Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 06-13-2018, 03:46 PM   #1
bgalla
Member
 
Join Date: Aug 2011
Location: Chico,Ca
Posts: 44
Default No Spark? '31-12V

One should be able to get a reasonable spark out of a coil with the ignition on and with access to the points opening them. Right! I have held the coil to distributor cap wire close to a good ground and nothing! Could a bad condenser do this? Or is it more likely the coil. There is a resistor interposed between the terminal box and the coil on the Black wire. Other than converting it to 12V it is totally stock. thanks Bruce
bgalla is offline   Reply With Quote
Old 06-13-2018, 04:16 PM   #2
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Upstate NY and western Florida
Posts: 4,664
Default Re: No Spark? '31-12V

Is this monster + or - grd ? Not that it matter that much for your problem, but, whatever the battery ground is, it should be the same thru the points.

Do you have voltage to the open point arm when key is on ? It should be about 8 volts if you have the correct coil or external ballast resistor, whichever you're using. If you have no voltage then work back until you do and you'll find the problem. If you have voltage then make sure there is none when the points close. Most of the no spark issues are in the primary circuit somewhere.

Yes, a bad condenser could cause no spark.

How much of a gap are you trying to jump ? 1/4" will do.
Patrick L. is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 06-13-2018, 04:17 PM   #3
Art Newland
Senior Member
 
Art Newland's Avatar
 
Join Date: Mar 2016
Location: Bellingham, WA
Posts: 1,378
Default Re: No Spark? '31-12V

Make sure what ever you are opening the points with is insulated.
__________________
"whatever works!"
Art Newland is offline   Reply With Quote
Old 06-13-2018, 05:47 PM   #4
bgalla
Member
 
Join Date: Aug 2011
Location: Chico,Ca
Posts: 44
Default Re: No Spark? '31-12V

Patrick: It is a negative grd. When you say "open arm of the points" do you mean open to current with the points closed or should the moveable point arm be open. I may have to refresh my knowledge of how the spark is generated. thanks Bruce
bgalla is offline   Reply With Quote
Old 06-14-2018, 05:00 AM   #5
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Upstate NY and western Florida
Posts: 4,664
Default Re: No Spark? '31-12V

With key on there should be voltage to the moveable point arm when it is open [high point on cam showing an air gap] . That indicates there are no problems such as opens or grounds in the primary circuit.

When points are closed there should be no voltage indicating that the stationary point contact is grounded.

With a 12v negative grd system, the coil primary wires will need to be reversed. The negative coil wire will be to end up going to the points.

You'll need to know what type coil you are using. Does it contain a resistor, it not, you'll need to and an external ballast. It'll either be a 1.5 ohm or 3.0 ohm coil. If its oil filled then it should be mounted with the secondary coil wire pointing to the sky.
Patrick L. is offline   Reply With Quote
Old 06-14-2018, 07:13 AM   #6
eagle
Senior Member
 
eagle's Avatar
 
Join Date: Aug 2011
Location: Eagle Bend, MN
Posts: 1,180
Default Re: No Spark? '31-12V

Use a point file or piece of emery cloth folded double to clean the points. Hand crank the engine over until points are closed, then turn on ignition. Use a wood splinter to snap the points open/closed. Should get a nice hot blue spark off the coil wire.
__________________
"There are some that can destroy an anvil with a teaspoon and shouldn't be allowed to touch anything resembling a tool."
eagle is offline   Reply With Quote
Old 06-15-2018, 04:50 AM   #7
Mike V. Florida
Senior Member
 
Mike V. Florida's Avatar
 
Join Date: May 2010
Location: South Florida
Posts: 13,523
Send a message via AIM to Mike V. Florida
Default Re: No Spark? '31-12V

Quote:
Originally Posted by bgalla View Post
One should be able to get a reasonable spark out of a coil with the ignition on and with access to the points opening them. Right! I have held the coil to distributor cap wire close to a good ground and nothing! Could a bad condenser do this? Or is it more likely the coil. There is a resistor interposed between the terminal box and the coil on the Black wire. Other than converting it to 12V it is totally stock. thanks Bruce

It could but if the condenser has been made in the last 10 years most likely not.


What has changed? Did it ever work on 12 volts? If you put a piece of paper between the points do you have voltage at the movable arm to a head nut? If so what is the voltage?
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II
Mike V. Florida is offline   Reply With Quote
Old 06-15-2018, 07:58 AM   #8
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 1,300
Default Re: No Spark? '31-12V

Have you checked both primary and secondary windings of the coil for continuity w/an ohmmeter?
__________________
Talk slow, think fast.
katy is offline   Reply With Quote
Old 06-15-2018, 10:31 PM   #9
Mike V. Florida
Senior Member
 
Mike V. Florida's Avatar
 
Join Date: May 2010
Location: South Florida
Posts: 13,523
Send a message via AIM to Mike V. Florida
Default Re: No Spark? '31-12V

Try this,


https://www.fordbarn.com/forum/showp...42&postcount=5
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II
Mike V. Florida is offline   Reply With Quote
Old 06-16-2018, 11:04 AM   #10
redmodelt
Senior Member
 
redmodelt's Avatar
 
Join Date: May 2010
Location: Portland OR
Posts: 3,608
Default Re: No Spark? '31-12V

Quote:
Originally Posted by eagle View Post
Use a point file or piece of emery cloth folded double to clean the points. Hand crank the engine over until points are closed, then turn on ignition. Use a wood splinter to snap the points open/closed. Should get a nice hot blue spark off the coil wire.
Very true! Even a little dirt/grease/what not will cause no fire.
__________________
I know the voices aren't real but damn they have some good ideas!
redmodelt is offline   Reply With Quote
Old 06-16-2018, 11:55 AM   #11
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,421
Default Re: No Spark? '31-12V

I agree , I always clean and lightly sand new points , If nothing else , sanding will remove any glaze on the contacts . As for the condenser , If you are using the original style A&L condenser that the better model A vendors sell , its not likely that the condenser will be the problem . I have often called the so called modern points setup a make shift rig . The V8 points are no advantage at all and are difficult to adjust . I always eventually had problems with them . The wireless lower plate that is often used with the V8 points can easily short against the housing . Its your choice but I would recommend switching back to the original points set up. I had lots of trouble with the low cost ignition switch. I had to change to the slightly over fifty dollar switch for dependability . When you set the timing , Set it like Tom Wesenburgs pic. Any rotational backlash in the distributor shaft should be in the counter clockwise direction where it will have no retarding effect on the timing when the cam screw is tightened . Any clockwise back lash in the distributor shaft after the screw is tightened will cause the timing to be retarded . The reason clockwise backlash causes retarded timing is the engine will have to turn to catch up the backlash .
Purdy Swoft is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 10:11 PM.