Originally Posted by JATownsend
I had to cycle the rear wheel about 20 revolutions before I was able to insert the 'Pin Tool'. I thought it was never going to relax.
Don't give up, just try it again. BTW, no screwdriver is required,
If you had turned the wheel backwards you would have gotten the tensioner to relax much easier, as that will put the tension on the bottom side of the chain, pushing the tensioner back.
Pushing the tensioner piston back cannot be done quickly, even with a screwdriver, because the hole in the cylinder that admits oil pressure when the engine is running to push the piston out is quite small so that when the engine is running the oil in the cylinder cannot be pushed back out by chain vibration. The tensioner has a spring in it to keep the tensioner slightly snug even if the engine has not run for some time, but it is oil pressure that does most of the work.
I don't understand the reluctance to use a small bar or large screwdriver to push the tensioner back, as BMW even does it. A is screwdriver pushed back on top of the lower run of the chain, and up against the cam bearing block, then some pressure up on the handle and you wil feel the tensioner slowly moving down. If you are pushing in lightly on the retainer pin you will feel it go in when the piston gets low enough.
The only reason this is done is to make re-installation of the cam sprockets much easier. If the tensioner is allowed to be pushed out by it's spring when the srockets are removed, the oil in the cylinder will prevent it being pushed back in easily, and getting the sprockets back on with a tightened chain is difficult at best, damage to the sprocket boss on the cam or the sprocket alignment pin is likely, especially if you don't get the sprocket seated well when you slip it on then tighten the sprocket retaining bolt. If the chain is tight, you may think the sprocket is seated, and when you tighten the bolt you are pushing it on with it likely not properly aligned.
USE THE SCREWDRIVER, it is a no-brainer. Simple, and it is the PROPER way to do the job.