Case Ports - jyrg
I have in several occasions mentioned I have ported the crankcase.
I am currently building an engine for my 72 H2, and will show you what I do regarding crankcase portwork.
Below is a Picture of my reworked 2mm copper gasket on top of the unported crankcase.
You can clearly see the amount of material I will remove on crankcase transfer edges.
I leave 1,5mm sealing surface Width.
This is a no go when using Stock gasket, but it Works very well using the thick copper gasket and a thin layer of my high temp gasket compound. (same brand as Mercedes use on their engines, German made off course)
The advantage is not only the increased transfer duct entrance area, but also that one can also make them upper transfer ducts and Windows wider for improved flow.
I believe if one does the wider upper duct/window WITHOUT doing the crankcase portwork, flow can in fact be less. Like in the old days, when bigger the holes the better "fact", that we know doesn't always work very well.
I have not done a back to back dyno of this mod, but my guesstimate about Power increase in total (With crankcase portwork and transfer ducts/Windows) is in the 10 rwhp area.
That is on top of all the other ponies, and youi might say these 10 horses are quite difficult to achieve.
But I also believe this mod alone, WITHOUT touching them transfer Windows (that requires special porting 90 degree Tools) also gives additional rwhp alone.
These copper gaskets shown, are off course a Direct match to the transfer entrance of the cylinders