Re: Hardblock Question
 

Although Hard Blok claims the expansion rate of their product is the same as gray cast iron, when I spoke to them, they could not tell me how they based their claim.

On the other hand, Embecco 885 is a fully tested product for use by the government, with lots of supporting data and it contains cast iron in its formulation. Never had any issues with the product and the blocks have never changes in the block dimensions.

Re: Hardblock Question
 

I'm sure there are people who do fine filling their blocks. Just telling of my personal experience. It NEVER settled down for me in any block used. To each his own. We may have actually applied it wrong.

Re: Hardblock Question
 

I wouldn't fill with hardblock or any aggregrate based filler. I have been using bowling ball epoxy with excellent results. Mix it to the ratio listed on the bottle and it is easier to fill and cleaner overall. Water jackets need to be clean though, no debris or coolant or oil.