920Xv6 Info Page

920Xv6.2 Belt Tension Tool

ArnnWorx belt tensioning tool features.
Fig.1 - 920Xv6.2 belt tensioning tool features.

ArnnWorx belt tensioning tool with reference bar.
Fig.2 - 920Xv6.2 belt tensioning tool with reference bar.

Support Resources

Updated Instructions:

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

Video Clips

With this new 6.2 version we began a journey to add video clips. We're working toward end-to-end demo of how to tension your Porsche 944 cam and balance belts. We still have a long way to go. Currently we are moving our videos to YouTube. Among other things, the videos will introduce you to three techniques. These are needed to get best results. These include: nudging, the "wiggle" and "overshoot your target."

920X Applications

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

920Xv6.1 Vs. 920Xv6.2

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 accurate measurements that are so small, we need a precison measuring tool and a good deal of user technique. In our v6.2 video clips above, we talk about nudging, the "wiggle" and "overshoot your target." We introduced these with our 920Xv6.2 tension tool but its good information for users of the earlier 920Xv6.1 tool as well.

Early Vs Late Engines

If you've seen the videos above you might be looking for better coverage of the 87 and later engines. Those later 944 engines came with an auto-tensioner (sometimes called a spring tensioner). The process for them is pretty much the same 1) we get the cam belt's slack moved to the upper span where we can measure it's tension. 2) We get the reading and move to making an adjustment. These videos below are from our demo of an ealier version of our tool. Generally, placement of the tool and basic content is still good info. Use the correct instructions for your 920X version.

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 way over into southern 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 are 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.