New 3D-Printed 944 Timing Belt Tensioner Tool

[Tom]

Here is our popular 3D-printed timing belt tensioning tool for the 8-valve 944 engines. The first file listed below is the original and most popular. The alternates have more durable drive ports, but require either an M12 triple square socket to drive it, or a heat-set insert from McMaster Carr.

Please note You need at least one post on Carpokes to download files!

Carpokes 944 Timing Belt Tensioner.stl

This is the version most people will want if you don't have an M12 Triple Square socket to use.

944 Belt Tool Triple Square by CP.stl

See post #494 here. This version has a more durable drive port that uses an M12 triple square socket to drive the tool.

Carpokes 944 Tensioner with Heat Set Threads.stl

This is the version I sell, with a heat-set metal threaded insert to drive the tool. This is the most durable version of the tool. For more info on this version, see post #143 here.


[Note: if you cannot download the .stl above, be sure you register and account and are logged in with at least 1 post on Carpokes. If, after that, you still have problems, feel free to email me at admin@carpokes.com.... ]






The basic idea is that it relies on a torque wrench to measure how tight the belt is. The tool has two small pointers that correspond to the new and used belt factory tensioning specs. The appropriate pointer should line up with the guiderail on the water pump when the torque wrench reaches 7 ft. lbs. (84 inch pounds).

The one in the video is posted in ABS with 100% infill and 4mm wall thickness. PLA should also work fine, if not better (as would CF filaments, nylon, etc.). The original version of the model has holes for six sheet metal screws (No. 6 screws, 1.5 inches long) to give the tool the mechanical strength it needs to hold together. The tab that applies pressure to the belt is prone to snapping off without the screws, and the 3/8" square drive socket is prone to cracking apart or rounding out. The screws seem to solve all that, as long as you don’t go past 7 ft. lbs. with the wrench. The alternate version of the tool add durability to the drive port, so don't need those screws, but ALL versions of the tool still need the two screws to reinforce the tab that presses on the belt.

See it in action in the video below! All feedback encouraged!




[This post last edited on 11/17/25.]

[stitch2k1]

I like this a lot. Definitely going to share this with anyone I see who's trying to do it just by hand. I would like to try one to compare with the Arnnworx tool I have, but I don't have a printer sadly. I probably ought to invest in one next year.

My inner aircraft mx has to ask, were any of the torque wrenches you tried calibrated by a shop and how many did you use?

[Tom]

I like this a lot. Definitely going to share this with anyone I see who's trying to do it just by hand. I would like to try one to compare with the Arnnworx tool I have, but I don't have a printer sadly. I probably ought to invest in one next year.

My inner aircraft mx has to ask, were any of the torque wrenches you tried calibrated by a shop and how many did you use?

Thanks! As always, for good active Carpokeans, I'll do my best to print them for folks.

Two of the wrenches had been calibrated maybe 2 or 3 years ago, and the one in the video was brand new (but a 4% cheapy from HF). I was going for a tool that would work with things people already had in their toolbox, like questionably calibrated torque wrenches, or could buy on the cheap like that HF wrench for $18.99.

[stitch2k1]

I like this a lot. Definitely going to share this with anyone I see who's trying to do it just by hand. I would like to try one to compare with the Arnnworx tool I have, but I don't have a printer sadly. I probably ought to invest in one next year.

My inner aircraft mx has to ask, were any of the torque wrenches you tried calibrated by a shop and how many did you use?

Thanks! As always, for good active Carpokeans, I'll do my best to print them for folks.

Two of the wrenches had been calibrated maybe 2 or 3 years ago, and the one in the video was brand new (but a 4% cheapy from HF). I was going for a tool that would work with things people already had in their toolbox, like questionably calibrated torque wrenches, or could buy on the cheap like that HF wrench for $18.99.

Like I commented in the other thread (not seeing the talk of your torque wrenches) I've seen one of those cheapo HF 1/4" wrenches calibrate better than a Snap-on one. I don't believe in any engineering that makes any better than the others in any department other than making you feel fancy. I will probably consider a nicer digital torque wrench when holiday sales come around, since I'm gonna be doing more engines in the future. 100% getting it checked out yearly.

And the inaccuracy of the HF one is probably still better than the inaccuracy of a twist or a clicker tool anyway. So it's better than nothing which is what makes this great.
Plans for a balance shaft tool next? Cause that seems to be even more of a PITA. I am still struggling to dial out the belt whine in my S2 and I did it dead to factory tolerances, with it right on the loose side of the scale.

[PTRogers85]

Thanks Tom! I'll definitely have to print one, good thing I recently bought a spool of ABS

[medic26bfd]

Need to print this.

[Pershe944]

Really looking to be able to try this out!

[Nathankel]

great help, thank you very much for this great job. the best is to print it in ABS?

[papasmurf]

Great job on designing this....this will potentially save some 944's from having a belt being too tight/loose and having it being catastrophic. I previously downloaded and printed the oil cooler alignment tool when I redid the seals on my car and it worked great (credit to whomever designed it) and this will no doubt be something I have printed and added to the tool box.

[JoeBudapest]

Hello,
I will test it on my early 944. Thanks for the tool.