Chain Tensioner Upgrade Questions

[jshape]

I was planning to do a chain ternsioner update to my 1979 911SC Targa this spring and now have some questions. My car is driven about 1,500-2,500 miles per year and currently has 77,500 miles on the odometer. It is not tracked – it’s merely used as a nice day driver:

1. Considering how I use my car, is the full upgrade really a necessity – or are safety collars for the OEM tensioners all that is really needed? I don’t like the thought of losing oil pressure at low RPMs and some of the posts indicate this is a problem.

2. If I go with the Carrera upgrade, many of the articles/discussion threads I’ve read also suggest replacing the sprocket support arms rather than using spacers. Again, if I go the oil-fed route, is this upgrade really needed as well?

Thanks in advance for your advice/suggestions.

[jfw834]

jshape,

I have a 79 SC as well and have the stock tensioners. I have made the economical and i believe smarter decision to go with the chain protector collars because this will prevent a failure from damaging the engine in the event that the chain collapses. Mostly i decided this because the upgrade is costly and I have read to many threads here about oil fed ones that fail as well and don't think that all that extra money justifies it. The collars don't fit the carerra oil fed tensioners....otherwise that would probably be the perfect setup.

the other thing you should know is that in 1980 they changed the ilder arms and made them wider in the SC and this reduced the tendancy for them to collapse. the 79 however will most likely still have the narrow ones. When i install the collars I am going to upgrade to the wider idler arms of a post 1980 sc and I believe this is the most economical and safe way to deal with this problem.

also i have read that most of the time, chain tensioners give a good amount of warning before a complete failure by making odd noises and you shouldn't necessarily be driving around just waiting for them to fail without warning. Anyways this is just IMO and i'm sure that others here will dissagree and tell you to do the oil fed route. for me, i would rather have faith in the originals and protect my engine and then deal with the problem of a tensioner failure if and when it happens.

hope some of that helps.....it's a very often debated topic here

[limble]

I added oil fed to my 2,2 engine. It had the collars on it prior and they were all beat to hell. The stock tensioners had no pressure at all. Never had any problems with the oil fed on the 2,2 or the 3,0 and I drive 3,0 pretty hard. The 2,2 had other problems, that's the reason for the rebuild.

[Grady Clay]

There is a Factory rebuild kit for the tensioners. Every year or few rebuild them with new seals and o-rings. Yes, the anti-collapse safety collars/parts are worthwhile.

Best,
Grady

[jeff1hughes]

jshape, I changed to the oil fed in my 2.2. This left me with a set of tensioners with the collars on them as extra parts. I am in the Detroit area, but I go out to Lansing for work quite often. If you're interested make me an offer and maybe we can meet up some time. If you can wait til December I'll be out in GR and would be more than happy to meet with you there too.

[Early_S_Man]

John,

As Grady said ... rebuild your tensioners with the $30 kits from Pelican!

My strong recommendation is to have 10.0 mm milled off the old tensioners and get the wider chain wheel [idler arm] supports. Then get the collars, and you will have a very reliable tensioner system!

[jshape]

Thanks to all for the response.

Warren, dumb questions: Mill 10.0mm off the tensioner where? And, more importantly, Why?

Jeff, I probably don't need the tensioners -- but do you have the idler arm supports?

[jfw834]

hey Grady, Warren,

what is this $30 kit you speak of.....can't seem to find it on pelican and also, i'm interested in modifying my stock tensioners when i install the collars like you said to make them less likely to fail. could you be more specific and are there shops that know how to do this in SoCal?

[911pcars]

The rebuild kit should be available from your local Porsche dealer.

Sherwood

[Wayne 962]

We sell it - it may not be in the catalog - give the sales guys a call at 1-888-280-7799...

-Wayne

[Early_S_Man]

With reference to the pics below ... and the 'spud' that the chain wheel carrier slides over, followed by the tensioner, and finally the cover ...

The double-bushing chain-wheel carrier [idler arm for sprocket] is thicker from end-to-end on the axis that slides oiver the 'spud' by 10.0 mm. The 1980.5+ tensioners are thinner on the 'boss' that slides over the spud, so 10.0 mm need to be milled off the backside [side closer to flywheel] of the boss of older tensioners.