OT: Why can't a petrol engine start itself?

[Johnny B Good]

The ignition switch wasn't (normally) equipped with the necessary 'condenser' across its contacts to suppress arcing at these makeshift 'CB Points' which would completely suppress the required back emf spike voltage (normally several hundred volts - not merely the 6 or 12 volts of the battery) which the ignition coil stepped up to the twenty or so kilovolts required to jump a 1mm spark plug gap when under compression.

At atmospheric pressure, only a couple of kilovolts would be needed to jump the spark plug gap. Yet another bit of good fortune for the conventional Kettering ignition system since the very much throttled idle setting reduced cylinder pressures allowing for the compromised spark performance at the very slow CB points opening speed which wasted most of the energy in arcing across the CB points to still be able to create a spark voltage where it was needed at the ignition plug's spark gap.

This 'Party Trick' must have relied both on serendipity (a cylinder just past its compression point with sufficient fuel/air charge remaining) and within range of the advance/retard adjustment in order to have any chance of firing the engine into life. As long as there was sufficient fuel air charge to crank the engine through just a single revolution, it would be sufficient to start the engine, assuming the engine was in good condition and had good carburation efficiency at tick over speed. At best, it was only a 'One Shot Deal' so if the trick failed, it was a case of using the starter (electric, crank handle or push).

[tabbypurr]

basic sense. They were a mostly typical 1960s car with some mods to adapt them to Russian use. For reasons that had nothing to do with their qualitie s or shortcomings a lot of people talked a lot of b- about them.

I don't especially need to know about Moskvitches.

You comment on Ladas while lacking the relevant information. It's weird how there's so much misinformation out there about what was a fairly unremarka ble car produced by a remarkable system. What is remarkable about the Lada is everything that surrounded it, not the car itself. Its few claims to fam e included unusually tough bodywork, a heater that provded a +20C interior in -40C outdoor temp, suspension designed to run loaded onto its endstops, and good safety (for its era) despite no crash testing. Of much more signif icance is all the cultural & economic weirdness that surrounded it, part of which includes popular misinformation.

And yes, I did work on them at one time.

NT

[tabbypurr]

ton is in the right position gets an injection of fuel and air mix and a sp ark and stars the engine rotating, without the need for a starter motor? E specially 8 cylinder engines, surely one is always in the right position to get it going?

the valves even without it turning. You'd need some backup plan for when i t doesn't fire first go, which will be often.

et a cylinder to go bang.

On this post you're being stupid to a bizarre extent.

[tabbypurr]

when not works fine with round posts, not so much with rectangular ones. Wi th those perhaps a big (market stall canopy sized) croc clip could hold the connector against the battery post, adding a bolt without nut to stop it s liding sideways.

f a human finger used. But it's only contacting with each of its teeth, no t the whole circle like if the proper connector is used.

fferent reason.

yes

I did too. A car that won't start isn't the most practical.

NT

[Fredxx]

Typical remoaner, his post makes him sound as if he's taking something.

[Fredxx]

Common to most starting handle dogs.

That was not my experience. The camshaft was a serious affair with 5 bearings.

[Fredxx]

They were based on a Fiat 124. They used thicker steel than the Fiat and had Russian brakes, engine and transmission. In short, apart from the look, they were all Russian.

You are the only person I have ever known mention camshaft failure. I and some friends had them and I am unaware of a single camshaft failure. Even if the duplex chain stretched after 70k miles or so the noise it made made the owner aware there was something obviously wrong.

I've even quickly googled and it doesn't seem to be a stock fault. Perhaps you can enlighten us with some links?

[Archibald Tarquin Blenkinsopp]

Relavant information: Reliability, brings up camshaft concerns, Cost: Low Popularity: High

If maybe you are looking for the number of defects per m^3 in the Xtal lattice of the bodywork, I did not really class it as pertinent, nor the range of colours the thing came in come to think.

What are you on?

AB

[Archibald Tarquin Blenkinsopp]

I would guess that it was more to do with lack of lubrication, and might have been addressed at a later point. Some local garages offerred an additional upgrade to "oil" the camshaft. I have no idea what it was or how it worked, the Lada craze had probably gone by then anyway.

It was amazing, almost overnight it seemed that the roads here were filled with Ladas bearing taxi signs, so they must have had something going for them.

Come to think of it the same could be said for a lot of Russian stuff, performance well exceeding it's price bracket, but prone to the odd stupid problem that was never addressed in time.

Zenit [or Zenith] cameras were an example, I had a few. A terrific device that I would treasure to the time the Olympus OM1 and OM2 came out. 'Trouble was the focal plane shutter, they jammed. Get a good one and the thing would clunk on for ever more, but a lot jammed out of the box, and stayed that way:-(

AB

[Archibald Tarquin Blenkinsopp]

Your choice of words!

Cylinder to go bang does not need a piston.

I pointed out a few times that some posters to the thread had to develop ideas well beyond the piston, crank, cam, mechanical interlock, but a cylinder going bang is a bit extreme.

Try to stay up to speed.

And if a cylinder did go "bang" it would probably be called a grenade.

Not strictly accurate, but it sums the event up.

AB

[Fredxx]

The only relevant reference I can see in google of Lada, reliability and camshafts is one where the camshaft is improved over the fiat.

Rather than resorting to inane nonsense, a few links corroborating your BS would have been more helpful.

[Dave Plowman (News)]

The camshaft is perhaps the part of any engine which has the highest load. Neglect servicing and it can wear out very quickly.

[Archibald Tarquin Blenkinsopp]

As you state, Googling does not provide all the information.

I prefer to rely on personal experience where possible.

A lot of "helpful" people in the NG think it's some kind of skill not available to the average user and go for Google to solve problems for others that they themselves are clueless about.

The resuts are then posted, often unquoted and are simply wrong or inappropriate.

Increasingly I'm finding Google worthless, the main purpose of search engines is to sell things by advertising their clients wares, services and websites. Searching is secondary.

AB

[Fredxx]

Which is counter to mine. The Lada series of engines was near bullet proof.

If this was a stock problem google would normally have come up with the issue. It hasn't.

[Fredxx]

The only service, apart from an oil change, was adjustment. It was similar to the Ford OHC with an adjustable post for the rocker.

The major difference was the rocker cover volume was bathed in oil. If I recall the camshaft was hollow and the base of the lobe emitted high pressure oil simply everywhere.

The only issue with the engines I had come across was from poor servicing and cam chain stretch. Otherwise it was bullet proof, as long as it had some oil in the sump!

[Dave Plowman (News)]

You've owned a Lada, then? And from new so you can be sure of how it was serviced, etc?

More likely you're one who hears about a fault on some old banger and says 'they're all like that'

[Archibald Tarquin Blenkinsopp]

My memory isn't wrong.

I know this simply because it was the only new first car that I would class as affordable. The evidence was all over the local press and garage billboards and I had a first hand view of the popularity.

Even now I tend to look at what taxi drivers use as a guide to what may be a good buy.

My company car days will end and I do want value for money when I buy my own vehicle.

I had a company car a Mazda3 turbo diesel that should never have come out of the factory.

We had dozens of Mazdas fail on Turbos, the ones that had the turbo replaced were then disposed of soon after because of the clag left in the engine.

Before the turbo went mine would just stop for no reason, it took months to get the thing sorted.

There was nothing on Google

AB

[Archibald Tarquin Blenkinsopp]

You didn't read the posts,

you have responded to the tail end of a thread without knowing what led up to it.

Leave the keyboard alone if your only desire is to increase bandwidth.

AB

[The Natural Philosopher]

Only camshafts I knew that regularly broke were Ford 2 liter OHCs.

Yep

[tabbypurr]

It is, and unnecessary. I had an ancient vehicle that started on the first spark every time. I couldn't tell you why it did and most don't, but I'm sure there are engineers that know why. It didn't even take a quarter of a second on the starter.

I know from the vehicle above that that's not the case.

NT