8ba block decking

[deuce_roadster]

If the shop that did the machine work was not familiar with flatheads, they could have machined the decks as if they were both at the same angle. I know of a block that was ruined this way.

[V8COOPMAN]

Originally Posted by deuce_roadster

If the shop that did the machine work was not familiar with flatheads, they could have machined the decks as if they were both at the same angle. I know of a block that was ruined this way.

The decks are BOTH at a 45 degree angle, but the valve angles are asymmetrical. The passenger side valves are at 49.5 degrees, whereas the driver side valves are at 52 degrees. Cam and cylinder bores are centered in block....crankshaft is offset 0.265" to the passenger side of center. The crank offset has to do with the DeSaxe principle. DD

[JWL]

Actually the cam is offset from the crankshaft .021 plus or minus .002 on the 46-53 engine block.

[Bored&Stroked]

Originally Posted by JWL

Actually the cam is offset from the crankshaft .021 plus or minus .002 on the 46-53 engine block.

The original 8BA drawings show the camshaft offset to be from .0192 to .0292 offset from the crank, so I "split the difference" and went with .0242 in my cad model. There are some minor differences in the 59x versus 8BA drawings - with the 8BA ones being easier to read.

I will have to test the cam offset at .019 to .023 and see what it does to the valve angles - will be an interesting 3D experiment.

The valve angles shown on the 8BA drawings are 3.38 degrees and 6.23 degrees - though obviously they change depending on the true CAM centerline offset. When I did my CAD model, I let the specific dimensions of the CAD models (off the prints) drive the final dimensioned values - so there will be some variance, due to the various variances in the drawings.