honegod

ok, the fuel injection distributor uses the FI computer to change the advance, the distributor hard mounts the hall senders.

so we will need to set the timing at full advance and leave it there.
paul yaws aritcle seems to say that doing this is a GOOD thing, so that doesn't seem to be a stopper.

the FI dist uses hall senders that are the same basic design as ours, only they look a little smaller, and seem to put out a little less (on the order of 1/2) signal than ours.

does this need to be a problem ?

all the ignitor needs is ENOUGH signal to tell it to do its thing, yes ???

{ I don't understand at ALL wtf ignitors do }

bill Shurvinton

This would work. Depends what you are trying to do. Be patient and you'll be able to do mappable ignition for $120 or so by the spring.

honegod

I saw your post about that in the other thread, but couldn't make myself go so far offtopic as to ask more about it.

now I can

that sounds WONDERFUL.

I googled the word you used and went to a site that came up. it talked about soldering up my own fuel injection computer.

that does indeed sound like fun, but a trifle overkill, as I run a holly.

I didn't see anything about a limited unit that would only do the ignition, which makes sense as it looks aimed at fuel injection types.

I would fear that it would get snotty with me for ignoring the FI inputs


is there a particular website that you recommend for me to read to get up to speed on this project ?

honegod

I got interupted while describing the vision I have

so, if the electrical hardware will work then comes timing the output of the senders.

we need one sender being triggered 4 times per distributor revolution for the leading plugs.
and TWO senders being alternatly triggered twice per D revolution for the trailing plugs.

the TII distributor has one sender with a 24 trigger fin cam, the other sender has a two trigger fin cam.

so all we need to do is mount a second sender at 90° to the stock top sender and there is the trailing sender setup.
for the leading grind off trigger fins until only 4 are left.
as in grind 5, skip one, grind 5, skip one, etc...

that does the leading signal.

choosing WHICH 4 fins to leave is the trick, since their relationship with the trailing fins affects trailing timing offset.

slotting the mounting holes for the trailing senders would allow final tweaking.


why won't this work GREAT ????

honegod

bringing us to ignitors and coils

we'd need 4 ignitors and 4 coils.

if I understand the TII trailing coils right they are two independant coils in a compact package, so a pair of them should take care of coils.
BUT I also understand that they are reletivly WEAK coils compared to larger single coils that we would need 4 of.

I like the idea of using four of the cheaper GM HEI ignitors but I wonder what it is that keeps us from using the ignitors that come with the trailing coils ?

as I understand it the hall senders put out AC current, why could we not use transformers to shape the signal into a form that the TII ignitors would find tasty ??

personally I would like to use 4 GM ignitors triggering 4 bosch blue coils like I used on my VW engine.

boosted12a

just strip the wireing harness and ecu out of any fi 2nd gen and wire up the ignition that way. cheep and simple.....well its a bit more complex that that, but it shouldnt be hard. plus you dont have to do as much fab work......

Pele

iTrader: (28)

Just to say a few things regarding Hall Effect sensors and Ignitors as I noticed some questions in skimming the thread.

The Hall Effect sensors are not much more than coils and magnets. They sense when magnetic metals come nearby. (In fact you can trigger the hall effects with a screwdriver.) A similar signal can be generated by using a speaker. Tap on the cone and see the signal come out on a low order Digital Volt Meter.

Ignitors are not much more than large power transistors, they act as amplifiers for the small signal from the hall effect to trigger the coils.

The Hall effects do not put out enough power to drive a transformer... Hence the transistorized ignitors.

honegod

the image of wiring my 1000w subwoofer amp to the distributor just floated past

the amplification business would explain the ignitor heat generation, and also explain the need for cooling.
plus the shielding on the low level wires going to the ignitors

it sounds like building our own ignitors to best use the TII senders signal would be doable, the idea being to use higher quality componants, and better heat sinking for improved reliability.

anybody an electronics wizzard ?? Pele ?

Pele

iTrader: (28)

If the 2nd gen Hall effects are enough to trigger the 1st Gen ignitors, why bother changing them?

In fact, why not use the whole 2nd gen ignitor and coil assemblies?

I'd bet Mazda has better resources than a couplea reference books, a scope, a DMM, and a dialup connection to the internet.

honegod

so I went back to points to see how the coil works.

the points are normally shut, allowing current to flow through the primary windings generating a field which pumps up the secondary windings.
when the points open the current through the primaries stops, the field collapses, and the charge that has built up in the secondary is dumped through the sparkplug to ground.

the ignitor uses transistors to do the stopping and starting of the primary current, the hall signal merely tells the transistors in the ignitor WHEN to switch.

so, the ignitor has to amplify the hall signal enough to actuate the transistors that are beefy enough to cope with the current the coil needs to work.


does THAT sound fairly accurate ????

honegod

as in changing to the GM units ? cost mostly.

plus ease of wiring, the old mazda ignitors are shaped funny, with plugs coming out the back where it mounts, the GMs have their connectors on the side, easy to get to.

Quote:

In fact, why not use the whole 2nd gen ignitor and coil assemblies?

part of my question.

the 2nd gen feeds the hall signal into the computer, and the computer sends a signal to the ignitor.

as I understand it there is NO connection between the hall and the ignitor.

who knows what kind of signal the computer puts out, and how does it relate to the hall output ?

honegod

yup, f'sure.

I really wish THEY would get the urge to put a hall triggered 4 coil direct fire ignition on a carburated rotary. it'd take them 3 minuts, using stock parts, I bet.

bill Shurvinton

No Website as I am still writing the code. I will post some more info as and when I get time.

One caveat with doing the cheap and chearful with a CAS to drive ignitors. It will allow you to do a Race type system where the lead and trail fire simultaneously with fixed timing. V.simple and should be V.reliable, albeit with a lumpy idle. Nice thing is that the CAS teeth are 30 degrees apart so you have a template to work off for your custom star wheel.

Bill

Jeff20B

iTrader: (13)

I wonder which one of you will be the first to make this work?

bill Shurvinton

Well I'm 12 months behind schedule on this. I know what to do, I just have to get around to coding and testing.

honegod

heh, my 13b is on the ground in the driveway.
I am in the process of getting as much stuff together to mantle it before I install it, so I am hitting junkyards to get things to modify, like distributors and waterpump housings (I plan to replace the cast iron housing on mine with an aluminium unit from a TII).

the engine won't go in until I get the frame reinforcements ,invented, created, and welded in.

so in this particular compitition I am not horny to win, soldering up a board that lets me use what I got come spring sounds swell.

honegod

I disassembled the GXL 13b crankshaft position indicator/dizzy.

the roll pin securing the drive gear came out no problem.

as I thought, the steel plate under the reluctors is the bearing stop plate/ thrust plate that keeps the shaft from coming out once the drive gear is off. removing the two screws holding the plate down let the shaft assembly slide out.

there is a sealed, I presume ball, bearing, the lock plate and the two reluctors on the shaft. that is the assembly.

the upper, two lobe/fin, cam is close to 5mm from the second cam{24 fin}, which is close to 4mm from the plate sitting on the bearing.

I got those numbers because those are the sizes of the allen wrenches that fit in there, I could have used feeler guages to refine those numbers, but I was impatient

I used a pair of the appropriat allens to support the assembly on the underside of the top cam, and drove the shaft out with a centerpunch.

(first I heated the assembly on the kerosene heater, nice and warm, maybe 120°f , to loosen it up )

the cams are a press fit on the shaft, there is NO indexing !
the shaft is round.

the top of the shaft is stepped, with the area where the top cam sits smaller in diameter than the area for the lower cam.

the shaft diameter at the top {two fin} cam is .490"

at the bottom cam it is .492"

the bottom cam fits over the top shaft with maybe .0005" or .001" clearance, unmeasured save by "machinists feel", so it looks like a .001 to .0015" press fit.

by the time I measured it the shaft had cooled down to the 60°f range.

the lower bearing is a bushing lubricated by splashed oil "pumped" by a spiral groove ground into the shaft.

my setup for driving the shaft out of the cams was a foot long chunk of 3" diameter aluminium tube, two bars of 3/4" X 2" aluminium across the top of the stood up tube, paralell to each other spaced so the cams barely fit between.
two of the right size allens fit under the cam, crossing the bars and suspending the assembly. put the center punch in the center hole in the end of the shaft and flail away with a carpenters hammer.

it took sincere impact, not tapping, but the 32oz ball peen would have been excessive. {estimate of force required @ ~ 100°f [it is CHILLY here the assembly cooled by the time I got to hammering ] }

the bearing is a koyo 83805, and feels great.

honegod

so far it looks like the main difference between the CPS senders and the early senders is the amplitude of the signal, and possibly the shape of the output waveform.

both of which are a function of the cam, eh ?

I wonder if the amplitude difference is mainly because of the different cam shapes, as in I am very interested in seeing what kind of output I get when I spin an early cam past a CPS sender.

if it looks ugly it doesn't look too tough to swap the CPS senders mount onto the early sender.

{ a main point of my wanting to use the CPS distributor body for this is that it is set up for the needed two cams, plus I like the cast in adjuster / hold down plate better than the bolt on steel job }

honegod

I took the early hall distributor {80 RX7, I think} partially apart.

I had noticed that the shaft the reluctor is mounted on is screwed to the main distributor drive shaft, and that the hole bored into the end of the reluctor shaft looked close to the size of the CPI shaft.

this turns out to be the case

the late shaft will fit nicely into the early reluctor mount shaft.

so now I envision cutting the old mount to length, adding the second reluctor and, using shim stock to center it, silicon sealing the two shafts together.

I don't think I need worry about a sharp acceleration tearing the two apart, and grinding a couple slots into the drive shaft and the ID of the reluctor mount would give the silicon seal a mechanical attachment to them both.

I don't want to destroy the '85 distributor to get its reluctor {cam} and $50 for yet another distributor is goofy.

(as it sits right now I can run with the stock points distributor that I have left on the engine since it is known to be timed right and functional, and the 85 will let me run it with an electronic ignition and DLSTFI {well it STARTS with DL } so I don't want to kill it for a total experimental setup, remember, I Like backups. )

anybody live near enough to Terre Haute for me to drive over and get that destroyed four lobe distributor that you have been saving for me ???

rusty reluctors accepted .

rotarydankus again

ive been screwing around with this in another thread you know the dankus direct fire , after screwing around with it first it was two gm dis coils and two hei modules , i thought it was great untill the wastefire effect on the trailing plug was explained to me , so i went to directfire on the leads and hei module driving the trails with a msd blaster coil , it throws big sparkee 6'' at least ,(dont pull coil wire off cap with engine running stupido !), its only worth about 2 horse power over the stock set up . butt the improvement in idle quality and lite throttle tip in arewell worth it, the gm and saturn dis coils have been known to sustain 60 kv on the sparkline , ive seen 3100 v6 135.000 miles plugs original, gap was .2o5 plugs were roasted car still run,im very happy sofar except for the disty cap, time for someone to make cap with no leading terms,

honegod

through the distributor cap, yes ?

Quote:

the gm and saturn dis coils have been known to sustain 60 kv on the sparkline , ive seen 3100 v6 135.000 miles plugs original, gap was .2o5 plugs were roasted car still run,

I am not familiar at all with these coils, can I use them to individually drive a plug, direct fire style ???

what would I find them in when I look in the junkyard.

sorry, I am not picturing them well at all.

except for huge flamethrower sparks

Quote:

I'm very happy so far except for the disty cap, time for someone to make cap with no leading terms,

I am all about doing it myself.

file the leading terminals down flush with the top of the cap, fill the remaining holes with bondo, or such, sand it smooth and paint it.

presto, three terminal distributor cap.