Timing Chain Stretch

[Bombardier]

My Australian delivered K12 1.4 auto has just clocked 157000km in 3 years and is starting to get a little rattly.
After enquiring about the cost of the timing components from Nissan - $1800- I decided to buy a kit from Ebay UK for 220 UK Pounds - $350. The adjustable gear is so bloody heavy it is no wonder the chains stretch!!!!! The inertia that that gear produces at speed would be incredible. A titanium item would be the answer but at a cost no doubt. Perhaps a fixed item the same as the exhaust cam with the cam ground to suit would also be a better option not only for cam chain life but engine responsiveness and outright power. Any thoughts?

 

[col85]

The timing chain stretch is normally due to the oil de-grading over time, and regular oil changes is all that is recomended to help prolong life.
The weight of the gear doesn't realy afffect the chain as the weight is taken by the camshaft. A fixed pulley on this engine would cause engine management faults as the solenoid that controls the Variable Cam Timing is ECU controlled.

 

[jacob_ts]

a fixed pulley would also result in extreme power loss, i work in main dealer and we don't have many problems with the chains, usually down to poor service history as col85 mentioned, i would also say to prolong the life make sure you stick to genuine parts and regular oil changes, also oil starvation is a big cause to stretched chains, so could possibly be oil pump failure, worth checking