Bore scoring
Rennlist Member
Joined: Dec 2019
Posts: 7,172
Likes: 5,810
From: Illinois
Ben, something to think about...
If you are losing sleep over bore scoring, then you have to drop the sump and scope it. No other way to confirm or deny. You may already have spoken to your indy about this, but if not, do yourself a favor and tell them you want to sump dropped, oil fimter analyzed and a bore scope done from the sump. It's not a common procedure, but it's becoming more common. As the Nike commercial says, "Just do it!"
You will be glad you did regardless of the outcome.
If you are losing sleep over bore scoring, then you have to drop the sump and scope it. No other way to confirm or deny. You may already have spoken to your indy about this, but if not, do yourself a favor and tell them you want to sump dropped, oil fimter analyzed and a bore scope done from the sump. It's not a common procedure, but it's becoming more common. As the Nike commercial says, "Just do it!"
You will be glad you did regardless of the outcome.
Drifting
Joined: Jul 2020
Posts: 2,405
Likes: 2,346
From: Washington DC
Have we seen confirmed scoring cases in the later 991.2 cars? It definitely might be too soon to say anything about 992 but I was under the impression that later 991 cars and on were switched to sumebore technology for cylinder surface treatment that should be much more durable. That said, with enough will power and some questionable practices one could score up a freshly built motor with Nickasil liners.
Rennlist Member
Joined: Dec 2019
Posts: 7,172
Likes: 5,810
From: Illinois
Have we seen confirmed scoring cases in the later 991.2 cars? It definitely might be too soon to say anything about 992 but I was under the impression that later 991 cars and on were switched to sumebore technology for cylinder surface treatment that should be much more durable. That said, with enough will power and some questionable practices one could score up a freshly built motor with Nickasil liners.
Thanks
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Joined: Oct 2017
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From: Momence, IL
No reports of any bore issues with SUMEbore. We have seen 991 bores fail that were alusil, just like the other 9a1 engines used in 997.2.
SUMEbore has been vert effective in all applications where it was used, except the Ford Coyote. VAG uses SUMEbore across the board with gas and diesel engines alike, even the large Scania and MAN diesel engines use this process.
This is a great quote that is very accurate. Previously before Mr. Raby shared the sump inspection process people were spending more money to perform a boroscope inspection through the spark plug holes only. This only shows the side of the bore above the piston at bottom dead center and one half of the problem area. Most all early onset scoring shows up at the bottom of the bore which is covered by the piston at BDC. The alternate method of scoping with the piston at TDC from the sump access shows the area of the bore most susceptible to scoring.
This is faster, cheaper and more effective than a spark plug inspection. If you do it at an oil change you can pay an extra 2 hours of labor and know exactly if you have an issue or not.
Sadly too many buyers still don't know this before they buy, and they have the scoping done later, only to find out that they have big issues that puts their love for the car to a test.
SUMEbore has been vert effective in all applications where it was used, except the Ford Coyote. VAG uses SUMEbore across the board with gas and diesel engines alike, even the large Scania and MAN diesel engines use this process.
If you are losing sleep over bore scoring, then you have to drop the sump and scope it. No other way to confirm or deny. You may already have spoken to your indy about this, but if not, do yourself a favor and tell them you want to sump dropped, oil fimter analyzed and a bore scope done from the sump. It's not a common procedure, but it's becoming more common. As the Nike commercial says, "Just do it!"
You will be glad you did regardless of the outcome.
You will be glad you did regardless of the outcome.
This is faster, cheaper and more effective than a spark plug inspection. If you do it at an oil change you can pay an extra 2 hours of labor and know exactly if you have an issue or not.
Sadly too many buyers still don't know this before they buy, and they have the scoping done later, only to find out that they have big issues that puts their love for the car to a test.
Rennlist Member
Joined: Dec 2019
Posts: 7,172
Likes: 5,810
From: Illinois
No reports of any bore issues with SUMEbore. We have seen 991 bores fail that were alusil, just like the other 9a1 engines used in 997.2.
SUMEbore has been vert effective in all applications where it was used, except the Ford Coyote. VAG uses SUMEbore across the board with gas and diesel engines alike, even the large Scania and MAN diesel engines use this process.
This is a great quote that is very accurate. Previously before Mr. Raby shared the sump inspection process people were spending more money to perform a boroscope inspection through the spark plug holes only. This only shows the side of the bore above the piston at bottom dead center and one half of the problem area. Most all early onset scoring shows up at the bottom of the bore which is covered by the piston at BDC. The alternate method of scoping with the piston at TDC from the sump access shows the area of the bore most susceptible to scoring.
This is faster, cheaper and more effective than a spark plug inspection. If you do it at an oil change you can pay an extra 2 hours of labor and know exactly if you have an issue or not.
Sadly too many buyers still don't know this before they buy, and they have the scoping done later, only to find out that they have big issues that puts their love for the car to a test.
SUMEbore has been vert effective in all applications where it was used, except the Ford Coyote. VAG uses SUMEbore across the board with gas and diesel engines alike, even the large Scania and MAN diesel engines use this process.
This is a great quote that is very accurate. Previously before Mr. Raby shared the sump inspection process people were spending more money to perform a boroscope inspection through the spark plug holes only. This only shows the side of the bore above the piston at bottom dead center and one half of the problem area. Most all early onset scoring shows up at the bottom of the bore which is covered by the piston at BDC. The alternate method of scoping with the piston at TDC from the sump access shows the area of the bore most susceptible to scoring.
This is faster, cheaper and more effective than a spark plug inspection. If you do it at an oil change you can pay an extra 2 hours of labor and know exactly if you have an issue or not.
Sadly too many buyers still don't know this before they buy, and they have the scoping done later, only to find out that they have big issues that puts their love for the car to a test.
Burning Brakes
Joined: Mar 2015
Posts: 793
Likes: 302
Yes will discuss with him. He's highly experienced Porsche mechanic so will obviously get the truth from him. This post was just all me trying to figure things out pre-appointment. 13 more days!
Rennlist Member
Joined: Dec 2019
Posts: 7,172
Likes: 5,810
From: Illinois
Did you ever listen to a drug advertisement on TV disclosing all of the potential issues of using the drug. As you are listening you say to yourself, holy crap...
Some Rennlist threads are like a drug commercial. It will scare the hell out of you until you are able to process all the info and realize that our threads are a clinical discussion of potential issues and solutions that are good to know depending on the path you choose to take. Not an everyday occurrence.
Get some good sleep tonight. The 996 is an awesome car with a very durable engine. Regardless of what your indy finds or doesn't find, there is a solution. That's the beauty of owning a 996.
Some Rennlist threads are like a drug commercial. It will scare the hell out of you until you are able to process all the info and realize that our threads are a clinical discussion of potential issues and solutions that are good to know depending on the path you choose to take. Not an everyday occurrence.
Get some good sleep tonight. The 996 is an awesome car with a very durable engine. Regardless of what your indy finds or doesn't find, there is a solution. That's the beauty of owning a 996.
Rennlist Member
Joined: Oct 2010
Posts: 7,773
Likes: 7,063
From: Alabama USA
Did you ever listen to a drug advertisement on TV disclosing all of the potential issues of using the drug. As you are listening you say to yourself, holy crap...
Some Rennlist threads are like a drug commercial. It will scare the hell out of you until you are able to process all the info and realize that our threads are a clinical discussion of potential issues and solutions that are good to know depending on the path you choose to take. Not an everyday occurrence.
Get some good sleep tonight. The 996 is an awesome car with a very durable engine. Regardless of what your indy finds or doesn't find, there is a solution. That's the beauty of owning a 996.
Some Rennlist threads are like a drug commercial. It will scare the hell out of you until you are able to process all the info and realize that our threads are a clinical discussion of potential issues and solutions that are good to know depending on the path you choose to take. Not an everyday occurrence.
Get some good sleep tonight. The 996 is an awesome car with a very durable engine. Regardless of what your indy finds or doesn't find, there is a solution. That's the beauty of owning a 996.
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Drifting
Joined: Dec 2005
Posts: 2,126
Likes: 103
From: ATL, GA w/a 996TT
A chevy small block, a ford small block, a Dodge slant 6, and Porsche Metzger motors are very durable engines. I know this will **** of some people off, but the M96 is far from durable no matter how good you take care of it.
Rennlist Member
Joined: Oct 2010
Posts: 7,773
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From: Alabama USA
What do you think would be the first thing most likely to break on your M96?? ( that hasn't already been improved with a updated version)
Drifting
Joined: Dec 2005
Posts: 2,126
Likes: 103
From: ATL, GA w/a 996TT
I would have to go with bore scoring as the most unimprovable design flaws. The IMS bearing is obvious and can be helped with updating, but damage could already be done by the time a new owner gets the car. There is also the timing chain guides and oil pressure issues. At least for me, the list is too long to gamble on. M96 motors are 20 odd years old and need significant attention that is expensive, for the same money you could get a 996TT and not have to worry about it and you would end up with a much faster and more desirable car that will hold its value better.. It kind of seems like a no brainer to me.
Rennlist Member
Joined: Oct 2010
Posts: 7,773
Likes: 7,063
From: Alabama USA
I would have to go with bore scoring as the most unimprovable design flaws. The IMS bearing is obvious and can be helped with updating, but damage could already be done by the time a new owner gets the car. There is also the timing chain guides and oil pressure issues. At least for me, the list is too long to gamble on. M96 motors are 20 odd years old and need significant attention that is expensive, for the same money you could get a 996TT and not have to worry about it and you would end up with a much faster and more desirable car that will hold its value better.. It kind of seems like a no brainer to me.
Other issues such as IMSB and AOS and oil pressure have very dependable fixes. Chain guides are a wear item and the newer version are much more durable...
I have actually seen more timing chains snap on 996TT engines for no reason. There was apparently a bad batch of them used, and of course everyone knows of the coolant pipes that need engine removal to fix ( pinned or welded) ... All engines will eventually wear out, someday someone will be crying over the cost to rebuild that 996TT .. it is much more expensive to rebuild a 996TT or GT3 engine than an M96...
Drifting
Joined: Dec 2005
Posts: 2,126
Likes: 103
From: ATL, GA w/a 996TT
I think engines that use no oil and/or have over fueling issues ( bad MAF sensor or fuel injectors) are more likely to have bore scoring than one that uses a quart oil every 1k miles ( more lube on the cylinders) ... I often wonder if using a "top end lube" would prevent borscoring by adding more protection for the cylinders...
Other issues such as IMSB and AOS and oil pressure have very dependable fixes. Chain guides are a wear item and the newer version are much more durable...
I have actually seen more timing chains snap on 996TT engines for no reason. There was apparently a bad batch of them used, and of course everyone knows of the coolant pipes that need engine removal to fix ( pinned or welded) ... All engines will eventually wear out, someday someone will be crying over the cost to rebuild that 996TT .. it is much more expensive to rebuild a 996TT or GT3 engine than an M96...
Other issues such as IMSB and AOS and oil pressure have very dependable fixes. Chain guides are a wear item and the newer version are much more durable...
I have actually seen more timing chains snap on 996TT engines for no reason. There was apparently a bad batch of them used, and of course everyone knows of the coolant pipes that need engine removal to fix ( pinned or welded) ... All engines will eventually wear out, someday someone will be crying over the cost to rebuild that 996TT .. it is much more expensive to rebuild a 996TT or GT3 engine than an M96...
Rennlist Member
Joined: Oct 2010
Posts: 7,773
Likes: 7,063
From: Alabama USA
you make some good points. In the 10 odd years ive owned a 996TT I have maybe seen 2-3 catastrophic engine failures pop up on the forums. We see that many every month here on the 996 n/a forum...Failed coolant pipes are an inconvenience at worst and a pretty easy and cheap fix in the scheme of things. Agreed, all engines were out from use, but the M96 has a tendancy to grenade itself that is higher than it should be. Replacing/rebuilding an M96 costs more than half the price of the car which is kind of nuts if you think about it.
I tend to not think in terms of $$$$$ , but I know that many/most people do....( I actually bought two 99 996's and a 2002 Boxster for under 20K and four m96 spare engines with minor reparable problems for 7K over the years) . My daily 996 has 190K ( I put 90K of them) and it has never left me stranded or broken down. The closest it has came was recently when I was experiencing a failing CP Sensor, I had to wait for an hour for the Sensor to cool off or spray it with something to cool it off before I could continue on my journey...A failing CP Sensor can happen to car no matter the brand/engine , even Toyota..
I run it hard and even use it for testing new things. I have removed the engine for IMBS update and of course have the UAOS/UIDS installed on it..But I use quality oil and monitor everything closely and take care of anything that can shorten the life of it ..
Not everyone wants/needs a Turbo 996 ...yes I would love to buy one with a blown motor and a few spare motors with minor repairable problems, but I can't afford that, so am truly happy without... ( also, I think I am cured of my boost/power addiction after setting a few world records years ago..lol)