Electronic distributor?

[Jaco Versfeld]

Hi There,

When I recently bought the '89 DC, it was already fitted with an electronic distributor. What are the advantages/disadvantages of the electronic distributor? Will it give me a better fuel consumption? How reliable is it, compared to a mechanical distributor?

If I plan to do an EFI conversion, hopefully somewhere next year, can the electronic distributor be used, or will it complicate the conversion?

Thanks,
Jaco

[BenHur]

If you want to do the EFI in the near future rather wait cause we use a different version Electronic dizzy on the EFI. But if you want to stick with the carb then the e dizzy is much more reliable and will give a stronger spark which will (when the vehicle is tuned properly) give an marginal increase in performance and fuel efficiency.

[Driko]

In the electronic dissy you have less moving parts , more accurate control over your coil charge time and you can use a coil that draws more amps to charge and produce a higher secondary ignition voltage.( point 2-3amps , transistor in module 10 or more amps )

You will need a different dissy though if yougo EFI route or youll need to adapt this dissy to recieve a proper speed signal to the ECU

[Mud Dog]

Perhaps I'm old school, and electronic gagetry is more reliable these days, but if one experiences an electronic failure in the styx, you're pretty much stuck. Whereas with a carb and mechanical dizzy one can always make a plan and get going again, even if it's just to limp home.

[BenHur]

Not really

There is nothing that needs servicing on the electronic dizzys, it is a contained unit and the last 4Ys and 22Rs came out with them in SA. In the rest of the world points and condenser systems (called breaker systems) on 4Y (which is highly unreliable) have been dropped in the early 80s already for breakerless systems i.e. non contact pick-up like a hall-, optical-, Capacitive discharge- or magnetic pick-ups, triggering an solid state igniter. It was just some grey heads at Toyota suffering from old school mentality that clung to this out dated technology for years longer than the rest of the world and there counterparts doing plat karre like the Corollas in which the breaker systems were also dropped a year or 3 before they did 4Y's.

I have yet to see or hear of an original Toyota Igniter or Coil that failed. I suspected OE Toy integrated coils once or twice but it was never the case. On the other side I have seen quite a few oil cooled conventional; coils leaving guys stranded same as with points and condenser. Because of the current that flows over the points (breaker) causing it to spark, the condenser was added to reduce the spark there, but eventually (just like with your plugs itself) the spark destroys the contacts and condenser. But on a breakerless system a high current transistor in the igniter switch the coil negative to earth (solid state) so this device should theoretically almost last for ever.

[BenHur]

In the electronic dissy you have less moving parts , more accurate control over your coil charge time and you can use a coil that draws more amps to charge and produce a higher secondary ignition voltage.( point 2-3amps , transistor in module 10 or more amps )

You will need a different dissy though if yougo EFI route or youll need to adapt this dissy to recieve a proper speed signal to the ECU

The problem that we had so far with converting the mechanical E-dizzy is once again a mechanical, and all it is. is to get the dizzys mechanical advance shaft locked so that it does not advance the timing any longer and then to lock the pick up in such a position that the trigger angle is at 45-50deg+ BTDC so that the ECU gets the pulse quick enough. In the beginning I struggled to get the mag adapters working satisfactory but through trail and error I have now learned their tricks and use them successfully to convert the saw tooth type analogue signal that the mag pick ups produce to a decent square wave pulse train that the after-market ECUs require.

[Riceburner]

One of my friends was a parts salesman at Toyota for 12 years, he replaced one in that time he was there!

[Driko]

I hear you r problem Ben , the locking of all the crap and geting the pick up at that angle is a real pian besides a bloody magnetic pick up produces an AC signal and if i remember correctly there is no TDC reference either on that design of reluctor wheel ( but you dont need that in a dissy ) , a HALL type would of course work wonderfull if you need a sqaure wave pattern

Personal opinion id go the route of fitting an crank angle sensor as you can get those in both HALL type and MAGNETIC .

Again just my opinion.

As for reliability on those distributors - all i ever replaced in 14 years on those was a few coils due to bad HT leads causing flashover and i had to replace one pick up thta starting getting weak so the AC signal was of to low a voltgage.

[BenHur]

You dont need a TDC signal if you dont do sequencial firing on the injectors or wasted spark ignition. With the normal dizzy and all injectors firing simultaneously a basic square wave pulse train is more than sufficient for most ECU types.

In the beginning I struggled with the Mag adapters and I thought that the AC signal looked like a pure sine wave but it is not, looking at it on a scope I saw it is more looking like a saw tooth.



At the point where the gear tooth goes passed the core of the pick up coil the polarity reverses almost instantaneously. The angle on this line is at almost 90 degrees and does not vary more that a degree or two as the engine speed increases and the amplitude of the AC wave increases. So if we read the trigger off the lagging edge of the positive part of the wave the trigger angle stays almost stationary as the amplitude increases, moving only about 1-2 degrees max as the engine speed goes up. That is absorbed in the timing map of the Dicktator easily.

The biggest problem is thus to get the trigger angle correct wile the rotor to cap timing stays in limits.

On Louis' (Megaworld) 4Y EFI, he initially bought a Dizzy from the guys at Toyota Bakkie Spares that was modified with a Golf type hall sensor and it trigged at 45 degrees BTDC and it worked great. Then after driving it a couple of weeks the bakkie would not start. We figured out the trigger angle moved by 45 degrees to 0 BTDC since the chopper was not properly secured to the shaft of the dizzy. He then took the dizzy back to the guys who built it and they glued in tight with something (most probably Pratley Steel as we can not get it unstuck again) but at 0 BTDC. They then moved the dizzy by 90degrees and one tooth to get the trigger angle better but then the engine ran very bad as it was firing when the rotor was already way past the pin. Louis polished the rotor tip and only the size of a needle point on the far left tip of the rotor turned black. So now this dizzy with the nice hall pick up is useless, ( I hope Louis manages to dissaeble the thing)

Subsequently we swapped his dizzy for a magnetic one and now his bakkie drives the way it originally did.

[Driko]

I am aware of the efect that you don't need tdc signal for those functions but it sure comes in handy if you have troubles and you start scoping , well I guess that can keep us around a fire for 7 days talking about all the crap we have sorted out with oscilloscopes but ill leave that to my courses , ever tried using the Dicktator wasted spark box from magnetic crank angle sensors? I helped a friend sort out his on his racer and works like a charm with a magnetic crank sensor.

[BenHur]

So far I only played with convectional dizzy type setups so I did not need to used crank angle sensors so far. I was toying with the idea of changing my 7M to wasted spark but was advised against it as I would add more cost and complexity for almost zero gain.

Apparently the only usable benefit from the added spark in the case of the 7Ms other then less mechanical parts, is when you run with boost on the motor ans that's why the 7M-GE used a dizzy and the 7M-GTE used wasted spark.

But ja I guess wasted spark is the way to go in modern engines but for now I play lekker with dizzy type ignition systems because of the money factor.

[Driko]

Ben reason fo rrunning crank angle sensor and wasted spark

HP - gain - NOOOOOOOOOOO , you gain very little
Better secondary ignition voltage - YEEEEEEEEEEEEEEESSSSSS

reason be the minute you run wasted spark you devide your coils into pairs which allows for a better controlled or longer charge time for that specific coil allowing a slightly higher voltage to be build up and obviously the coil takes less strain , normally wasted spark alos allows a bit of better rev response due to this

Crank sensor - water aint gonna bother you - as long as you keep it free form oil and metal shavings and reasonably clean your safe

[BenHur]

With the clever okes at Toyota putting the coil under the dizzy cap on the 4Y water is also much less of a risk as the killer is normally the coil wire, if individual plug wires gets wet you will have misfire but not a complete engine stall.

Pity I cant get such a set-up for the 7M though

[Driko]

Ben if you want to go overboard as far as reliability is concerned take taht 7 of yours throw a crank sensor on there and run some serious coils - 6 of them , yes 6 , we refer to it as COP - coil over plug system - very wicked and then you can seal of the whole thing , just about makes it a submarine then

[BenHur]

Anyone out there willing to sponsor the parts for the experiment to test and see if we can really make a 7M run under water

[Mud Dog]

You guys lost me faaaar back ......