1989porsche928

Are you saying the Porken Tensioner causes engine failure?

Wisconsin Joe

Maybe because the now locked thread that was a technical question (Why did this happen?) turned quickly into a "I hate Ken's tensioner so it must be the cause" thread. Filled with insults towards Ken and his product.

He held his temper a lot longer than I would have.

I see a lot of the critics flinging a lot of insults and pejoratives. Filled with questions asked over and over again. Along with misinformation and outright falsehoods about it. Enough so that the real questions about the tensioner got lost in the noise.

And when Ken fires back, now he's the "bad guy."

The level of passive-aggressiveness towards Ken in both threads is ridiculous.

This post is not necessarily directed at Jim, but towards everyone.

ptuomov

That's what they're not so subtly hinting at, although it's not true. You can speculate about their motivations.

ptuomov

I would also note that I think it's amazing how some people can behave the way they did (lies, name calling, etc.) in that thread (https://rennlist.com/forums/928-foru...-death-30.html) and then expect other people to just take them seriously and at face value in a next thread as if the immense quantities of lost credibility would've magically been restored.

jcorenman

I certainly haven't insulted Ken. There is a huge different between questioning or criticizing a design and insulting a person.

My questions and concerns were technical design issues. What Ken "fired back" with were insults and sarcasm. If the designer believes that a 90-deg flathead is appropriate for a 82-deg countersink, then explain why. That's a concern about a part, not a slam at Ken.

No design is perfect, and feedback is how designs get better. In the "real world" this is done by formal design reviews: folks check their egos at the door and go over every aspect of a design. Technical questions get technical responses.

docmirror

Define "you".

If you were implying that I said, or implied, or intimated, or suggested that the product causes engine failure you are completely mistaken.

GlenL

And generally being thin-skinned. "Don't call me Ken." Sorry, Ken.

It'd be irresponsible to not speculate about people's motivations and impugn them with ad hominem attacks. Isn't that the way the internet works?

Imo000

Ok so, the hardware upgrade is a service bulletin as opposed to a product recall? Leaving it in place is perfectly acceptable?

ptuomov

I think that you're right in saying that the old bolts were not ideal.

That was improved in both gold bracket bolt upgrade kit (that was supplied to users free of charge after a single confirmed failure) and the new PKT-Black system. So it's not like Ken (and Roger) aren't open to improving the product. I personally think they handled this extremely well, but expectations may of course vary.

However, I don't think that you haven't so far presented sufficient evidence or engineering calculations to say that it's not ok to leave the older bolts in until the next time you have to go under the covers for other reasons. (I'm referring to this post: https://rennlist.com/forums/928-foru...l#post13342015.)

ROG100

The communication regarding the countersunk screw and the upgrade kit was sent to all PKT customers.
It recommended checking the tightness of all the bolts and as soon as practical to change the countersunk screw. The upgrade to the through bolts was the customers own decision.

There were zero reports of any loose screws or bolts.

hwyengr

+1, but I'll be the first to admit that the design review protocol works miserably with non-engineers and designers. Or my wife.

bureau13

I have to agree with this.

bureau13

Oh, you've been here before I see

Jfrahm

This is exactly my concern. It's not a ratchet but rather an damper. If, with the engine stopped, the belt is held tight against this style tensioner by the valve springs I wonder if it will compress in the same manner it does when I compress this style tensioner to re-pin and re-use it after a belt change? This could put a lot of slack on the non-tensioner side of the motor and throw a loop at the crank pulley upon restart/kickback. IMO it's worth looking into.

I have 5 engines with these style tensoners, Porsche, Audi and Toyota, and no problems with any of them but they are stock and there are slack management rollers in these engines. Interestingly the roller arrangement changes between the 310HP and 360HP version of the Audi 40V V8, so I assume a change in cam, valve springs, redline, etc. changes the timing belt management scheme.

Research question: Is there a position one can rotate the engine into that is stable and also which causes the PKT to compress over time? i.e. max tightness on the tensioner side belt run?

Eplebnista

Is there a link between Porkensioner use and ovarian cancer?