Nice theory, but it just adds to the misinformation out there.

I've been working on Volvo's for a long time. And I very, very, very rarely see a timing belt, idler or tensioner fail before the service interval. I'm talking less than a handful and I can't even remember a specific instance off hand. That goes for all intervals they have had. 50k, 70k, 105k, 120k. Way, way better than the theorized 50% failure rate. In fact, I've seen many, many cars come in beyond the interval with customers who are not aware of the interval. Some do the belt, some decline it. Not sure how long they put it off and how long it winds up lasting.

 

Yeah, nice thing about nice theory is it has to consider much more factors than any single human being could ever experience in his whole life. For example: different temperature, humidity, surrounding air chemical composition, etc..

 

Yeah, because if a car is sold in one state and the driver moves, they certainly don't take their car to the new region.

And there's no way I've worked in more than one region.

And there's no way I know dealer techs from all over the country.

I would actually theorize the maintenance interval is set below the actual failure point because they know people will neglect their cars.

If you want to change your belt every 50k, go for it. I can guarantee your theory of 50% failure is way off though.

 

:facepalm: Dude please.......

 

Actually I am working on this device right now after some prior art search:

I found one patent:

US Patent No.: 20010045835 A1, Method and apparatus for detecting timing belt damage by inductive coupling, Nov 29, 2001

and one paper:

A Novel Failure Diagnosis System Design for Automotive Timing Belts M. Ucar, R.E. Ergun, and A. Cengiz, Machine Design and Manufacturing Department, Technical Education Faculty, Kocaeli University, Kocaeli, Turkey, December21, 2011

Both methods, one uses inductive coupling which involves wires imbedded in belt and one uses laser, are much more complicated than what I suggested here.

I am installing a kill switch inside the tensioner right now and it will turn on a LED light on the dashboard to indicate timing belt breakage.

So please be my witness when I need you help to prove I am the first one disclosed this idea here on 08-01-2015, 02:20 PM when I apply patent for it.

 

Again, pointless. Even at idle speed, when the belt breaks, it's too late. So have your light illuminate a display that reads "Bent Valves".

Just maintain your car.

 

How can an engine "idle" without power/fuel? A perpetual motion machine? :-)

 

Ok I'll play.....

When 250 pounds of mass (crank, 2 camshafts, pistons, rods and valves) is turning at anywhere from 800 to 3200 revolutions per minute, how will your device take that mass from that speed to zero before one of the 4 valves in a cylinder slam against the piston?

Engines are not light switches....

 

When an engine lost power/fuel, inertial will be lost in air compression.

 

Just like turning off the key right?

 

And disengage the transmission if the car is moving...

 

So again, your invention will stop the car from cranking if the belt decides to fail while the car is off. That doesn't happen.

If the belt breaks at 750 RPM, you can cut all the fuel and spark you want, it will still rotate enough to bend valves.

 

All experienced driver should know this: Timing belts break most often at start up and shut down of the engine, because that is often when the most tension is on the belt...

Also as Hylton suggested: if you turn off the key when your car is parked, your engine stops immediately.

 

Actually I was just trying to understand your logic. The truth is that a crankshaft can turn another 5 times from the time you turn off the ignition to the time it finally stops. You will never be able to instantly stop an engine without destructive failure. Not possible with the material manufacturers are using.......

 

Then I have to count on the fact: "Timing belts break most often at start up and shut down of the engine, because that is often when the most tension is on the belt" to prevent most damage.

 

And an experienced tech knows this: it usually isn't the belt that fails, it's the idler or tensioner. Those can fail at any time. But it does not matter when they fail. As Hylton said, the engine continues to turn when shut off. That means bent valves.

Your fact isn't a fact at all. The belt is under the same tension at startup as it is while running. In fact, many Volvo tensioners adjust to temperature. So the tension is always the same. And even if that was a fact, keep reading the paragraph on the website you googled that from where it mentions bent valves for a failure at idle.

The simple solution is maintain your car.

 

If a metal part can't over last a plastic/rubber part, then this world is in trouble and even an experienced tech can't do anything about it... :-)

"tension is always the same" -- yeah, Newton's second law doesn't apply here... :-)

 

The fact is I've seen way more tensioner and idler failures than belt failures. Pick it apart however you want, that's the way it is. And it's been because of improper maintenance. They are moving parts... They have a wear life too.

The tensioner adjusts. Since you have one that you are wasting your time installing a cut off switch on, you should know this. It adjusts so it can maintain proper tension.

 

Yeah, if any metal tensioner/idler/pulley fails before the belt riding on it, it should be considered as a joke (like wheels fall off before tires)... :-)

Tensioner can only adjust static tension and it can't respond to dynamic situation like starting/stopping: same reason your engine keep running when you turn off the key...

 

Not if it fails after the service interval. There are bearings in there. They don't last forever. Neither do tires.

Push on the belt and watch the tensioner. Or watch the tensioner with the engine running.