Technical Classis 500 Wasted Spark

[Alex9721]

Hi All
I have heard that getting a wasted spark conversion improves reliability, so was trying to look on the forum to understand what is how easy a conversion is and the benefits. Has anyone done a conversion on a classic fiat 500? If so can you details on how this went and pointers on the parts and steps needed to undertake the conversion.
Thanks Alex

 

[Pete O]

nope, wouldn't work.

all it would take is one plug gap to be slightly smaller than the other, and it would only ever fire that plug,

just stop and think about it for a bit and you'll go ... ahhhh

SteveC

Of course! I got this far into your post before I went ...'ahhh'! The HT current will take the easiest- even infinitesimally easiest- path to ground and ignore the other. Thanks for pointing that out. Funny that I imagined otherwise.

I was also going to guess Repco Brabham before I read the rest of the posts.

BTW I think the 500 is already ahead of the game with coil soak, having only 2 cylinders to provide for.
Back in my petrolhead days, one of the 'desirable' performance mods was the Mallory twin-point distributor, although the two sets of points operated in parallel, simply delivering a stronger path to ground for the primary windings. Nothing nearly as fancy as described above.

 

[Pete O]

Thank you, I was aware of that, as I said at #2, also the mention of Mazda rotary engines with leading and trailing distributors using contact points etc. I worked as a foreman of a Mazda Dealership in the 1970s and rebuilt a few RX3s and RX4s.

You must have been just a few years ahead of me, I did my apprenticeship in a Mazda dealer starting in 1979, just after the rotary failure plague. The guys ahead of me had spent a couple of years doing little other than rebuild those engines under warranty.

 

[bugsymike]

You must have been just a few years ahead of me, I did my apprenticeship in a Mazda dealer starting in 1979, just after the rotary failure plague. The guys ahead of me had spent a couple of years doing little other than rebuild those engines under warranty.

I started my apprenticeship 1969 in a mixed vehicle garage, basically anything that came in we would work on, I used to say on the same day I could service a Mk1Ford Cortina, fix the bosses outboard motor engine, repair brakes on Mk9 Jags, weld an old ladies shopping trolley and do a puncture on a split rim wheel from a muck spreader fresh from the farm. I left there in 1975 to work at the Mazda Dealership at the time when three year old Mazda RX3 coupes could be bought for £150 with engine issues, people used to complain about rotor tip chatter, but if oil metering was set correctly during it's service that wasn't a problem. The main issue was boiling up and throwing all the water out due to side seals failing in the housings, so like a head gasket on normal cars, the modification then was a thin tin shim that went on the spark plug/combustion side to deflect the heat from the rubber side seals. I left there in 1982 to go self employed until retirement.
I felt the RX3s were nice looking cars, but the same age 818s were as good looking, without the problems. The first Mazda RWD 323s were just coming out and no sign of RX7s yet.

 

[thefiatfactory]

You have piqued my interest Steve----who made the engine initially---was it Lancia? Please put me out of my misery.

Alfa Romeo, engine began life as the Tipo33 project, went on to be developed as the F1 engine.

Car shown is a Brabham-Alfa, in Australia was owned by Alec Mildren, one of two cars produced to run the Tasman series in Australia / NZ in what was back in the 60's the off season of F1 in Europe.

Long story, but the third engine that was specially cast as a spare, ended up shoehorned into an Alfa GTaM, and my Father was lucky enough to own that car for about 40 years... and yes, a genuine factory Autodelta produced , documented GTaM that was originally a 4 cylinder with all the specialty magnesium bits and mechanical fuel injection



The Tipo33 V8 found its way back into the second Brabham, which had been badly crashed and had damaged the engine block in an accident in the 1980's, and that now runs in various F1 historic races including recently at Monaco, it's value would be stratospheric.

The GtaM got completely restored and the guy found the original 8 spark plug mono sleeve all magnesium bits engine, did a beautiful restoration back to original livery, car is worth easy north of $500,000usd

Production car was the Alfa Romeo Montreal.

 

[the hobbler]

Alfa Romeo, engine began life as the Tipo33 project, went on to be developed as the F1 engine.

Car shown is a Brabham-Alfa, in Australia was owned by Alec Mildren, one of two cars produced to run the Tasman series in Australia / NZ in what was back in the 60's the off season of F1 in Europe.

Long story, but the third engine that was specially cast as a spare, ended up shoehorned into an Alfa GTaM, and my Father was lucky enough to own that car for about 40 years... and yes, a genuine factory Autodelta produced , documented GTaM that was originally a 4 cylinder with all the specialty magnesium bits and mechanical fuel injection

View attachment 484097

The Tipo33 V8 found its way back into the second Brabham, which had been badly crashed and had damaged the engine block in an accident in the 1980's, and that now runs in various F1 historic races including recently at Monaco, it's value would be stratospheric.

The GtaM got completely restored and the guy found the original 8 spark plug mono sleeve all magnesium bits engine, did a beautiful restoration back to original livery, car is worth easy north of $500,000usd

Production car was the Alfa Romeo Montreal.

Thank you Steve---a VERY interesting engine, and story

 

[Alex9721]

Hi. I've just finished my wasted spark conversion and pretty please with the result bearing in mind I've got no mechanical experience - only possible due to all the great advise on the forum. Thanks all. I should have taken a photo of the cables running to the sparks. Is this okay?

 

[Mike1alike]

I have heard that getting a wasted spark conversion improves reliability, so was trying to look on the forum to understand what is how easy a conversion is and the benefits.

That's just fairy tales you've heard.
Let it be!

 

[bugsymike]

Hi. I've just finished my wasted spark conversion and pretty please with the result bearing in mind I've got no mechanical experience - only possible due to all the great advise on the forum. Thanks all. I should have taken a photo of the cables running to the sparks. Is this okay?

Nothing to do with the wasted spark side, but I was cautioned many years ago re "induction tracking" where HT cables laying along side each other can cause engine firing problems, which is why many vehicles have a plastic guide that you push the HT leads into which separates them from the next one, this was on a training course by Lucas or Motorcraft in the 1970s.
Indeed in damp weather I have seen cheap carbon HT leads with sparks jumping to the joining leads.
Original copper cored HT leads on early Fiats and other vehicles were less prone to this phenomenon.

 

[Pete O]

Nothing to do with the wasted spark side, but I was cautioned many years ago re "induction tracking" where HT cables laying along side each other can cause engine firing problems, which is why many vehicles have a plastic guide that you push the HT leads into which separates them from the next one, this was on a training course by Lucas or Motorcraft in the 1970s.
Indeed in damp weather I have seen cheap carbon HT leads with sparks jumping to the joining leads.
Original copper cored HT leads on early Fiats and other vehicles were less prone to this phenomenon.

I fitted a CDI ignition system that I built from a kit, into an Alfa that I had in about 1980. With the factory HT leads, under the bonnet looked like a fireworks display with spark jumping between the leads. Had to fit a heavily insulated set of aftermarket leads and lay them carefully with guides.

Given that the wasted spark ignition system described in this thread does away with the dist cap and rotor, I guess it eliminates failure of those components but the resulting improvement in 'reliability' in a well-maintained car will be very slight.
It's way into the future with my project, but I'm kinda thinking of playing with hall sensor and coil-on-plug. Wasted spark in a 2-cylinder engine should make this reasonably simple to acheive.

 

[thefiatfactory]

A light show under the bonnet can be "leakage" of electrical energy, and that will lead to poor performance, but the thing that kills engines is usually inductance. I'll pinch a quote from Wikipedia,

"electric current produces a magnetic field around the conductor. The magnetic field strength depends on the magnitude of the electric current, and therefore follows any changes in the magnitude of the current. From Faraday's law of induction, any change in magnetic field through a circuit induces an electromotive force (EMF) (voltage) in the conductors, a process known as electromagnetic induction"

which a long winded way of saying that the current passing along the ignition lead generates a magnetic field around it, and this field can induce a current into an adjacent ignition lead...

Not really a problem with two cylinders 360 opposed, but engines like a chevrolet V8 which have nearby cylinders (5 and 7) following in firing order (90 degrees apart), the inductance that can occur along these leads can destroy an engine if number 7 fires off instead of number 5.... if number 7 lights off 90 degrees before it's supposed to at WOT and under load, stuff can break.

The best answer is something like a spiral wound ignition lead. The name is self explanatory, the lead has a copper wire, a grounding wire, spirally wrapped around the electrical core of the ignition lead along it's length, which presents a kind of faraday cage around the lead, preventing the magnetic field. Magnecore make great ignition wires, not cheap for the real stuff, plenty of crap knock offs.

SteveC

 

[bugsymike]

A light show under the bonnet can be "leakage" of electrical energy, and that will lead to poor performance, but the thing that kills engines is usually inductance. I'll pinch a quote from Wikipedia,

"electric current produces a magnetic field around the conductor. The magnetic field strength depends on the magnitude of the electric current, and therefore follows any changes in the magnitude of the current. From Faraday's law of induction, any change in magnetic field through a circuit induces an electromotive force (EMF) (voltage) in the conductors, a process known as electromagnetic induction"

which a long winded way of saying that the current passing along the ignition lead generates a magnetic field around it, and this field can induce a current into an adjacent ignition lead...

Not really a problem with two cylinders 360 opposed, but engines like a chevrolet V8 which have nearby cylinders (5 and 7) following in firing order (90 degrees apart), the inductance that can occur along these leads can destroy an engine if number 7 fires off instead of number 5.... if number 7 lights off 90 degrees before it's supposed to at WOT and under load, stuff can break.

The best answer is something like a spiral wound ignition lead. The name is self explanatory, the lead has a copper wire, a grounding wire, spirally wrapped around the electrical core of the ignition lead along it's length, which presents a kind of faraday cage around the lead, preventing the magnetic field. Magnecore make great ignition wires, not cheap for the real stuff, plenty of crap knock offs.

SteveC

Remember years ago we had a good "light show" from a Volvo 265 with the V6 engine which I had diagnosed as the HT leads. I fitted a genuine set of Volvo leads which cured the misfire but cost almost half a weeks wages for a mechanic at the time. I used to complain when someone asked us about what we got paid, I would say we were paid weekly as in very weakly, usually as a subtle hint if the boss was nearby.
I was always ready for a "wind up" and one day a lad from the marine department was nearby using some of our equipment, so I talked to another mechanic saying along the lines of "well I suppose that £5 pay rise is better than nothing" knowing full well what would happen due to competition between departments, he finished what he was doing and went back to the boat side, within minutes I saw his manager race across the road to the showroom where boss had his office, my phone rang and the boss was on it saying "what is all this about a pay rise?" to which I replied "Oh we are having a pay rise?"