2 most vulnerable parts of the modern car engine

1. the nut at the top of the wheel ;o)

How does that differ from recording any other important servicing information? Every car with a cam-belt that I have owned has space in the service book to record belt changes.

Many modern cars will take some sort of action to prevent cooking the engine. For example, some Fords will shut down alternate pairs of cylinders every other stroke. The air pumped by the none-firing part of this cycle helps to cool the engine. Eventually, if the temperature continues to rise, it will shut the engine down.

Well, no, you're not!

Chris

That's not the car's fault - that's an owner fault.

Again that's an owner fault. Some cars don't have a coolant temperature gauge, just a warning light. Many others have a gauge that shows the driver what the ECU reckons, so it's either "cold," "warming up," "normal," "warm" or "overheat." Sometimes just three states. This is because most drivers don't bother monitoring the coolant gauge.

Older generation coolant gauges, that actually told you what the temperature was (scale or otherwise) rather than tell you the engine state, were more useful. Again the driver needs to look at it.

It's down to the owner in both cases. Running a car means one must be reasonably sure about what to do to it and when, or have the knowledge and ability to get somebody else to do it.

As I see it, cars are complicated machines and although technololology has advanced so that they can run well without much human intervention, faults still need to be recognised, servicing requirements still need to be heeded, and they have to be used sympathetically.

If an owner doesn't have the capabilities or desire to look after their machine properly then they either shouldn't own one or should expect their failure at some point.

There.

Si

one of the most common breakdowns is the wrong fuel (owner/driver error yet again)

I think the first thing i`ll do if I ever buy a diesel is to put a second flap over the filler cap ! (i.e. double-sided sticky tape a plastic thing you have to move out of the way to get the cap off)

You are right; these are remaining the Achilles heels of the Otto's engine. Further work needs to be done to the present day highly developed and electronically assisted design.

1) Cambelt: Wankel engine has eliminated the cambelt, but the increasing high cost of decreasing fossil fuel (100 USD/barrel now in sight) has throttled its further development. If the cambelt is built with an integrated continuous marker and the pulleys (belt and bracer approach) have electronic sensors, then breakage, slippage, and as an additional advantage accurate timing can be achieved. The extra cost is minimal compared to that of replacing a broken engine. 2) Engine Cooling: The current cooling strategy is brittle. An accurate coolant temperature readout (in degrees C, not in relative 'risk bands') is helpful but not enough (at present accurate and reliable only in gauges used by the racing fraternity, costing hundreds). An air cool design is an altogether better approach. Is this out of fashion today? The noise would have been be solved if the promising flat four VW engine development had continued, as had been successful in diesel engine.

Knowing the cambelt has failed does not help with avoiding engine destruction, when at X000RPM. One approach that might work is simply two cambelts, both with markers, to detect failure. Engine shuts down on first fail.

Or electronic valves, which have their own advantages.

Err, crap Air cooling has its own host of problems, and is pretty much inherently limited to small engines, without enormous efforts to blow cooling air over them. The cooling failure causing damage problems could be entirely eliminated by one or two extra sensors measuring overheat and coolant level. Even a simple bimetallic device with a reset button in the fuel pump or injector circuit would work just fine.

Ian Stirling ( snipped-for-privacy@mauve.demon.co.uk) gurgled happily, sounding much like they were saying :

Cobblers.

Big air-cooled diesels are far from unusual in trucks and rail.

The message from Adrian contains these words:

I recently bought a Chinese clone of a Wacker vibrating compaction plate. The cloned Honda engine had to have a cutout fitted which kills it if the oil runs low before it could get a CE mark.

Never mind that. Your petrol car is only as reliable as the piece of rubber driving your alternator. Or the alternator itself. If either fail you will come to halt in no time at all.

No, you're wrong. The only point of failure is the owner.

The message from snipped-for-privacy@tesco.net contains these words:

I've covered a hundred miles with no alternator at all. Provided it's daylight the battery will hold up for a considerable time - particularly on older cars without all the electronics on the engine.

Well bugger me, I've driven magic cars.

Care to explain why losing the alternator will stop the car in a very short time?

I like the idea of double indemnity using two cambelts. If one snaps, the ECM can then change to a Limited Service Strategy, 'limping home' at no more than 50 mph and for a distance of not more than 50 miles, even though in all other aspects the engine is working perfectly.

I don't think the bimetallic device (assuming this is for opening/closing an electric circuit) works, for it's unlikely that it works in liquid with free ions. Instead, something like a high melting point wax-based thermostat mechanical device part in and part out of the hot liquid may work.

I'm inclined to think an air cooled Wankel engine is a very feasible solution to these two engine destroying vulnerabilities. But to be real, let's brainstorm what can be done now. I'd suggest, in addition to the blinking indicator lights on the dashboard, continuous *loud* *piercing* beebs, which can only be turned off by the ignition key inserted in a separate keyhole! A simple improvised circuit can be rigged up easily.

Bimetallic thermostats are widely used, in everything from washing machines, to irons, ...

Indeed, some overheat stats for gas boilers intended for pressurised operation may almost suit.

I don't follow. Surely not with the temperature sensitive device immersed in an electrolyte, of which the engine oil and the coolant are examples!

(For those whose knowledge of chemistry is a bit rusty : The 'break' in the 'make or break' operation of a bimetallic strip doesn't work for the freely moving, dissociated, charged ions of the electrolyte conduct electricity, keeping the circuit intact.)

Engine oil is not appreciably conductive.

Err, no. You don't have the temperature sensitive element immersed in the fluid to be sensed, but inside a metal casing, which stops gunk getting to i.

Coolant temp is not what should be measured. The coolant can depart the engine and it will read OK or even cool. It needs direct cylinder head temp sensor for 100% reliable engine temp. Or fluid detector at temp sensor location to check that coolant temp is real. Even the flaot switch in the expansion tank can get it wrong as you can have water in the expansion tank and air at the temp sensor.

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