I have been flying under the radar in most of these forums pilfering knowledge and helpful notes from others for quite a while. While recently rebuilding the motor on a 2008 M50 I had hit a bit of a snag in dealing with the cam chain tensioners, there is a special tool for them, but it comes at a premium (for what it really is). I figured out a "cheat" or "life hack", and now it is my turn to pay it forward to those who have helped me out when I needed it. I am not going into the specifics of the rebuild here, this is simply to save someone the cost of a tool, wait time for delivery, or allow that person to finish a job when the local shop is too far or closed for the night...
YOU WILL NEED:
two 8" zip ties
a razor blade/sharp knife
a little bit of patiece, it may take two or three attempts to find the right thickness and or sweet spot to lock the tensioner device.
Step 1) trim the zip tie profile, thinning it out so it slips into the ratchet opening, then narrow its width.
Step 2) with any narrow and long device, release the wratchet, maintain presure on it until you can fully compress the tensioner.
Step 3) control the release of the tensioner by one or two clicks, you'll notice the wratchet opens and closes a little bit with movement, when the opening is at its largest, wedge your zip tie device into it, this will effectively lock the tesioner. You are now free to work with the rest of your assembly.
Step 4) as you reassemble the heads and set the timing, prepare to place the cover back on, be sure to carefully rout the tails out the valve inspection opening without pinching the plastic between mating surfaces, or it will not come free after torquing the bolts.
Step 5) once you are satisfied that the cover is torqued, simply give the tails a tug, they will come free of the engine and you'll hear the ratchets activate (rapidly clicking into place).
NOTE: This is where the routing in step 4 comes in, if they don't pull out easily, you have likely pinched the zip tie upon reassembly.