Timing belt tensioner pulley/roller 1.8T - stud vs bolt

[vtraudt]

I ordered a timing belt kit for the car (transverse engine, TT180), but forgot that car is using the head from a different car (I think A4).
The kit is using the BOLT version of the tensioner pulley/roller, but the head has a (fairly thin, long) STUD.

What pulley do I need to order to match the head?

Looks like B5 A4, B6 A4, B5 Passat (all longitudinal 1.8T) use the STUD version 06B109243B

While Golf/Jetta/TT180 use BOLT version
06B109243

[vtraudt]

https://drive.google.com/file/d/1RLA...ew?usp=sharing
https://drive.google.com/file/d/1Apf...ew?usp=sharing

[Seerlah]

Difference is the way the pulley will tension. My AWM is original with the stud in the head (AWM had both these versions, with a vin split carrying into the B6 with the stud. early AWM used the pin style bolt while later AWM/AMB uses the stud). I changed it up to the bolt style one (allen head pin with male threads on the end vs nut for the stud that is attached to the head. the one in your pic and removed the stud from my AWM block). Difference is the way the tensioner pulley is set. The one with the stud you have to manually tighten the belt (tensioner tool), then tighten the locking nut for proper position of the tension pulley. The one with the pin style bolt with allen head you just torque down. Then when you pull the hydraulic tensioner pin to release the rod, there is no adjusting of the tensioner pulley to have the rod of the hydraulic tensioner extend the proper distance (which should be very minute). One with the stud requires proper tension on the belt before locking down the pulley down with the nut to have the hydraulic tensioner rod have the proper travel distance (both should be little to none if done right). Only difference!

You can remove the stud, thread the pin style one on (pictured in your Google pic) and should work just fine (should also have a washer in the kit that sits between the rod shaft and block). I converted mine to the pin style bolt for ease of install. But the stud version is more efficient, since you can tighten the belt to it pretty snug to the correct belt deflection before locking down the pulley with the nut, making the rod travel of the hydraulic tensioner less than the one with the bolt style one.

But if you want to keep the stud and install the pulley to be used with it, then the pulley from the later vin AWM or AMB is the one you would want. Otherwise, just take the stud out and thread the rod in there, but don't forget the washer (route I took with my car). I would just take this route since you already have parts in hand. But if you want to replace it with the same part you took out, link is below.

If you click the links below, both are AWM:
https://www.ecstuning.com/b-genuine-...ler/06b109243/ (early AWM and what I converted mine to, when my car is a late AWM model. same one with same part number you have in your possession)
https://www.ecstuning.com/b-genuine-...er/06b109243e/ (later AWM and AMB to be used with the stud, and what my car originally came with)

[vtraudt]

Thanks Seerlah, excellent information.
I like the 'pin' (bolt) much better; the stud is finicky to get the tension right.

BUT: the stud (thread size) looks so much smaller than the pin (bolt). Sure its the same size/thread? The pin (bolt) looks like its at least M8.

If so, I will certainly take the stud out and convert to pin.

Just to be sure, I ordered a roller for the stud version as well.

[Seerlah]

All 06A cylinder heads should be the same. Should be a direct swap. The male threads that are already in the block will be thicker than the shaft of the stud. You will see once you take it out.

[2stroke]

Difference is the way the pulley will tension the belt.
My 1.8T 20v is original with the stud style in the head
I changed it up to the bolt style one ( allen head pin with male threads on the end vs nut for the stud that is attached to the head )

Difference is the way the tensioner pulley is set:
* Stud Style , The one with the stud you have to manually tighten the belt (tensioner tool), then tighten the locking nut for proper position of the tension pulley.
( The stud type requires proper tension on the belt before locking down the pulley down with the nut to have the hydraulic tensioner rod have the proper travel distance. )

* Bolt Style , The one with the pin style bolt with allen head you just torque down.
( Then when you pull the hydraulic tensioner pin to release the rod,
there is no adjusting of the tensioner pulley to have the rod of the hydraulic tensioner extend the proper distance.

Only difference !

You can remove the stud, thread the pin style one on and it should work just fine (should also have a washer in the kit that sits between the rod shaft and block).
I converted mine to the pin style bolt for ease of install.
But the stud version is more efficient, since you can tighten the belt to it pretty snug to the correct belt deflection before locking down the pulley with the nut,
making the rod travel of the hydraulic tensioner less than the one with the bolt style one.

However, one wonders why VAG used 2 completely different systems to tighten the belt,
even on the same year models.
It feels like there are underlying causes.