Exploded Ignition Coil - Mercedes-Benz Forum

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 15 (permalink) Old 12-13-2015, 08:01 PM Thread Starter
BenzWorld Junior Member
 
MeanGreenLoveMachine's Avatar
 
Date registered: May 2015
Vehicle: 1972 Mercedes-Benz 250 w114
Location: Pennsylvania
Posts: 11
Mentioned: 0 Post(s)
Quoted: 2 Post(s)
(Thread Starter)
Exploded Ignition Coil

Hi guys,

As I'm scrambling to get my 1972 250 ready to get running before Christmas trouble hits in the form of a fried ignition coil. The car has been sitting a while as I had the tank cleaned and install all new rubber fuel hose and a filter. Today was the day I finally got the beast to fire up. I tried to start it a couple times watching to see if the pump was drawing any fuel to the filter. After a couple of failed attempts I trickle charged the battery --which was already almost dead-- and put a little gas into the carbs just to get it the engine to fire up and start sucking gas. First try it started and immediately raced up to a high idle and oil pressure. I let it sit a little while then drove it around my loop and parked it again happy that she was running once more.
I gave it another trickle charge at 10amps and checked on it every commercial during the Eagles game. The last time I checked I came out to find the ignition coil smoking and burning plastic on the underside of my raised hood and scattered across the ground. I disconnected the battery which stopped the plastic inside the housing to stop burning. Obviously I'm going to need another ignition coil. The previous owner installed a Crane Cam 700 fireball and I'm wondering if I need to buy an ignition coil to complement this or just a bosch 12 amp coil which is similar to what was previously installed. Electrical stuff is not my forte as you can probably see. Is there anything else that I should check for a short or just replace to be safe?

Thank you!
MeanGreenLoveMachine is offline  
Sponsored Links
Advertisement
 
post #2 of 15 (permalink) Old 12-13-2015, 08:06 PM
BenzWorld Elite
 
rumb's Avatar
 
Date registered: Oct 2012
Vehicle: 1968 250S, 1991 300se, 1998 SL500, 2x 1977 450SEL 6.9. Past MB's; 300SD, 300E, 300TE, 190E, ML420
Location: Colorado
Posts: 2,352
Mentioned: 5 Post(s)
Quoted: 425 Post(s)
Garage
did you happen to leave the ignition key on while charging?
rumb is online now  
post #3 of 15 (permalink) Old 12-13-2015, 08:34 PM Thread Starter
BenzWorld Junior Member
 
MeanGreenLoveMachine's Avatar
 
Date registered: May 2015
Vehicle: 1972 Mercedes-Benz 250 w114
Location: Pennsylvania
Posts: 11
Mentioned: 0 Post(s)
Quoted: 2 Post(s)
(Thread Starter)
Yes! Rookie mistake?
MeanGreenLoveMachine is offline  
post #4 of 15 (permalink) Old 12-13-2015, 09:16 PM
BenzWorld Elite
 
flyboyike's Avatar
 
Date registered: May 2003
Vehicle: 2012 Focus SE
Location: Ormond Beach, FL
Posts: 7,699
Mentioned: 1 Post(s)
Quoted: 68 Post(s)
Quote:
Originally Posted by MeanGreenLoveMachine View Post
Yes! Rookie mistake?
Affirmative.

Felicita e un bicchiere di vino con un panino.
flyboyike is offline  
post #5 of 15 (permalink) Old 12-14-2015, 05:09 AM
BenzWorld Extremist
 
kavadarci's Avatar
 
Date registered: Aug 2008
Vehicle: 1971 250C
Location: Toronto, Canada
Posts: 1,056
Mentioned: 0 Post(s)
Quoted: 14 Post(s)
I have the same setup with fireball ignition, let me know what coil ahold match it as mine is factory.

Thank you
kavadarci is offline  
post #6 of 15 (permalink) Old 12-14-2015, 05:26 AM
BenzWorld Elite
 
rumb's Avatar
 
Date registered: Oct 2012
Vehicle: 1968 250S, 1991 300se, 1998 SL500, 2x 1977 450SEL 6.9. Past MB's; 300SD, 300E, 300TE, 190E, ML420
Location: Colorado
Posts: 2,352
Mentioned: 5 Post(s)
Quoted: 425 Post(s)
Garage
That helps know what to do next. Now we know the cause and dont have to look elsewhere. New coil and look at your ballast resistor while down there and make sure it is still good also.

I learned that lesson when I was 16 years old and melted the coil in my 48 Plymouth while cruising and hanging out in the A&W drive in listening to my 8 track.....


BTW, those little trickle chargers say to use only on a fully charged battery for some reason.


anyway, glad you didn't burn your car to the ground!
rumb is online now  
post #7 of 15 (permalink) Old 12-14-2015, 08:46 AM
BenzWorld Elite
 
MBGraham's Avatar
 
Date registered: Oct 2006
Vehicle: '72 350SL, '85 300D, '98 E320, '14 GLK250
Location: Ont, Canada
Posts: 7,834
Mentioned: 1 Post(s)
Quoted: 8 Post(s)
Quote:
Originally Posted by MeanGreenLoveMachine View Post
I gave it another trickle charge at 10amps and checked on it every commercial during the Eagles game.
10 Amps isn't exactly a trickle charge! 1 or 2amps is.

Most chargers self regulate the amperage. How did you set it at 10Amps?

Anyway, the other guys seem to have sorted the main problem

1972 350SL 4.5L - MBGraham, near Kingston, Ontario
MBGraham is online now  
post #8 of 15 (permalink) Old 12-14-2015, 09:35 AM Thread Starter
BenzWorld Junior Member
 
MeanGreenLoveMachine's Avatar
 
Date registered: May 2015
Vehicle: 1972 Mercedes-Benz 250 w114
Location: Pennsylvania
Posts: 11
Mentioned: 0 Post(s)
Quoted: 2 Post(s)
(Thread Starter)
Is the ballast resistor the top box with the blue bracket in the second picture here? If so then what is the function of the bottom white/silver box that bolts in underneath it?
Also in the 1st picture what is the relay(?) with the broken plastic star knob on top. I know the plastic knob wasn't broken before this I'm just wondering if the flying piece of metal got it or if something electrocuted it to death?

Thanks everyone for the help
Attached Thumbnails
Click image for larger version

Name:	IMG_1800.JPG
Views:	114
Size:	124.2 KB
ID:	1707193   Click image for larger version

Name:	IMG_1798.JPG
Views:	177
Size:	92.9 KB
ID:	1707201  
MeanGreenLoveMachine is offline  
post #9 of 15 (permalink) Old 12-14-2015, 09:37 AM Thread Starter
BenzWorld Junior Member
 
MeanGreenLoveMachine's Avatar
 
Date registered: May 2015
Vehicle: 1972 Mercedes-Benz 250 w114
Location: Pennsylvania
Posts: 11
Mentioned: 0 Post(s)
Quoted: 2 Post(s)
(Thread Starter)
MBGraham- I thought I could beat the system by charging it in half the time!

Lesson learned
MeanGreenLoveMachine is offline  
post #10 of 15 (permalink) Old 12-14-2015, 01:28 PM
BenzWorld Veteran
 
Date registered: Aug 2009
Vehicle: '72 250C, '74 280C, '85 500SEL, '81 300CD.
Location: Tucson, Az.
Posts: 679
Mentioned: 3 Post(s)
Quoted: 51 Post(s)
The cover you are asking about is a junction box.

Your original wiring set-up used both resistors. The second isn't needed with the Crane system.

You don't need the resistors if you use an aftermarket coil with the proper resistance.

The resistors were to limit voltage to the ignition contact points extending their service life.
Mike D is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > General Mercedes-Benz Forums > Vintage Mercedes-Benz

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











  • Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     
    Thread Tools
    Show Printable Version Show Printable Version
    Email this Page Email this Page
    Display Modes
    Linear Mode Linear Mode



    Posting Rules  
    You may post new threads
    You may 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
    Trackbacks are On
    Pingbacks are On
    Refbacks are On

     

    Title goes here

    close
    video goes here
    description goes here. Read Full Story
    For the best viewing experience please update your browser to Google Chrome