Generators and Motors
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Electric Motors General Discussion > Onan Generators
Forgot Password? Join Us!

Notices

Onan Generators Restoring, operating and maintaining vintage Onan generators.

Onan Generators

Onan 4GBE spark problem


this thread has 75 replies and has been viewed 2284 times

Reply
 
Thread Tools Display Modes
  #21  
Old 03-06-2017, 11:52:00 AM
Pete Spaco Pete Spaco is offline
Registered-II
 
Join Date: Dec 2009
Location: Baldwin, Wisconsin USA
Posts: 808
Thanks: 25
Thanked 556 Times in 281 Posts
Default Re: Onan 4GBE spark problem

Re magnet polarity:
It can matter big time. Check out Hall effect sensors, or go to:
https://www.youtube.com/watch?v=IWsqIPXExgo

Pete Stanaitis
----------------
Reply With Quote
Sponsored Links
  #22  
Old 03-06-2017, 12:05:04 PM
len k len k is offline
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 15,735
Thanks: 421
Thanked 5,681 Times in 4,121 Posts
Default Re: Onan 4GBE spark problem

Can try drilling a magnet, but I think some are very hard. I like the way they are mounted in the video, the aluminum supports against centrifical stress and the epoxy just holds them from vibrating out. Onan had problems with magnet adhesive failing on their inverter gens ( HDKAJ types)

Polarity does matter , but from a practical standpoint you can mount the magnets, then if that doesn't work swap the polarity.

Or you can look at polarity of remaining rotor arm magnet and look at valve motion to determine what magnet polarity fires the coil before TDC. Can use an spare small magnet to match arm's polarity to new magnet. (On a compass the part of the needle that points north is compass magnet's south pole, went thru this at work.)

Last edited by len k; 03-06-2017 at 12:39:10 PM.
Reply With Quote
  #23  
Old 03-06-2017, 05:38:02 PM
bbqjoe bbqjoe is offline
Registered
 
Join Date: Mar 2017
Location: Wikieup, Arizona, USA
Posts: 41
Thanks: 6
Thanked 1 Time in 1 Post
Default Re: Onan 4GBE spark problem

I'm really close. I've got spark now.
The biggest challenge is keeping the magnets on for testing purposes
I've tried hot glue, zip ties, and bailing wire.
The stickler is that the backside of the fins are at an angle, so everything wants to slide towards the thinner end.

I believe I'll drill a hole in each corresponding fin, and use some of this stuff I have called PC 11.
It will severely hold two things never made to be held together, together.
It takes well over 24 hours for a full cure.

The next mission will be to set up the sensor a little better so I can slide it one direction or the other to adjust the timing.

The engine is burning ether and wants to start, but I think my timing is off just a hair or two.
It wants to run almost as bad as I want it to.

If I can get it to fire, I'll put the carb back on, and go from there I guess.

Also, this engine has never had a real snappy spark from day one.
It's never been a bright blue, more like a hot yellow.

I realize this is all very crude.
Attached Thumbnails
Click image for larger version

Name:	IMG_4089.JPG
Views:	52
Size:	166.5 KB
ID:	276668  
Reply With Quote
  #24  
Old 03-06-2017, 06:12:38 PM
len k len k is offline
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 15,735
Thanks: 421
Thanked 5,681 Times in 4,121 Posts
Default Re: Onan 4GBE spark problem

When I was thinking of doing something like that I was thinking of using smaller cylindrical magnets say 3/16 inch in dia by ~ 1/2 inch long. Also I would drill into SIDE of flywheel, parallel to it's shaft axis so glue will not need to fight centrifugal force. ( less stress in the glue). I'm assuming there is clearance on side of flywheel , would guess magnet would only have to stick out 1/4 inch or less.

I would mount the ignition modual so it is adjustable to move to different angles, as firing angle before TDC will vary with how far ( strong) the magnet field reaches out to it. ( you'll have to trial and error it with a timing light)

One way to get magnets like this is use the magnet from a door alarm security sensor ( 3-rd link).

http://www.grisk.com/images/product_...re_magnets.pdf
http://www.grisk.com/images/product_...ty_magnets.pdf
http://www.grisk.com/images/product_..._press_fit.pdf <---- can disassemble this type to get the magnet.
http://www.grisk.com/magnetic-reed-switches.php

Last edited by len k; 03-06-2017 at 06:37:12 PM.
Reply With Quote
The Following User Says Thank You to len k For This Post:
  #25  
Old 03-06-2017, 09:47:02 PM
bbqjoe bbqjoe is offline
Registered
 
Join Date: Mar 2017
Location: Wikieup, Arizona, USA
Posts: 41
Thanks: 6
Thanked 1 Time in 1 Post
Default Re: Onan 4GBE spark problem

https://www.youtube.com/edit?o=U&video_id=bE2SGqMLyZ4

There's some more work to do, butI'm doing a happy dance.

I think I need to go over all the internal connections in the box. For some reason it seems to briefly run better with a positive wire run to the positive terminal on the coil.

I'm guessing videos don't embed here?
Reply With Quote
  #26  
Old 03-06-2017, 09:55:22 PM
Pete Spaco Pete Spaco is offline
Registered-II
 
Join Date: Dec 2009
Location: Baldwin, Wisconsin USA
Posts: 808
Thanks: 25
Thanked 556 Times in 281 Posts
Default Re: Onan 4GBE spark problem

I just looked up neodymium magnets on Ebay. I noticed several styles that already have holes drilled in them! Some have straight holes and some are even countersunk.
I've used a 1/4" round X 1/16" thick solid version with Hall Effect sensors and they will work up to about a quarter inch away from the sensor reliably.

Several years ago, all four magnets let loose from the distributors, trigger wheel on a Genese "electronic ignition" kit the the previous owner had installed. It was due to a interference problem between the trigger wheel, the rotor and the top of the distributor cap. Caused enough heat to swell the trigger wheel and free up the cast-in-place magnets. Anyway, I JB Weld epoxied them back in place after fixing the interference problem and it has worked well ever since.

Pete Stanaitis
---------------
Reply With Quote
  #27  
Old 03-06-2017, 09:58:45 PM
bbqjoe bbqjoe is offline
Registered
 
Join Date: Mar 2017
Location: Wikieup, Arizona, USA
Posts: 41
Thanks: 6
Thanked 1 Time in 1 Post
Default Re: Onan 4GBE spark problem

https://www.youtube.com/watch?v=bE2SGqMLyZ4
Maybe this will work.
Reply With Quote
  #28  
Old 03-06-2017, 11:31:08 PM
David C David C is offline
Registered-III
 
Join Date: Mar 2006
Location: Lake Jackson,Texas
Posts: 1,369
Thanks: 1,033
Thanked 855 Times in 557 Posts
Default Re: Onan 4GBE spark problem

If the module is the same part number as the system that uses the module under the flywheel, can an ignition rotor added behind the flywheel. I would bet the front cover has the mounting bosses for the module. This would make it an OEM setup. Below is link to an OEM setup.
http://www.ebay.com/itm/Genuine-Onan...cAAOSwY45UP9iq

Here is a link to a used rotor.
http://www.ebay.com/itm/CASE-Ingerso...YAAOSw5cNYcTme

David C.
Reply With Quote
  #29  
Old 03-07-2017, 03:41:20 PM
len k len k is offline
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 15,735
Thanks: 421
Thanked 5,681 Times in 4,121 Posts
Default Re: Onan 4GBE spark problem

bbqjoe ..... well, anything could work. But I'ld want something stable that doesn't stand a chance of moving or falling off. That's why I recommend the small cylindrical magnets press fit or glued into holes drilled into flywheel, even if you have to make up a bracket to hold the ignition modual sensor. I'ld avoid drilling into fins if I could, or at least not the base of fins

I don't think you need LARGE magnets. Their large weight just makes for higher centrifugal forces trying to pull them off flywheel. The magnets are pulling ~550 G's at edge of flywheel. If magnet weighs 1 ounce then that's ~ 35 pounds of force trying to pull magnet off. I'm a mechanical engineer

Last edited by len k; 03-07-2017 at 04:41:29 PM.
Reply With Quote
  #30  
Old 03-07-2017, 04:50:03 PM
bbqjoe bbqjoe is offline
Registered
 
Join Date: Mar 2017
Location: Wikieup, Arizona, USA
Posts: 41
Thanks: 6
Thanked 1 Time in 1 Post
Default Re: Onan 4GBE spark problem

You've got one up on me, I've never driven a train.
JK

You're correct here.
The magnets are pure overkill, and were just an easy find for test porpoises.
I have a few magnets out of I hard drive that I will try next.

Thanks.
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

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Onan Emerald I Genset Spark Problem Saulfun1971 Magnetos, Ignition Coils and Spark Plugs 2 06-13-2016 12:26:10 PM
onan 65nhl genreator spark problem Bob25359 Onan Generators 2 08-03-2014 09:11:14 PM
'94 Onan DKD Spark Arrestor Fitting Problem Pete Miller Onan Generators 1 08-03-2014 07:49:35 PM
Spark Problem Cruiser Onan Generators 16 10-29-2010 07:53:54 PM
Lincwelder 225 Onan CCK spark problem distinguished1 Onan Generators 4 09-11-2008 10:34:52 PM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 02:38:14 AM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277