What It Is
A set of 4 OEM Volkswagen pistons for the 1.9L TDI, sized .5mm over stock for a rebored block. The set includes pins and rings, manufactured by Nural/Federal Mogul, the same supplier VW dealerships use for replacement pistons.
Part Numbers
Critical Installation Note
When replacing the engine block, rods, crankshaft, or pistons, piston protrusion at TDC above the block deck must be measured before selecting a head gasket. Projection needs to fall between .91mm and 1.20mm, paired with the correct head gasket thickness, to land on the correct compression ratio. KermaTDI provides a piston projection reference guide to walk through this measurement.
Fitment
1996-2003 Volkswagen Golf, Jetta, and New Beetle with a 1.9L TDI engine (AHU, 1Z, ALH), sized for a .5mm overbore.
Common Questions
Do these include rings and pins?
Yes, the set includes pins and rings along with the 4 pistons.
How do I know which head gasket thickness to use with these pistons?
You'll need to measure piston protrusion at TDC first. It should fall between .91mm and 1.20mm, and the head gasket thickness should be selected to match that measurement for the correct compression ratio.
Are these genuine OEM pistons or aftermarket?
They're manufactured by Nural/Federal Mogul, the same company that supplies VW dealerships with replacement pistons.
Will these fit a standard, non-bored block?
No, these are sized .5mm over stock, meant for a block that's already been bored to accept oversize pistons.
https://kermatdi.com/files/1-9-piston-and-connecting-rod-overview.pdf
https://kermatdi.com/files/1-9-piston-dimensions.pdf
https://kermatdi.com/files/piston-projection.pdf
