360 Belt Hydraulic Thightener (Tensioner) questions

It can't hurt to replace them, but they are probably ok. If you have method of checking the belt frequency, then you can check the belt tension before removing the old belts. If you want to replace the LH tensioner, but have an early mounting bracket, you just have to remove the dowel pin from the new tensioner before installing it. You don't have to replace the original bolts unless someone has damaged them, they are supposed to be torqued to 25nm/17 ft/lb which is standard for an 8x1.25 mm fastener with an 8.8 rating.
The new tensioner might use a longer bolt for the side with the dowel pin, if you were replacing the mounting bracket to the new style with the dowel pin, as the dowel pin takes up some of the threads in the mount casting. If you are removing the dowel pin and reusing your old bracket you should not need a new/longer bolt.

 

To use the new style l/h tensioner p/n 202784 on your original bracket without removing the dowel I ended up machining my bracket to accept the dowel and saved the $300 or so they wanted for the updated bracket. I used one of my CNC mills with a 10mm drill to counter bore the M6x1.0 hole out just enough to clear the dowel. You could also do this if you had a good drill press and a vise, you just need to make sure you center up and squared up on the original hole and slow rpm.

 

If memory serves me well when I did mine back in 2010, mine did the same as yours (slack then correct tension, it was confusing). Not knowing when they where last changed and it did not have the new updated tensioner or bracket I just went ahead and did the job and never looked back. I also had to do the valve cover gaskets and cam seals as well which were a pain, bought my car it in Los Angeles and drove it back to Portland and then they started leaking and had to fix a bunch of other things that shops in LA cobbled together on the Kreissieg exhaust.

 

Good on you for tearing into it, get the proper tools like I did from Hill Engineering from Ricambi as well as a sonic meter to measure belt tension, 95972938 timing belt tensioner wrench, 95973207 clutch lock. It was confusing at first from the WSM but you combine the tension side and non tension side to get to the 190-220 Hz per the manual. The 32mm crank bolt is blue loctited on and torqued to 196Nm so its a bugger to get off to access the belts, a good 1/2 long snap on with a extra pipe helps to break loose.

Do you have a WSM?

While you are at it you might want to think about coolant hoses and coolant and the dreaded heat exchanger before it pumps coolant into your transmission, motor mounts and transmission mounts (get the 430 trans mount) needs tool 95973219 installer/remover-trans mount/upper.

I've been considering getting another 360 again as I love the lines and the engine sound of them and prices are affordable, a 458 would be nice as well but twice the price but to many electronics to go wrong.

 

It means there are points along the cycle where the tension is not equal on both sides of the same belt and that is totally normal. It has been that way forever and does not necessarily mean the tensioner is bad.
Looking at the adjustment on the cam pulley, you probably should do the cam timing again on the engine using a degree wheel. Good luck, there is not a lot of space to work with while the engine is in the car with the header on, and the aluminum sub-frame in its place. A typical magnetic base won't fit well.

 

The tensioner works like a hydraulic lifter. If constant compression is applied it will collapse. If the motor kicks back slightly on shutdown which is quite common it will leave your tensioner looking that way. It other words a visual inspection carried out that way is an invalid determination if the tensioner is good.

 

If it rattles when cold, its bad. If the left is an early version it's bad.

 

So is it safe to say that the gap and tension frequency measured are only valid once engine is rotated two revolutions and a 2 min wait period has expired? My tensioner gaps and frequency are spot on after the WSM procedure but start to collapse somewhat after several hours at rest and obviously frequency gets affected.

 

I realize this is an older thread but I just thought I would add some of my own experiences.
Firstly the crank pulley bolt- I did not have the locking tool but used the old accessory belt and it worked great. Take the belt and wrap around the crank pulley all the way around then pinch it tight facing downwards. Then fold the rest back up the left side and loop around the water pump, As you turn the crank bolt it will tighten enough to allow the bolt to loosen. Tightening was the reverse just run the belt on the right side. I was able to tighten to 146ft pounds using this method so it certainly wont budge.
I used the marks that were already on the pulleys from the factory but I added marks onto the old belts just in case I needed to reset back to where it was. I had the engine perfectly timed before undoing anything.
My tensioners were so far out I needed to remove and reset them. I used a large builders clamp took my time to not damage them. Inserted a small drill bit.
To set the tension on the new belts I tightened the tensioner pulley enough for it to hold but still able to move with the tool this allowed me to do very fine adjustments. I bought the Audi/VW tensioner tool as it is cheap to buy. It is not offset like the OEM one but it still works OK. I was able to get mine to about 1.8mm while the pin/drill could still slide in and out easily. It’s a little on the tight side but I put that down to the new belts. Leave the pin in while tightening the bolt.

I would say to anyone thinking of doing this job definitely give it a go.