I'm looking at a 1997 Skoda Felicia with a 40kw engine, and I'm wondering what I would need to change to get it up to a 50kw engine.

The blocks are the same, no? So maybe I could just swap out the throttle body and air intakes?

Edited 1 hour ago1 hr by keywacat
Mistake in terms

The below text is not mine but it will help you:

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To upgrade a 1997 Skoda Felicia 1.3 MPI from the 40 kW (54 hp, engine code 135M) version to the 50 kW (68 hp, engine code 136M) version, the engine blocks are fundamentally identical, but the internal pistons and the cylinder head are different.

Because the 40 kW and 50 kW models use the same engine block footprint, you do not need to alter engine mounts or swap the gearbox. However, achieving the extra 10 kW requires addressing the differences between the two factory setups:

1. The Pistons (The Core Difference)

• 40 kW (135M): Features pistons with a deep dish/recess in the center. This lowers the compression ratio to roughly 8.5:1 to accommodate lower-octane fuel.

• 50 kW (136M): Features flat-top pistons. This increases the compression ratio to approximately 9.7:1, which is the primary source of the extra 10 kW.

• What you need to do: To do this properly, you must swap the 40 kW dished pistons for the 50 kW flat-top pistons.

2. The Cylinder Head & Camshaft

• While the cylinder heads look identical externally, the 50 kW (136M) head has a slightly altered combustion chamber volume to work with the flat pistons.

• The camshaft profiling on the 50 kW version is also slightly optimized for better breathing at higher RPMs.

• What you need to do: It is highly recommended to source a complete cylinder head assembly (including the camshaft) from a donor 50 kW (136M) engine rather than mixing 135 parts.

3. Engine Management (ECU)

• Both engines use the Siemens Multi-Point Injection (MPI) system, but the fuel maps and ignition timing parameters are configured differently to match the compression ratios.

• What you need to do: You will need to swap the ECU for a 50 kW version or get your existing ECU remapped to match the new compression profile.

The Reality: Is it worth the teardown?

Tearing down the engine block just to replace pistons and liners for a 10 kW gain is a labor-intensive project. If you want to proceed, you have two primary options:

Complete Engine Swap (Recommended) : Easiest, fastest, and cheapest. A full 50 kW 1.3 MPI drop-in engine is highly affordable. Requires pulling the whole engine unit.

Internal Parts Conversion : Keeps your original engine block/serial number. Requires a full engine teardown, new gaskets, and piston ring installations.

In short I should swap the complete engine from my rustbucket LXi Felda into the LX if I buy it, jo? 😃

Cheers for it, would you know if the exhaust assemblies are different?