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Magnafluxing,
Shot Peening, and Pressing Rod Bolts
After finishing the rod beams on my own, it was time to turn
the work over to the professionals. To take the rod, cap,
and piston assemblies to the finish line, I turned into a
spectator while Auggie Steinert demonstrated the rod preparation,
reconditioning, and balancing techniques that require experience,
training, and special equipment... that's most of them!
Since I was going with ARP Wave-Loc bolts that have a
radiused shoulder, it's best to put a chamfer on
each rod's bolt hole. Factory bolts have a 90 degree shoulder. |
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The chamfer will allow the bolt head to sit squarely on
the rod. This is
critical for accuracy when torqueing the rod bolts to
specification.
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The magnaflux process is intentionally done after the
parting line is removed from the beam. Maganfluxing involves
applying a magnetic field to the iron rod, placing it
under a UV light, and dusting the rod with iron powder. |
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Cracks will show themselves as purple veins where the
powder interacts with the "broken" electromagnetic
field that is passing through the part. In our case, all
eight rods passed. |
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Now it was time for shot peening then rod beams. Shot
peening compacts the metal surface by bombarding it with
steel balls. |
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Compacting the rod's grain structure is further insurance
to prevent stress cracks from arising. Auggie was careful
not to shot-peen recklessly toward any machined surfaces. |
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This rod was removed halfway through the shot-peening
operation. The portion of the beam toward the big end
has been shot peened. Note the matte finish. All eight
rods were processed with the shot-peener. |
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Using a cap grinder, a minimal amount of material is machined
from the cap AND the rod mating surfaces for all eight
sets. |
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Here's one rod's freshly cut mating surface. |
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Auggie uses a hand file to carefully deburr any sharp
edges left from the cap grinder operation. Again, this
is performed on all eight rod and cap sets. |
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After applying some lube to the rod bolts and the rod
bolt holes, the new ARP Wave-Loc's are pressed into position. |
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By torqueing the nuts to 50 lbs, loosening, then retorqueing
to 50 lbs. again, the caps are secured to all eight rods
confidently. |
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A hand file across the fastened rod and cap assembly removes
any burrs that may cut into fellow rods/caps when the
parts are stacked. |
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 (Grinding
& Honing, Balancing, and Pressing Pin)
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