Porsche t belt tensioner or porken tensioner ?
#61
Rennlist Member
I believe that messed-up bores are quite rare (the bimetal washers are located by the pin, not the bore) so refreshing is generally just cleaning and new seals (boot, o-ring, gasket).
#62
Captain Obvious
Super User
Super User
The OE tensioner doesn't NEED oil to transfer the heat from the engine block. The oil might slightly speed up the heat transfer when the engine is cold started. I think it's there mainly for lubrication.
#63
You ever think the high pressure the stock tensioner puts on the belt led to the siezed water pump? not to mention somebody could've over-tensioned it to add even higher pressure by a 1/2 or so turn of the nut somewhere in the cars past, I mean just to have a water pump sieze on any car is like hitting lotto powerball...when my water pump gave me problems it went this, first warning sign was a tiny leak that I couldn't locate and then the water pump started making a squeak as it impeller started to rub against the inside of the pump and that's when I found it, pump was ready to come apart and throw the belt, the warning light never came on.
#64
Rennlist Member
I've always viewed the presence of the belt warning system (that no other car has seen a need to implement, as far as I know) as tacit admission by Porsche that their whole timing belt arrangement was less than optimal. I love the idea behind Ken's use of the Audi tensioner system, but I'll admit...stories of water pumps seizing and breaking the belt with no warning system made me nervous. That's what makes...for me, anyway...the combination of the Porken tensioner and Ed's Guardian water pump so attractive. I still lose the warning system, but I also lose the primary motivation for keeping it...the potential for a seized water pump to break the belt. Perfect!
I do like the idea of re-purposing the tension warning for something else like belt tracking though. Not sure how that would work, but I like the idea.
Someone mentioned that Porken's tensioner was a solution to a problem that didn't exist. I don't view it that way. I view it as an improvement to a system that, in and of itself, has not been known to cause many problems, but does require some due diligence to keep it working properly, and which does protect against some problems that are logical possibilities, even if we can't point to specific examples of those failures. Sorta like Greg's fuel lines....maybe we can't point to specific cars that went up in flames due to the use of rubber hose with barbs and clamps, but there is sound logic behind a belief that it could happen. I've chosen to go with the Porken/Ed/Greg solution suite (ha ha...not sure all those folks want to be part of the same "suite") and your affinity for the rubber hose with clamps is well known... ;-)
I do like the idea of re-purposing the tension warning for something else like belt tracking though. Not sure how that would work, but I like the idea.
Someone mentioned that Porken's tensioner was a solution to a problem that didn't exist. I don't view it that way. I view it as an improvement to a system that, in and of itself, has not been known to cause many problems, but does require some due diligence to keep it working properly, and which does protect against some problems that are logical possibilities, even if we can't point to specific examples of those failures. Sorta like Greg's fuel lines....maybe we can't point to specific cars that went up in flames due to the use of rubber hose with barbs and clamps, but there is sound logic behind a belief that it could happen. I've chosen to go with the Porken/Ed/Greg solution suite (ha ha...not sure all those folks want to be part of the same "suite") and your affinity for the rubber hose with clamps is well known... ;-)
The belt warning system of the 32V engines alone is worth keeping the stock tensioner. Said it many times that it saved my engine when the water pump pulley siezed. There are pictures on this forum of what my belt looked like and how close it was from snapping. If you think the belt warning system is useless and you would sacrifice it to extend the life of the cam gears then by all means, go with the Audi tensioner.
#65
Nordschleife Master
I wouldn't purchase a new tensioner. I would rebuild it. They are likely to be expensive (?).
See this for servicing the tensioner. Have your mechanic have a look too...
http://dwaynesgarage.norcal928.org/1...0Procedure.htm
See this for servicing the tensioner. Have your mechanic have a look too...
http://dwaynesgarage.norcal928.org/1...0Procedure.htm
A new 85-95 tensioner from Porsche is $1210 list ($880 if you shop around), a good used one is $450 from 928 Int'l (half price sale on now), rebuilt is $350 (plus core) also from 928 Int'l. There's also got to be a lot of good used ones available here for cheap.
I believe that messed-up bores are quite rare (the bimetal washers are located by the pin, not the bore) so refreshing is generally just cleaning and new seals (boot, o-ring, gasket).
I believe that messed-up bores are quite rare (the bimetal washers are located by the pin, not the bore) so refreshing is generally just cleaning and new seals (boot, o-ring, gasket).
Ken if you're still here, can you comment on what phantom said about changing the tensioner. Do you have a recommendation on the interval for this, and also a brief how to.
Thanks,
Craig
#66
Captain Obvious
Super User
Super User
You ever think the high pressure the stock tensioner puts on the belt led to the siezed water pump? not to mention somebody could've over-tensioned it to add even higher pressure by a 1/2 or so turn of the nut somewhere in the cars past, I mean just to have a water pump sieze on any car is like hitting lotto powerball...when my water pump gave me problems it went this, first warning sign was a tiny leak that I couldn't locate and then the water pump started making a squeak as it impeller started to rub against the inside of the pump and that's when I found it, pump was ready to come apart and throw the belt, the warning light never came on.
#67
Inventor
Rennlist Member
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Ken if you're still here, can you comment on what phantom said about changing the tensioner. Do you have a recommendation on the interval for this, and also a brief how to.
I believe the Audi parts will last much longer and the water pump is happier so I will probably go at least 60K, myself (if you have looked at the size of the components you know what I mean). My S4 has a Racing belt on it, so that's probably still conservative.
To the OP: If I had to use the factory tensioner, for example if I could not do it myself and had a grouchy mechanic doing the work, I would get a rebuilt from 928 Intl. Be aware that you will be revisiting that mechanic at 1500 miles/2400 kms and possibly every 15K/24K thereafter. And, don't expect a rebuilt or even a new one to be leak free, even with careful installation.
(They leak even when not installed... )
#68
Shameful Thread Killer
Rennlist Member
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You ever think the high pressure the stock tensioner puts on the belt led to the siezed water pump? not to mention somebody could've over-tensioned it to add even higher pressure by a 1/2 or so turn of the nut somewhere in the cars past, I mean just to have a water pump sieze on any car is like hitting lotto powerball...when my water pump gave me problems it went this, first warning sign was a tiny leak that I couldn't locate and then the water pump started making a squeak as it impeller started to rub against the inside of the pump and that's when I found it, pump was ready to come apart and throw the belt, the warning light never came on.
B. My tensioner was adjusted perfectly before my belt seized. I checked it before my trip to Marble Falls. No leaks, no noises, but I admit to driving rather spirited when it died. The pump still seized. If not for the belt warning, there would be another 928 broken down for parts.
C. I've seen belts and stock tensioners on 100,000 mile cars before. If the service interval is 45k miles, and one does their diligence with the proper pump and belt, it's work. It - just - works.
Poorly made pumps, and/or poor service actions can't be blamed on the stock tensioner. In fact, given the sad state of service affairs on many 928s, it rather amazing that we don't have more catastrophic failures.
#69
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Join Date: Oct 2014
Location: Montréal, Québec, Canada
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Hi,
I didnt imagine this poste would go this far in détails, Thank alot guýs!
After talk with my mecanic at IMAC AUTO in montreal we décides to go with a probable refurbich of the original tensioner but Will see if it stil good to go with that option when its off the car...
Ill keep you posted in january when we do the job.
A big hand of applaus to all
I didnt imagine this poste would go this far in détails, Thank alot guýs!
After talk with my mecanic at IMAC AUTO in montreal we décides to go with a probable refurbich of the original tensioner but Will see if it stil good to go with that option when its off the car...
Ill keep you posted in january when we do the job.
A big hand of applaus to all
#71
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Over 100k with one customer.
About 65K on my GTS
Lots who are on the second or third iteration of the belt.
About 65K on my GTS
Lots who are on the second or third iteration of the belt.
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
#73
Administrator - "Tyson"
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The "wear" items are the dampener and the roller and there is some debate over how often those should be replaced (some say never, which is wrong).
These are "off the shelf" parts for an Audi so they will always be available at a reasonable cost.
Personally I would replace both with every belt change. In the Ferrari 355 world (with an almost identical arrangement) most suggest replacing the roller with each belt, the dampener every other......
These are "off the shelf" parts for an Audi so they will always be available at a reasonable cost.
Personally I would replace both with every belt change. In the Ferrari 355 world (with an almost identical arrangement) most suggest replacing the roller with each belt, the dampener every other......
#74
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I prefer to change the tensioner when I change the belt - I sell one of the better tensioners for $87 however you can get one of reasonable quality for about $65.
The 100k customer - 2 belts only and did not change the tensioner.
The 100k customer - 2 belts only and did not change the tensioner.
#75
Nordschleife Master
Thanks, Guys. I didn't know that the Audi tensioner was considered a "wear" item.
How many people are afraid to post here for fear of jinxing their T-belts?
How many people are afraid to post here for fear of jinxing their T-belts?