Keeping Those Evo and Twin Cams on the Road
Last year saw Wiseco follow-up the launch of
its top-of-the-line ArmorX and ArmorFit Black
Edition pistons with their Tracker Series V-
twin pistons - an advanced feature, high
performance product, but one that is
available at "a more affordable price" thanks
to manufacturing technology developments
at their Mentor, Ohio factory.
Available in various overbore and compression ratio
options, development on the new Tracker Series
began at the end of 2017, with manufacturing
starting in the spring of 2019.
"We needed to be realistic," says Wiseco. "If we
were going to achieve a price point that made sense
for a performance upgrade replacement piston
program for Evo engines from 1984 and up and Twin
Cams from 1999 and up, and the Sportsters from
that 30 plus year arc, in the M-8 era and beyond,
then we needed to find a balance between
performance and price.
"We needed to make contemporary production and
performance values affordable. Our engineers
succeeded by blending classic piston manufacturing
processes with state-of-the-art techniques." That
new technique is what is known as near-net shape
forging.
"The major challenge in this project was to decrease
the end cost to the consumer. That's where near-net
shape forging came into play. It is a technique where
we form most of the geometry on the top of the
piston - it is built-in at the forging process.
"The crown and the valve pockets are forged into the
part. Those areas are machined in most other piston
manufacturing processes. Conventionally you forge
an aluminum slug, then have to machine all of that
metal away to get the valve pockets and the crown
in order to achieve whatever specific design you're
trying to hit, or the specific compression ratio you are
looking for.
"At Wiseco we are forging those features directly
into the piston. When our near-net forged pistons
come off the presses they need less finishing and
machining as they go through the factory. The whole
crown area comes right off the press and looks like
a finished product. It's a really unique way to form a
piston."
The company says that upon inspection, "it doesn't
take a metallurgist to realize that different processes
were utilized during construction of a Tracker Series
piston. The mirror-like sheen of the machined area is
offset by the textured surface of the forged aluminum
left during near-net shape forging.
"Those visual differences are also noticeable on the
underside of the piston. One of the upsides to nearnet
shape forging is that it gives the piston added
strength, since the features are being forged in. This
process allows the aluminum to flow through the
features of the piston with an aligned grain flow. That
grain flow condenses the aluminum for better fatigue
strength and overall durability.
"The other upside, of course, is the cost compared to
the combined forging and machining needed for
piston ranges like our Black Edition series and
ArmorPlating featured pistons. Those cost savings
trickle directly down to the consumer - a Tracker
Series piston is roughly $80 - $100 (at retail value)
less than the higher price point offerings."
Aside from outstanding durability and a very
attractive price point, Wiseco says that the Tracker
EVO TRACKER PISTON OPTIONS
Application C/R C/R W/ Bore Size Oversize Stroke Dome
SE Heads (in.) (in.) (in.) Volume
1340 EVO Flat Top 8.5:1 9.5:1 3.498 STD 4.250 -1.5cc
1340 EVO Flat Top 8.5:1 9.5:1 3.508 0.010 4.250 -1.5cc
1340 EVO Flat Top 8.5:1 9.5:1 3.518 0.020 4.250 -1.5cc
1340 EVO Flat Top 8.5:1 9.5:1 3.528 0.030 4.250 -1.5cc
1340 EVO Domed 10.0:1 - 3.498 STD 4.250 +12.9cc
1340 EVO Domed 10.0:1 - 3.508 0.010 4.250 +12.9cc
1340 EVO Domed 10.0:1 - 3.518 0.020 4.250 +12.9cc
1340 EVO Domed 10.0:1 - 3.528 0.030 4.250 +12.9cc
Series piston "has a secret weapon in the
performance department. ArmorGlide is our solution
to reducing friction and is applied to the skirt."
The forgings for Tracker Series pistons have crown
features designed into them, so when the piston is
forged, valve pockets and any other crown designs
are already complete, requiring no additional
machining.
The valve pockets show a forged aluminum finish
because they required no machining. Other features,
such as the oil drain backs, are also forged into the
part instead of machined, to keep the cost down.
ArmorGlide skirt coating is a proprietary dry-film
lubricant designed to reduce friction and operation
noise for the life of the piston. "Wiseco spared no
expense in the Tracker Series piston kit," the
company says. "V-twin riders are getting nearly the
same level of features, but with less cost on our side,
so we can pass the savings on to the end user."
Premium rings are supplied with each piston, with
Wiseco using a new high-tension 3 mm oil ring set
in Twin Cam applications.
"That is really important in that market because we
can control oil consumption in the engine. The
premium rings, wrist pin and circlips are also found
in our Sportster and EVO (Evolution) applications. It
pays that we know our audience. We found that the
majority of V-twin owners wanted to not only
increase the displacement of their engine, but also
raise compression. The Tracker Series pistons
accomplish both.
"One of our most popular kits for the Twin Cam
engine takes it from the stock 96-cubic inch to the
103-cubic inch size. You can increase the stock bore
without having to bore the crankcases. Simply bore
the cylinder, install the piston, get a bump in
compression, and you're at 103 cubic inches.
"Not only that, but we also offer a 106-cubic inch
piston option for the Harley-Davidson Twin Cam
engine."
If you have an EVO generation engine, then "thanks
to the Tracker piston, you have the choice between a
flat top or a domed piston. The flat top piston has an
8.5:1 compression ratio, which is for a standard
application. The domed piston is the higher
performance offering with a beefy 10:1 ratio."
Wiseco's number one selling piston in the V-twin
market is the Sportster big bore piston kit that takes
the stock 883 cc engine up to 1200 cc. "That's a lot
of power for a small-scale package - upsizing offers
a nice increase in performance. The customer has the
choice of stepping up to a slightly higher 9.5:1
compression ratio or going 'whole hog' with the 10:1
ratio. The latter option is preferred in the burgeoning
Flat Track series and with Hooligan bike builders and
tuners."
Wiseco also offers gasket kits (available separately)
for each application for the complete top end rebuild
solution.
WISECO PISTON INC.
Mentor, Ohio, USA
Tel: 440 951 6600
[email protected]
www.wiseco.com
PARTS AND ACCESSORIES
30 AMERICAN MOTORCYCLE DEALER - SEPTEMBER 2020