PKT warning light?
#61
Captain Obvious
Super User
Super User
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.
#62
Inventor
Rennlist Member
Rennlist Member
Thread Starter
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...
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...
#63
Nordschleife Master
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 moment the pulley walks forward at all the light is triggered and you know to shut down immediately.
#64
Captain Obvious
Super User
Super User
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...
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...
#65
Rennlist Member
Join Date: Jan 2012
Location: Oklahoma City, Oklahoma
Posts: 1,158
Likes: 0
Received 0 Likes
on
0 Posts
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.
#66
Nordschleife Master
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?
#68
Rennlist Member
Join Date: Jan 2012
Location: Oklahoma City, Oklahoma
Posts: 1,158
Likes: 0
Received 0 Likes
on
0 Posts
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?
#69
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
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.
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.
#70
Inventor
Rennlist Member
Rennlist Member
Thread Starter
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.
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.
#71
Inventor
Rennlist Member
Rennlist Member
Thread Starter
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?
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?
#72
Nordschleife Master
Join Date: Dec 2004
Location: Guelph, Ontario, Canada
Posts: 6,164
Likes: 0
Received 5 Likes
on
5 Posts
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.
What? It is the only point.
Really? This is what you KNOW this to be for? Could you share the Porsche document which states this? I have never seen it.
#73
Inventor
Rennlist Member
Rennlist Member
Thread Starter
#74
Captain Obvious
Super User
Super User
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.
#75
Rennlist Member
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
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