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bradnree
01-27-2007, 05:57 PM
I'm working on a '47 new to me and have never heard it run. It backfires at the carb and not continuously. It has fire to each old plug which is clean and gapped. It is gapped at .020 with new points and condenser. The old distributor is set just for the points to start to open as per manual. It's getting fuel. It has an old coil, cap, rotor and wires. It will not run. What troubleshooting can be done...........Brad

RHO
01-27-2007, 07:09 PM
Check the wires inside the ditributor for fraying and check the rotor button for wear, maybe the cap for cracks.

'55 Commander
'55 President

gordr
01-27-2007, 07:17 PM
quote:Originally posted by bradnree

I'm working on a '47 new to me and have never heard it run. It backfires at the carb and not continuously. It has fire to each old plug which is clean and gapped. It is gapped at .020 with new points and condenser. The old distributor is set just for the points to start to open as per manual. It's getting fuel. It has an old coil, cap, rotor and wires. It will not run. What troubleshooting can be done...........Brad


Backfiring in the carb could be a symptom of sticking intake valves, and if the car has been sitting for a long time, that could be quite likely. Another possibility could be that the car was retired due to the timing gear having stripped.

Time to try a compression test. Normal compression in several cylinders, and low compression others would tend to confirm the sticking valve theory. Uniformly low compression would be attributable to a stripped timing gear.

In the case of an unknown, possibly tired engine, I'll qualify "normal" in this instance to be from 75 to over 100 psi, at cranking speed while cold, and a range of +/- 10 psi from the median would be "even". This assumes an engine that has not run for while, possible sticky rings, scanty lubrication on cylinder walls, etc. Once the engine gets warmed up and run for a while, it should be held to stricter standards.

As a "for instance:" 75-90-95-55-80-45 could be a couple of stuck valves. 45-40-35-55-45-40 could be stripped timing gear.

You could try removing the spark plugs and putting about a tablespoonful of Dexron in each cylinder, and then reinstalling the plugs and attempting to start. Will help the rings seal and boost compression a bit. If it starts, the mosquitoes won't be thanking you.

Gord Richmond, within Weasel range of the Alberta Badlands

bams50
01-27-2007, 09:32 PM
Don't forget wrong firing order- plug wires in wrong places, or dist. way off;)

Robert K. Andrews Owner- IoMT (Island of Misfit Toys!)
Parish, central NY 13131
http://www.cardomain.com/ride/2358680/1

John Kirchhoff
01-27-2007, 10:51 PM
Sometimes if two or more old cracked plug wires in a bundle, they'll cross fire and cause some crazy things.