Fast Thinking and light Saved the Valves!

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04-17-2014, 02:29 PM

#31

PorKen

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Quote:

Originally Posted by Tyrell

But, uh, this - all of this is academic.

This has all been said before, since 2006...but I repeat myself.

Belt tension is only one factor in keeping the belt on the crank gear. The factory tensioner is just that, a 'tensioner'. It is not an active belt manager. It does not react in any significant way to actual belt conditions.

If anyone is confident in the factory system, please demonstrate by starting your engine from dead cold, then immediately rev it to over 5000 rpm - as if you had to pull out of your driveway quickly, not having seen the truck barreling down on you. Hopefully the special BELT TEN. o<O light you see will not be followed by all the others...

Quote:

Originally Posted by jcorenman

Calling the factory tensioner a "detensioner" misstates its fundamental purpose: To compensate for thermal expansion and maintain a constant tension.

A constantly high tension. The factory belt-management-system requires a high belt tension as it uses belt stretch as an additional component to compensate for cold conditions.

FAIAP the Gates Racing belt does not stretch...how does one 'tension' it?

Quote:

Originally Posted by jcorenman

Once the adjustment is set, any change in belt tension signals a change in the belt geometry, and a change in belt geometry is always bad.

Automatic tensioners use springs for tension. Springs are subject to oscillation and need damping-- either friction or hydraulic.

The factory tensioner bi-metal Bellville washers (when new) are a spring and, if the oil has not already leaked out, the tensioner may provide a small amount of damping...then again it only needs a small amount of damping as the 'spring' can only provide a small amount of movement.

Quote:

Originally Posted by jcorenman

The advantage of an auto-tensioner is convenience: Install it, pull the pin, and you are done-- free to forget about it for another 60K miles. I don't see the advantage, personally.

Heck yeah! That's why '85-'86 LH2.2 is so cool. One is able to adjust the base injector PW (MAF CO screw) for sensor age, weather, oneself.

'87-'95 LH2.3: so pedestrian. Adjusting itself to it's enviroment...why!?

It would be even cooler to have the prototype carbureted manifold on there!

Quote:

Originally Posted by jcorenman

P.S. As to why no one used the Porsche system, it might be that they had a patent or two

Here are some other great inventions to peruse - http://www.patentlysilly.com/

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04-17-2014, 02:42 PM

#32

Ninespub

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Be nice boys.

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04-17-2014, 03:23 PM

#33

Imo000

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Quote:

Originally Posted by PorKen

Out of millions of tensioner/dampers, some will fail, especially if not maintained.

You don't see millions of posts about how good something is when it works.

You are taking mybpost out of context. It was a reply to the post that said they don't fail but since we are on tensioner failing topic, how many 928s had a tensioner faliure? Tensioner ONLY!