Ok, I know this has been beaten a thousand times, but I did a search and couldn't find the answer to my question. I know my car has the updated water pump as it has the guid rail, but I'm pretty sure it has the old style toothed-roller, unless I'm looking at the wrong roller. It is the roller right below the water pump pulley, right? Does anyone have a picture of the updated setup? I'd imagine the updated setup would have the roller contacting the back side of the belt vs. the toothed side.

 

No, the roller right below the waterpump pulley is the tensioner pulley. It will either be mounted to a stud, or a part of the auto-tensioner depending on what year your engine is. The tensioner pulley contacts the toothed side, and the smooth side drives the waterpump. There is a timing belt idler roller that mounts above and to the right (if viewed from the front) that should be against the smooth side of the belt.

 

From Clarks garage (www.clarks-garage.com)

Early style with eccentric roller tensioner:


Late style with auto-tensioner:

 

Awesome diagram thanks. So the smooth idler pulley is the one that is increased to a 46mm diameter for the update?

 

Oh, and one more question. Can the auto tensioner be installed on the earlier cars? Or were the blocks recast with the appropriate mounting bosses? I can't tell because the rear timing cover is still on.

 

The bosses are there, but from what I've read, it's a PITA to drill and tap them properly.

 

...get the roller/belt kit and keep as is...save yourself some $ and bloody knuckles.

 

So in your guys' opinion, is it better to stick with the early pump if it hasn't been updated yet? Or should a guy update to the newer?

_______________________________
'86 951, stock (hopefully not for long)

 

Updating to the newer style waterpump is not an issue. Updating a pre-autotensioner engine to the auto-tensioner is where it can get tricky.