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1947 DODGE WC / FLATHEAD 6 CYL

I've replaced the coil, dist cap, rotor, points, condensor, plugs and wires, all original / replacement parts. All I'm getting is an occasional backfire out of the carb. I've checked and rechecked wire location. Help!!!

 

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So it runs with occasional backfire through the carb?

 

Sticky valve, lean mixture, timing 180o out.

 

I hope you had some symptoms before you replaced all those parts. Diagnosis is better than throwing money=parts at it.

 

If you ran it on old fuel (sitting in the tank for months or years), sticky valves can result. It did for me.

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Truck ran when I parked it 15 yrs ago. 50k orig miles, very little rust, clean title. Put some mystery oil in the cylinders and worked the fan back and forth by hand to free everything up this winter. Dropped pan, cleaned, pulled filter canister and cleaned, installed new battery and turned over for a while to distribute oil. No spark to coil, replaced wire from starter motor to ignition, no spark out of coil, replaced coil, spark to distributor but not to plugs, installed ignition tune up, now I have spark everywhere, carb leaks if you pour gas into it from can, professional rebuild. Pumping fuel from a can, not the old tank, got fuel and fire but now when I crank it over all I get are some occasional burps out of carb. Just thought maybe someone would say, hey dummy, you forgot A, B , or C

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Update, got a suggestion to run a compression test, 2 dead cylinders and marginal / inconsistent on the other 4, Going to pull the head and see if I can get away with a valve job. Any advice would be appreciated.

Thanks all.

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1 hour ago, Surf City '38 said:

If your pulling the head be sure to harden the valve seats so you can use today's fuels.

Most Chrysler products of the day had hardened seats from the start.

Edited by keiser31 (see edit history)
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Just a suggestion. Before pulling the head take the valve covers off and observe the valves to see if they are operating properly. I have been able to free stuck valves this way to avoid pulling the head. Plus it will let you know if it's valve related or rings stuck.

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Thank you, someone else had suggested that so I am in the process, boy those intake/ exhaust manifolds are quite the test of your patience!!

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Ok Guys, Valve covers are off and after some marvel out and on blaster everything seems to be moving good except one valve on #4 will not come back down, if I stick s screwdriver in the spring it pops right back down, hard even, but on the next rotation stays open, suggestions?

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Keep working it. It might take a while. I had a stuck exhaust valve and it took a fair bit of messing around to make it close consistently. I made a wedge arrangement to leave in the spring and turned it over on the starter a few times, checked, turned it over some more, checked, pushed the wedge back in, .... I also used an old oil bottle (for very thin oil like sewing machine oil) with a long nozzle, with a piece of small tube pushed on, to feel around inside the plug hole for the valve stem and put a few drops of 50-50 ATF and acetone around the valve stem. Initially I turned it over w. the crank handle to prove my dicky system would work, then used the handle and the starter, with the handle during battery charging. It took a while.

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3 hours ago, Spinneyhill said:

Keep working it. It might take a while. I had a stuck exhaust valve and it took a fair bit of messing around to make it close consistently. I made a wedge arrangement to leave in the spring and turned it over on the starter a few times, checked, turned it over some more, checked, pushed the wedge back in, .... I also used an old oil bottle (for very thin oil like sewing machine oil) with a long nozzle, with a piece of small tube pushed on, to feel around inside the plug hole for the valve stem and put a few drops of 50-50 ATF and acetone around the valve stem. Initially I turned it over w. the crank handle to prove my dicky system would work, then used the handle and the starter, with the handle during battery charging. It took a while.

 

My my old engineering teachers would take that step from Spinneyhill after they would cross two plug wires first, the one in question with a known good , to force an internal backfire in the bad piston, to knock off any stuck deposits on the bottom of the valve and top of the piston ....I always hated when they did that, made the loudest sound coming back up the carburetor.....take caution when doing that on a 70+ year old engine.

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Kind of depends on what the stuck deposits are? I think mine came from starting it with old fuel after is sat for a year or two.

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If it was bad gas you could try alternating back and forth between brake clean and the penetrating oil, each time before you open the valve.

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Thanks for the help guys, I'll keep working it. I've got plenty else to do, 3 out of four of the bolts holding the top and bottom manifold together broke whilst I was trying to remove them so I've got those to drill out. The heat riser assembly seems to move ok but the spring doesn't have a lot of tension in it. Anyone? The shop manual isn't very clear on how much it should have and I don't know how you'd measure it anyway.

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You can leave closed the heat riser but expect to have to idle for a while on cooler days to prevent carburetor icing. It is bad on my Dodge 8. Start it, idle for 5 minutes, shut down, go and fetch your jacket, water bottle, camera, phone, lock up, etc., then come back, restart and drive away. The manifold heat will warm up the venturi and prevent icing.

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PB Blaster is my penetrating oil of choice.

 

On your broken bolts I would apply some of the above and let it soak awhile then if there is any part of the bolt sticking up I would weld a nut to it that is large enough to just fit over the broken bolt and weld through the center of the nut. The heat will help in the loosening and then you can use a wrench on the nut to twist it out.

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Mine as well, and it did it's job on that valve, everything is moving smoothly. Great idea on the broken bolts, I'll give that a try on the two that are protruding.

I pulled the fuel pump to clean it up while I've got the side of the truck torn apart, why not right? Well the "black" bowl turns out to be a glass bowl covered with grease and full of the cork gasket material that was apparently the stock gasket. My newly rebuilt carb is back at the shop to be cleaned (if necessary) , my carb guy laughed at me, haha very funny. Which leads to my next question, do you suppose the standard thick grey paper gasket material will be sufficient where that little cork gasket was under the bowl?

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Heat risers generally don't have much tension, especially at room temp. They shut barely at room temp, flop open when hot.

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1 hour ago, RTS 5215 said:

Mine as well, and it did it's job on that valve, everything is moving smoothly. Great idea on the broken bolts, I'll give that a try on the two that are protruding.

I pulled the fuel pump to clean it up while I've got the side of the truck torn apart, why not right? Well the "black" bowl turns out to be a glass bowl covered with grease and full of the cork gasket material that was apparently the stock gasket. My newly rebuilt carb is back at the shop to be cleaned (if necessary) , my carb guy laughed at me, haha very funny. Which leads to my next question, do you suppose the standard thick grey paper gasket material will be sufficient where that little cork gasket was under the bowl?

On the ones that are not protruding make sure you are centered and try to find a left handed drill bit that is smaller than the tap drill size for your broken bolts.

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Thick paper on the fuel glass bowl? I haven't seen it that way, always cork. But it is easy to try it! You will know very soon if it works. The only problem I foresee is that in your attempt to seal it you will over-tighten the stirrup that holds the bowl on, and bend the upper part of the pump. If that happens it will never seal and the upper part will need straightening.

 

If it needs straightening, come back for the method. Don't attempt with standard bending equipment because you will break it - die casting metal is brittle.

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