The Ford Barn

30aadoodlebug · 06-19-2021, 05:48 AM

So the 41 is running rough and chugging. blue/black smoke only out if the left tail pipe (duals). When she backfires, or goes up hill, it comes out both. The fuels system has checked out. Rebuilt carb and such. I have replaced the condenser, and have checked to make sure I am firing on all 8 plugs. I have a good strong spark to all 8. The car is vibrating hard and acting like a vacuum leak, but all lines have checked out. Im lost on this one.....

ponymare · 06-19-2021, 05:54 AM

Black smoke means over rich, or weak spark, blue smoke is burning oil, might want to replace that rebuilt carb with a known good one and see what happens.

30aadoodlebug · 06-19-2021, 05:59 AM

im leaning toward ground and ignition switch on this one...

Terry,OH · 06-19-2021, 06:57 AM

Suggest put a vacuum gauge on it and check compression. If you believe ignition then jumper out the ignition switch then the resistor as a temporary measure to see if condition improves. Could also jumper any suspected grounds to see if there is an improvement, use a battery jumper cable. Are you running a Stromberg or Holley Carb.?

Check engine oil for fuel. Could be a bad power valve, sticking valves ???? Backfires can rupture the diaphragm on the 94 power valve.

30aadoodlebug · 06-19-2021, 07:14 AM

Terry, I rebuilt the carburetor. All new internals. Now I'm wondering if the vacuum diaphragm in the distributor blew with the backfire.

Terry,OH · 06-19-2021, 09:49 AM

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41 distributor does not have a vacuum diaphragm, it does have a vacuum brake assembly. The vacuum brake assembly slows the mechanical advance. What engine do you have?

corvette8n · 06-19-2021, 03:42 PM

Just got my ‘41 distributor back from Charlie NY, I could barley get the car home one day. He rebuilt it totally, new bearings, points etc, runs great.

30aadoodlebug · 06-19-2021, 04:34 PM

Terry, stock 41 engine. Over bore .125. It's the carb

30aadoodlebug · 06-20-2021, 09:24 AM

More frustration! I put a known good carb on and it's still acting up. No black smoke now, just white. Time to chase the ignition. Small constant backfiring and missing.

30aadoodlebug · 06-20-2021, 09:41 AM

I'm only getting. .010 volts off the positive side of the coil. I'm think ignition switch or cable???

06-19-2021, 05:48 AM	#1
30aadoodlebug Senior Member Join Date: Jul 2014 Location: Boxborough, MA Posts: 274	Possible Ignition issues in a 41 So the 41 is running rough and chugging. blue/black smoke only out if the left tail pipe (duals). When she backfires, or goes up hill, it comes out both. The fuels system has checked out. Rebuilt carb and such. I have replaced the condenser, and have checked to make sure I am firing on all 8 plugs. I have a good strong spark to all 8. The car is vibrating hard and acting like a vacuum leak, but all lines have checked out. Im lost on this one.....

06-19-2021, 05:54 AM	#2
ponymare Senior Member Join Date: Sep 2014 Posts: 160	Re: Possible Ignition issues in a 41 Black smoke means over rich, or weak spark, blue smoke is burning oil, might want to replace that rebuilt carb with a known good one and see what happens.

06-19-2021, 05:59 AM	#3
30aadoodlebug Senior Member Join Date: Jul 2014 Location: Boxborough, MA Posts: 274	Re: Possible Ignition issues in a 41 im leaning toward ground and ignition switch on this one...

06-19-2021, 06:57 AM	#4
Terry,OH Senior Member Join Date: May 2010 Posts: 4,743	Re: Possible Ignition issues in a 41 Suggest put a vacuum gauge on it and check compression. If you believe ignition then jumper out the ignition switch then the resistor as a temporary measure to see if condition improves. Could also jumper any suspected grounds to see if there is an improvement, use a battery jumper cable. Are you running a Stromberg or Holley Carb.? Check engine oil for fuel. Could be a bad power valve, sticking valves ???? Backfires can rupture the diaphragm on the 94 power valve.

06-19-2021, 07:14 AM	#5
30aadoodlebug Senior Member Join Date: Jul 2014 Location: Boxborough, MA Posts: 274	Re: Possible Ignition issues in a 41 Terry, I rebuilt the carburetor. All new internals. Now I'm wondering if the vacuum diaphragm in the distributor blew with the backfire.

06-19-2021, 09:49 AM	#6
Terry,OH Senior Member Join Date: May 2010 Posts: 4,743	Re: Possible Ignition issues in a 41 Sponsored Links (Register now to hide all advertisements) 41 distributor does not have a vacuum diaphragm, it does have a vacuum brake assembly. The vacuum brake assembly slows the mechanical advance. What engine do you have?

06-19-2021, 03:42 PM	#7
corvette8n Senior Member Join Date: Jul 2010 Location: 36 miles north of Albany NY Posts: 2,943	Re: Possible Ignition issues in a 41 Just got my ‘41 distributor back from Charlie NY, I could barley get the car home one day. He rebuilt it totally, new bearings, points etc, runs great.

06-19-2021, 04:34 PM	#8
30aadoodlebug Senior Member Join Date: Jul 2014 Location: Boxborough, MA Posts: 274	Re: Possible Ignition issues in a 41 Terry, stock 41 engine. Over bore .125. It's the carb

06-20-2021, 09:24 AM	#9
30aadoodlebug Senior Member Join Date: Jul 2014 Location: Boxborough, MA Posts: 274	Re: Possible Ignition issues in a 41 More frustration! I put a known good carb on and it's still acting up. No black smoke now, just white. Time to chase the ignition. Small constant backfiring and missing.

06-20-2021, 09:41 AM	#10
30aadoodlebug Senior Member Join Date: Jul 2014 Location: Boxborough, MA Posts: 274	Re: Possible Ignition issues in a 41 I'm only getting. .010 volts off the positive side of the coil. I'm think ignition switch or cable???

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