Bilal928S4

Excellent!

PorKen

I don't normally do requests, but since folks interest is piqued...

BTW, Jim, since you have been 'born again' with praise for the stock tensioning system, maybe you can help Greg out with measuring its temperature compensation and damping range, if any, when tensioned to the 32V spec.

What hand is it getting out of, exactly? The first I heard that you switched back to the stock tensioner system was on Rennlist. As you noted, your PKT system 'worked fine' - through two belt changes, IIRC.


In the last year there have been two fastener related issues which happened on significantly modified engines. There have been no problems with the Audi components themselves. Out of an abundance of caution, both types of fastener issues were addressed with the PKT-B design. Previous customers were notified individually to check the tightness of the upper two bracket bolts at their convenience and that an updated fastener kit has been made available for when the time comes to change the belt.

Jim was offered two different mitigation strategies for his older kit, but it appears that he was not satisfied with those. I can only assume he wanted a new PKT-B kit to replace his ~7 year old, ~70K mile unit, with which he personally had no problems.


Previous customers can email Roger@928srus.com for more information.

jcorenman

This has nothing to do with my view of the stock tensioner system, it works fine as long as the various parts are all properly maintained. What's changed is a loss of confidence in the PKT as a result of the "issues" you mentioned, which prompted me to do some engineering analysis-- and which I shared with you months ago.

It is not my intent to disparage anyone's design, we all make mistakes. The important thing is how those mistakes are handled. I've waited months for some acknowledgement of issues and what folks should watch for, yet you continue to insist that a few cars going 50, 70 or even 100k miles somehow validates the design.

Uhhmmm, how does "significantly modified" effect the suitability of a particular tensioner system? Isn't the Audi auto-tensioner touted as being better able to control belt tension? I am not being argumentative, just curious as to what modification would disqualify an engine from using a PKT?

And we can discuss whether the PKT-B addresses the issues. But to do that, we need to get down to design details, and I think you need to explain what the "issues" were.

Just to be clear, I didn't ask for any mitigation or consideration. I simply detailed my concerns and offered my analysis of the issues, and then I made my own decisions. So we're square, no worries there.

PorKen

You waited for months to read your interpretation of distant events? Perhaps it is your ego that is getting out of hand, my friend?

I will neither discuss proprietary information, nor customer experiences on a public forum.

I thanked you for your unsolicited analysis, but Roger and I did not share your opinion on (all of) the causes, remedies, or severity.

James Bailey

Trust me when I tell you how great it is but I am not going to mention or discuss the problems which we already have had. Just rest assured I have fixed them even though I did not know I had them until there were failures.....new design is perfect....just as perfect as the old one...probably just as perfect as design 3 if I need one. Silence....

ROG100

Jim - you chose to make changes to your system based on your own findings - all power to you. Every PKensioner user received details of our findings and remedies with a free upgrade to the PKensioner Black system. As the supplier of the system I had to make my own decisions and trust 1000% the actions Ken made to the design.
There were two cases where the bolts came loose on the bracket - one on a racetrack and one under normal conditions. No secret has been made of the one issue under normal conditions and this was the reason why my safety bulletin was issues to all PKensioner users. We requested that all users check the tightness of the bolts holding the bracket in place. Not one report was returned saying that the bolts were found to be loose. We also supplied a replacement CSK bolt to replace the original where the angle did not meet exactly the CSK angle in the bracket.
Ken, based on information from the Audi boards, also upgraded the bolts for the "Black" system so that they bolted through the bracket and are now secured with a nut as opposed to the threads in the bracket. I have already supplied hundreds of upgrade kits to PKensioner users around the World free of charge.
Jim Mayzurk suffered from the issue under normal conditions and immediately replaced the PKensioner with a new PKensioner.
I personally checked all the PKensioners on my own cars and found zero issues - I continue to use the system and certainly would never return to the antiquated original tensioner system - EVER!!!
Again I respect your decision based on your own research to return to the old system - this I hope is still a free World in America. I also have every respect for Greg and again he is entitled to his opinions.
Why you would intimate that some delay was made in notifying the PKensioner users is beyond my comprehension. We took all the inputs into consideration and also did not "kneejerk" a hasty safety bulletin until ALL facts were known from ALL parties and not just your defined results.
As an example you researched the amperage found on my blower system upgrade to be dangerous to the wiring and after due consideration I now sell the blower system WITH the upgraded harness system which increased the price dramatically. Was it actually required???? I have the motor upgrade without the harness on a number of my cars with zero issues.
Greg's lifetime fuel hoses - by my own words the best in the World - do they leak? Well some of the first ones did and Greg immediately pinpointed the problem and rectified the issue to 100% satisfaction of the customer.
My point is that there are always issues but more importantly it is how those issues are dealt with. I stand by Ken's decisions 1000% and the actions of 928sRus in notifying all users with a safety bulletin which was followed up by a more detailed report for those who requested further information.
Apart from stirring the pot Jim what else would you like us to do?

jcorenman

No, I waited months for you to post something about the "issues", and let folks know that there were some things to check for.

We debate failures of all sorts of parts, with the goal of identifying weaknesses and making improvements. That is one of the great strengths of the interweb and this forum in particular, the sharing of information. The potential issues of the stock tensioner system have been debated at length: worn bushings, potential for bending the shoulder bolt on early cars, etc. Whenever something nasty happens with a stock tensioner, it is gets discussed and analyzed and hopefully understood so that it can be avoided in the future.

Shouldn't the same be true for the PKT? Why the great reluctance to let folks know what happened? It may have just been a "fastener issue" but when parts get unfastened and valves get bent then I think it becomes an issue worthy of discussion.

jcorenman

I misread that, apologies. My understanding was that the countersunk bolt was free of charge, and that an upgrade to the "black" tensioner would be available. Thanks for the clarification, and that is terrific.

What I would like is for everyone to have the same information, and to be able to discuss the PKT just like we discuss any other part or system on these cars. I appreciate that you are satisfied with the design and the changes, but the whole point of an open discussion is to allow everyone to contribute. And preferably without being insulted.

Here's a very simple case in point: The bracket is steel, fastened to an aluminum block with three M8 machine screws: One flat-head, two flange-heads. All three holes are oversized. Given the difference in expansion of steel and aluminum, the bracket will shift around at least two of the fasteners as things expand and contract. This is inevitable with dissimilar metals.

Flathead fasteners in countersunk holes cannot shift of course, so the bracket is effectively pinned at that point. And flat-head screws also self-center when tightened, this is important because the thru-hole is oversized (except for earliest PKT's) and only the head is in contact. But the flat-head can only self-center if the bracket is free to move while the screw is being tightened. Which means that the flat--head must be tightened first.

If either of the flange-head screws are torqued first then the flat-head will be tightened off-center, making contact on one side only. As the bracket shifts with temperature then the screw head will no longer be in contact with the countersunk surface, and the screw will be loose.

The PKT instructions from Ken's website say "Torque flange head bolts, counter sunk bolt – 15 ft.lbs". To me, that says "Torque the flange head screws first and then the countersunk screw". But I have had the opportunity to work with some very good machinists and knew that flat-heads need to be centered, and in this application would need to be tightened first-- so that's what I did.

Hopefully everybody knows that, but I believe this is critical, and needs to be clearly stated in the instructions. Assemble the three fasteners loosely, then tighten the flat-head first, then tighten the other two fasteners, then torque each to spec starting with the flat-head. This was a part of my comments last Nov/Dec but the instructions remain unchanged.

And I appreciate that no loose fasteners have been reported, that is great. Any hopefully folks took things apart enough to remove the Audi/NTN tensioner to get to the flat-head and check its torque. That is the key fastener- the one closest to the cantilever that supports the tension roller, a flat-head in an oversized hole which could have been tightened off-center, the one with the wrong countersink angle, and the one that broke on Jim's engine.

I'm sorry that you feel this is "stirring the pot". That isn't my intention at all. My point is simply that folks need information, and if this is a technical forum then we ought to be able to discuss technical things with all of the facts available.

ROG100

Jim like many others I took this to be stirring the pot - you made it sound like some secret that the World should not discuss - sorry if I misunderstood. AT NO TIME HAS THIS BEEN KEPT A SECRET. Jim M and Sean talked about it openly to anyone interested as so did I. We hesitated to say anything publically until some factual background work had been concluded. Once conclusions were drawn my safety bulletin was issued to all users on my books along with a second email to those who wished for more detailed information. That was a long time ago.
You are entitled to your opinion and engineering philosophy and drew your own conclusions. Please start another thread if you want to "sound" your ideas to the 928 World so all can see and not those who are just participating in this thread if that is what you are trying to achieve.

As the supplier of these products I am totally satisfied with the actions taken by the designer and the warnings issued by my company. I will continue to use the PKensioner on all my cars.

Rob Edwards

Roger/Ken (Ken/Roger? )

Since I was a bit of an early adopter, certainly before Roger took on the distribution of PKTs, perhaps I was not on the mailing list RE: the safety bulletin (?) I don't recall hearing anything about this. (Maybe my hardware is different from what is being discussed, I dunno.)

Since that early PKT is on a car I no longer own, it's a bit of a moot point for me, but I'd hate for Cardinal to have a problem if there's potential for a problem. I'd be happy to forward any info (if it applies to that PKT) to the new owner.

CardinalCar

The new owner is watching with interest :-)

ROG100

If I knew who Cardinal car was I would be happy to send a copy of my safety bulletin

pdejong

This is an interesting discussion.

Roger,

I did not buy the PKT from you. It was on my car before I bought it and I think you weren't yet selling the product yet, when the previous owner installed it. I think the car ran about 50k miles on it, altogether.
First of all, have had NO problems. I had the whole thing apart when I had my engine out and installed the turbo's. And I did not find any loose bolts.
I did replace the bearing just for the hell of it.
But I am interested in your bulletin regarding the alleged problems. Can you please send me that?

Thanks,

Peter deJong
'90 GT_TT
'95 968 Cab

ROG100

Hi Peter - no problem and will do tomorrow.

We use a mass email service and have a complete notification of all customers our safety bulletin was sent to and a confirmation of those that read it and those that did not. It included all of our customers that had purchased a PKensioner in the last 6 years. Lots of customers.

Paul & Thomas I have your emails and will forward tomorrow and tell you if you received it originally.

GregBBRD

Sound familiar?

I personally know of 4 versions of Laso water pumps. Will the current version solve all the problems of the first 3 versions?

Who knows? And I'm betting that they actually have engineers, with real calculations and real data.

Make your choice and pay your money.