cures but wanted to note this here. A friend with a '41 110 has clothespins on his gas line to dissapate the heat via additional surface area, like finned heads do. Not sure how effective this is but he was given the tip by an old timer and he believes it has helped. The general consensus in his local (non AACA) club is "those old Packards ran hot anyway, so the problem is not new".

I wonder if I can hang a rag or polishing cloth in there with the clothespins?? :)

Anyway, I thought I would add that as a "possible" additional step...

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sorry to have taken so long to answer mike: been taking a nap ;), the item that is installed on my pump is about 1 1/2 inches tall, about 3/4 in diameter, has a 1/8 pipe thread to screw into the pump, discharge side, has no lines going to or from, beats the heck out of me....

b.j.

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....... A friend with a '41 110 has clothespins on his gas line to dissapate the heat via additional surface area, like finned heads do. Not sure how effective this is but he was given the tip by an old timer and he believes it has helped. The general consensus in his local (non AACA) club is "those old Packards ran hot anyway, so the problem is not new".

I wonder if I can hang a rag or polishing cloth in there with the clothespins?? :)....

A picture to add to Steve's words.

post-52046-14313866141_thumb.jpg

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