AUGUST 2020 | ENGINEBUILDERmag.com 39
as they could do it.”
Many suppliers will sell a balanced rotating
assembly, but they are typically weight-matched
at the warehouse and boxed up. But because
Scat is a little unique in that they manufacture
the heart of the rotating assembly – the
crankshaft – they don’t need to overcompensate
on the counterweights and can more closely
match the bobweights.
“ ere’s a bit of bene t, cost-wise,” says
Lieb. “First o , we don’t charge the same that
you would in the job shop or machine shop
for balancing. What the shops that buy from
us do is list each part individually and include
a balancing charge of what it would cost to do
it in their shop, even though they never turned
the power on. We perform a service for the
customer by taking on that responsibility, and
we’re in a di erent position to do that than the
customer.”
Lieb says they have ve balancers that
they run 10 hours a day. “If you went out on
the shop this morning after they pulled the
parts, each one of our machines handles eight
assemblies a day, so there are 40 or 50 jobs that
they’re doing.”
One of the things that Lieb alludes to that
makes a lot of sense is how you buy parts for
your rotating assembly can make the balancing
job a lot more di cult if they are not weight-
matched. When you buy pistons, from your
supplier A, you may get four pistons or eight,
and then you’re stuck with whatever is in that
box. One piston could be a lot lighter than
the other. But when the supplier has weight
matched the parts, they got a full shelf to choose
the ones that are the closest to each other in
weight.
“When we make a crankshaft, the problem
we have is we don’t know where it’s going to
go,” says Lieb. “We have to make the crank
heavy if we don’t know what components you’re
going to use. If you’re matching parts to a
generic crankshaft, the balancing job will be a
nightmare. In our shop, every part number has a
work order, which gives the people on the shop
oor absolute direction of what has to be done.”
According to Lieb, they know how much to
lighten the crank because it is all spelled out for
the operator on the shop oor. “In some cases,with someone using a 6 ̋ rod, we may actually
balance the 5.7 ̋ connecting rod counterweight
because it’s lighter, and we don’t have to drill a
bunch of holes. From there, if the crank is still
too heavy, we stick it in the lathe and turn the
counterweight down and put a couple of holes
in it just to ne-tune it for the balance.”
A balance shop may not necessarily have a
big lathe to turn the crankshaft counterweights
and may end up making the thing look like
Swiss cheese. “Of course, they will destroy the
counterweight in the process,” says Lieb. “You
can take the weight o , but to put it back on is
expensive.”
Lieb says they have a lot of options that
most builders just don’t have. “As I said earlier,
when a customer buys that box, we’re taking
responsibility for everything in there and doing
the job as best we can... Again, to meet his
expectations.”
While buying a pre-balanced rotating
assembly may seem like the easy way out, it
can free up time for other things in the engine
building process and allow you to tackle more
jobs than before.
Some shops charge as much as $400-$500
to balance a V8 rotating assembly, but Lieb says
because of their advantages as a manufacturer,
they only charge $120. Even if you add on a
balancing charge, you will still come out ahead.
A pre-balanced rotating assembly may not be
for every shop, depending on your speci c
situation, but it is good to have a combo meal
option when you need it.
Is any one else craving a burger? EBWe have to make the crank
heavy if we don’t know what
components you’re going to
use. If you’re matching parts
to a generic crankshaft,
the balancing job will be a
nightmare. In our shop, every
part number has a work order,
which gives the people on the
shop fl oor absolute direction of
what has to be done.
36-39 eb.aug20 Crankshafts.indd 39 8/7/20 10:02 AM
Naresh Jariwala