Sonntag, 22. Juli 2007

Cylinder Head Preparation - Part II

This is a view through the inlet port on the open intake valve before porting an polishing the inlet port. At 1600cc engines the valve guides are not much penetrating into the port. They needn't to be shortened nor machined.
The head is milled to a total heigt of 111.2 mm. As a consequence the diameter of the in-head combustion chamber is only 77 mm. It is 1 mm smaller compared to the engine bore of 78 mm. To avoid collision with the piston a chamfer is often recommended when milling the 1600cc head to achive high compression ratios. I measured the volume of the in-head combustion chambers to 63 cm³ each.

These are the new parts of the valve spring mechanism. You can see the inlet valve (bottom), the sodium filled exhaust valve, spring seat, shim, inner and outer valve spring, spring retainer and two valve keys.
As you can see, the valve keys at the outlet valve are different from the original Alfa inlet valve. They have three "rings" instead of one. I sourced them directly from TRW Automotive GmbH, Hauptstraße 10, D-31699 Beckedorf (TRW No. K8A090M0).

In addition to that there are a set of new valve guides, valve gaskets and valve seats with a three angle valve job (15/30/60 deg). To be continued ...

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