by Jon Mikelonis
Introduction
In the world of small block Fords, the choice to go with a
high
performance aftermarket connecting rod isn't as much a decision
about
performance as it is about economies of scale and common sense.
With so many manufacturers offering inexpensive forged I-beam
rods for most Ford motors, the days of spending time preparing
an OEM rod for your 351W or 5.0L block are all but gone. However,
if you are unique enough to cut against the grain and build
something different like a 351C, 400, or an FE motor, then
taking on some old-fashioned rod work can go a long way towards
strengthening the rod beam and reducing reciprocating weight.
While not as common in the street performance or drag racing
scene, the art of preparing an OEM connecting rod is still
alive and well in the circle track arena where local classes
prohibit the use of aftermarket rods.
|
|
Pictured just after tearing down a
Ford 400, here are the subject connecting rods for this
article. |
|
For this article,
I hooked up with Auggie Steinert of Superior Machine in Sparks,
Nevada to prepare, recondition, and balance a set of Ford
400 rods that will be used in an engine build I'll be documenting
for FordMuscle throughout 2008. Auggie was considerate enough
to show me his methods for processing the rods by meeting
up with me at Superior's shop on a couple of Sundays this
Fall. Determined to do all that I could on my own, anything
that didn't take years of experience and machining skill,
I took on myself. Unfortunately, this didn't leave me much
but the task of grinding and polishing the rod beams using
Superior's equipment. When it came time for the special machine
operations, I was there to photograph each step so I could
share them with you here. In addition to the rod work, the
following pictorial sections cover the balancing of the rod
and piston assemblies.
Getting Started
There are a number special machine
shop processes that need to be performed to any OEM rod and
piston assembly before it's ready for engine pre-assembly.
These processes sometimes fall under the label of "Rod
Reconditioning" and "Rod Preparation" although
the procedures and what's included can vary from shop to shop.
For example, one shop's idea of inspecting a rod may be purely
visual as another shop may take the time to Magnaflux.
Furthermore, one shop may use a torch to install a press-fit
wrist pin while another shop may do it the right way using
a Sunnen
Rod Heater that is purpose-built for the task.
While you do not need to know how to "resize the big
end of a connecting rod" or how to operate a "cap
grinder", knowledge of the rod reconditioning process
helps in your communication with and qualification of the
machinist. This can be especially important if you decide
to take on some of your own rod preparation like I did here.
If you do, you'll be working in tandem with the shop. You'll
need to be able to communicate effectively and try your best
to comprehend the industry jargon. Since each shop has their
ways of doing things, it's best to discuss your intentions
with them before you simply have your rods hot-tanked, perform
the beam grinding/polishing at home, and unload the rods to
the first shop you find in the yellow pages.
With that said, here's how I did it working with Superior
Machine. Keep in mind that your local engine builder may have
a slightly different approach.
After delivering all eight piston, rod and cap assemblies,
the pins and rod bolts were pressed out. The rods and
caps were hot tanked. |
|
Using this wide belt sander at Superior's shop, I removed
the parting lines along the beam of each rod. Notice that
I'm removing the parting line parallel to the beam. |
|
|
|
The belt sander makes for some fast results. I was sure
not to cut into the rod itself by only removing the raised
parting line.
|
|
Since most of us do not have a belt sander of this caliber,
the same work can be done at home with a die grinder and
a carbide cutter. |
|
|
|
Following the carbide cutter, I used a cartridge roll
along the beam to begin eliminating the cut marks left
by the belt sander. |
|
This is the rod after finishing up with the cartridge
roll. |
|
|
|
In three stages, I used an angle grinder and these 3M
abrasive discs to work over the beam. |
|
It's best to control the angle grinder so RPM's are not
too high. A common mistake is to get lost shooting for
a high reflective polish. |
|
|
|
The goal is to remove the cut marks still left after the
cartridge roll operation. Once at the polishing stage,
I approached the rod bolt shoulder to deburr any sharp
edges. |
|
Eight rods, two sides each, and a total of five grinding
and polishing operations can make for some time consuming
work. No sense paying a machine shop to do this kind of
work. We need them for their skills not manual labor. |
|
|
|
It's best to take on 2 or 3 rods a day to preserve your
patience and quality control. Since I was a guest at Superior's
shop, I got them all done in about 6 hours. |
|
Here's a shot of a rod after all five operations were
performed. Notice it doesn't glimmer, yet all the cut
marks are removed and there's no sign of a parting line. |
|
|
|
A shot of four rods completed. Take note that I did not
touch the rod balancing pads. To pursue absolute minimum
reciprocating weight, some people choose to eliminate
as much of the pad as possible at this point while still
leaving enough material to balance the rods.
Per Auggie's recommedation and since this was a street
application, I left the pads as insurance for when it
came time to balance each rod and cap assembly. |
|
|
(Mangafluxing,
Shot Peening, Pressing Rod Bolts)
|