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 07-04-2021, 11:23 AM   #1
GPierce
Senior Member
 
GPierce's Avatar
 
Join Date: Dec 2014
Location: Germantown,TN
Posts: 344
Default Worn-out Distributer Cap Carbon Brush

500 miles on new A-12115 Distributer Cap. ??
I was checking the newly installed original points from NAPA as my timing had changed slightly at 500 miles and found this. I expected the point gap to close up slightly but not a worn out rotor brush. Noticed the brass particles when I glanced at the cap and thought gee I need to investigate where those brass particles came from.
Attached Images
File Type: jpg Brush.jpg (106.6 KB, 114 views)
GPierce is offline   Reply With Quote
Old 07-04-2021, 11:53 AM   #2
J Franklin
Senior Member
 
J Franklin's Avatar
 
Join Date: May 2010
Location: Oregon
Posts: 5,003
Default Re: Worn-out Distributer Cap Carbon Brush

Check or replace the rotor as needed. Was it fully seated in the down position?
J Franklin is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-04-2021, 12:42 PM   #3
GPierce
Senior Member
 
GPierce's Avatar
 
Join Date: Dec 2014
Location: Germantown,TN
Posts: 344
Default Re: Worn-out Distributer Cap Carbon Brush

I also installed new rotor. Good point, the rotor was fully seated I thought as there just a little springy feel as I set the cap on. Not being fully seated would certainly cause that problem.
GPierce is offline   Reply With Quote
Old 07-04-2021, 06:06 PM   #4
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,177
Default Re: Worn-out Distributer Cap Carbon Brush

I would think Brass particles are from the rotor or body terminals. You need to “ with no side play” on your rotor shaft, set the gap to around .025” on all four body tits. Also check to make sure all four lobes of the distributor cam give you the same point gap. As for the carbon button wearing out prematurely, you may not have had the rotor fully seated as you surmised. The other possibility is the spring pressure from the top of the rotor is too much. When you set the cap down, you should have a small amount of spring pressure.
Chuck Sea/Tac is offline   Reply With Quote
Old 07-04-2021, 06:50 PM   #5
GPierce
Senior Member
 
GPierce's Avatar
 
Join Date: Dec 2014
Location: Germantown,TN
Posts: 344
Default Re: Worn-out Distributer Cap Carbon Brush

The brass dust was from the the worn down brass bushing surrounding the carbon brush. The brass bushing wear can be seen in photo. The rotor and plug contacts tits are untouched. I did have very slight spring back from the cap when I put it on. The hold down springs snapped right on. The distributer body had just been overhauled by a vendor and shaft and bushings were new. I am still leaning toward soft carb or the rotor was not down tight on shaft.
GPierce is offline   Reply With Quote
Old 07-05-2021, 03:31 AM   #6
old31
BANNED
 
Join Date: Jan 2016
Posts: 1,638
Default Re: Worn-out Distributer Cap Carbon Brush

Sponsored Links (Register now to hide all advertisements)
Quote:
Originally Posted by Chuck Sea/Tac View Post
I would think Brass particles are from the rotor or body terminals. You need to “ with no side play” on your rotor shaft, set the gap to around .025” on all four body tits. Also check to make sure all four lobes of the distributor cam give you the same point gap. As for the carbon button wearing out prematurely, you may not have had the rotor fully seated as you surmised. The other possibility is the spring pressure from the top of the rotor is too much. When you set the cap down, you should have a small amount of spring pressure.
There you go again Chuck with that technical talk "body tits".
old31 is offline   Reply With Quote
Old 07-05-2021, 06:47 PM   #7
1930 coupe
Senior Member
 
Join Date: May 2010
Posts: 226
Default Re: Worn-out Distributer Cap Carbon Brush

...

Last edited by 1930 coupe; 09-07-2021 at 12:06 AM.
1930 coupe 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 12:14 PM.