Ignition build questions.

[Beck]

I would like to put together another ignition for my 4 cylinder motor. The distributor cap will not clear a custom intake manifold.

I have converted one distributor from the original points setup to a HEI using a Chrysler reluctor and pickup triggering a GM 4 pin HEI module. It seems to work fine but the distributor cap is still there. For this ignition every other rib is removed from the V8 reluctor.

I am wondering if it would work if I just left just 2 ribs on the reluctor, 180 deg apart, and installed dual pickups 90 deg apart. Each pickup would trigger separate HEI modules.  I would switch to the 7 pin HEI module for this one. They handle more power. Each HEI module would fire a dual plug coil pack. I would then have a wasted spark system without having to use the distributor cap.

Do the dual coil packs like those used on the GM 3800 motors actually contain 2 sets of windings, or is the output from a single winding split to the 2 outputs? I was wondering if the HEI module would have enough power to trigger 2 separate coils, like those used on the LS motors? Would these coils work with the HEI modules?

I am not sure I can get 2 pickups in the small distributor with 90 deg spacing. Part of the timing would need to be set inside the distributor cover. #1 would be set as normal by turning the distributor base. The opposing cylinders would need to have timing adjusted by moving their pickup coil on the distributor plate. That would be a pain, but should only need to be done once. I would need to make a 2nd timing mark on the balancer, 90 deg from the original.

Am I all messed up or do I have the "clocking" of all the parts right?

[GPster]

You certainly have given a lot of thought to this set-up. My problem is when I do so many corrections to a problem is that I "over-think" the problem. Can you devise a "Crank Triggered" ignition?  If not off the front of the engine something off the flywheel (but you aren't using one are you)? A 4 cylinder 4 cycle engine fires a cylinder every 180 degrees so if you had a "Wasted Spark" two pick-ups and two coils (old Harley Davidson ?) could do it. Just to let you know that I read other people's problems too. GPster

[wayne petty]

edit... forget what i posted... you will need two poles.. i think


mopar reluctor..  with only ONE pole/finger

dual mopar pickup coils mounted exactly 180 apart

2 GM 2 pole coils... each one needs i think only 2 wires.  so yes.. you could make it work..

whats interesting.. i think that 4 cylinder reluctors have a slightly different shape.. instead of [ [ [ [ [ [    they have _-_   _-_  _-_  _-_    toyotas run a single pole reluctor in some of the electronic controlled ignitions..  this might be an effort to start the positive sine wave build up better..

you could also find  an i know you spend a ton of time.. on the mopar reluctor.. by checking the polarity of the magnets in a pertronixs pole piece.. you might be able to remove 7 magnets from it and put some new tape back on it..

or you could use 2 pertronix pickup coil modules with a single magnet in the pole piece in a second distributor saving your work in case it does not function properly.  so... yes... you can..  

if you have 2 poles 180 apart... and you have 2 pickup coils..  and TWO, 2 tower coils.. you would have spark at the bottom dead center of the other 2 cylinders  right at the end of the compression stroke..  not where you want a spark at.  might not light it..

what ever you do.. please power it up on a scope. to check the primary phases out of the pickup coils.. .  mount a degree wheel on a spindle to drive the distributor with timing lights aimed at the degree wheel since distributor machines are hard to come by..

PS..   if you use 7 pin GM HEI modules... they have timing curve built in..  you would have to figure out how to keep it out of ESC.. but i think just leaving the extra 3 pins empty it won't lock out the timing.. its been a long time since i looked in the book behind me on the shelf..  i don't think it describes what happens with the ESC disconnected..

hope this helps..

[Beck]

you will need two poles.. i think

dual mopar pickup coils mounted exactly 180 apart

 if you use 7 pin GM HEI modules... they have timing curve built in..  you would have to figure out how to keep it out of ESC.. but i think just leaving the extra 3 pins empty it won't lock out the timing.

I am not understanding/agreeing with mounting the coils 180 apart. My firing order is 1-3-4-2. If the pickups are 180 apart on the distributor plate the pulses will occur on the 1 & 4 cylinders. Those 2 fire from the same dual coil. (wasted spark system) Cylinders 3 & 2 would not see a firing pulse.

Since the distributor is turning half the speed of the crank, 180 at the distributor is 360 of the crank. There is a cylinder requiring ignition every 180 degrees so in my mind the pickups would need to be spaced half of that or 90 degrees. With 2 ribs on the reluctor spaced 180 apart that would happen.

I don't think the Mopar pickups will work in my distributor. At 90 degrees apart there isn't enough room. The photo is of my distributor that I mounted 1 Mopar pickup into creating a HEI style system. The pickup is too long to get them that close.

I have not used a 7 pin HEI module before. The information I read off the web (which isn't always correct) said to let the extra 3 pins unconnected. That information said one of the pins was switched to ground to activate the retard system. I would need to research the true use of the extra pins, or just use the 4 pin module.

Thanks Wayne

[Beck]

Can you devise a "Crank Triggered" ignition?  If not off the front of the engine something off the flywheel (but you aren't using one are you)? A 4 cylinder 4 cycle engine fires a cylinder every 180 degrees so if you had a "Wasted Spark" two pick-ups and two coils (old Harley Davidson ?) could do it.

I am trying to get an economical motor running well to power my little tractor. I am also working on getting the "nasty" motor together. The "nasty" one is taking more time than I expected. I want to test the chassis and the rest of the setup using a motor I can put together quickly without breaking the bank.

Crank trigger would be cost prohibitive for me I believe.
I am back to using a flywheel. The auto trans has been removed. (at least for now)
The Harley coils don't have dual outputs I don't believe. They are single coils for each cylinder. The pickup for the Harley would be a bit different because they have a unique firing pulse, not 360 apart.

I started this distributor thought again because I just picked up yet another of these motors. The distributor is there but the points are gone, the cap and rotor are junk. Some of the guys using these motors have adapted half of an early hemi stack fuel injection system. Most of them have used adapters with a large radius to clear the distributor. I would like to shorten or flatten that adapter, which would interfere with the distributor cap (just the top of the cap is in the way). I want to retain the distributor drive on this motor because it also drives the oil pump. The "nasty" motor will have an external oil pump and the distributor will be removed. It will be full EFI which will also control the ignition.

[enjenjo]

It seems to me the easiest solution would be a flying magnet crank trigger with two magnets 180 degrees apart, and use that to control an amplifier with two wasted spark coils. Then just retain the base of the distributor to operate the oil pump. This could also be used on the Nasty motor with EFI. If you need an ignition curve you can use a EDIS instead of the amplifier.

[wayne petty]

brain damage here..  sometimes thoughts get lost..  too many concussions.. mostly stupid things when i was a kid.. i was so bad that mom made me wear a motorcycle helmet when i rode my bicycle.. that was 1969.. i did not wear it when i was not on my bike that is mostly when they happened.

you need a pulse the crank at #1 TDC every turn.. you need a pulse at BDC every turn on a different coil..

5 pin GM modules have the 10 degree retard  but those are hard buggers to get to work without the external spark control module.

7 pin HEI modules advance and retard the timing in a very creative way.   when not in ESC mode.. the module fires directly as the sine wave drops from positive to zero..

in ESC mode... the computer and module see the pickup coil drop to zero then start a variable delay to create the spark.. this gives the computer full control of the spark event timing..  this is why cracked small cap HEI reluctors create ghost spark issues sometimes..  random sine waves get picked up by the module and start another count down that could be out of phase with what is needed..

i used to have a antique snap on distributor machine. i never got the bulbs i needed for it.  i know that the computer varies the voltage to one of the 3 pins to change the timing.   this could give a person with a few electronic parts the ability to easily change spark timing... my plan was to use this for engine dyno runs..  to see if a little more timing here or there would effect the horsepower and torque curves..  but i kinda gave up as dyno runs are done as a progressive RPM test..  not a fixed RPM test.


i drew up this chart.. but i am still lost in how you will get 2 different coils to fire 90 degrees of distributor rotation apart.  without triggering additional spark events in the first

http://i.imgur.com/qA8R0qy.jpg

now... if you had a lathe... and a section of aluminum.  you could turn your own distributor housing..    you could turn your own upper section of the advance .. so there was room for 2 reluctors on it. with a piece of MU metal between them..  audio master tapes came in MU metal cans.. prevented magnetic fields from passing thru.

with a plastic block. a hot screw driver.. one could use these for a reluctor.. http://www.allelectronics.com/item/mag-82/mini-neodymium-block-magnet/1.html   one would have to verify the polarity prior to installing then verify with a scope the sign wave..

l like the ford pickup coil you used..  i don't know why i was saying dodge..  the dodge versions don't have the correct resistance to really work great with a GM module.. the ford versions do..

ps.. and you know this.. that is an early 80s pinto/fairmont 4 cylinder design distributor top..  but you knew that.

[GPster]

I just reread my suggestion and I missed the word old about the Harley Davidson ignition coils. Back when Harley still used points for their ignition their coils had two spark plug wire towers. My '77 Shovel Head and my '84 Evolution stil had point ignition and both of them only had one coil and had wasted spark ignition. GPster

[Beck]

l like the ford pickup coil you used..  i don't know why i was saying dodge..  the dodge versions don't have the correct resistance to really work great with a GM module.. the ford versions do..

ps.. and you know this.. that is an early 80s pinto/fairmont 4 cylinder design distributor top..  but you knew that.

That is a Dodge/Chrysler pickup in my distributor, not Ford. I am unfamiliar with the Ford pickups. I will need to look into them.

I thought it was Chevy II design distributor. A Vega cap and rotor is what I am using.

[Beck]

I think I have the distributor part finished. I ran the dizzy with a small drill motor. I had the 2 outputs hooked to an oscilloscope. It took a bit of adjustment but I have them firing as close to 90 degrees apart as I can with that resolution. I'm sure there will be more adjustments needed after running the motor. Unfortunately I don't have a running motor right now to drop it in and continue testing. I still need to buy the GM HEI modules and coils too. I milled the towers off the distributor cap and filled them with epoxy similar to JB Weld, then painted with a spray bomb.

[wayne petty]

that looks better..

do you still have a rotor to fit on top of the shaft... can you screw down a round degree wheel or round plastic compass so you could aim a timing light at it hooked to the various leads.

you don't have to have it in a motor either.. weld 4 spark plug shells together.. run a ground wire off the shells..   plug your spark plug wires from your 2 coils into them..  see what happens..

don't forget that many GM modules ground thru the top of the module via the hold down screw..   that the spark plugs shells and the module grounds all need to be connected to the negative battery..

this might work nice for home build distributor spinning machines.. http://www.harborfreight.com/2-inch-mini-lathe-chuck-with-mt-1-shank-65132.html

nice work so far.. i wish my brain was not so bashed up from concussions..