Engine Overhaul | Schmid Congo Motors

Disassembly

After disassembly the engine is fully cleaned in an industrial washing machine. Then all parts are thoroughly inspected and a complete diagnosis is made.

washing machine

Most common is wear of the cylinder walls. This is caused by the large number of up and down movements (some 100,000 times per hour). Contributing factors: poor cooling and / or lubrication.

damaged cylinder wall

If this wear becomes excessive, the compression pressure will fall and eventually the engine will no longer function properly.

Drilling the cylinder block

We always minimize the excess-diameter drilling.

drilling of the engine

If the wear is excessive or if this is a second overhaul for the engine, cylinder “liners” can be fitted.

engine with major wear

cylinder liner

Honing of the cylinder walls

The honing after drilling is a very precise operation that requires a lot of experience.

The honing profile must be perfect because it ensures the distribution of oil. If not done properly the cylinder can overheat due to lack of cooling or lubrication. The graphite veins in the metal should be safeguarded.

This operation is done with a specially designed machine and can only by accomplished by an expert.

honing of cylinder walls

detailed honing profile

Grinding of the crankshaft

before grinding

after grinding

Engine block and cylinder head surfaces

After drilling both the engine block and cylinder head must be flattened.. This operation is important because the engine block and cylinder head must fit perfectly together. We used a chisel or a grinder depending on the material the engine and cylinder head are made of.

We can do this for large engines and V-engines as well.

flattening of cylinder head

Cylinder head “hot” pressure test

To avoid unnecessary costs the cylinder head will be put under pressure first. If this test fails, the cylinder head is not worked on any further.

cylinder head pressure test

Cylinder head treatment

After flattening the cylinder head a few other operations are necessary. Replacing the valve guides, grinding and polishing of the valve seats and installing the valves.

The valve seat is a critical component of the engine. A common problem is valve leakage that will adversely affect the engine compression ratio and therefore the performance.