Not using the cylinder/head gasket..., ...and dropped valve seat? Options

[larss]

If I don't fit any gasket at the top of the cylinders (which is what every expert suggests) will this affect the type/thickness of shim used at the bottom or is the increase in compression so marginal that standard shims can be used?

This is for a all standard 1,7 D-jet engine rebuild.

/Lars

[Dave_Darling]

VW did issue a tech bulletin bout omitting the head gaskets on at least some of their Type IV motors. Also notching the rods to get a little more splash to the underside of the piston.

Porsche issued no such bulletin.

Many builders omit the gaskets, and use a shim of the same thickness as the gasket under the cylinder. Some builders go with the way the motors were originally built, with head gaskets.

For a quick-and-dirty build, you can use a shim of the same thickness as the gasket. To do it right, though, you need to measure all of the volumes and do a little math. Google "compression ratio calculator" for some nice tools that help the math--but there is no substitute for doing the measurements. Relatively small changes in volume can make for relatively large changes in compression ratio.

--DD