amirpc

Just got our 920x today and tried to tension the belt, with somewhat disconcerting results. We're looking for any assistance!

So using the reference bar (Ours was 6" is that right?) positioned as well as we can, barely touching the water pump roller, we measured an initial reading on our used cam belt of 0.5.

Adding the deflection value of .198 we got an ideal tension setting of .698 with a min of .707 and a max of .689.

After removing the reference bar the value we have on the gauge is .665. The problem we have is that we can ONLY make the value on the gauge go DOWN. The gauge seems to be at the highest position it'll go, no matter how much slack we add to the belt. Even if we push the belt completely off the roller, the gauge still says .665.

Now this belt is only 3k miles old, so we thought maybe it was new enough to use the "new cam belt" deflection value of .173, which based on our reading of 0.5 gets us very close to the maximum of 0.666 (We're at 0.665). Again, we cannot make this value go up at all, we can only make it go down.

We're not really sure what to think at this point, all we can think is that somehow our initial reading is wrong - but we've taken it several times with the same results, only varying if we change the positioning of the reference bar.

Does anyone have any ideas as to what we could be doing wrong here? Specifically with a 3k mile belt should we be using "new" cam belt deflection values or "used" cam belt deflection values?

Also, our reference bar didn't seem to provide a "natural" straight line for the belt between the cam sprocket and the water pump roller, it seemed like the belt was at a somewhat unnatural angle no matter how we positioned the reference bar, we could never agree. The values provided above all have the reference bar positioned so that it just slightly contacts the water pump roller.

75ohm

Assuming you have set to TDC and a flywheel lock on...

Did you bump the cam back as per the instructions?

75ohm

What year?

amirpc

Its an '86 951. We did not use a fly wheel lock but we did set TDC and check and rechecked this. We did kick back the camshaft as per the instructions. We were as meticulous as we thought possible, and followed all instructions and did things exactly as explained in the video on Bruce's site.

75ohm

E-mail Bruce yet?

How do you have the eccentric set?

amirpc

Got a hold of Bruce, he thinks that my 920x was damaged somehow. He's shipping me a new one and we'll see.

amirpc

Quick question for anyone who has a 920x? What does your gauge read when not installed into the body of the tool? Also what does it ready when installed onto the body of the tool but not installed onto the car?

JakeS2

Belt tensioning and no flywheel lock? Good luck.

F18Rep

I'm not quite sure I understand that. I don't think the FSM has a lock required for tensioning, but maybe I missed that day at tensioning school. BTW, I'm pretty sure AMIRPC's situation is due to a defective tensioning tool. The fix is on the way...bruce

Darwantae951

The gauge does not have calibration, when you tension with it, you are taking readings and calculating a tension from them.