yoni_d

Hi Guys,

I have to replace the timing belt soon so in addition to the water pump replacement, I want to rebuilt the timing belt tensioner. I must say that I dont know that exact problem with the tensioner but my mechanic told me that it is not working well and has to be replaced / rebuilt.

Is there a replacement kit or I just have to buy certain parts.
If I have to buy some parts, can you please let me know the part number / name?

I own 928 1980 S

Thanks!

giddyupp

IMHO - You should forget rebuilding the original and install kens - "porken tensioner". Roger sells them. Once installed no need to go back in to check tension. A very nice upgrade and simple to install. Here is a link to Kens site.

http://liftbars.com/indexpk.htm

James Bailey

I doubt your "mechanic" knows anything about how the 928 tensioner works. It NEVER adjusts to add tension. It only loosens with heat changing the cup of the internal washers to compensate for the expansion of they alloy engine. It is not oil fed or pressurized the oil the mechanic puts in is just to transfer heat to those washers. It is a very simple device.

yoni_d

Well James, my mechanic indeed didnt understand how it should properly work :-\
Giddyupp, thanks for your advice! I will look this up.

Is it better to buy this "porken tensioner" and not a rebuilt one? I saw in 928int.com that they sell those for 295$

GlenL

Rebuilding a tensioner is taking it apart, cleaning it, and putting it back together. You'll likely want the boot for the front. Your car doesn't have a gasket on the back. Look closely at the insides when you take it apart, or take pics, as getting the washers back right will make it adjust for temperature changes correctly.

Some listers will push changing the tensioner but it's not necessary. Check for other posts and how-tos but the important things are to replace rollers that aren't smooth (including the water pump), to tighten the pivot bolt right and to set the tension right.

928s have run a billion or more miles with the stock tensioner. Failures are from neglect and mechanic mistakes.

davek9

Also if you do decide to rebuild the old unit, don't forget to replace all the tensioner pulleys and shaft bushings, if the tensioner arm is not rock solid and true, the belt will not track correctly.

As said it a High Maintenance part and no modern car uses that method of belt tension compensation.

GregBBRD

The boot for your tensioner is no longer available, which makes replacement very problematic.

I designed and make an adaptor piece that attaches over your tensioner. This allows the use of a standard later model boot, clamp, and idler arm pushrod.

If your tensioner is not worn out internally, these are all the pieces you will require to rebuild it, although I frequently also replace the adjusting bolt to ensure that the oil the tensioner must be filled with does not seep out the threads (the bolt has a special sealant to keep it from leaking which wears away with repeated adjustments.)

My kit is available from several souces....928 Classics, 928 International, 928's R Us, and from me directly.

The stock tensioner system is very robust and very reliable. Inspection and adjustment of the timing belt should be done every 15,000 miles. While the Porken designed tensioner does not require regular adjustment, it's pretty much a sucker's bet not to look at the belt every 15,000 miles anyway, so the actual difference in labor between the two systems isn't worth talking about.

yoni_d

Thank you guys! when I will get to it, I will update this thread!