Crank Scraper Installation

Overview

Installing a crank scraper on your Porsche 944 S2 (3.0L engine) is a great way to boost performance and improve oil flow. It reduces the air dragged by the spinning crankshaft, which can mix with oil at high RPMs, lowering oil levels in the pan and creating foam. This upgrade also cuts down on crankshaft drag, freeing up a bit of power. It’s a smart add-on during an engine overhaul since you’ll already have the oil pan off. This guide focuses on fitting an all-metal crank scraper, which needs careful grinding for clearance, but a Teflon self-fitting option is available too.

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Tools Required

• High-speed air or electric die grinder (or Dremel-style tool)
• Bench grinder
• File (optional, for smoothing)
• 19mm (3/4 inch) wrench
• 19mm crowfoot wrench (for tight spots near the oil pickup)
• Torque wrench (capable of 30 Nm (22 ft-lbs) and angle torque)
• Marker (e.g., felt pen)
• Hot soapy water and cleaning supplies
• Silicone-based gasket maker (for temporary gasket fitting)

Parts Required

• All-metal crank scraper with included washers (IJ-944-S2-M)
• O-ring for oil pickup (944 107 135 01)
• Oil pan gasket (if not reusing old one, 944 107 147 03)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Oil Pan Removal
• Engine Removal (optional, if working with engine out of car)

Step-by-Step Procedure

Step 1: Remove the Oil Pan and Oil Pickup

1. Start by removing the oil pan. Follow this link to ensure this step – Oil Pan Removal – of the process is followed accurately.
2. Once the oil pan is off, unbolt and remove the oil pickup from the engine block. Set it aside for now.

Step 2: Check Crankshaft End Play

3. Measure the crankshaft end play using a dial indicator. For the S2’s 3.0L engine, the new spec is 0.11–0.31 mm (0.004–0.012 inches), with a max wear limit of 0.40 mm (0.016 inches).
4. If end play exceeds 0.40 mm (0.016 inches), the thrust bearing (part of main bearing #3) may be worn. Consider replacing the main bearings before proceeding.

Step 3: Remove Main Bearing Nuts

5. Locate the five 19mm (M12) main bearing nuts on the left side of the engine block (driver’s side in LHD cars).
6. Using a 19mm (3/4 inch) wrench, remove these nuts. Discard the old washers—they’ll be replaced with the thinner ones supplied with the crank scraper.

Step 4: Test Fit the Crank Scraper

7. Position the all-metal crank scraper (IJ-944-S2-M) over the main bearing studs. Secure it lightly with three nuts (front, center, rear) using the 19mm (3/4 inch) wrench.
8. Rotate the crankshaft by hand (never use the starter motor!) to check clearance between the scraper and the crankshaft, especially at the connecting rod caps and counterweights.
9. Ensure a minimum clearance of 1 mm (0.039 inches) as recommended by Ishihara-Johnson. Shift the crankshaft forward and backward gently (without prying on bearings) to see how clearance changes.
10. Use a marker to mark any spots on the scraper where clearance is too tight.

Step 5: Grind the Scraper for Crankshaft Clearance

11. Remove the scraper and use a high-speed die grinder to carefully remove material from the marked areas.
12. Clean off all grinding dust with hot soapy water to keep debris out of the engine.
13. Reinstall the scraper and recheck clearances. Repeat grinding and cleaning until you achieve at least 1 mm (0.039 inches) clearance everywhere.

Step 6: Fit the Scraper to the Oil Pan

14. Smear contrasting grease (e.g., bright red or yellow) along the outer edge of the scraper’s backside.
15. Cut two 254 mm (10 inch) sections from an old oil pan gasket. Temporarily glue them to the oil pan’s gasket surface with silicone gasket maker to act as spacers.
16. Try fitting the oil pan over the scraper. It’ll likely hit the scraper before seating fully, transferring grease to show contact points.
17. Remove the scraper and mark the grease spots with a felt pen. Grind these areas on the scraper’s backside with a bench grinder, then smooth with a file or die grinder.
18. Clean the scraper and reinstall it. Repeat the grease test and grinding until the oil pan fits without touching the scraper.
19. For the S2’s baffled oil pan, check the back edge near the baffle tray. Trim and round the scraper if it hits the plastic tray or a mounting bolt. Shorten the bolt if needed, or grind the scraper to clear it.

Step 7: Final Installation

20. Once fitment is perfect, give the scraper a final wash with hot soapy water to remove all debris.
21. Reinstall the oil pickup with a new O-ring (944 107 135 01).
22. Mount the scraper using the supplied thin washers and torque the five 19mm (M12) main bearing nuts in two stages: first to 30 Nm (22 ft-lbs), then an additional 60-degree turn. Use a 19mm crowfoot wrench for the nut behind the oil pickup.
23. Install the oil pan with a new gasket (944 107 147 03) if needed. Follow this link to ensure this step – Oil Pan Removal (reversed for installation) – is followed accurately.

Post Procedure Checklist

• Check for oil leaks around the oil pan after running the engine for 5–10 minutes.
• Verify crankshaft rotates smoothly by hand with no scraping sounds.
• Inspect oil pickup O-ring seal for proper seating.
• Drive 5 miles (8 km) and recheck for leaks or unusual noises.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• YouTube