rotarydankus again

initially i thought the trailing igniter was bad no fire to the trails, come to find out the leading ignitor had failed and someone had swapped the coil leads to fire the leadings with the trailing pickup and ignitor, then tney went so far as pull the disty and dropp it back in so they could line the yellow mark, man i was confused for a while, noticed after i installed hei module spec'd for 75 corvette, that the dwell and spark saturation on the scope was much better with the gm module than the mazda ignitor, so i did the traileng ignitor too, now i can use cheaper eaasily obtainable parts, car runs much better, no puttter at idle any more and my no load cruise sputter is gone, gotta love these cars!! trevor

inittab

Sounds interesting, can you post some pics of your GM HEI ignitor install? I have an HEI ignitor and might add it to my 2GCDFIS (2nd Gen coil direct fire ignition).

Rx7carl

Very nice. Yes please provide details.

slashdawg00110

I've been looking at the DLIDFIS and the 2nd gen leading coil solutions. Has anyone stacked up all three against each other? I haven't seen anything specific about the HEI.

slashdawg00110

Sounds fine to me, Jeff. Still doesn't roll off the tongue very smoothly, though.

Jeff20B

iTrader: (13)

Hey rotarydankus again, I had a similar project to yours. It was a rotary B2000 that had a dead leading ignitor. Somebody had both coils and both sets of plugs running off the trailing ignitor with the dizzy rotated so it was firing on the leading mark. This means it had 0º LT split.

I'm not sure how long it was running like this, but the trailing ignitor eventually died while I was driving it. We threw a new leading ignitor on it and I drove it to my place. I then installed one more coil on the inner fender and three GM HEI ignitors on an aluminum sheet 1/8" thick. I gutted both dead ignitors and soldered some jumper wires inside.

No cutting pickup wires for me!

Then I wired everything up and retimed the dizzy (static timing) and it ran pretty well. Then I got some better plug wires and new plugs and it ran tons better.

It went from a single ignitor on [b]both]/b] coils with NGK B8EV plugs and old failing plug wires, to three GM HEI ignitors, one more coil for a total of three, a true L/T split, good used NGK blue plug wires, BUR7EQ plugs on leading, and BR8EQ-14 plugs on trailing. The difference is as I would expect with DLIDFIS, although the old setup was set up much worse than even a stock FB, so the results are a little scewed. Then again, it does happen from time to time, as it to rotarydankus again.

My thoughts on spark plugs.

If you're going to run a direct fire ignition system that is the same basic setup as a stock FC, it's a good idea to use FC plugs with it (on leading).

Those B8EV plugs were supposed to be used on a high powered rotary, according to what's his face over at Racing Beat. Well that may be all well and good IF you've got their thin wall spark plug socket and a STOCK FB ignition system. Even then, the concept of a boinger plug in a rotary just makes no sense to me. You ought to at least 'two stroke' the ground electrode or something to unshroud the spark.

The people at Racing Beat will continue to push these plugs for the reasons I mentioned above, but when you ask them about upgrading the ignition system itself, they'll wish you good luck, and that's about it.

In my opinion, B8EV plugs are expensive and unecessary. They only fit without the need of a thin walled plug socket on older rotor housings from the early to mid '70s.

New BR8EQ-14 plugs are fine for the stock FB ignition system, and I'm running a set that has a lot of miles on them with DLIDFIS. I'm sure I'd have some misfires if they were on a stock FB ignition system though, do to their amount of wear. I'll upgrade to BUR7EQ on leading next.

BUR7EQ plugs are stock 2ng gen leading plugs and they're perfect for DLIDFIS. They're a little harder to jump a spark across their gap, according to the guy at Racing Beat (he called them surface discharge or something), but that's fine with a direct fire ignition system. Use these plugs on the leading circuit, and BR8EQ-14 on trailing.

When the plug type matches the ignition system, you're good to go.

Jeff20B

iTrader: (13)

True, but neither did DLIDFIS.

Try it like this: two gee see, dee yef high yes

inittab

I agree and have added this acronym to the FAQ. Here ye here ye!.... from this day forward this mod shall be called 2GCDFIS!


PS- Sorry Jeff20B, I accidentally deleted your post. Ooops, my "moderator trigger finger" hit EDIT instead of QUOTE.

rotarydankus again

finished my dankus direct fire, i used saturn DIS coils , but any gm double post will work, two hei modules actually hanging in the factory igniter location plan to move them two coil bracket when i find a connect similiar to the pickup socket, did both leading and trailing, so no cap , roter or wires anymore, dig that! gonna machine a cap to cover rotor nub on disty, heres pic

Jeff20B

iTrader: (13)

lol I'm glad you didn't delete the long one with the info about the rotary B2000 and spark plugs. Whew!

For those that missed it, I'll try to reconstruct the post from memory and bits 'n pieces of text I posted earlier.
---------------------------
FCDFIS is a little weird because FC isn't an acronym for anything. I guess it could mean Fun Car, but lots of people say the FB is actually more fun to drive. Ahem.

FC refers to a couple letters in the 2nd gen RX-7s' VIN. DFIS stands for direct fire ignition system. What we're doing is using the 2nd gen DIS coil only. Everything else is pure FB. In my opinion, FCDFIS should not be used to identify this particular upgrade for a 1st gen (or older) rotary.

What if we called it 2GCDFIS? That stands for 2nd Gen coil direct fire ignition system. This acronym is more accurate and very descriptive. It is also the same amount of characters as DLIDFIS (seven, the lucky 7 hehe), and therefore, shouldn't be any harder to remember. In fact, it may be a little easier since its got a '2' in it. You know, as in 2(two) plug wire outputs on the coil.

The more I say 2GCDFIS, the more I like it.

Jeff20B

iTrader: (13)

Hey rotarydankus again, that's cool. Have you fired it up yet?