cover Genuine Porsche part 99710551690

• Porsche 997 MK1 TURBO 2007-09
• Porsche 997 MK1 GT2 2007-09
• Porsche 997 MKII Turbo 2010-11
• Porsche 997 MKII GT2 RS 2011-11

• The timing chain transfers rotational motion from the crankshaft or intermediate shaft to the camshaft(s) (and/or to the secondary shaft) allowing valves to open and close in synchrony with piston movement.
• A “duplex” chain (two rows of links) provides greater strength and durability under the high loads and high engine speeds typical of a Porsche 911 performance engine.
• Because the chain drives critical timing, any slack, wear or movement will affect valve timing, ignition timing, engine management, and can result in noise, performance loss or engine damage.
• In this context, this chain is often replaced as part of a full timing drive overhaul (including guides, rails, tensioners) rather than alone.

• Rattling or clattering noise from the front of the engine (timing cover area), often heard at idle or on start-up — typical of chain slack.
  
• Check engine light related to camshaft or timing chain position sensors, or codes showing timing deviation.
  
• Loss of engine power, mis-firing, rough running — could indicate timing drift due to chain wear.
• High mileage or older engine with original chain: preventive replacement recommended to avoid catastrophic failure.
• During major engine service (removing timing cover, replacing chains/guides) — because labour is high, replacing the chain proactively makes sense.
• If inspection reveals visible wear: elongated chain links, damaged chain guides or missing/broken tensioner components.

• Protects the entire engine: A failed timing chain can lead to valve-to-piston contact, major damage and extremely costly repairs — replacing the chain is preventive.
  
• Restores proper timing & performance: A new chain ensures correct valve and ignition timing, helping engine run smoothly, powerfully and reliably.
  
• Eliminates noise & wear risk: Worn chains and guides cause noise and degrade timing drive integrity — a new chain reduces risk and improves sound.
  
• Cost-efficient when engine is opened: Since accessing the chain involves removing major parts (timing cover, possibly front of engine), replacing the chain while it’s open saves re-labour.

• Porsche 997 MK1 TURBO 2007-09
• Porsche 997 MK1 GT2 2007-09
• Porsche 997 MKII Turbo 2010-11
• Porsche 997 MKII GT2 RS 2011-11

• The timing chain transfers rotational motion from the crankshaft or intermediate shaft to the camshaft(s) (and/or to the secondary shaft) allowing valves to open and close in synchrony with piston movement.
• A “duplex” chain (two rows of links) provides greater strength and durability under the high loads and high engine speeds typical of a Porsche 911 performance engine.
• Because the chain drives critical timing, any slack, wear or movement will affect valve timing, ignition timing, engine management, and can result in noise, performance loss or engine damage.
• In this context, this chain is often replaced as part of a full timing drive overhaul (including guides, rails, tensioners) rather than alone.

• Rattling or clattering noise from the front of the engine (timing cover area), often heard at idle or on start-up — typical of chain slack.
  
• Check engine light related to camshaft or timing chain position sensors, or codes showing timing deviation.
  
• Loss of engine power, mis-firing, rough running — could indicate timing drift due to chain wear.
• High mileage or older engine with original chain: preventive replacement recommended to avoid catastrophic failure.
• During major engine service (removing timing cover, replacing chains/guides) — because labour is high, replacing the chain proactively makes sense.
• If inspection reveals visible wear: elongated chain links, damaged chain guides or missing/broken tensioner components.

• Protects the entire engine: A failed timing chain can lead to valve-to-piston contact, major damage and extremely costly repairs — replacing the chain is preventive.
  
• Restores proper timing & performance: A new chain ensures correct valve and ignition timing, helping engine run smoothly, powerfully and reliably.
  
• Eliminates noise & wear risk: Worn chains and guides cause noise and degrade timing drive integrity — a new chain reduces risk and improves sound.
  
• Cost-efficient when engine is opened: Since accessing the chain involves removing major parts (timing cover, possibly front of engine), replacing the chain while it’s open saves re-labour.

• Porsche 997 MK1 GT3 / GT3 RS 2007-09
• Porsche 997 MKII GT3 / GT3 RS 2010-11
• Porsche 991.1 GT3 3.8L (475 Bhp) 2014-16  

Timing chains are designed for extended service life, but they operate continuously whenever the engine is running. Repeated mechanical loading, friction, heat and lubrication conditions can gradually cause wear to the chain pins, links and contact surfaces. Associated guides, tensioners and sprockets can also deteriorate over time.

As wear develops, the chain's effective length can increase, creating excessive slack and potentially affecting timing accuracy. Severe deterioration can allow the chain to jump, derail or fail, creating a risk of significant internal engine damage.

What This Product Does:
The timing chain transfers rotational movement through the engine timing system while maintaining the required mechanical relationship between associated components.

Depending on the specific engine configuration, it helps support:

• Accurate engine timing
• Correct camshaft operation
• Correct valve timing
• Reliable mechanical synchronisation
• Consistent rotational drive
• Smooth engine operation
• Stable combustion
• Consistent power delivery

Correct chain tension, adequate lubrication and accurate engagement with the associated sprockets are essential for dependable timing-system operation.

Symptoms Of Wear Or Failure:
Possible symptoms of timing-chain or associated timing-system wear include:

• Metallic rattling or clattering
• Rattle during cold starts
• Noise immediately after engine start-up
• Mechanical noise from the timing area
• Excessive chain slack
• Timing-chain elongation
• Noise that changes with engine RPM
• Rough or irregular engine operation
• Unstable idle
• Difficult starting
• Reduced engine performance
• Misfires
• Engine warning light
• Timing-related diagnostic fault codes
• Camshaft-position faults
• Crankshaft/camshaft correlation faults
• Variable camshaft timing faults where applicable
• Visible chain wear during inspection
• Worn or damaged chain guides
• Abnormal sprocket wear
• Metal or plastic debris in the engine oil or oil filter

These symptoms do not automatically mean the chain itself has failed. Guides, tensioners, sprockets, lubrication problems and other engine faults can produce similar symptoms, making correct diagnosis important.

Why Replacement Matters:
The timing chain is a critical internal engine component. Once excessive wear, elongation or physical damage has been confirmed, replacement is important for restoring dependable timing-system operation.

Replacing a worn IWIS Timing Chain can help:

• Restore reliable mechanical synchronisation
• Maintain accurate engine timing
• Restore correct chain operation
• Reduce excessive chain slack
• Reduce abnormal timing-chain noise
• Maintain reliable sprocket engagement
• Protect timing-chain guides
• Protect associated sprockets
• Reduce the risk of timing deviation
• Reduce the risk of the chain jumping
• Reduce the risk of chain derailment
• Support smooth engine operation
• Protect expensive internal engine components

Continuing to operate an engine with a confirmed timing-chain problem may allow deterioration to progress and substantially increase the cost of the eventual repair.