Rennvision on Porsche Bore Scoring: Updated Insights, Diagnostics, and Fixes
Jake Raby’s Rennvision channel has revisited and expanded its Porsche engine content with a renewed focus on Porsche bore scoring—integrating lessons learned since the 2018–2019 videos and the post-2020 period. This guide summarizes the series’ key takeaways and pairs them with proven repair strategies from Flat 6 Innovations and technical resources from LN Engineering.
Related resources: Rennvision: Focus On – Bore Scoring playlist | LN Engineering: Porsche Cylinder Bore Scoring
What’s New Since the 2018–2019 Videos?
- Context: A 2021 update reframes prior bore-scoring content with fresh field data and refined procedures.
- Education-first: The series doubles down on clear diagnostics (proper borescope technique, cam deviation review) and realistic fixes.
- Community & membership: Viewers are encouraged to subscribe and consider paid learning for deeper technical dives.
Bore Scoring 101
What it is: Longitudinal scoring of cylinder walls (common in M96/M97) that increases oil consumption, noise, and—if ignored—can lead to major engine damage.
Why it happens: A combination of factors: surface finish and coating behavior (Lokasil/Alusil), heat cycles and oil film management, piston skirt coating loss, fueling and injector condition, and operating patterns. No single cause explains every case; prevention and correct diagnosis are key.
Fast Symptoms vs. Subtle Clues
| What You Might Notice | What It Can Mean | Next Step |
|---|---|---|
| Ticking/knock from one bank (often Bank 2), hot idle | Possible skirt wear and wall scoring; noise may vary with load/temp | Stop hard use; schedule borescope from the sump side |
| Rising oil consumption, sooty tailpipe, smoke on start/overrun | Oil bypass from scored walls; ring sealing compromise | Compression/leakdown and visual cylinder inspection |
| No obvious noise, car “feels fine” | Scoring can still be present—especially on cylinders not visible from plug holes | Use correct borescope approach before assuming “all clear” |
Diagnostics That Actually Work
- Borescope correctly (from the sump side): Many M96/M97 problem areas aren’t visible from plug holes. Use the proper angle and access points documented by experienced Porsche rebuilders.
- Cut and inspect the oil filter; pull the sump plate: Look for metallic debris/glitter and document findings.
- ECU interrogation: Review over-rev counters and camshaft deviation values for corroborating clues.
- Fuel system check: Verify injector health and fueling (leak-down, spray pattern); poor fueling contributes to skirt/coating distress.
- Operating profile review: Heat cycles, short-trips, extended oil intervals, and oil choice matter; adjust practices to slow progression.
Prevention & Slowing Progression
- Oil strategy: Use the recommended high-quality oil and change on conservative intervals; monitor temps.
- Injector hygiene: Keep injectors clean/healthy; address fueling anomalies early.
- Driving patterns: Avoid chronic short-trips and babying; get the engine to full operating temperature regularly.
- Listen and log: Record sounds, oil use, and maintenance; consistent records help trend small issues before they grow.
Proven Fixes When Scoring Is Confirmed
There is no “in-car” magic cure for true cylinder scoring. The durable repair is a full engine teardown with cylinder work and updated components. A widely used approach is to machine out the damaged material and install robust replacement cylinder sleeves (e.g., Nickies) along with updated pistons/rings and any model-specific upgrades discovered during inspection. Pair this with best-practice rebuild processes (checking IMS shaft/runout, timing components, oiling, and cooling system health).
Rennvision Series Timeline (Key Milestones)
- 2018–2019: Initial bore-scoring videos establish fundamentals (inspection and failure modes).
- 2020: Pandemic disruptions pause normal cadence.
- Mid-2021: Update video announces refreshed and expanded content, integrating new shop data and procedures; encourages subscriptions and paid education for deeper learning.
What to Do Next
If you suspect bore scoring—or you simply want to baseline your car—book a borescope inspection with a Porsche specialist who follows the sump-side method and can interpret results in context. If scoring is present, discuss a full, parts-validated repair plan rather than chasing temporary measures. For deeper training and case studies, subscribe to Rennvision, and for rebuild options, review Flat 6 Innovations and LN Engineering resources below.
More info: Rennvision – Bore Scoring (playlist) | LN Engineering – Porsche Cylinder Bore Scoring | How to Borescope Your Porsche Engine
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