SBC block filling ?

[Reed Granrt]

Originally Posted by randy wilson

I see no advantage to filling any block. When we used to do it on stock blocks, not one rebuild were the cylinders round. Quit filling, and everything stayed straight. The stones just chattered after a teardoiwn using hardblok.

Randy
I would like to address this with my opinions and observation. Filling a block is a lot like purchasing a new block and putting it into service and is a lot like pouring new concrete. Lets address each one individually. If you purchase a new block, lets say a Dart, it will take a couple of tear downs and re-hones to get the bores to stabilize as the block has to go thru a "settling & curing" time. The aspect of pouring the block goes thru much of the same process as concrete. It will take that pour a couple of tear downs and re hones to stabilize also. Where I have seen definite advantages is where the block cylinders walls are thin and flex in the every firing pulse. I feel the poured block is a definite advantage but I also feel is does have a disadvantage. And that is the poured section runs at a different temp than that section with water going thru it, therefore they are 2 different dimensions. I have found that there is a definite small taper from top to bottom as a result of that temp difference. Most good machinist and racers know how to minimize that problem. Is the filler material a temp stabilizer? Not in my thought process. On any given run, the temperature in the block will begin to climb and will continue to grow thru the run. The filler material will continue to increase in temperature but the water cooled section will hit a maximum and then water will begin to cool it or stabilize it. This is not a perfect world, but with stock blocks, sometimes it is a necessity. There is another plus of a poured block over a stock block and without any doubt, the filler adds rigidity to the block. No doubt, in my mind, it strengthens the bottom end in the crank area. Is there a definite advantage to a poured block. I feel you have to look at each situation. A 9 to 1 motor doesnt need it as much as a 12 to 1 motor does and it goes on and on. But I feel if you do indeed pour a block, then by all means try to cure it after the pour for it to stabilize and shrink as much as possible before you machine it.
And I most certainly agree with Carl, that I never like a poured block over most after market blocks but as we all know, some manufactures do not have the advantage of an approved after market block and are forced to work with what they have and improve it any way that they can.
Hey just my thoughts.
reed