Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts New!  See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Engine and coil problems
Forum Index -> Performance/Engines/Transmissions Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
samuelsantana
Samba Member


Joined: February 11, 2010
Posts: 4
Location: orlando,fl
samuelsantana is offline 

PostPosted: Thu Aug 25, 2011 6:29 pm    Post subject: Engine and coil problems Reply with quote

Hey guys, I am having a bit of a problem with my recently rebuilt 1641cc motor. Sad when I leave the car the car on idle for like 20 minutes (hatch open) the coil will heat up more than normal and then the motor will start to heat up also. I have replaced the coil 3 times with new and original ones and they do the same thing. What I am wondering is if these 2 problems are connected. The motor was also placed in the correct timing position with a timing light. Any help is appreciated thank you.
Back to top
View user's profile Send private message Classifieds Feedback
Bikerchris
Samba Member


Joined: May 08, 2010
Posts: 290
Location: Texas
Bikerchris is offline 

PostPosted: Thu Aug 25, 2011 7:20 pm    Post subject: Reply with quote

I had a problem similar to this once and it seems to me it turned out to be the wiring in the ignition switch. Does that sound logical to you?
Back to top
View user's profile Send private message Gallery Classifieds Feedback
RailBoy
Samba Member


Joined: March 10, 2008
Posts: 2794
Location: Virginia
RailBoy is offline 

PostPosted: Thu Aug 25, 2011 7:27 pm    Post subject: Reply with quote

Resistor....????? RB
Back to top
View user's profile Send private message Gallery Classifieds Feedback
lostinbaja
Samba Member


Joined: December 19, 2004
Posts: 4036
Location: Frankfort, Illinois
lostinbaja is offline 

PostPosted: Thu Aug 25, 2011 7:31 pm    Post subject: Reply with quote

Some coils have an internal resistor and some require external resistors. A coil spec'd for a 12v VW will have an internal resistor. I take it you have a 12v system?
_________________
Jerry...
If it's being towed, it must be a trailer!
"Vee Grow Too Soon Oldt Und Too Late Schmardt"
RIP Morgan

My photos
http://www.manxgallery.org/gallery/album92
Back to top
View user's profile Send private message Gallery Classifieds Feedback
RailBoy
Samba Member


Joined: March 10, 2008
Posts: 2794
Location: Virginia
RailBoy is offline 

PostPosted: Thu Aug 25, 2011 8:18 pm    Post subject: Reply with quote

Not so sure about that, have seen motors with 12 Volt & Resistors mounted to the fan shrouds, they looked stock..... But it was a while ago, could have been 6 volt systems though..... RB
Back to top
View user's profile Send private message Gallery Classifieds Feedback
samuelsantana
Samba Member


Joined: February 11, 2010
Posts: 4
Location: orlando,fl
samuelsantana is offline 

PostPosted: Fri Aug 26, 2011 3:17 am    Post subject: Reply with quote

Yes its a 12v system and as far as I know the coil has a built in resistor. We thought it was a resistor problem but all 3 of my coils got hot. I don't think I have 3 bad coils. This motor is in a 1966 bus and before I purchased it, it was converted to 12v from 6 volt. Also when I rebuilt the motor I changed the generator to an alternator. Thanks guys
Back to top
View user's profile Send private message Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 23637
Location: Colorado Springs
modok is offline 

PostPosted: Fri Aug 26, 2011 3:34 am    Post subject: Reply with quote

The coil should have a resistance of 3-4 ohms for points or the usual modules. Across the 12V and points lugs.
The resistance is the main thing that determines how much power they draw.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
RockCrusher
Samba Member


Joined: August 03, 2010
Posts: 4596
Location: Parkesburg, PA
RockCrusher is offline 

PostPosted: Fri Aug 26, 2011 3:52 am    Post subject: Reply with quote

modok wrote:
The coil should have a resistance of 3-4 ohms for points or the usual modules. Across the 12V and points lugs.
The resistance is the main thing that determines how much power they draw.
You're up mighty early today! E=IR or I(4amps)=E(12volts)/R(3ohms).
Don't let the 4 amps scare you coz it's intermittent current and peak at that. The inrush current is 4 amps and decreases as the magnetic field builds and the total time is 50* x 2 per engine revolution of 360* so the heat rise should be less than the equivalent of 1 amp at 3 ohms full time....more like .25 amp heat. Of course the faster the engine turns the higher the average current.

RC

EDIT-I said that backwards (I see, now that I'm awake) The resistance is high at the beginning and lessens as the with time so the current gets higher with time on each cycle BUT as cycle frequency increases with RPM the inductance shows increasing impedance so the current becomes less and less with increasing RPM. That's why the output voltage starts to drop off over the coils RPM limit in typical ignition systems.
_________________
[email protected] Please use email for all general inquiries.

I will be happy to speak to anyone who has a serious inquiry (meaning real potential business for RC enterprises) or a parts order. Due to machining noise causing missed calls all calls will be returned promptly.


Last edited by RockCrusher on Fri Aug 26, 2011 8:28 am; edited 2 times in total
Back to top
View user's profile Send private message Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 23637
Location: Colorado Springs
modok is offline 

PostPosted: Fri Aug 26, 2011 4:07 am    Post subject: Reply with quote

Oh crap, I forgot to sleep
Back to top
View user's profile Send private message Gallery Classifieds Feedback
samuelsantana
Samba Member


Joined: February 11, 2010
Posts: 4
Location: orlando,fl
samuelsantana is offline 

PostPosted: Fri Aug 26, 2011 4:46 am    Post subject: Reply with quote

please help, I'm loosing sleep over these. Shocked
Back to top
View user's profile Send private message Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 23637
Location: Colorado Springs
modok is offline 

PostPosted: Fri Aug 26, 2011 4:38 pm    Post subject: Reply with quote

man, this morning was rough

Anyway, if the points have somewhere near the right gap and dwell, and the coil has the correct resistance, and it's hooked up right, and you tried three coils, then it must be ok.
right?
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Performance/Engines/Transmissions All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2020, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB