Ignition Advance

[Gennaro]

On my '74 1.8 L when testing for leakage of the distributor advance I get no leakage on the advance side and some leakage on the retard side. Is there more than one diaphragm? If only one how can there be one way leakage? I know I'm crazy for owning a 914 but this seems more than normal.

[porschetub]

Originally Posted by Gennaro

On my '74 1.8 L when testing for leakage of the distributor advance I get no leakage on the advance side and some leakage on the retard side. Is there more than one diaphragm? If only one how can there be one way leakage? I know I'm crazy for owning a 914 but this seems more than normal.

Most don't worry about the function of the retard side and cap off the line @ the source.
Its more about the action of the advance plate,they do gum up after 40 odd years and can cause slow or restricted advance or in some cases none @ all.