Minerva Project, PorkenTensioner help
03-08-2017, 01:05 AM
#1
Racer
Thread Starter
Minerva Project, PorkenTensioner help
Gentlemen: I am looking for help in the 928 community. What I need is a PKT tensioner system that I can install for troubleshooting.
Background:
The refurbish project for Minerva has had one vexing issue.
We have been hearing an engine whine whose tone changes with RPM. It sounds like belt whine.
Actions:
- Remove all accessory belts (air pump, AC comp., power steering, alternator
o Result: No Change
- Replace the brand new (Geba) water pump
o Result: No Change
- Replace Oil Pump with 'like' early cast pump
o Result: No Change
- Replace new tensioner pulley
o Result: No Change
- Rebuild already rebuilt tensioner
o Result: No Change
- Remove water from the system and run engine (very briefly)
o Result: No Change
- Add tensioner arm bracket from later car
o Result: No Change
Using a stethoscope, we have been trying to trace the location of the whine. It is most obviously from the front of the motor, and seems most obvious on the tensioner arm mounting bolt. The only thing behind that bolt in the block is a water passage.
The purpose of the PKT is to experiment and try to rule out any noise related to the factory tensioner set up. We know that the ’78 needs the A/C bracket modifications to work, but we don’t care about that as it is just to bench test the tensioner with no other accessories functioning.
If you have a PKT bracket you are willing let us experiment with, or have any insights that might help, please let me know.
Thanks in advance,
William
Background:
The refurbish project for Minerva has had one vexing issue.
We have been hearing an engine whine whose tone changes with RPM. It sounds like belt whine.
Actions:
- Remove all accessory belts (air pump, AC comp., power steering, alternator
o Result: No Change
- Replace the brand new (Geba) water pump
o Result: No Change
- Replace Oil Pump with 'like' early cast pump
o Result: No Change
- Replace new tensioner pulley
o Result: No Change
- Rebuild already rebuilt tensioner
o Result: No Change
- Remove water from the system and run engine (very briefly)
o Result: No Change
- Add tensioner arm bracket from later car
o Result: No Change
Using a stethoscope, we have been trying to trace the location of the whine. It is most obviously from the front of the motor, and seems most obvious on the tensioner arm mounting bolt. The only thing behind that bolt in the block is a water passage.
The purpose of the PKT is to experiment and try to rule out any noise related to the factory tensioner set up. We know that the ’78 needs the A/C bracket modifications to work, but we don’t care about that as it is just to bench test the tensioner with no other accessories functioning.
If you have a PKT bracket you are willing let us experiment with, or have any insights that might help, please let me know.
Thanks in advance,
William
03-08-2017, 01:33 AM
#2
Rennlist
Basic Site Sponsor
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Gentlemen: I am looking for help in the 928 community. What I need is a PKT tensioner system that I can install for troubleshooting.
Background:
The refurbish project for Minerva has had one vexing issue.
We have been hearing an engine whine whose tone changes with RPM. It sounds like belt whine.
Actions:
- Remove all accessory belts (air pump, AC comp., power steering, alternator
o Result: No Change
- Replace the brand new (Geba) water pump
o Result: No Change
- Replace Oil Pump with 'like' early cast pump
o Result: No Change
- Replace new tensioner pulley
o Result: No Change
- Rebuild already rebuilt tensioner
o Result: No Change
- Remove water from the system and run engine (very briefly)
o Result: No Change
- Add tensioner arm bracket from later car
o Result: No Change
Using a stethoscope, we have been trying to trace the location of the whine. It is most obviously from the front of the motor, and seems most obvious on the tensioner arm mounting bolt. The only thing behind that bolt in the block is a water passage.
The purpose of the PKT is to experiment and try to rule out any noise related to the factory tensioner set up. We know that the ’78 needs the A/C bracket modifications to work, but we don’t care about that as it is just to bench test the tensioner with no other accessories functioning.
If you have a PKT bracket you are willing let us experiment with, or have any insights that might help, please let me know.
Thanks in advance,
William
Background:
The refurbish project for Minerva has had one vexing issue.
We have been hearing an engine whine whose tone changes with RPM. It sounds like belt whine.
Actions:
- Remove all accessory belts (air pump, AC comp., power steering, alternator
o Result: No Change
- Replace the brand new (Geba) water pump
o Result: No Change
- Replace Oil Pump with 'like' early cast pump
o Result: No Change
- Replace new tensioner pulley
o Result: No Change
- Rebuild already rebuilt tensioner
o Result: No Change
- Remove water from the system and run engine (very briefly)
o Result: No Change
- Add tensioner arm bracket from later car
o Result: No Change
Using a stethoscope, we have been trying to trace the location of the whine. It is most obviously from the front of the motor, and seems most obvious on the tensioner arm mounting bolt. The only thing behind that bolt in the block is a water passage.
The purpose of the PKT is to experiment and try to rule out any noise related to the factory tensioner set up. We know that the ’78 needs the A/C bracket modifications to work, but we don’t care about that as it is just to bench test the tensioner with no other accessories functioning.
If you have a PKT bracket you are willing let us experiment with, or have any insights that might help, please let me know.
Thanks in advance,
William
03-08-2017, 02:21 AM
#5
Archive Gatekeeper
Rennlist Member
Rennlist Member
Conti Synchrobelt.
03-08-2017, 02:24 AM
#6
Racer
Thread Starter
Hi Jim,
We did try changing belts, no change.
Also, tried different tension and only slight difference. When it was a loose as we dared, it was still prominent though improved which should mean something.
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03-08-2017, 02:32 AM
#8
Inventor
Rennlist Member
Rennlist Member
Told you He'd have some. 
I can send you a new hardware kit for whatever gold you pick out of there.
(I couldn't help as I recently recycled all the latest 'S' prototypes and all new ones go to Roger.)
I can send you a new hardware kit for whatever gold you pick out of there.
(I couldn't help as I recently recycled all the latest 'S' prototypes and all new ones go to Roger.)
03-08-2017, 03:29 AM
#9
Rennlist
Basic Site Sponsor
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03-08-2017, 04:03 PM
#11
Rennlist
Basic Site Sponsor
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Did the water pump get replaced with the same brand?
__________________
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
03-08-2017, 04:19 PM
#12
Addict
Rennlist Member
Rennlist Member
This is interesting. My 79 did the exact same thing and sound was worse at the pivot bolt. I suspected the new roller. The sound went away when I changed out the arm, pivot bolt and bushings with the later style. All the original items were new as well. Now granted, my belt was tracking off slightly and I assumed it was putting uneven pressure (causing the noise) on the roller but I was never sure.
Does adjusting the belt more toward the front of the window on the Kempf tool result in any change? That was another theory of mine.
Does adjusting the belt more toward the front of the window on the Kempf tool result in any change? That was another theory of mine.
03-08-2017, 08:14 PM
#13
Racer
Thread Starter
Greg, we bought 2 brand new Geba water pumps, the first one we replaced was perfect so I have a spare, lol! I will get by your place and you can show me where to dig up the PKT pieces you have. Thanks again!
This is interesting. My 79 did the exact same thing and sound was worse at the pivot bolt. I suspected the new roller. The sound went away when I changed out the arm, pivot bolt and bushings with the later style. All the original items were new as well. Now granted, my belt was tracking off slightly and I assumed it was putting uneven pressure (causing the noise) on the roller but I was never sure.
Does adjusting the belt more toward the front of the window on the Kempf tool result in any change? That was another theory of mine.
Does adjusting the belt more toward the front of the window on the Kempf tool result in any change? That was another theory of mine.
So the plan is to eliminate the factory tensioner with the PKT and see if anything changes (again, isolating the timing belt by not installing any accessory belts in the test).
If that makes no difference, we will install the Porsche factory belt (silly expensive but running out of options) and see what happens.
If none of those make a difference, we will try to replace all the gears with round toothed and install the corresponding belt.
Here is the link from the initial start up right after the car was delivered to 928 Intl. I didn't notice at the time, but if you listen you can hear the whine about which I am referring. At the time, the exhaust was shot and everything else was so noisy I guess I didn't notice it.
[YT]
Will report back soon. If any other ideas come to mind, I am all ears!
Thanks for all the great input and questions.
William
03-08-2017, 11:25 PM
#14
Rennlist
Basic Site Sponsor
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Greg, we bought 2 brand new Geba water pumps, the first one we replaced was perfect so I have a spare, lol! I will get by your place and you can show me where to dig up the PKT pieces you have. Thanks again!
While I understand the desire to save money, I would question the sanity of using a metal impeller water pump on a matching number engine to that beautifully restored car.
At the very least, I would have installed a Laso the second time around...just to make sure the source of the noise wasn't a chronic bearing issue in the Geba pumps.
The Porken tensioner brackets I have are actually brand new....and are appropriately in the bottom of the scrap barrel in the rear....unless someone has recycled them. Not sure which of the four versions they are....and not sure about which one of the multiple hardware changes came with them. You might want to talk to Ken, about this. Good luck, with that.
Guy, interesting input. so did you have the support bracket installed with the new setup? We found that the cam belt covers would not accommodate the fan mounts with the addition of the bracket. We tried all types of Kempf adjustments, and none really made an appreciable difference.
So the plan is to eliminate the factory tensioner with the PKT and see if anything changes (again, isolating the timing belt by not installing any accessory belts in the test).
If that makes no difference, we will install the Porsche factory belt (silly expensive but running out of options) and see what happens.
If none of those make a difference, we will try to replace all the gears with round toothed and install the corresponding belt.
Here is the link from the initial start up right after the car was delivered to 928 Intl. I didn't notice at the time, but if you listen you can hear the whine about which I am referring. At the time, the exhaust was shot and everything else was so noisy I guess I didn't notice it.
[YT]https://www.youtube.com/watch?v=8YQJMz9vQoo[YT]
Will report back soon. If any other ideas come to mind, I am all ears!
Thanks for all the great input and questions.
William
While I understand the desire to save money, I would question the sanity of using a metal impeller water pump on a matching number engine to that beautifully restored car.
At the very least, I would have installed a Laso the second time around...just to make sure the source of the noise wasn't a chronic bearing issue in the Geba pumps.
The Porken tensioner brackets I have are actually brand new....and are appropriately in the bottom of the scrap barrel in the rear....unless someone has recycled them. Not sure which of the four versions they are....and not sure about which one of the multiple hardware changes came with them. You might want to talk to Ken, about this. Good luck, with that.
Guy, interesting input. so did you have the support bracket installed with the new setup? We found that the cam belt covers would not accommodate the fan mounts with the addition of the bracket. We tried all types of Kempf adjustments, and none really made an appreciable difference.
So the plan is to eliminate the factory tensioner with the PKT and see if anything changes (again, isolating the timing belt by not installing any accessory belts in the test).
If that makes no difference, we will install the Porsche factory belt (silly expensive but running out of options) and see what happens.
If none of those make a difference, we will try to replace all the gears with round toothed and install the corresponding belt.
Here is the link from the initial start up right after the car was delivered to 928 Intl. I didn't notice at the time, but if you listen you can hear the whine about which I am referring. At the time, the exhaust was shot and everything else was so noisy I guess I didn't notice it.
[YT]https://www.youtube.com/watch?v=8YQJMz9vQoo[YT]
Will report back soon. If any other ideas come to mind, I am all ears!
Thanks for all the great input and questions.
William
He seems to think that this noise was present before the engine was removed for the restoration work?
