Here is a picture of Henry Schmidt’s modification on the early idler that shows the larger bearing surface. Much cheaper than Porsche’s prices for the upgraded ones and should work the same.http://forums.pelicanparts.com/uploa...1552192931.jpg

Are you sure? That wider busing, it is my understanding, requires the narrower version (turbo) tensioner . Read here post #10 http://forums.pelicanparts.com/911-engine-rebuilding-forum/876205-new-chain-tensioners.html#post8735673

Chain tensioner advice for a newbie please
 

I did the same thing also about 15 years ago. One thing to stay away from is Mechanical Tensioners! If you're a racer and opening the engine weekly maybe they work, but for a driver I recommend the factory Tensioners and if funds are available, (the hydraulic ones with the oil lines running to each to pressurize them).

I also installed the safety collars, simple and they work.

LarryT
74 911 EFI

1) The new idler arms do not work with the old mechanical tensioners BECAUSE of the spacing - but they may work with the last 930 tensioner revision - but not ones previous.


2) The new Carrera-style hyraulic tensioners can work with the old idler arms by purchasing the very inexpensive "Life Saver" looking spacer for $5 that fits on the shaft - however, when you think about this it's really defeating the purpose of the upgrade because the spacer doesn't move with the idler arm, nor does it provide any new bearing or bushing surface (ie lubricating surface or surface area in general).

Yes the wider idler arm bush is a worth while upgrade. FWIW the SC motor I rebuilt had definite scoring between the idler arm and the shaft with the originals, even though it had Carrera tensioners.