Quiet the opposite. The stock system does show indirrectly a siezed pump pulley. It certainly did for me. The sized pulley makes the belt warm up and stretch, this triggers the warning light way before the temperature light comes on. I'm telling you guys, the factory system does its job extremly well.

 

The factory system may show a water pump problem precisely because it does not work that great as a belt-management-system.

The factory 'tensioner' cannot compensate meaningfully for excess belt length, thus requiring a light to tell you to bring the car to a Porsche mechanic to adjust a bolt.



Most folks will not shut off the engine immediately when the light comes on. Even if they do shut if off, they will then try to restart it to see if the light comes back on...

 

How about coating the inside of the center cover around the oil pump gear, and WP pulley with a conductive material. Attach the belt light wire to it and then put it through a 5 pin relay to switch it from missing a ground to seeing a ground.
The moment the pulley walks forward at all the light is triggered and you know to shut down immediately.

 

The factory syatem does EXACTLY what was designed to do and does it well. You are inventing extra features that are irrelevent if the system is looked after regularly. The bottom line is the Audi tensioner is a set it and forget it system BUT the warning light can not be retained and has to be eliminated. The factory one keeps this very important feature. The OE belt management is called THE OWNER.

 

These are all facts that have been stated over and over. This thread is meant to try and find a way to set up a warning system using the Audi tensioner. Why not try and focus on that rather than stating the same thing for the 100th time? Because this seems like the only issue you have with using the Audi tensioner you could contribute to the resolution. But then you wouldn't be able to complain about it anymore.

 

How about figuring out a way to detect that the belt has jumped a tooth or two? That usually not an engine failure automatically, which is seconds away at that point. This is in the realm of science fiction of course, but in that spirit how about a reflective paint strip on the belt and the cam gear sprocket? Then an electronic deus ex machina to measure the alignment of the two strips?

 

Not a bad idea, but do you really want to wait until the belt jumped a tooth? That might be to late....

It has to trigger the warning when the tension becomes insufficient IMHO.

 

There is always going to be a little bit of travel in the piston. Would there be a way to measure if the piston moved a longer than normal distance over a short period of time?

 

If this were a more "industrial" application, with room for instrumentation, I'd equip it with a simple LVDT position transducer, a piezo "load cell" to measure the pressure applied to the roller, and map those sensor readings against engine block temperature. After a few "normal" cycles, we'd have baseline data to build expected position and pressure maps based on the block temperature. Simple Arduino controller. Deviation from either would set a warning.

Unfortunately, this isn't something you'd do with a single switch contact. The closest you'd get to this would be a bimetallic metal strip ('thermostat spring') attached to the tensioner arm, with a magnet at the end. Add a reed switch to sense the presence of the magnet to actuate the warning system. This assumes that the temperature in the timing belt cover is following or at least related to block temp. Similar to a simple home thermostat in operation, but with a reed instead of mercury-wetted contacts.

 

The piston and lever are moving all the time, dampening belt movement. The movement is much more pronounced when the engine is cold due to the uneven firing of a cold engine and the extra length of the belt as the engine is smaller in size. A mm or two at idle. When warm, the lever moves only slightly at idle, but will move quite a bit at higher rpm to stop fluttering.


Tension is not really the point with the PKT. It is a factor in the stock system, because you must pre-stretch the timing belt for the stock system to have enough range. The goal of a belt-management-system is to keep enough belt wrapped on the crank gear with enough force to keep the teeth engaged. With a PKT the timing belt should never touch the crank idler pulley(s)...

If the crank idler assembly were replaced with a bracket holding a roller micro-switch, such that the roller is not quite touching the belt, it would trigger if the belt is able to move off the gear. The Central Warning box needs only a single break from ground to trigger the light and keep it on.

Having the sensor below the crank would keep it out of the belt system, which is one of my fears, that the belt sensor would cause problems instead of preventing them.

 

Unfortunately there is still the 3 minute delay at startup.

That and the thought of pulley(s) to keep the belt on the crank gear when the engine is cold/at high rpm...shiver.

Who thinks of these things?

 

What data do you have to support this? There is just a lot of conjecture as to why the belt is doing what it is on your part. If the tensioner was stopping flutter, why would it be moving so much? Fluttering belts are actually one of the best reasons to have a fixed tension system as the Audi tensioner reacts too slowly. It then takes more force to compress the tensioner. These factors do not help the system at all.

What? It is the only point.

You clearly have no concept how the factory system works. Or you are trying to spread misinformation. The stock system deals with the temperature change with the washer pack inside the tensioner. This system was calculated by people smarter than you and me, to make the car reliable. There is a system approach to these kinds of things. You cannot just replace one component without it having an influence on the others. Without doing the research, at best you have a guess that may work and the only way to know is statistical data and failure analysis. None of which has been shared here.

I don't know about yours, but my rollers beneath the crank pulley were full of crud and had never be touched by a belt for a VERY long time.

Really? This is what you KNOW this to be for? Could you share the Porsche document which states this? I have never seen it.

 

That pretty much sums it up.

 

Ken you are inventing new terms and theories that are hard to beleive. How many engines do you knownthwy had issues with cold start and high RPMs? Until your theories, this was not a problem.

 

Guys PLEASE stay on topic, this is NOT a PKT debate thread!!!!

If you don't like or want to use a newer style Dynamic belt tensioner, stop reading or at least stop turning this PKT Light thread into one.

We all have and make our own choices and mods, we that have made the move are just looking to see if we can enable a freak n light! I for one would never go back to the stock tensioner, period.

Thank you,

Dave K