Chain tensioner kit contents
 

I upgraded my 78SC to hyd chain tensioners 6 mos or so ago. I got the kit from SSF and it was an easy install. What I can't remember is if the kit contained the spacers that go between the tensioner and the sprocket. For the life of me I can't remember installing them.

What kicked off this question was when I repaired my 79SC an eagle eyed mechanic noted that it did not have them. The upgrade was done many years ago by the PO. The parts are inexpensive and don't show in PET. They carry PN 930-105-513-00. Maybe they are not really needed.

I noticed that the picture of the upgrade kit from our host does not look like it contains the spacers.

The info that I have on the update kit shows the need for 2 of 930 105 513 00, spacer bushings. This is for engines 1980 and earlier models up to engine numbers:

-630 1091
-630 9033
-640 0450
-630 8135
-670 0106
-689 1301
-689 0684
-670 8023

I don't know if this answers the question, it is from a Porsche Factory TSB.

Good info, but how many people have TSB's on their shelf, much less refer to them. I'll bet there are more people than me that were unaware and may now be wondering the same thing I am, (IE) 'did I install or get them installed, when I did my upgrade.'

John,

I do not recall getting the spacers in my kit, and I did not need them because I put updated idler arms. FYI, here is a picture of a kit similar to mine (930105911912):

http://forums.pelicanparts.com/uploa...1226862548.jpg

Aurel

For what its worth, I have given this a lot of thought,-for a while now, and I have concluded that the spacer does nothing when the engine is running.
Assuming that the idler and its sprockets are aligned axially on their shaft by the timing chain, the idler cannot not go near the back of the chain case,or move out into the 10mm space [where the spacer goes]unless the tensioner was to fail ,allowing the chain to go loose and derail the tensioner sprocket.
The only advantage I can see for the upgraded idler arm , either Porsche or
Supertec, is an increase in bearing area from the 10mm longer bronze bush,on the idler shaft--I dont know if excessive wear on this shaft was a problem previously.
Interesting that Henry mentioned that they have seen increased wear on the layshaft bearing suggesting to me that the Carrera hydraulic tensioners are really loading the chains.
Of course I could be completely wrong but I too, would certainly appreciate some discussion from more experienced board members.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/432615-camchain-tensioners-again.html

Thanks, Bob

It is a big problem. The last few motors I've been into with the old style idlers have had major galling and wear on the shaft. This causes binding on the idler and can result in serious strain on the tensioners, chains, and layshaft bearings.

Do yourself a favor, get a pair of the updated idlers along with the upgrade. Well worth it. They are now horribly expensive new. Worst case, you could get a used pair, rebush them and install new idler wheels, for far less than the cost of new units.

Posting malfunction .... big time. Or maybe this is a new obscure Porsche tech problem?

I put the spacers in one engine and will do the other soon.

Here is the alternative we came up with in lieu of buying expensive factory update tensioner arms. We install these on every engine rebuild.
They offer full width support and none galling rotation to help prevent tensioner failure.
If earlier (narrow) arms are used (not recommended) spacers should be installed.


http://forums.pelicanparts.com/uploa...1243608161.jpg
http://forums.pelicanparts.com/uploa...1243608185.jpg
http://forums.pelicanparts.com/uploa...1243608205.jpg