SeanR

I've never seen a flattened washer but I have seen several bent "bearing pins" (bolt that holds the idler arm to the pump)

mark kibort

There is such a small amount of movement possible with the washers and the system is so stiff anyway. there is not much movement with their spring pressure. if you didn't care about tension adjustment , hot vs cold, you could weld the washers together and just be fine. the belt has enough flex /stretch in it to dampen any vibrations. after all, it is the longest timing belt in the industry! HEY, GB, I just thought of something, maybe that's why I don't need the "damping" oil.... I use your favorite "Conti belt" which is a "rubberband", so I don't need damping oil.

don't forget the distance from Mars on that adjustment day.

Ive seen some pretty jacked up tensioners..... as long as I could get the tension proper, and knew it wouldn't change, I didn't care. I think scots 1st engine had a mis match of all sorts of compoents. the wheel didn't even line up straight. arm was bent, washers welded shut from corrosion and no oil, etc. it still worked fine. later, we swapped out parts to make it closer to stock and more adjustable , but it worked. just so you all know, try to compress the washers...... then try and stretch the belt. the belt and its flexibility is NO match for the basically rigid shaft of the tensioner. if you think there is damping going on with the oil, or even movement due to spring pressure... think again.

GregBBRD

I have no idea.

I did not design, build, or test it......so I don't see why I would have any clue.

GregBBRD

And do you think those bent pins are from "virgin" vehicles and point to a defective design, or from some hack working on the car and doing something wrong?

Truthfully, I never take a chance.

I consider the pin to be a one use item and always replace it.....there are very few 928's still around with the original belt....and I have no idea how tight that bolt was tightened with someone's impact.

PorKen

Um...because you are THE stock-tensioner-guy? The big cheese, the man with all the answers, the hero of Anachronism, OH. Greg.
Because your minions mouth the words you write about how wonderfully engineered the stock tensioner system is - with temperature compensation, damping - there's even a light!

The truth is you read some service bulletins and called it good. Tighten the belt enough and it stays on, mostly. Changes over the years, centerline, pulley(s), a light? Improvements! Gear wear? Normal!
By your own admission, you have no idea if the thing actually does correct significantly for temperature or a clue if it provides any actual damping, (especially when tightened to the 32V specification).

You keep asking for data, but have nothing to compare it with...for all you know, it is no different than Un Système Kibort.

dr bob

The ultimate and perhaps definitve answer would be to test the belt tension in a hot engine, and compare it with the tension on a cold engine. But what would that tell us? That the factory considered that tension (actually "those tensions" if they are not identical) to be sufficient to drive the cams.



Solely my own independent opinion, not necessarily those of this station or its sponsors:

I'm a big fan of Ken's tensioners. For the average guy who doesn't replace lots of belts regularly (the .not. GB's), who has faith in the Audi-style tensioner, and who isn't worried about that one-in-NN chance that there will be some other failure that might otherwise set the alarm light. Meanwhile, --I-- depend on the light to tell me when something else is marginal in the drive system. Is the belt stretching due to internal cords failing? Water pump bearing giving up? something else that might allow the belt to try and jump a gear? Ken's tensioner saves folks from the possible valve damage that might accompany those problems, by continously taking up the "extra" belt length. Looking solely at the tensioner itself, and without regard for the potential problems in the rest of the system, Ken's tensioner would be a significant upgrade on my car. But, with my engineering roots, I need to consider the system as a whole, and decide if the better tensioner is worth the added risk of missing a symptom of impending failure.

Ken-- Let's figure out an effective early-warning system that warns me when the tensioner position is further out than I might otherwise expect, given the current state of block thermal expansion. I've scratched my head a few times trying to come up with a bulletproof method, but it hasn't come to me yet. I'm thinking that it will be a bimetallic spring and a limit switch, maybe in combination with the little switch at the bottom crank roller. When we have that, your tensioner will go onto my car.

James Bailey

Learned something from this ...
."min·ion
/ˈminyən/
noun

noun: minion; plural noun: minions

a follower or underling of a powerful person, especially a servile or unimportant one.

synonyms: underling, henchman, flunky, lackey, hanger-on, follower, servant, hireling, vassal, stooge, toady, sycophant; ...... "

Did I just get insulted ?? or did I do that myself

PorKen

I think the Tensioner/Damper ground isolation will work. It should show if the T/D is fully extended or retracted, (or stuck) as soon as the belt is able to flutter at all.

I am waiting for Han's fan shroud before I tear into my '88 to work out a complete kit and begin testing.

x98boardwell

Ken, I have one on order from Rog... that is the one thing holding me back from proceeding but I would rather wait than put my stock on back on. Seems ridiculous to me to use a stock tensioner when this is available and the cost is very reasonable.

I am a 911 guy by heart but the short time I have had my 928 it is growing on me faster than I could have imagined.

Thanks for putting out a great product!

Cheers,
Bryan

jcorenman

Ken, this is getting out of hand. We put 70k miles on a PKT with our GT, worked fine. Then I pulled it for inspection after getting home from S'Fest and Third Coast last November, and replaced it with the stock tensioner. Do you want to tell the folks why, or shall I?

FredR

kmascotto

+1

But...if I was to guess....the hydraulic seal let go and there was no dampening effect left...

mark kibort

I want to see someone race the PK tensioner for a full season. at least 6-7 weekends.

James Bailey

Hello darkness, my old friend
I've come to talk with you again
Because a vision softly creeping
Left its seeds while I was sleeping
And the vision that was planted in my brain
Still remains
Within the sound of silence

In restless dreams I walked alone
Narrow streets of cobblestone
'Neath the halo of a street lamp
I turned my collar to the cold and damp
When my eyes were stabbed by the flash of a neon light
That split the night
And touched the sound of silence

And in the naked light I saw
Ten thousand people, maybe more
People talking without speaking
People hearing without listening
People writing songs that voices never share
And no one dared
Disturb the sound of silence

"Fools", said I, "You do not know
Silence like a cancer grows
Hear my words that I might teach you
Take my arms that I might reach you"
But my words, like silent raindrops fell
And echoed
In the wells of silence

And the people bowed and prayed
To the neon god they made
And the sign flashed out its warning
In the words that it was forming
And the sign said, "The words of the prophets are written on the subway walls
And tenement halls"
And whispered in the sounds of silence ........

Chalkboss

Well...?