collars on stock tensioners, does this work?

It seems like a simple, cheap, and quick solution to prevent catastrophic failure in the event the spring collapses on the stock tensioners.

The question is how would you know when the tensioner failed if the collar is holding the chain tension?

Has anyone had the tensioners fail with collars installed?

What is the general opinion of the collars?

Tony
'78 911SC

My bet is, the engineers at Porsche had a good reason for giving the tensioners the range of motion they have.
get piece of mind; carrera tensioners.

The collars are better than nothing. And the oil feed tensioners are better than the collars. At the very least I would install the collars, but only until the oil feed tensioners could be installed.
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Paul
78SC Targa

What's with the new tensioner kits?

I was spending more money then allocated on my top end rebuild, and it was not the right time for the oil fed tensioners.

I looked at the collars, but opted for the solid inserts. They were only $34 for the SC. I just didn't feel comfortable with the collars, at least not as much as the inserts. I know the inserts will have to be adjusted, but there hasn't been a need yet.

Hello

This things are stupid and can cause a fatal engine disatre on missshifts.

Normaly a misshift with overreving is "lived" out in the engine and will not harm a standard CIS engine.

With the collars there is not enough way forcing big costs.

No free lunch.

But missshifts hapen sudenly in real life and failing tensioners generate noises far ahead of failure.

Porsche are long lasting cars but need maintance.

And tensioners are cheap things changed in 3-6 hours a bend valve or even worser is big $.

Think if Porsche would have chosen the oppesite way everyone would say that that is stupid or even never regognize it as they will not understand that kind of engeniering.

Grüsse

Thanks for the input guys.

I think Roland makes a good point. The tensioners need to have the ability to compress, otherwise porsche would have just made a mechanism that was adjusted to tighten the chain and then locked in place. Since collars defeat the compression ability of the tensioners this is probably not a good idea.

I think I'll wait until I get enough funds to do the carrera tensioner update.

Tony
'78 911SC

solid tensioner inserts have to be adjusted when the engine is hot. that means a quick removal of the muffler, tin, and chain covers. the chains get tighter as the engine gets hot.(thermal expansion). if you take the slack out of the chains w/cold, they will stretch when the engine gets hot. the guards are the best way to go if you have to run the old style tensioners. the spacer in the kit allows sufficient movement of the tensioner piston.

Hello

The tensioner is not only working to keep the tension, it also is used as a shook absorber.

Those chains are heavy and can swing very bad.

A weak tensioner has lost the damping abilty and so you will hear that "ugly" noise.

A solid tensioner will force the prolonging from the cains and also forces wear on all chainparts including the gears. Worn indermediate shaft gears force to split the case.

Never had seen a solid tensioner in my life and i had seen a lot of the Porsche race stuff. Could it be that Porsche is so stupid and is not using such a simple device ? Never investigate on that.

The idear behind the collars was used by several indipendend enginebuilders in the 60īs & 70īs when Porsche had the early 901 lifters.

But not a clamp on design, just a cut tube as a sleeve.

Was asking the whereabouts then and all said very similar whre the trouble kicks in. But guys like Kadach or Wagner made race engines in that time. Race engines see misshifts but donīt get to old...

I do not think the collar will destroy the engine but if the chain snaps over or destroys the ramp caused by that thing ? The chances are higher on engines with higher milage due to lenghted chains.

Hadnīt seen that one 930 tensioners failed on my rebuilds. OK they get weak under hard use. But had seen them failing on other rebuilds and seen pressure feeded failing too ( just browse few days back ).
So there is no sense for that part in my eyes. Maybe only for people who will go for absolut sure and never race there cars.

Sorry for thinking german.

My 83SC made it for 170,000 miles with collars.When I had the tensioner update done last summer my mechanic said the tensioners were at the collar.My car was running fine,
I just decided to do the update for my piece of mind.

it seems we're missing the point here. the collar is not to limit the travel of the tensioner in normal use, but to prevent it's total collapse if it fails, which can result in serious engine damage. for $20, it's a good insurance policy. you can still hear the chain noise if the tensioner fails, but no damage is done.