920X Info Page

Why Choose Our 920X Tension Tool?

ArnnWorx belt tensioning tool with reference bar - front.
Fig.1 - ArnnWorx belt tensioning tool with reference bar.

ArnnWorx belt tensioning tool with reference bar - rear.
Fig.2 - ArnnWorx belt tensioning tool with reference bar - rear.

Support Resources

Updated Instructions:

Click this Link to Updated Instructions to see a pdf file of the latest instructions for use with 920Xv6.2.

Video Clips

920X Applications

Porsche 924S
Porsche 944 (all models/years including S, S2 & Turbo)
Porsche 968

More Info on Placement

Belt tensioning is accomplished by deflecting the belt with a specific force and then measuring how much the belt deflects. A spring provides the force and a machinist's gauge provides a means to measure the deflection value. The ranges of acceptable deflection values are about five thousandths of an inch. For measurements that are so small, the placement of the tool on the engine becomes very important. This section is about tool placement and tips to avoid problems.

Balance Belt

I like to place the tension tool near the upper balance belt cog but if the lower cover is present and especially on the early cars (944 models prior to 87), then the the lower, front cover itself can get in the way. If this is the case, move the tool down the upper span of the balance belt nub by nub until a location with minimum contact with the engine is found. In some cases I have even turned the crank a tiny bit to help.

When you think you have a good location, go ahead and "wiggle" the belt as shown below and in our video clip "Read & Set Balance Belt Tension." The tension tool will bump into the water pump and rest on the lower belt cover but this is not a problem so long as it doesn't get jammed up against something.

Cam Belt

If you watched our clip on nudging you've seen about all there is to know. But here are a few reminder pics of the problem areas.

Mouse Vs Cam Belt Cover

With so many pictures and notes about the belt covers, maybe this is a good place for my mouse story. In the spring of 2019, I borrowed my wife's Toyota Sequoia. I made my errand over into Illinois to drag home a frame for my pickup; I got home late in the afternoon. It was April but still cold. I parked the car out of the way at the corner of the driveway. The next morning she tells me it won't start. I was able to get it started but it was definately not running right. So I get it in the garage and begin pulling things to see what I could find. I'l admit there's not much that I know about these Toyota engines ...because I never have to work on them. Here is what I found.

Can a mouse get inside your timing belt covers?

About the Calibration Bar (aka Reference Bar)

On the underside of our reference bar there is a two numbers, expressed as a fraction. The numerator is for cam belt tensioning and the denominator is for balance belt tensioning. These numbers will vary slightly from tool to tool.

It's easy to use the reference bar; just insert the bar as shown, loosen the outer ring securing screw and rotate the gauge's outer ring until the gauge displays the calibration value. Don't forget to tighten the securing screw.