Re: Several questions...

Posted by PackardV8 On 2012/2/18 8:20:40

Rolled thread bolts or studs are used so that a good portionm of the SHANK (UNthreaded portion) of the bolt will be BELOW the top of the surface that it is screwed into. This keeps the surface of the block from distorting when the bolt or stud is torqued very tite. Otherwise there is threads of thebolt pulling against the LAST TOP MOST thread of the block and thus causeing the the last female threads to mushroom up out of the surface of the block.

THis distortion of the area around the female threaded portion of (in this case the engine block) can often be detected by running a razor blade over the hole. In many cases the distortion can be easily detected by this method.

Note that rolled threaded bolts usualy have a smaller diameter SHANK than the diameter of the thread. Usualy rolled thread bolt has LESS threads than a die cut bolt. Which allows for clearence at the TOP few threads of the FEMALE threads in the block.