Problem that has me stumped

If you can get a vacuum gauge hooked up and watch it as it warms up you can probably diagnose your problem. My guess is sticky valves. Your car may be running rich for whatever reason and carbon has built up on them. I had this problem with my 49. MM down the carb and some in the tank took care of it. Also had carb rebuilt.
 
No and Yes, pull the plugs, and read the color, should be all light pink or pure white, corn gas is hard to read, now the most telling "" A COMPRESSION "" check/test ,,, all plugs are out, prop the throttle wide open.... best with the engine is warm, but if it's running poor, don't push it. .. do comp. test and take notes, did I read in a early post, some plugs were black, ..to much gas, running rich ?? or bad plug, new or not, could be bad, move the plugs around, or put some old ones back in for a test ?? ......OLD.....BILL
 
My folks had a 100 horse in a 49 ford, it was a pretty hot ticket in the day (or so the story goes). Mom used to stop and fill the tank at the local gas station, the attendant always hated having his butt kicked by that 49, so he used to pull 4 plug wires off while he was under the hood checking the oil, and it always tweaked him off that she could start that thing up and drive away like nothing was wrong. They will run well on 4.
 
Took out the new plugs,replaced them with used plugs,engine starts and runs great.Who would have guessed that NEW plugs whould have caused my problems.Thanks for all the suggestions Phil
 
I guess that shows the quality of the new plugs you previously installed. Please tell us the brand that you had all the aggravation with so we can possibly not buy them. ken ct. 4 out of 8 new plugs N/G. That was a cheap fix in the end. ken ct,LOL
 
With all due respect, I doubt that the fault is entirely the fault of 4 spark plugs.
For four new plugs to be crook on one side of your engine, would be a 1 in a million, what ever brand they are.
What plug are the plug gaps, Are the HT leads proven? What about the cap and rotor?
Does it have any air leaks?
IF your plug gaps are different, with a weak spark, crook leads, metal or tracking in the cap, rotor tracked.
Those things could cause failure to fire. Sometimes a big gap will make the spark go when a narrow one won't fire the plug.
What ever it is, apart from flooding, I would discount the fuel side, due to each barrel feeding two cylinders on each side.
What I am trying to say, is that I think you are on the edge of another problem.
I do concede you might have bought a number of faulty plugs, but even if you dropped a box full, you are unlikely to have a failure in four.
Just my thoughts and trying to help.
I hope this make sense, I have found that I can't read back more than a page, once I've started posting.
 
6 volt ignitions SUCK! I had 1967 Triumph Bonnevile years ago, my friend had an earlier one, was a 6 volt. His motor was running poorly, Sunday so no parts back then. I took the plugs out of my bike and exchanged them with his plugs. His bike ran fine with my plugs, my bike ran fine with his shot plugs. 12 volt is the only way to go.
 
Bluebell has a good point. Swapping the plugs may have fixed the problem for now. If you are using period correct HT leads in the metal loom I would suspect that as the root cause.

36-5window, If every thing is tuned and set up correctly the HT output of either 12volt or 6volt systems IS the same. Your buddy's bike was out of tune. Yours was in tune and could run on his fouled plugs.
 
thanks for all the help guys, I always enjoy this forum more than any of them. Just for the record,I WAS RIght!! I CAN'T WAIT TO TELL my wife!!:o
 
Bluebell said:
With all due respect, I doubt that the fault is entirely the fault of 4 spark plugs.
For four new plugs to be crook on one side of your engine, would be a 1 in a million, what ever brand they are.
What plug are the plug gaps, Are the HT leads proven? What about the cap and rotor?
Does it have any air leaks?
IF your plug gaps are different, with a weak spark, crook leads, metal or tracking in the cap, rotor tracked.
Those things could cause failure to fire. Sometimes a big gap will make the spark go when a narrow one won't fire the plug.
What ever it is, apart from flooding, I would discount the fuel side, due to each barrel feeding two cylinders on each side.
What I am trying to say, is that I think you are on the edge of another problem.
I do concede you might have bought a number of faulty plugs, but even if you dropped a box full, you are unlikely to have a failure in four.
Just my thoughts and trying to help.
I hope this make sense, I have found that I can't read back more than a page, once I've started posting.
Click to expand...

I understand what you are saying.But after changing the plugs, the engine starts instantly and runs great from the get-go.You can't fix perfect!I agree that the chances of getting 4out of 8 new plugs bad and putting them in the same bank of cylinders is remote.BUT,I guess I will have to wait and see.
 
I once had a new-plug miss that drove me crazy...after hours of chasing the problem I discovered that 2 of my new plugs had cracked porcelain down at the business end on the electrode, and the little sleeve of porcelain was apparently sliding up and down in action turning my two missing cylinders on and off at random!!
I suspect that someone somewhere had dropped the 10-plug box and cracked the two plugs closest to the drop zone.
 
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