The Porsche bore scoring issue is well known among owners, enthusiasts, and mechanics. Porsche models from 1997 through 2008 including the 911, 996, and 997 as well as the Boxster, Cayman, 986, and 987 have all experienced the Porsche bore scoring problem. This issue can cause the Porsche engine to develop an audible tick associated with cylinder bore scoring that can be misdiagnosed as bad lifters or even an exhaust leak. LN Engineering wants to educate current owners and those considering purchasing one of these vehicles as to what Porsche bore scoring sounds like as well as the symptoms of bore scoring in Porsche engines.
In this blog we're covering:
- Porsche Bore Scoring Symptoms
- Porsche Bore Scoring Sounds
- Diagnosing Porsche Bore Scoring
- Preventing Porsche Cylinder Bore Scoring
- Solutions for Porsche Cylinder Bore Scoring
What are the symptoms of Porsche Bore Scoring?
There are many contributing factors to the Porsche bore scoring issue. However, there are some tell tell symptoms that indicate your engine may be suffering from cylinder bore scoring that include:
- Audible Tick
- Increase in Oil Consumption
- Sooty Tailpipes
- Soot in the Engine Oil
- Oily/Sooty Bumper Cover
- Cylinder Misfires
The audible Porsche bore scoring sound, or tick, is the earliest indicator that your engine might have scored cylinder bores, even before any other symptoms are present. As Porsche bore scoring progresses, the symptoms will worsen proportional to the severity of the failure.
Another tell-tale sign of Porsche bore scoring are sooty tailpipes. To be specific, the exhaust tip associated with bank 2 cylinders end up having more soot on it than the bank 1 exhaust tip. On a 996/997, the driver's side exhaust tip being sootier is often associated with scored cylinders on cylinders 4-6 (bank 2). The bumper cover will also often have oily/sooty residue on it if oil consumption is excessive. (shown above, right)
Here are additional photos showing other symptoms of Porsche cylinder bore scoring:
Cylinder misfire caused by oil fouling of the spark plug
Soot in oil and oil sump platecaused by excessive oil consumption
What causes the Porsche Bore Scoring Sound?
The Porsche bore scoring sound, or tick, will be one of the first symptoms an engine suffering from scored cylinder bores will experience. This noise is caused by an increase in the piston to cylinder clearance as the cylinder bore and piston skirts wear. The increased clearance creates "piston slap," and in its early stages, the sound that accompanies cylinder bore scoring can be mistaken as a tick caused by a bad lifter or even an exhaust leak. Before you replace the lifters on any Porsche engine susceptible to the bore scoring problem, it is important to first rule out that you don't have a scored cylinder bore. In the videos below you can clearly hear the Porsche bore scoring sound, in this case we have a Porsche 911 C4S engine with severely scored cylinder bores:
How do you diagnose Porsche Bore Scoring?
Typically the best way to determine if your Porsche engine is suffering from bore scoring is to have the cylinders checked with a bore scope to verify if the engine has signs of damage, even if you don't have any symptoms. It is critical to bore scope cylinders 4 through 6 on bank 2 from the sump with each piston at TDC, as cylinder bore scoring starts at the bottom of the cylinder. Checking for Porsche bore scoring through the spark plug with the piston parked at BDC often will not show there is a failure until the engine has multiple symptoms and the bore scoring has gotten significantly worse. Check out our blog post onhow to properly pore scope your porsche engine for cylinder bore scoring.
Aside from the obvious symptoms of Porsche bore scoring or inspection with a bore scope, used oil analysis is a valuable tool that can identify potential engine problems. If carried out at every oil change, a healthy engine will maintain similar levels of wear materials from oil change to oil change, but when there is a sudden increase in wear and contaminants such as iron, aluminum, and silicon, then you know you might have early signs of bore scoring.
How do you prevent Porsche Bore Scoring?
It is important to correct any problems with an engine that might cause or are contributing to Porsche bore scoring. Although it may not be possible to prevent 100% of all Porsche bore scoring cases, it is certainly possible to reduce the likelihood of a failure by following a few easy steps. We have outlined common issues that can be addressed through preventative maintenance that all Porsche Boxster, Cayman, and 911 owners should know about, which first starts by using a quality engine oil with lots of moly such as Driven DT40 with an oil change interval of 6 months or 5,000 miles, whichever comes first.
How do you fix Porsche Bore Scoring?
There are effective solutions to the Porsche bore scoring issue. If you have any, or worst case, all of the associated Porsche bore scoring symptoms listed above, your Porsche Boxster, Cayman, or 911 engine unfortunately is already likely to be suffering from cylinder bore scoring and will need to be rebuilt to correct this type of failure. Depending on the severity of the symptoms, you may be able to slow down the progression of bore scoring in your Porsche engine and continue driving the car for some time by using a thicker oil like Driven FR50 and by changing your oil no less than every 3 months or 3,000 miles.
LN Engineering pioneered the Nickies process allowing for increased displacement and performance using custom sleeves like the aluminum nikasil liners used in Porsche's 996 and 997 GT3, Turbo, and GT2 models to correct for the cylinder bore scoring as well as other cylinder failures associated with the M96 and M97 engines used in Porsche Boxster, Cayman, and 911 models. Check out our blog on Porsche Bore Scoring Fixes to learn more about our processes.
Contact our team for help with diagnosing Porsche Bore Scoring issues today!
