Success with powerpack to GM ignitionn swap

[Vigilante]

After about 40 hours of research and development, 6 hours of fabrication, 4 hours of tuning/trouble shooting along with some very useful input from the iboat regulars (thank you very much) I have a proven design for the ignition modification. I clocked my 16 1/2’ fiberglass boat at 35MPH via GPS out on the river so you can’t argue with success. It’s about a ten hour project to complete for those of you who are as insane as I…..so the journey begins……<br />There is plenty of room behind the ’73 85hp Evinrude to fabricate a mounting plate with four GM coils from a ’77 Chevette. The mounting plate is just a flat piece of metal with 2” machine screws suspending the coils with nuts. With the screws extending through coils this allows for an additional plate to be suspended with nuts to mount four GM ignition modules. The wiring is fairly simple for the 4 pin ’75-’81 GM Ignition module’s pins are marked “W” “G” “B” “C”. Sensor #1 connects directly to “W” (the smaller pin) of module 1 and sensor #3 to “G” of module 1. Module 3 is reversed since the Sorenson module I used only triggers when voltage is passed through in 1 direction. Sensor #1 connects to “G” and sensor #3 to “W”. The same line of thinking works for 2 and 4. The black yellow wire that is normally ground works as an ignition +12volts if it’s changed at the ignition switch. This ignition switched +12 volts connects to the “B” pin of all four modules and the positive lead of the coil leaving “C” to connect to the negative lead on the coil. Bear in mind the module’s mounting plate must be grounded to the engine block since this is the switch needed to trigger the coil.<br />For some reason this system fires about 20 degrees later than the PPK. My resolution for this involved machining out another woodruff key slot in the flywheel via a flat ******* file and a sawzall (took about an hour and I’m sure it threw the flywheel out of balance slightly but honestly I can’t tell if it is). <br /> The last thing is the sparkplug. I’ve had the most success with the Autolight 4092 gaped at .035 which is the ’77 Chevette coil’s gap specification. Any input in this area from anyone would be helpful. Good luck to all who attempt this modification ‘cause you’ll need it. I can email a photo of the unit to all who respond upon request. You also need a lot of patience and a very understanding spouse.

 

[rickdb1boat]

Re: Success with powerpack to GM ignitionn swap

Can you post a few pictures here? I'm sure others would like to see it as well. Heck of a project....

 

[Indymike]

Re: Success with powerpack to GM ignitionn swap

Cool! I'd like to see a pic too. Lends itself to the old saying...more than one way to skin a cat.<br /><br />Question though...is she mad about her chevette being up on blocks . hehe

 

[Silvertip]

Re: Success with powerpack to GM ignitionn swap

The last Chevette I rode in was a diesel. No coils, no power, but lots of noise and good fuel mileage. Interesting project and you get an "atta boy" for creating a solution to a complex problem. I would think though that with all the distributorless ignition systems on the market today that one of the auto makers would have a four cylinder coil pack that would be a little easier to manage. Even the six cylinder versions are relatively small. Just a thought.

 

[Vigilante]

Re: Success with powerpack to GM ignitionn swap

I need an email address to send the phone pic to. I don't have real email it just sends text to my phone

 

[Paul Moir]

Re: Success with powerpack to GM ignitionn swap

I'll put the picture up here if you want. Fire it off in an email to paul.moir@gmail.com<br /><br />I'm anxious to see how this looks!

 

[Vigilante]

Re: Success with powerpack to GM ignitionn swap

Actually you'd need four chevetts to make the project work. I just bought all the parts I needed from Advanced Auto Parts. Oh yea Upinsmoke I did think of using the DIS style coils. Part of that 40 hours of research was realizing that they fire on the exhaust stroke as well as compression stroke which would be catastrophic on a two cycle. **** EPA. It's in your email by the way paul.

 

[Paul Moir]

Re: Success with powerpack to GM ignitionn swap

<br /><br /><br />Nice and neat. Good looking job!

 

[Vigilante]

Re: Success with powerpack to GM ignitionn swap

Thanks Paul, that is all I wanted was an ataboy!

 

[bigtwin]

Re: Success with powerpack to GM ignitionn swap

I have been an A.S.E. master automotive tech. for over 20 years, and have worked on every thing from Yugo to Bently, and a whole lot of "fine" GM products . It's hard to think of a worse ignition system period. Do your self a favor and keep a spare module in the boat also if you have'nt already done so remove the modules from there mounting plate and coat the back sides of the modules with silicone dielectric grease this will aid in heat transfer from the module, also try to find a large heat sink panel to mount them on (like a car audio amp. housing). Keep them cool! good luck!

 

[rodbolt]

Re: Success with powerpack to GM ignitionn swap

actually waste spark is common on outboards.<br /> they dont care if it sparks on the down stroke.<br /> they do care that the spark is initiated at the correct point of upward piston motion for a given RPM.

 

[bigtwin]

Re: Success with powerpack to GM ignitionn swap

Sorry for being soo harsh on GM electronic ignition system on my last post. I forgot about FoMoCo TFI ignitions, also how could I have forgoten Jaguar's Lucas ignition system.(I am still going to counsoling for the last one I worked on!!) A d.i.s. ignition would be great idea, because the d.i.s. ignition fires every 360 deg. of crank rotation, just like a 2 cycle. D.I.S. is also knowen as a "wasted spark ignition" because on a 4 stroke one of the sparks are "wasted" on the exhaust stroke (a compresson stroke happens only once every 720 deg. rotation on a 4 stroke) GOOD LUCK once again!