nimrodTT, no offense, but that sounds like disinformation to me.

Dielectric grease is supposed to prevent electrical contact, right? That's what dielectric means. You put it on spark plug boots etc to prevent arcing. The heatsink grease can also act as an electrical insulator (probably), but the ignitors have brass sleeves in the screw holes that act as supports and electrical contacts from the screws to the aluminum heat sink. It's pretty obvious they were designed that way for this reason.

Personally, I'd use a ballast resistor. There are too many stories of dead ignitors not to use one. I also don't want to run the risk of burning out a J-109 if I can.

You're the only person, (that I know of) so far, who has said the ballast resistor is unecessary in this type of setup. I wonder how much more power the leading coil will be capable of without the resistor inline? I'd bet it's not worth killing an ignitor.

Remember, this is supposed to be a super easy direct fire upgrade. It's not supposed to cause people to have to go out and get heatsink compound, or even know where their ignitors are. The ballast resistor is staying in the mix. You'll have to do a lot more convincing to make us change our minds.

Wow, that turned out longer than I thought it would.

 

In actual fact, it doesn't matter which side of the coil the resistor goes to. Either way it's still part of the circuit.

 

hmm.... I don't know the answer to that. I just wired it up like it was stock. It works, and that's all that matters to me!! Frankly, I don't think it would matter too much either way.

 

The heat sink compound that Mazda put on the backs of the ignitors is way old and useless at this point in it's life (17+ years). Whether you do this mod or not, I recommend that EVERYONE pull off their ignitors, clean the backs and replace them using heatsink compound. I'll speculate that the majority of J109 failures happen because they can no longer dissipate heat the way they were originally designed.

 

I agree. I wasn't not saying to reapply heatsink grease.

I've noticed something a bit odd about the heat the J-109s produce. At idle, they stay fairly cold. I'm sure they heat up during normal driving, but their staying cold at idle threw me for a loop. I guess the DLIDFIS heatsink mounted on the inner fender may be able to extend the life of the J-109s to many years beyond what they would have had on the hot dizzy housing.

Of course at idle, there are less sparks per second, and the engine only has to produce enough power to keep itself running at a low RPM under no load (well, the waterpump etc are still using some power but yeah).

 

I know Jeff, I just posted that for posterity sake.

 

It's been long enough that I don't really remember what I used, I think it was dielectric grease, but maybe not. Either way I haven't had any trouble with it functioning as it should.

I have about 6 spare J109s laying around, so forgive me if I am a little careless about taking every possible precaution.

I'm not saying for anyone to follow my example, but I set mine up like it is before I had heard of anyone retaining the ballast resistor in the circuit. I don't have anything against using the ballast resistor and I have no reason to think one way is better than the other. I am simply stating that you can get away without using it, and you won't automatically blow an igniter. The last thing we need is more false rumors going around the boards.

 

You got that right. ATF this, 12As can do 20K RPM that. Ok, so the ballast resistor is optional.

I used to have six spare ignitors.

 

i already have the MSD direct fire. can i use this for the trailing instead? HMMMMMMM

Carl.

p.s. i still want my tach to work.. give me some cake..

 

I don't see why it wouldn't work since you are still using all the stock wiring.

 

This will NOT work with the trailing. Do not attempt to use this configuration on the trailing ignition. Honestly, I think it might blow the engine!

 

right.

so how DO we get direct fire on the trailing ????

 

I'm working on it.

 

After much scatching, I won't be running trailing direct fire. I wrote up a longish post, but it borders on off-topicedness. I may post it later...

 

i did the mod last night. and wow the difference is awesome according to the butt dyno.
the mod took about an hour

45 minutes going to lowes and oogling over power tools while slowly buying a little red crimp connecter for the + wires and a couple good sized self tapping screws for the top (used a threaded holes at the bottom)
15 minutes to do the mod

i used good sizes self taps for the top that have a 3/8 inch head which is fairly close to 10mm by pure luck. the stock negative eyelette worked fine on the fc coil. i moved the fc's negative which had the resistor already on it to the postive side and then wire the positive off the old coil to the resistor's other wire. only one cut factory wire :-D

 

i dunno, when i got my first fb and installed plugs i had the leading and trailing coils hooked up backwards and the motor was fine. the motor ran realllllly poorly but it ran even with the messed up ingnition

 

Come spring I should have rotary ignition code up and running on the megasquirt. This will allow you to use the EFI CAS and coil packs directly. Then you can have the ignition you always wanted.

As with all things MS the code will be open source so you can just build up the MS and load the code.

Bill

 

It's because stock ignition doesn't fire both leading plugs together. If it did, your engine would be very unhappy.

 

Well...

That motor did end up blowing up anyway!

 

Heh, taking my quote out of context makes it look like I'm an idiot.

 

Do Please, I have Serious Wood for trailing direct fire.

 

I already got it figured out on a three rotor engine. The amount of work to get it on a two rotor engine is somewhat similar. However, to me, trailing is not worth the effort. Especially when it can be run through a cap and rotor.

I guess it's just the whole naked dizzy cap thing that's got people so hot and bothered.

It's simply not necessary (other than the looks), and I'll tell you why. You're still thinking with pistons on the brain. That is, thinking each plug needs a whole lot of power, when in reality, they don't. NSU only had one plug per rotor, as does Moller (on their 530cc at least; I'm not sure about their 650cc, but it's safe to say it's only got one also).

Mazda only truly needs one per rotor as well. The other set are for emissions and a supposed 15% increase in economy and power over leading ignition alone. Huh?

To that I ask, "well then how come my engine doesn't seem to follow this uh rule?"

Of course I'm running DLIDFIS and the leading plugs are doing all the work.

The trailing holes are very small on the inside. It doesn't add that much power. It can't. There's physically no way that it could, without enlarging the holes.

I know the R26B had an extra set of late trailing plugs that fired after the normal L and T plugs. The difference here is that there was no L/T split on the regular L and T plugs. You basically had two leading plugs per rotor face and one trailing plug. They should have had a second spark on their bottom-most leading plugs firing 180º after the first one. That could have given each rotor face up to four sparks per revolution instead of three. You know, like regular simultaneos firing, like what we're all running here.

Ok, back to reality. Some people have driven on trailing alone and complained of less power and harder starts (well duh, it's like 15º retarded).

When I removed an electric fan and went back to a clutch fan on my REPU, it lost enough power so that I could feel it easily. Throttle response was less instant etc. Then I wired up trailing to a switch so I could turn it on and off as I drove. I felt no difference. The only time when I think I may have percieved a difference was at full load, floored driving up a steep grade. The clutch fan used more power than trailing ever added. Clutch fans use like 5HP, right? If that's true, then trailing adds less than 1HP.

That's just on my engine with DLIDFIS though. Your results may vary.

Recently, there was a guy who dynoed his car with and without the clutch fan. He gained 14HP without it. That's cool, and it means trailing still does nothing at low to mid RPM, where the fan is sucking vary little air.

I've decided to abandon trailing on my 20B for now. It's simply not worth the extra components required. Three more pickups, ignitors and coils for maybe 3 more HP? Those same parts would be better used on three other 13Bs or 12As.

You've also got to realize that my 20B will have the two rotor engines' equivilant of simultaneous firing, but timed correctly for three rotors instead of two. Yeah, it's DLIDFIS with a T (and I'm not talking about trailing here).

I may do trailing on it some day, but not right now. lots of other more important things to do still.

 

Ok...I am getting ready to do this mod or the MSD 6a mod. Reading over this mod I have pretty much figured out how to install everything but I have two questions. Question one is step 9. Move your trailing wires to the leading position on the dizzy. Umm...why? Why can't you just leave it where it is? If you move the trailing to the leading position, how can the trailing still fire if the leading coil is gone? Just a question I can't seem to grasp right now.

The other one is that my car has two yellow and black wires hooked to the leading coil. It is a 1980. What's up with that? It has a wire connected to the other side. What do I need to do?

 

Some images weren't showing so I took a few photos of my install.

Edit:

I forgot to say that this was a very simple install and a nice upgrade to the stock system. I can't wait to try the DLIDFIS and compare the two. There is a slight typo in step number 5, the negative side of the coil is connected to the "TOP" of the ballast resistor and the bottom is to be connected to the wire sticking out the top with the female bullet connector.

Nice work to Jeff20B for DLIDFIS and Metallic_Rock for the 2GCDFIS. Looks like my summer of unemplyment has an upside...

Haha.

will post details regarding my 2GCDFIS vs DLIDFIS setups. What should I use as criteria to test against. The stock system will be my control group.

Joe Breese
82 GS

 

Sweet!