69 smog pump resto

[Danzo]

All the marks that were there before i started are still there. they are deep enough that you can feel them with your fingernail.

[firstgenaddict]

The housings are pressure cast aluminum... just like a muncie side cover, tailshaft housing, steering box cover, and valve covers.
After being released from the molds they have machining done. the fly cut marks externally are likely locating areas for the tooling required for machining the internal tolerance surfaces.

[z28z11]

Send the casing to Jerry MacNeish and get him to tumble it. Accelerated tumbling media is the deflashing and deburring technique used by a lot of automotive parts manufacturers to de-scale and smooth the surface of aluminum castings, does a great job of refinishing aluminum and restoring the "mill finish" look. Jerry's technique works very well on manifolds and valve covers, ASL used to do this on alternators and smog pumps to restore finishes to bead blasted and polished cases. Contact him and see what he can do -

Regards,
Steve

[69Z28-RS]

OR... check with local electrical (alternator) rebuilders and see if they have such a tumbling machine.   A friend here once owned an auto electrical rebuilding shop and when he closed it he moved the 'tumbler' to his personal shop.   They make a helluva racket when operating, but do a great job on cast aluminum parts.

[KurtS]

The housings are pressure cast aluminum... just like a muncie side cover, tailshaft housing, steering box cover, and valve covers.

The finish of these parts (aka die cast) are totally different from sand castings. That's why an original Muncie case looks very different than the tail housing.