1983 Porsche 928: How to Swap Engine Parts Needed – A Complete Guide

The 1983 Porsche 928 is a classic grand tourer with a front-mounted V8, but as these cars age, engine reliability and performance often become concerns. Many owners consider swapping engine parts—either rebuilding the original 4.7L V8 or installing a more modern powerplant like an LS-series V8. This guide covers what parts you need for both approaches, common pitfalls, and practical steps to get the job done.

Understanding Your 1983 Porsche 928 Engine

The 1983 model year features the 4.7-liter (283 cu in) M28.22 V8, producing 234 hp in US spec. This engine uses Bosch K-Jetronic mechanical fuel injection, which can be finicky. Before attempting a swap, assess whether you want to keep the original character or modernize.

Engine Swap vs. Rebuild

• Engine swap: Replacing the entire engine with a different unit (e.g., LS, 928S4, or even a 5.4L from later models). Requires adapters, wiring work, and often new transmission.
• Parts swap: Replacing individual internal components (pistons, rods, cams) to improve durability or performance—usually during a rebuild.

Required Parts for a Complete Engine Swap (LS Swap as Example)

The most popular swap for the 928 is an LS (especially LS1, LS3, or LS6). Here’s a list of parts you’ll need:

1. Engine and Transmission

• Donor LS engine: Complete with accessories (alternator, starter, etc.).
• Transmission: LS engines typically use GM transmissions. A common choice is the 4L80E or a manual T56. You’ll need an adapter to mate to the transaxle.
• Adapter kit: Companies like Lasso or 928 Motorsport make bellhousing adapters for LS-to-928 transaxle.

2. Mounting and Cooling

• Engine mounts: Custom fabricated or aftermarket (e.g., Renegade Hybrids LS swap mounts).
• Radiator: Upgrade to a larger aluminum radiator; the 928’s cooling is marginal for an LS.
• Electric fans: The stock fan clutch may not fit; dual Spal fans are common.

3. Fuel System

• Fuel pump: LS engines need higher pressure. Use a Walbro 255 lph pump mounted in the tank.
• Fuel lines: Replace old rubber lines with PTFE stainless braided lines.
• Regulator: Adjustable fuel pressure regulator for return-style systems.

4. Electrical

• ECU and wiring harness: Use the LS’s stock ECU (e.g., E38/E67) with a standalone harness from PSI or Speartech.
• Adapter for gauges: Will need signal converters for tachometer and speedometer.
• Battery relocation kit: Often necessary for weight distribution.

5. Exhaust

• Headers: Custom LS swap headers (available from 928 Motorsport) or modify the stock 928 headers.
• Exhaust system: Mandrel-bent piping from headers back to stock mufflers or aftermarket units.

6. Miscellaneous

• Power steering: LS pump may need different bracket; some use a remote reservoir.
• A/C: LS compressor may require custom lines.
• Air intake: Cold air intake kit or custom tubing.

Required Parts for Rebuilding/Upgrading the Original 4.7L V8

If you prefer to keep the original engine, you can swap internal parts to improve reliability and power.

Bottom End

• Pistons: Forged pistons (e.g., JE or Wiseco) for higher compression or boost.
• Connecting rods: Stock rods are good to about 400 hp; upgrade to forged H-beam rods for more.
• Crankshaft: Stock is forged and durable; consider polishing or knife-edging.
• Main and rod bearings: Use King or ACL tri-metal bearings.
• Oil pump: Upgrade to a high-volume unit (Melling M-136? Verify for 928).

Top End

• Camshafts: Regrind stock cams or install aftermarket (e.g., Elgin). Match to your intake/exhaust goals.
• Valves: Stainless steel valves (1-piece) for durability; stock size or +1mm.
• Valve springs: Dual springs for higher RPM.
• Cylinder heads: Porting or replacement with later 928S4 heads (smaller ports for better torque).

Induction

• Intake manifold: Stock is adequate; port match or install a later 32-valve intake (requires head swap).
• Fuel injection: Upgrade to a standalone EFI system (e.g., Haltech or Megasquirt) to replace K-Jetronic.
• Throttle body: Larger unit (e.g., 80mm) if standalone.

Cooling and Timing

• Water pump: Rebuild or replace with new.
• Timing chain and guides: Replace with upgraded duplex chain (available from 928 Motorsport).
• Oil cooler: Add an external oil cooler for track use.

Step-by-Step Overview for Swapping Engine Parts

1. Preparation

• Park the car on a level surface, disconnect battery, drain fluids.
• Remove front bumper, radiator, and front end parts for access.

2. Removing the Original Engine

• Disconnect fuel lines (watch for pressure), wiring, exhaust, and transaxle bolts.
• Pull engine with a load-leveler; note that the 928 has a “power take off” unit (PTU) that must be aligned during reinstallation.

3. Installing the New Engine

• For an LS, install adapter plate and torque converter (if auto) to the transaxle.
• Place engine on mounts, connect fuel, cooling, and electrical.
• Use a standalone harness; wire the ECU per instructions.

4. Testing and Tuning

• Prime oil pressure, start engine, check for leaks.
• Tune with wideband O2 sensor; LS engines often need custom mapping.
• Road test, adjust shift points and idle.

Common Challenges and Solutions

• Transaxle strength: The 928 transaxle is weak with high torque. Upgrade to a later S4 unit (stronger) or aftermarket (e.g., 01E from Audi).
• Wiring complexity: Label everything; use a dedicated LS swap harness to simplify.
• Weight distribution: The LS is lighter than the cast-iron original, improving handling.
• Cooling: Install an auxiliary oil cooler and high-capacity radiator.

Final Recommendation

For a 1983 Porsche 928, swapping engine parts often means choosing between a rebuilt original V8 with upgraded internals (good for authenticity and moderate power) or a full LS swap (best for reliability and over 400 hp).

• If you want a weekend driver with classic feel: Rebuild the original engine with forged rods, better cams, and a standalone EFI kit. Expect $5,000–$10,000 in parts.
• If you want modern performance: Go with an LS3 and 4L80E trans. Budget $12,000–$20,000 for parts, adapters, and tuning.

Always buy parts from reputable suppliers like 928 Motorsport, Renegade Hybrids, or 928 Intl. Have a shop experienced with 928s handle the swap if you lack mechanical skills. A well-executed engine swap transforms the 928 into a reliable, powerful machine that can handle modern traffic and road trips.