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Broken Advance

Posted: Thu Nov 27, 2025 2:20 pm
by mrkprsn
Hi Peeps,

My NC Sebring stopped running suddenly last week. Felt like an electrical issue so I went through everything: coil, condenser, spark plug, connections, battery, points, switches, etc. Finally I decided to check the timing and something seemed off. Tried to move the advance and it didn't move clockwise and I couldn't retard the spark enough using the point plate. Decided to take the plate off and this is what I found.

So my questions to you are: The springs look OK. The posts that hold the springs were sheared off. You can see one in the picture. There was another one behind the advance. I guess if I experience a similar thing again I should check the advance unit sooner? How common is this? What would cause the posts to shear off? As always thanks and Happy Thanksgiving to the Americanos.

-Mark

DucatiAdvanceSmall.jpg

Re: Broken Advance

Posted: Thu Nov 27, 2025 3:14 pm
by Duccout
Weird. I wonder if all of the debris at the bottom of the housing had something to do with it? Maybe a good time to switch to an electronic system....


Cheers,

Colin

Re: Broken Advance

Posted: Fri Nov 28, 2025 11:33 pm
by LaceyDucati
I've only seen this sort of destruction when a screw fixing the points or condenser is installed into the backplate that is too long. Another cause of failure could be trying to alter advance by bending or tweaking the stops, resulting in cracks, maybe something broke off or came adrift. Normally these units seem pretty robust.

Nigel

Re: Broken Advance

Posted: Sun Dec 14, 2025 6:51 pm
by mrkprsn
Well Nigel was right (again)! The screw I used to secure the points to the point plate was too long. In my parts book I can see the two short (5mm) screws that hold the point plate to the timing cover and the only other screw around it was 10mm.

When attaching the point plate to the cover and setting the points gap, the longer screw interfered with the advance and bent the point plate when I tightened it. That is why the timing kept moving when I went to tighten the point plate screws when setting/locking the timing plate.

I straightened the plate and used a shorter screw when attaching the points to the plate and when setting the points gap. The point plate didn't move when setting/locking the timing since the plate was straight.

All of this was self induced. I feel like a flagellant.

Flagellant.jpg

Re: Broken Advance

Posted: Mon Dec 15, 2025 11:10 am
by Duccout
I bet we have all felt like that a sometime! Mistakes make us human.

Cheers,

Colin

Re: Broken Advance

Posted: Mon Dec 15, 2025 2:00 pm
by blethermaskite
Yeah, if we were honest we would admit to getting it wrong :cry: I was that 19 year old who stuck a tyre lever in the head to jam the camshaft from turning......resulting in cracking a lump out of the top of the head ......arrrgh !!
Cheers George

Re: Broken Advance

Posted: Mon Dec 15, 2025 4:31 pm
by DBDBrian
The person who has never made a mistake, has never made anything. I think quite likely we've all been there, I know I have.