Brand new hydraulic tensioners.......

[boyt911sc]

Anyone recently purchased hydraulic tensioners from our host? This was the second set that I got from PP that were defective right from the box (?). The first pair was returned in August 2016 and were immediately replaced and received in September 2016. The Customer Service was very accommodating and issued a RMA# (Return Merchandise Authorization).

Long before I called Pelican Parts Customer Service, I did some testing and investigation to determine and compare the new hydraulic tensioners from some of the tensioners I have at home. The test should be comparable and reproducible from test to test. And I came up with this contraption:





And these are the subjects:





The second from the left (Jason P.) are known collapsed tensioners I found a couple months ago and had to be replaced. Since the new tensioners came with no oil inside the cylinder, I did a compression tests with the other tensioners namely Jason P., Paul Z., Alvin T., and lastly the new tensioners (aka Wayne D.) with no oil.

Compression test with out oil and no weight added just the bar:
Jason P...............25% down.
Paul Z................25% down.
Alvin T...............25% down.
Wayne D............25% down.

Compression test oil primed into the system and no weight added:
Jason P................fully extended (zero down).
Paul Z..................fully extended (zero down).
Alvin T..................fully extended (zero down).
Wayne D..............fully extended (zero down).

So far so good.

Compression test oil primed and added weight (W1):
Jason P.................100% down (totally collapsed).
Paul Z...................100% up.
Alvin T...................100% up.
Wayne D............... 100% down (totally collapsed).

Compression test with more added weights:

Paul Z....................100% up and very stiff to compress. Feels like solid rock.
Alvin T....................100% up and very stiff to compress. Feels like solid rock.

I could have added more weights but the above tests have demonstrated the difference between a good tensioner and a bad one. BTW, I have three (3) other tensioners in my '78 Targa, '87 Carrera 3.2, and '89 Carrera 3.2 that are all working great (knock on wood).

What would I do if the 3rd. set came out to be collapsed again? Get another set? I had primed the tensioners several times and repeated the tests more than 3 times and the results were all the same. Anyone has a comment, recommendation, or suggestion how to evaluate these new tensioners?

Lastly, The new tensioners that has been primed with oil are soft and spongy. I am not that strong yet, I could insert the pin using my fingers! The good tensioners are so stiff that I could barely press it down a mm. Thanks.

Tony

[timmy2]

Just curious, are they the genuine Porsche ones or one of the other 2 types available?

[boyt911sc]

Originally Posted by timmy2

Just curious, are they the genuine Porsche ones or one of the other 2 types available?

Dennis,

The four (4) sets in the pictures are all different. The castings characteristics and markings are not identical. All except that came from PP have the triangular logo which I believe are OEM. The two (2) good units came from running engines that needed rebuild. The bad unit came from the engine I am rebuilding and confirmed collapsed. So I ordered from PP. Now on my second pair and still waiting for a good set.

What are the two types you are referring? Not familiar with those. Pelican Parts Technical Service should address this problem. Are these tensioners made in China? These are not cheap by any means. It is more $300 a piece plus the time wasted in putting and removing them from the engine and sending back to PP.

Tony

[0396]

Congrats on your scientific research to expose a potential QC with possible new tensioner.
I'm curious if these were sold as OEM to this site and were simply 'labeled ' as such. These days, counterfeiting has gone hi-tech. Example- look at all the counterfeit Rolexs out there. I wonder where the new tensioner originated from. A local Porsche dealer or from a "parts wholesale " company. Good luck with your build

[timmy2]

Hi Tony,
When you do a search of the part number on the box 3 different products come up.
They range in price from $327 (Sebro brand) to $414 (genuine Porsche)
with "OE" Supplier at $342.
Just wondering which ones you are getting, I had someone mention to me just yesterday the OE ones may not be the same quality as genuine Porsche.

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

[timmy2]

Great testing by the way. Sent you an email.

[Trackrash]

The next step IMO is to find the cause of the failures.

They can be disassembled. Is the check valve at the bottom functioning? Is the orifice at the top clogged?

Worth checking out.

Post your results here. Carrera tensioner questions

[0396]

Originally Posted by Trackrash

The next step IMO is to find the cause of the failures.

They can be disassembled. Is the check valve at the bottom functioning? Is the orifice at the top clogged?

Worth checking out.

Post your results here. Carrera tensioner questions

Great suggestion, only problem is. Will any sales outfit accept them back as they have been tamper with?

[boyt911sc]

Originally Posted by Trackrash

The next step IMO is to find the cause of the failures.

They can be disassembled. Is the check valve at the bottom functioning? Is the orifice at the top clogged?

Worth checking out.

Post your results here. Carrera tensioner questions

Gordon,

I can not do any dissecting with these tensioners at the moment because they are under warranties unless Wayne Dempsey gives me a go ahead approval. They sent me another RMA #(Return Merchandise Authorization) but I am not optimistic to get a good unit for the third time. Right now, I have more confident on buying a good used tensioners than using these new tensioners from Pelican Parts. If they pass the test, how long before it fails?

The primed tensioners (PP product) were so soft and spongy that I could insert the pin by hand. While the 20-year old used tensioners were so stiff and hard that you would need a vise to compressed them when installing the pins. However, the person from the Customer Service explicitly proclaimed that they never had any problem with this product (?). And this was the reason I decided to find a way to test the tensioners and share my findings. This product should be recalled.

Tony

[turbo owner]

Originally Posted by Trackrash

The next step IMO is to find the cause of the failures.

They can be disassembled. Is the check valve at the bottom functioning? Is the orifice at the top clogged?

Worth checking out.

Post your results here. Carrera tensioner questions

The shop that did the engine from my turbo got repair kits and rebuilt mine.

[Trackrash]

There is a circlip on the bottom that holds the check valve in. I can't imagine that removing and replacing it would be detectable. Try it on one of the old failed units.
Also punching the "plug" out of the plunger should not be detectable either.

Edit: here is a better idea from Never ending problem for the 13th engine rebuild (very long post)......

Originally Posted by 911pcars

....... In addition, inject a jolt of pressurized air into the tensioner oil inlet. This can sometimes dislodge a stubborn check ball to close as designed......
Hope this helps,
Sherwood

From what I have discovered, there are three things that have to work in concert to allow correct operation. You need oil in the supply chamber, a functioning check valve, and an orfice plug that will bleed out trapped air.

Maybe if you removed the piston and used compressed air to see if the check valve is stuck?

[Trackrash]

Originally Posted by turbo owner

The shop that did the engine from my turbo got repair kits and rebuilt mine.

Show us a repair kit for the oil fed tensioner. I have never seen one.

[Trackrash]

Originally Posted by boyt911sc

Gordon,

I can not do any dissecting with these tensioners at the moment because they are under warranties unless Wayne Dempsey gives me a go ahead approval. They sent me another RMA #(Return Merchandise Authorization) but I am not optimistic to get a good unit for the third time. Right now, I have more confident on buying a good used tensioners than using these new tensioners from Pelican Parts. If they pass the test, how long before it fails?

The primed tensioners (PP product) were so soft and spongy that I could insert the pin by hand. While the 20-year old used tensioners were so stiff and hard that you would need a vise to compressed them when installing the pins. However, the person from the Customer Service explicitly proclaimed that they never had any problem with this product (?). And this was the reason I decided to find a way to test the tensioners and share my findings. This product should be recalled.

Tony

Are the casting numbers the same on all of the tensioners you have?

[turbo owner]

Originally Posted by Trackrash

Show us a repair kit for the oil fed tensioner. I have never seen one.

Mine were manual not oil, may not be a kit for oil fed, I don't have time to search to see if there is.

Leaves are coming down and I have yard work to do.

[manbridge 74]

From another forum by a guy who installed many pressure feds back in the day...

"There have been issues with the air bleed channel at the tips of pressure fed's over the years, so I disassemble these, knock the hardened tip out of the piston, clean any metal debris that might of occurred during the original assembly, that clogs the air bleed channel, test and reassemble. There are no O rings in the internals of these. Great choice."

[boyt911sc]

PP Customer Service left a message on my answering machine yesterday to hold the shipment. After several phone calls, I got hold of the customer service rep and she explained to me that the vendor/supplier wanted more information why I was returning the hydraulic tensioners. The vendor/supplier alledgely claimed that they have not experienced such problem/s(?). The vendor wanted to know how I did the test.

So I informed the customer service rep that the test has been documented in the 911 Tenchnical Forum under the heading 'Brand new hydraulic tensioners'. And vendor could read and find all the related information about the collapsed tensioners. An hour later, PP advised me that a pair of tensioners have been approved for replacement.

While I am thankful that PP and the vendor are very accommodating, I still have a lingering question. What if the 3rd. pair failed the test? What would you suggest is my next course of action? Try a different vendor/supplier? Thanks.

Tony

[Trackrash]

What are the casting numbers on the tensioners you have (had?) all the same?
Mine appear to be OE. Notice the triangle P logo.

[0396]

Originally Posted by boyt911sc

PP Customer Service left a message on my answering machine yesterday to hold the shipment. After several phone calls, I got hold of the customer service rep and she explained to me that the vendor/supplier wanted more information why I was returning the hydraulic tensioners. The vendor/supplier alledgely claimed that they have not experienced such problem/s(?). The vendor wanted to know how I did the test.

So I informed the customer service rep that the test has been documented in the 911 Tenchnical Forum under the heading 'Brand new hydraulic tensioners'. And vendor could read and find all the related information about the collapsed tensioners. An hour later, PP advised me that a pair of tensioners have been approved for replacement.

While I am thankful that PP and the vendor are very accommodating, I still have a lingering question. What if the 3rd. pair failed the test? What would you suggest is my next course of action? Try a different vendor/supplier? Thanks.

Tony

My 02, most will simply expect the "new " tensioners not to fail and simply install them - hopefully they will not fail in the future, thus no feed back to the supplier. Even if they did, would they admit to it and possibly tarnish their reputation?
Since you've already created a test stand, it's probally best to test the third set..if it fails, request a full refund and buy the OEM units and be done with it.
Good Luck

[boyt911sc]

Originally Posted by Trackrash

What are the casting numbers on the tensioners you have (had?) all the same?
Mine appear to be OE. Notice the triangle P logo.

Gordon,

All hydraulic tensioners have the triangular logo except the new tensioners from Sebro. The casting numbers or characteristics are all different from each other's. But the main difference is the 'Sebro' tensioners do not have the triangle logo and the good sets that passed the tests have the triangle logo. And I believe they are OE or Porsche parts. I will give one more try and if the 3rd set fails again, I would have to switch and order the Porsche parts.

I have requested through the Customer Service to inform the technical guy from Sebro to participate in this thread. If they (Sebro) has a specific method or technique in priming their hydraulic tensioners, they should share that information with us (customers).

Tony

[Trackrash]

That may explain some things. It is my understanding that the triangle with the P is Porsche's manufacturers logo for OE parts.