We can repair Cayenne blocks
07-13-2015 | 06:20 PM
#17
Nordschleife Master
Joined: Dec 2004
Posts: 6,164
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From: Guelph, Ontario, Canada
And why not just over bore and put in new oversize pistons? 99% of the uses of this vehicle preclude the need to do rocket science coatings. I don't know what Porsche does from the factory but if I was looking at rebuilding an engine I would certainly look at this route. What's a set of pistons with coating 2k-ish?
07-13-2015 | 11:17 PM
#18
Rennlist Member
Joined: Jun 2014
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It seems they have modified the replacement parts if the engine is repaired by Porsche due to this issue
This is from an official TSB
Due to
^ modified production methods during the manufacture of the crankcase --> from smooth honing to structural honing
^ and the use of a different coating on the piston rings (now DLC-coated)
This is from an official TSB
Due to
^ modified production methods during the manufacture of the crankcase --> from smooth honing to structural honing
^ and the use of a different coating on the piston rings (now DLC-coated)
07-14-2015 | 08:30 AM
#20
Nordschleife Master
Joined: Dec 2004
Posts: 6,164
Likes: 5
From: Guelph, Ontario, Canada
It seems they have modified the replacement parts if the engine is repaired by Porsche due to this issue
This is from an official TSB
Due to
^ modified production methods during the manufacture of the crankcase --> from smooth honing to structural honing
^ and the use of a different coating on the piston rings (now DLC-coated)
This is from an official TSB
Due to
^ modified production methods during the manufacture of the crankcase --> from smooth honing to structural honing
^ and the use of a different coating on the piston rings (now DLC-coated)
07-14-2015 | 11:17 AM
#21
Thread Starter
Developer
Joined: Dec 2001
Posts: 7,005
Likes: 60
From: Horicon, WI
And why not just over bore and put in new oversize pistons? 99% of the uses of this vehicle preclude the need to do rocket science coatings. I don't know what Porsche does from the factory but if I was looking at rebuilding an engine I would certainly look at this route. What's a set of pistons with coating 2k-ish?
1) I have had to bore as deep as almost 0.030" to get all the gouges out... then the cylinder walls are thinner than I like... the thin cylinder walls contribute to ovation during loading and hot spots in the cooling jacket. So the metal we re-apply (the NiCom/Nikasil process? puts metal back on that cylinder wall so the finished bore is maybe .010" over-sized. Strong. Stays round, cools correctly, no hot spots.
2) to just punch it out and drop in pistons is to likely face this problem again if you own the car long enough. You haven't fixed the problem...
07-14-2015 | 02:50 PM
#22
Pro
Joined: Jul 2004
Posts: 677
Likes: 3
From: Minnesota
Not in this case.
I have not come to a firm decision what is causing it yet, but I do have my doubts about it being caused by high-sulpher content in the fuel.
Early specualtion was that it was caused by the cast pistons they used in the non-turbo motors.... because he turbo motors had forged pistons and they were reported to be fine. Until the Turbo Cayenne's started showing up the same way also...
Another speculation is the ambient temp where the car is kept. Like a car in SOCAL, for example. Might get into the 50's at night. So even a "cold" engine is relatively warm compared to up here, where a piston has to go from below 0 to operating temperature (big range). That theory has holes in it too.
We dont know everything that Porsche does. They might know that the problem engines came from boring machine or shop A and the engines from boring machine/shop B have no trouble. If it is internal like that, we'll never know because the truth will be buried. For example: look carefully at the circumferential lines near the bottom of the piston skirt in the picture on Post 10 above - those sipes are deliberate, from the factory, and meant to hold oil up on the cylinder wall... interesting..... wonder what they know/knew that they are not sharing.
I have not come to a firm decision what is causing it yet, but I do have my doubts about it being caused by high-sulpher content in the fuel.
Early specualtion was that it was caused by the cast pistons they used in the non-turbo motors.... because he turbo motors had forged pistons and they were reported to be fine. Until the Turbo Cayenne's started showing up the same way also...
Another speculation is the ambient temp where the car is kept. Like a car in SOCAL, for example. Might get into the 50's at night. So even a "cold" engine is relatively warm compared to up here, where a piston has to go from below 0 to operating temperature (big range). That theory has holes in it too.
We dont know everything that Porsche does. They might know that the problem engines came from boring machine or shop A and the engines from boring machine/shop B have no trouble. If it is internal like that, we'll never know because the truth will be buried. For example: look carefully at the circumferential lines near the bottom of the piston skirt in the picture on Post 10 above - those sipes are deliberate, from the factory, and meant to hold oil up on the cylinder wall... interesting..... wonder what they know/knew that they are not sharing.
"The area of the main bearings
is provided with a double screw connection (four main bearing
screws per bulkhead). The distinctly improved equalization
in cylinder pressure distribution thus achieved enabled
the screw stress to be lowered and as a result cylinder distortions
were reduced by up to 28 % compared to the previous
engine generation."
In this Brochure they talk about improvments for the Porsche V6/V8 engines.
I found this Brochure on the web. Interesting stuff. It seems lots of mfg's are having various problems with Aluminium Blocks and many of the problems don't show up right away. One thing that is clear that you must know what you are doing when rebuilding aluminium engines. You just can't bore them out like the old days of cast iron.
07-15-2015 | 12:56 AM
#23
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Joined: Jun 2014
Posts: 802
Likes: 7
Engine - Crankcase/Piston/Piston Ring Replacement Info.
Service
1
25/13 ENU 1010
Jun 20, 2014
The present document was valid at the time of print. A later version may be available online
Crankcase/Pistons/Piston Rings Need To Be Replaced - Mixed Installation Is Not Approved (25/13)
Model year:
as of 2008
Revision:
This bulletin replaces bulletin Group 1, # 25/13, dated June 11, 2013. Section "Information - Spare Parts Requirements" for pistons and piston rings: Text changed to "now available again".
Vehicle Type:
Cayenne S (9PA)/Cayenne Turbo (9PA)/Cayenne Turbo S (9PA)
Cayenne S (92A)/Cayenne Turbo (92A)
Panamera/Panamera S/Panamera Turbo/Panamera Turbo S
Concerns:
Cylinder liner in crankcase
Information:
If piston rings/pistons or the crankcase need to be replaced, a mixed installation can damage the cylinder liner.
NOTICE
Combination of piston rings and crankcase.
^ Risk of damage to cylinder liner.
--> Observe specifications for permissible combinations.
Due to
^ modified production methods during the manufacture of the crankcase --> from smooth honing to structural honing
^ and the use of a different coating on the piston rings (now DLC-coated)
only the combinations specified below are permitted.
--> Before carrying out any other work, check whether the cylinder liners are smooth-honed or structurally honed:
Date of Introduction:
Only engines with structurally honed cylinder liners are used in vehicles as of the shown engine numbers:
References:
--> 101055 Replacing crankcase
--> 131020 Removing and installing pistons
--> 131037 Disassembling and assembling pistons
92AAH1, 92AAI1, 92AAL1, 970110, 970111, 970120, 970121, 970410, 970411, 970420, 970421, 970430, 970431, 970440, 970441, 970450, 970451, 9PAAH1, 9PAAH7, 9PAAI1, 9PAAL1, 9PAAL7, 9PAAN1, 9PAAS1
Model year as of 2008
C02, C36
Service
1
25/13 ENU 1010
Jun 20, 2014
The present document was valid at the time of print. A later version may be available online
Crankcase/Pistons/Piston Rings Need To Be Replaced - Mixed Installation Is Not Approved (25/13)
Model year:
as of 2008
Revision:
This bulletin replaces bulletin Group 1, # 25/13, dated June 11, 2013. Section "Information - Spare Parts Requirements" for pistons and piston rings: Text changed to "now available again".
Vehicle Type:
Cayenne S (9PA)/Cayenne Turbo (9PA)/Cayenne Turbo S (9PA)
Cayenne S (92A)/Cayenne Turbo (92A)
Panamera/Panamera S/Panamera Turbo/Panamera Turbo S
Concerns:
Cylinder liner in crankcase
Information:
If piston rings/pistons or the crankcase need to be replaced, a mixed installation can damage the cylinder liner.
NOTICE
Combination of piston rings and crankcase.
^ Risk of damage to cylinder liner.
--> Observe specifications for permissible combinations.
Due to
^ modified production methods during the manufacture of the crankcase --> from smooth honing to structural honing
^ and the use of a different coating on the piston rings (now DLC-coated)
only the combinations specified below are permitted.
--> Before carrying out any other work, check whether the cylinder liners are smooth-honed or structurally honed:
Date of Introduction:
Only engines with structurally honed cylinder liners are used in vehicles as of the shown engine numbers:
References:
--> 101055 Replacing crankcase
--> 131020 Removing and installing pistons
--> 131037 Disassembling and assembling pistons
92AAH1, 92AAI1, 92AAL1, 970110, 970111, 970120, 970121, 970410, 970411, 970420, 970421, 970430, 970431, 970440, 970441, 970450, 970451, 9PAAH1, 9PAAH7, 9PAAI1, 9PAAL1, 9PAAL7, 9PAAN1, 9PAAS1
Model year as of 2008
C02, C36
07-15-2015 | 10:58 AM
#24
Thread Starter
Developer
Joined: Dec 2001
Posts: 7,005
Likes: 60
From: Horicon, WI
If piston rings/pistons or the crankcase need to be replaced, a mixed installation can damage the cylinder liner.
This also occurs elsewhere: Replacing camshafts? You put in all new lifters too at the same time. or your old lifters may ruin your new cams.
Last edited by Carl Fausett; 07-15-2015 at 12:32 PM.
07-16-2015 | 11:55 AM
#27
Burning Brakes
Joined: Jul 2011
Posts: 944
Likes: 20
From: Winnipeg, Canada
--> Before carrying out any other work, check whether the cylinder liners are smooth-honed or structurally honed:
Date of Introduction:
Only engines with structurally honed cylinder liners are used in vehicles as of the shown engine numbers:
References:
--> 101055 Replacing crankcase
--> 131020 Removing and installing pistons
--> 131037 Disassembling and assembling pistons
92AAH1, 92AAI1, 92AAL1, 970110, 970111, 970120, 970121, 970410, 970411, 970420, 970421, 970430, 970431, 970440, 970441, 970450, 970451, 9PAAH1, 9PAAH7, 9PAAI1, 9PAAL1, 9PAAL7, 9PAAN1, 9PAAS1
Model year as of 2008
C02, C36
Date of Introduction:
Only engines with structurally honed cylinder liners are used in vehicles as of the shown engine numbers:
References:
--> 101055 Replacing crankcase
--> 131020 Removing and installing pistons
--> 131037 Disassembling and assembling pistons
92AAH1, 92AAI1, 92AAL1, 970110, 970111, 970120, 970121, 970410, 970411, 970420, 970421, 970430, 970431, 970440, 970441, 970450, 970451, 9PAAH1, 9PAAH7, 9PAAI1, 9PAAL1, 9PAAL7, 9PAAN1, 9PAAS1
Model year as of 2008
C02, C36
I asked my dealer to look up my engine number and received: 83811101. How does one jive that with the numbers in the TSB?
07-16-2015 | 02:19 PM
#28
Nordschleife Master
Joined: Dec 2004
Posts: 6,164
Likes: 5
From: Guelph, Ontario, Canada
Just a diamond coating on the piston rings.
DLC Coating
Bore out the cylinder, structural hone it (etch the aluminum away) and buy over sized pistons. Should cost less than 2k if your machine shop can handle the honing process.
DLC Coating
Bore out the cylinder, structural hone it (etch the aluminum away) and buy over sized pistons. Should cost less than 2k if your machine shop can handle the honing process.
07-17-2015 | 03:04 PM
#29
RL Community Team
Rennlist Member
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Joined: Apr 2002
Posts: 3,755
Likes: 157
From: Seattle
Can anyone explain, in lay terms, the difference between "smooth vs. structural" honing and what is the coating on the rings to which the TSB is referring?
I asked my dealer to look up my engine number and received: 83811101. How does one jive that with the numbers in the TSB?
I asked my dealer to look up my engine number and received: 83811101. How does one jive that with the numbers in the TSB?
If I have to hazard a guess, we will find that the tiny number of '08 CTTs with cylinder scoring will be of the earlier generation, before they changed the process...
I hope mine is a later build!
Cheers,
TomF
07-21-2015 | 08:14 PM
#30
RL Community Team
Rennlist Member
Rennlist Member
Joined: Apr 2002
Posts: 3,755
Likes: 157
From: Seattle
As an update, I dug up my engine number (84801658) and it falls into the earlier, non-structural honed block. My engine is still going strong at nearly 80k.
I will re-state my suspicion that the cylinder scoring that many S owners have had is due to the earlier process. Anyone have thoughts on this?
Jake, Carl, anyone?
Cheers,
TomF
I will re-state my suspicion that the cylinder scoring that many S owners have had is due to the earlier process. Anyone have thoughts on this?
Jake, Carl, anyone?
Cheers,
TomF