Quote:
Originally Posted by Bill Bogues
I know what he's going through. I used to have a fairly good running car until I finally just wore my factory block out. I then went and put a Dart little m block in it and 4 years later I still can't make it run no matter what I do. Tried heads, all different kinds of ring packages(total seal luniac etc etc) cams and I've never had it leak less than 10%. Is it possible for a dart block to not be any good. Ive had some pretty impressive machinist hone the block and nothing seems to work. I'm about ready to go back to a factory block. Hope you find out what's wrong.
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Bill, Dart makes a great product, although their customer service on some things can leave a bit to be desired. That being said, it is possible, but very unlikely, to have a bad block.
I will say that those blocks can drive even an excellent machinist insane trying to get the cylinders done correctly. Really good and experienced guys, way better than me, have struggled with them. A couple shared what they learned, and helped me figure out what I needed to do. I damned near ruined the first one I honed, the truth is, that one didn't seal up really well until we freshened that engine, changing pistons and rings, and honing it again.
A couple of things I can suggest. First, it is necessary to use extremely soft stones, it is near impossible to get them too soft. Second, flood the cylinders with hone oil, good clean fresh hone oil, it is near impossible to flow too much. Third, use light to medium pressure, never more. Finally, use coarse stones right up until the last 0.001" or so, then use your last two finish stone sets for only that last bit of stock removal. Dart blocks are extremely hard, they will glaze over, and load up a set of stones in an instant.
Once you get the bores correct on a Dart block, they'll hold up well and last forever, you can literally touch them up with maybe 5 light strokes of soft 400 grit stones and a finish pass or two with the Total Seal suggested finish technique.