theiceman

Actualy Micheal i was serious . i would be curious as to the prcentages of collars vs hydraulic an the failures on each . There may not be a big enough population here. But Pelican would give you a really good idea.

whalebird

I had similar experiances to Pete. I have retrofitted many tensioners and It was never a financial decision. Hell we gave away more than we made, or so it seemed. We always did the job that was best for our customers cars, and the customers after that. The aftermarket collars were an afterthought that served a few nieve owners that thought that saving money on cheap component was going top net them the same results as the expensive stuff. This was always the first(and expensive) mistake most first time 911 owners make. There was some concern about hydrolic tensioner failure and IIRC it was a factor of the tensioners manufacture. I always used the original Porsche kit, not an assemblage of after market parts, and also, shelf life before install. There was possibly a Porsche Technical Service notice issued. Again this is all from my foggy memory and I hope that I am not propogating the misinformation so rampant about these cars.

flatsixnut

I read that they also use a machined piece that goes inside the tensioner used along with the collars.
The tensioners are good for 100k miles...if the tensioner fails the collar prevents them from total colapse. Then the rebuild kits for the tensioners are a few bucks. It all sounds good, but its not a complete fix.

Soooo...it sounds to me that the best sleep a person could expect is to install the Carrera Tensioners along with the collars.

Oh and edgy, If asking questions to gain knowledge and save myself from spending more money in the future is considered cheap, I will take that as a compliment.

Traud

Michael - I recently purchased an '82 SC with 200K on the engine. It was topped at 160K but never had the tensioner upgrade. I researched this and consulted with an long time Porsche mechanic and he indicated the Carrera (oil pressure fed) were the best way to go. I had them installed and that engine sings. No leaks. With high mileage on the engine (excellent leak down/compression though), plus knowing that I drive the car once or twice a week, the upgrade was worth while as I hope to drive the car for a few years before a zero time engine rebuild.

Mike Traud

Edgy01

I'm sorry that you interpreted my suggestion to go with the 1984 Carrrera tensioners as insulting. There is plenty of history on this issue in the annuls of Rennlist because it was a big deal a long time ago when they were first introduced in 1984. For many years the chain tensioners were the Achilles heel of the 911 engine, ultimately the source of problems. The collars were a fine work-around prior to 1984 but once Porsche found the solution to the premature chain tensioner problem it became the standard thing to do for pre-1984 cars. I think it was about a $300 kit then. (It can't be that much more now). Even Porsche AG admitted that they appreciated the extra business in parts sales by selling retrofit kits to the older 911s.

When you consider the collateral damage that can occur with these engines as a result of C.T. failure it is fiscally responsible to bite the bullet and retrofit to the latest design.

As I stated before, if you are buying a used 911 (pre-1984) without the latest C.T. retrofit then you are buying a car from someone who took shortcuts on their repairs or had a poor 911 repair facility guiding them. All reasonable 911 engine shops from those days recommended the retrofit.

The collars are designed to prevent total collapse of the C.T. when they fail. It was a smart/clever safety to put on but is not the ultimate solution. When I had mine done in 1985 we never put the collars back on because the newest C.T.s were so reliable that it just wasn't necessary.

I hope this sheds a little more light on the issue of pre-1984 C.T.s; I always approached my 911 maintenance as something that I couldn't shortcut on because I knew the ramifications could be even more expensive if I chose to err on the fiscally conservative.

Peter Zimmermann

No collars on Carrera Tensioners! The oil-fed units are a completely different animal!

flatsixnut

911pcars

FWIW, owners use both types with equal success.

The problem with collars is that when the tensioner collapses, and the owner isn't aware of the increased commotion in the chain box, the collar may end up to be a sacrificial part (it wasn't meant to be). A few minutes of oversight could result in the collar transforming itself into smaller pieces as the idler arm beats down on the non-pressurized tensioner plunger.

If you have collars installed on your tensioners, be aware of the sounds of tensioner failure, then stop the engine immediately. In fact, same with pressure-fed tensioners.

IMHO, commercial facilities take a less risky path to repairs. They want to keep their customers happy and satisfied, thus their repair strategies may tend toward the conservative to reduce the potential for expensive comeback repairs. DIY repairs can either mirror the pros or take their calculated chances with alternate options. DIYers can afford to be more involved with the machinery without added cost.

Sherwood