OST-019: Collaboration

[oldeskewltoy]

cavey Wrote:Not too sure, pictures are a bit unclear and not an engine builder/rebuilder: but it seems there are a lot of little ridges around the valve areas, potential hotspots for pre-detonation?


Looking forward to more pictures, especially of the head gunk cleaning process (or would that be just a nice washing machine?)

hehehehe... no washing machine here, local shop does it for me.

the ridges around the valves can and will cause ping(pre-ignition, or detonation). I will be attending to those during the porting process, but those are common in all 4AGE heads.

from another forum Wrote:the machining for the valve seats doesn't looked to be lined up well at all with the ports, especially in cylinder 4

VERY good call...



the 2 views are of the same chamber... the views are slightly off angle to better show the bowls and seats





For comparison... this is chamber 2.






As bad as that is... when porting you must remember the direction of flow... the flaw above is bad enough, it pinches the airflow, but the real criminal in this port isn't the flaw you see....

its the flaw you DON'T see that is the problem!!!!



The above view is from below, the head is hung over the edge of the bench, the dental tool is hanging on the inside of the mismatched seat/bowl. This flaw is far more serious, as it not only pinches flow but it causes serious eddies which cause far more flow issues.


More to come....