BHJProducts.com - High Performance Engine Builder Tooling and Harmonic Dampers
Part Numbers: Part No: BTK-XXX (various, per application)
The Bor-Tru is specially designed for cylinder bore location on semi-finished factory cylinder blocks. These blocks have rough-bored holes which must be accurately aligned before the finish boring operation. The Bor-Tru can also be used on any stock block when a sufficient overbore will allow correction of out of position cylinders.
The Bor-Tru Kit is the only commercially available fixture that enables the machinist to quickly and accurately locate the cylinder bores over the correct crankshaft centerline. When properly installed, the Bor-Tru references from the rear main surface or rear main thrust surface (depending on block configuration) as a zero datum for front to rear positioning of the fixture on the deck surface. In addition, it spaces the bores at the correct center-to-center distance from one another.
Provisions have also been made for correction of cylinder head dowel hole locations for both solid and ring/split dowel applications. This is accomplished by installation of drill bushings at the correct dowel hole locations. In the standard configuration the I. D. of the drill bushings used are on size to the dowel O. D. Special drill bushings with a larger I. D. are also available to facilitate the use of a specially ground cutter to oversize the existing hole for installation of a stepped dowel pin.
The Bor-Tru Kit consists of one deck plate which is engine family specific, one pair of universal alignment bars (1 front & 1 rear) which fit any V-8 or V-6 engine application, one set-up spacer plus all fasteners necessary for assembly.
Use of the Bor-Tru requires the 2-Inch Precision Support Bar and Main Bearing Bore Adapter Rings which are purchased separately.
When using a deck mounted or portable boring bar or any type of boring equipment that must contact the deck surface of the block while boring, the Bor-Tru Deck Plate can be counterbored at the head bolt hole locations to ensure an absolutely flat surface. There is a nominal charge for this operation, specify part number BT-CB when ordering.
Once the initial Bor-Tru Kit has been purchased, subsequent upgrades can be made to other engine families by purchasing a Bor-Tru "Step-Up" kit. This kit consists of one deck plate and one set-up spacer.
"Deck Plate Only" kits are also available, for applications where the locating dowel coordinates are already blueprinted.
Note: A prerequisite to use of the Bor-Tru is a perfectly square deck surface, which can be achieved by use of the Blok-Tru.
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