The Flex-Hone® for Dart SHP Engine Blocks

Dart Machinery is a Michigan-based manufacturer of high-performance cylinder heads, engine blocks, and intake manifolds for automotive and marine applications. The company’s special high performance (SHP) engine blocks are more expensive than junkyard cores, but cost hundreds of dollars less than full racing blocks. The engine cylinders in a Dart Machinery SHP block also arrive ready for flexible honing, which imparts an ideal surface finish for optimum lubrication. By using the Flex-Hone® tool from Brush Research Manufacturing (BRM), mechanics and hobbyists can produce a final finish on cylinder walls.

Crate Engine or Engine Restoration?
As Dart Machinery explains in an article entitled Debate: Dart SHP or Restored Stock Block?, buying a new engine block or crate engine eliminates the uncertainty of a junkyard find. For example, if you’re picking through junkyards for a small-block Chevy 350 engine, you’re liable to find one that’s 30 to 40 years old. Until your SBC 350 is cleaned and checked by a machine shop, you won’t know much about the engine’s condition. Metal fatigue from heat cycles and loading can cause cracks in the cast iron, and unanswered questions about engine maintenance will remain.       

DIY Automotive Projects
For some engine builders, however, the risks in buying a used stock block are offset by the rewards of completing a do-it-yourself (DIY) automotive project. The author of Dart Machinery’s “Debate” article understands this, and offers a series of recommendations for refurbishing and resurfacing old engine blocks. Line honing or line boring the main bearings and cam bearings “restores worn out, out-of-round or damaged bores”, the article explains, correcting engine problems that can be caused by overheating or loss of oil pressure. As with new Dart SHP engine blocks, engine rebuilds also involve flexible honing. 

The Flex-Hone® for Engine Rebuilds
“The only way to give your build a chance at survival,” Dart warns, “is to restore the inside diameter of the bores by line honing. As if to prove Dart’s commitment to engine hones, the article adds that “we even go as far as honing the lifter bores when prepping a used block for racing applications”. The Flex-Hone® tool from Brush Research Manufacturing (BRM) isn’t built for re-sizing cylinder bores, nor is it designed for extensive material removal. The Flex-Hone® tool is unlike any other honing tool, however, because BRM’s flexible cylinder hones produce an unmatched controlled surface condition.