Crank Scraper Install – 2.5L NA

Overview

Installing a crank scraper on all Porsche 944 variants (8-valve engine) is a performance upgrade that reduces oil aeration and crankshaft drag, improving power and oiling efficiency. The scraper minimizes air carried by the rotating crankshaft, preventing oil foaming at high RPMs. This guide covers the installation of an all-metal or Teflon crank scraper, requiring careful fitting to ensure proper clearances with the crankshaft and oil pan. It is tailored for pre-1985.5 (83-85.5) and 1985.5 onwards (86-88) models, with distinctions noted for oil pan designs. This procedure is often performed during major engine work, such as rod bearing replacement, due to the need to remove the oil pan.

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Tools Required

• High-speed die grinder or Dremel-style tool
• Bench grinder
• File
• 19mm (3/4 inch) socket
• 19mm (3/4 inch) wrench
• 19mm (3/4 inch) crowfoot wrench
• Marker
• Felt pen

Parts Required

• All-metal or Teflon crank scraper: No specific part number
• Thinner washers for main bearing nuts: No specific part number
• Oil pickup O-ring: 944 107 197 01
• Oil pan gasket: 944 107 195 03
• Silicone gasket maker

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Oil Pan Removal 
• Oil Pan Installation
• Engine Removal (if performed with engine out of car)

Step-by-Step Procedure

Step 1: Prepare the Engine

1. Remove the oil pan by following this link to ensure this step – Oil Pan Removal – is completed accurately. If the engine is out of the car, follow this link to ensure this step – Engine Removal – is followed accurately.
2. Remove the oil pickup tube from the engine block.
3. Check crankshaft end play using a dial indicator. Specification is 0.11–0.31 mm (0.004–0.012 inches), with a maximum wear limit of 0.40 mm (0.016 inches). Excessive end play may indicate a worn thrust bearing, requiring main bearing replacement.
4. Inspect rod bearings and thrust bearing for wear. Replace if necessary, as a worn thrust bearing can cause the crankshaft to contact the scraper.

Step 2: Remove Main Bearing Nuts

5. Use a 19mm (3/4 inch) socket or wrench to remove the five 19mm (M12) main bearing nuts on the left side of the engine block.
6. Discard the original washers, as they will be replaced with the thinner washers supplied with the crank scraper.

Step 3: Test Fit the Crank Scraper

7. Install the crank scraper using three of the main bearing nuts (front, center, and rear studs). Lightly tighten to position the scraper properly.
8. Check clearances between the crankshaft (connecting rod caps and counterweights) and the scraper. Rotate the crankshaft by hand (do not use the starter motor) to verify clearances at all points.

Minimum clearance should be 1 mm (0.039 inches), as specified by the scraper manufacturer. Ensure the crankshaft does not touch the scraper, even when moved forward or backward.

Use a marker to mark areas on the scraper where clearance is insufficient.

9. Remove the scraper and use a high-speed die grinder or Dremel-style tool to grind material from marked areas. Clean the scraper thoroughly to remove all grindings.
10. Reinstall the scraper and recheck clearances. Repeat grinding and cleaning until all clearances meet the 1 mm (0.039 inches) minimum specification.

Step 4: Fit the Oil Pan

11. Smear contrasting-colored grease on the outside edge of the crank scraper to identify contact points with the oil pan.
12. Cut two 254 mm (10 inch) sections from an old oil pan gasket. Temporarily glue these to the oil pan gasket surface using silicone gasket maker to aid positioning.
13. Attempt to position the oil pan. If it contacts the scraper before the gasket meets the engine block, note where the grease transfers to the pan’s interior.

For Pre-85.5 models: Pre-85.5 models use a shallower oil pan with less internal baffling, which may require less grinding for clearance. For 85.5 Onwards models: The oil pan has an internal baffle tray. The scraper may interfere with the tray’s plastic edge or a tray mounting bolt. Shorten and round off the scraper at these points, and remove plastic from the tray’s edge. If necessary, shorten the tray mounting bolt or grind the scraper to clear it.

14. Remove the scraper and mark contact areas with a felt pen. Grind material from the back side of the scraper using a bench grinder, then smooth with a file or die grinder. Clean thoroughly.
15. Reinstall the scraper and repeat the fitting process until the oil pan fits without touching the scraper.

Step 5: Final Installation

16. Perform a final cleaning of the crank scraper to ensure no grindings or debris remain.
17. Install the oil pickup tube using a new O-ring (944 107 197 01).
18. Install the crank scraper using the supplied thinner washers and torque the five 19mm (M12) main bearing nuts to specification: first stage to 30 Nm (22 ft-lbs), second stage an additional 60 degrees. Use a 19mm (3/4 inch) crowfoot wrench for the nut behind the oil pickup tube.
19. Install the oil pan with a new gasket (944 107 195 03) by following this link to ensure this step – Oil Pan Installation – is completed accurately.

Post Procedure Checklist

• Verify crankshaft end play is within 0.11–0.31 mm (0.004–0.012 inches).
• Check that the crank scraper does not contact the crankshaft or oil pan.
• Inspect for grindings or debris in the engine and oil pan.
• Start the engine and check for oil leaks around the oil pan.
• Drive 5 miles (8 km) and recheck for leaks or unusual noises.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube