Worn Timing Chain and Adjusting Timing

[landtoy80]

As the timing chain gets old, I assume it stretched, right?
IF so, then the timing will change as it stretches, right?
Will it advance or retard?
Is it enough that you have to compensate for the slop in the chain when adjusting the timing?

I just checked the timing and it was set at 3 (some time ago) and was half way between the 3 and 0.
With 459,000 mi, there should be some stretch in the chain, right?

I have seen articles that say to adjust the timing with a vacuum gauge. But that was with older vehicles that don't have a ECU that adjusts the timing.

 

[inkpot]

If you put a jumper in the diagnostic port the ECU will not effectbase timing.

 

[landtoy80]

I used the jumper to set the timing.

 

[bloc]

If you use a timing light to illuminate the marks on the crank pulley the crank is your reference, so chain stretch is accounted for on ignition timing.

Thing is, with any chain stretch now your cams and therefore intake/exhaust valves are out of time with the crank. How important that is? Got me.