Monday, January 23, 2023

Heads up!


The moving parts of the VW engine get every more exciting. We're on to the cylinder heads, with their valves. 

These are driven from the shaft in the centre, via pushrods (on the right in the photo) which operate through pushrod tubes (on the left). These move in and out, operating the rockers (tomorrow's blog) which move the valves. 

Anyway, the valves are made up of three parts, including a metal spring, which push together through the head. Those springs are ingeneously supplied threaded on a cable tie, so they don't get lost in transit. 

The heads are attached to the crank case with screws, and some carboard gaskets, not far off the thickness of the real thing, fit between the two. Getting these to sit flat might not matter for the engines operation, but they do for looks, so it's shiny white side against the crank case as the depression from the die cutting alots them slip in easily. 

Those push rod tubes are solid on the real engine, although collapsable versions are sold so you can replace one without removing the head. Removal can be a brutal operation, and it's essential to ensure the seal at each end seats, as they are full of oil which will otherwise "mark the spot" where the vehcile stands!


 

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