If I was pulling the other cylinder head before reassembling the engine and finally decided I was having enough problems with the exhaust bolt holes stripping on the other one that I probably should pull it and Helicoil all of them on this one also and there has been enough weirdness with this engine that I probably should take a look...

Well, I guess it was a good thing:

I found 3 mud dauber nests inside the cylinders...

 

OK...that's a first for me.

 

Man, those little %*@$ers get in anywhere.

 

Wow, that's crazy. I have the mud wasps that like to fill all the orifices in the engine(s). They did the fuel lines that were un capped, trans cooler lines, bolt holes.... such a PITA to clean out too

 

I got the big chunks out with a shop vac, but I'm not sure what to do with the stuff stuck to the top of the pistons. I chipped the big stuff off but it comes off like concrete and I don't want that getting into the piston ring lands. The best idea I have so far is to find a brass brush to use in a Dremel and try to hold the vac nozzle next to it as I go but I've been to 3 hardware stores and I can't find any brass brushes (everyone has steel and stainless, neither of which do I really want to be using on a piston top inside an engine).

 

Perhaps a chemical approach? Brake clean, purple power, simple green might dissolve it?

 

Try Marvel Mystery Oil mixed with acetone.

 

I actually already have that mixed up in the garage, it makes a decent lube for machining aluminum...