For any of you that has dealt with the SSI ignition on a Tecumseh motor either knows about the failed SSI module bug or has got bitten by it, I got "lucky" and got bit twice in 1 month leaving me with two non working OH160 motors/tractors. No way was I gonna pay $150-250 for a used 35 yr old ignition module from Evilbay. Next step was hit the net and do some searching for a fix. I came across Ed Stoller's website http://www.enginesandmagnets.com and decided to do his upgrade. Ed provides some great info and is a really nice guy to talk to. There are also available upgrades from Dale at Overnight Solutions and Brian Miller has a set up on gardentractorpullingtips.com, this is a thread on a different type of setup.
I was talking about it to a friend Jon (searstractorfan) who I met on MTF and he said if I could wait a month or two, he was working on a prototype ignition he was adapting to a Tecumseh 12hp. He had a prototype and needed a real world test mule, I had a broken "mule" that needed a new ignition and we only live 45 mins apart.
Here is link to a thread Jon started on his setup if you would like to read how we got to this point.
Here is my thread on MTF of my install on the tractor, basically same thing I'm posting here, but does have some questions from other members.
So the basic solution is to remove the SSI module which is the signal pickup/coil unit and replace with a magnetic or proximity pickup on the flywheel then to Chrysler control module/HEI module, then to a battery fed coil using the factory flywheel signal pins to trigger pickup. The system that Jon has come up with uses a micro switch which is triggered by a small magnet glued to flywheel then straight to a Bosch Blue coil. Jon had came up with the idea from using this magnet/switch on his alcohol fed pulling tractor. Worked well on a single Kohler puilling motor...why not adapt to a Tec motor. Once Jon did some bench testing, we transferred his parts to my OH160 and off to work it.I cut a field for almost 2 hours, plowed a garden, and some general work.
I will say, this motor has ran better than it ever has, seems to run a little cooler and actually quieted down some.
The only drawbacks I see with this system is
1. Since system is now battery fed coil, must have good battery and charging system, but you will have to do this with any of other systems
2. You must remove trigger pins and drill/glue in magnets into flywheel. This is permanent,, but so is new system, I really didn't care.
3. Since this system uses the advance pin position on the flywheel, you may get some kickback on startup since the long pin is used for
low rpm spark then it jumps to advance. I used a toggle switch to power coil so I just spin motor some, then flip coil on, not had
So, here is the list of parts and prices to complete the system. Jon figured about $110 to do complete system, but since he sees the vendors at local pulls, he can get discounts with out shipping,. My costs ended up around $140-150 which is about same as Ed's, Dale's, or Brian's so I guess it's a wash.
1. Single cyl flywheel pickup trigger
This comes from Midwest Super Cub and primarily used on Kohlers. I emailed them, asked for trigger only with out magnetic ring or bracket. Total was
$69.xx, make sure you ask for USPS flat rate mine was $6.25, UPS is $15 for shipping.
2. Bosch Blue coil
Jon recommended going through Nichols performance. You have to make sure you get a 3ohm coil, they had best price even with shipping and Ohio tax.
I paid $47.xx to the door.
I did find a no name brand coil that is supposed to be same as the Bosch, I can't recommend, use at your own risk.
3. Spark plug wire
Jon was using performance MSD auto wire and adapter on his coil, I happen to have an old set from a points car so I used that so no $$$ in this one.
Nichols lists wires on above link. I think Super Cub and also Brian Miller sell them. Maybe able to get just coil wires at local auto parts store also.
4. Off/on toggle switch
Pretty self explanatory, used to feed coil. Could also feed coil off ignition hot lead. I got a 20 amp switch from Tractor supply for $3.99.
5. Trigger bracket
Jon spent some time making this little bracket to get timing set to about 25* while running. I made a copy and can provide one if needed. You can make your own, just a same strip of steel with couple holes to match mount on old SSI unit, then mark where the SSI pickup lies, then mount the new trigger on the strip No $$$$
6. Various connectors, wire, nuts/bolts
Depends on what you have. We both had most of spade/butt connectors/wire.
I did have to buy 2, 4-40 machine bolts and lock nuts from Menards, These cost about $1.29 or so total. These are super small bolts needed to hold trigger on brackets. Anything much bigger and they won't fit, super small.
I also used heat shrink on connections and installed fuse in line before switch, both I already had.
7. Magnet for Flywheel
Jon said he used the magnet from on old magnet screwdriver tip? The original pin holes are about 3/16" so I ordered 2 sizes just in case. I ordered both 3/16 and 1/4 and drilled flywheel to 1/4 and used the 3/16 glued in with JB Weld. It is important to make sure magnet is oriented properly to trigger switch. I hooked up entire system, turning coil on and grounding plug on motor so you can see spark.
I then had magnet on end of a nail then checked to see which side triggered coil. Mark that end and make sure it gets mounted up so it triggers switch. Make sure you are touching tractor or plug when triggering coil.....don't ask how I know, DOH!!!!
3/16 x1/8 magnet http://www.kjmagneti...il.asp?prod=D32
1/4 x 1/8 magnet http://www.kjmagneti...il.asp?prod=D42
Pics in next post,......