Walnut blasting a.k.a Dreaded Cylinder Head Blues

[silverstreak18]

In hindsight I had not considered a more powerful blasting system. That makes sense. Just curious, do yours come out more/same/less clean than the photos I show above? I'm sure in less the time and elbow grease, too!

Filippo

Those look perfect to me. A lot of times there will be a little bit of discoloration where the vacuum adapter mounts in the port since the walnut shells can't hit there.

 

[derekgates]

Derek, plugging the head is simple. 10/32 tap (use lube - any grease will work), and install the plugs with loc-tite. You may need to back the tap out to clean it after going in about half way. Keep in mind the plug screw goes in at an angle so you want it deep enough that it does not sit proud of the head surface. Also remember, the tap's tip does not cut full threads (it's not a bottom tap); make sure you cut threads deep enough to set the screw plugs below surface. It's a good thing to capture the aluminum bits. We folded some shop towels and coated them with white lube to help catch them bits: one towel to catch dry bits during the tap procedure, then a second towel we pushed in the hole when we blew the hole out with brake cleaner. For the second towel that gets wet, it catches lots of bits.

Filippo

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Fantastic reply, thank you. I need to pull the cover and get this finished. Will pick up a tap and try to find those plugs or buy more. Rob@RB told me over email a long time ago how to obtain more but I have misplaced that email.