Weird Science
By JD Boyd
Always looking for every little tweak he can find
for the upcoming season of the CMDRA, I recently accompanied Mick Cawthorn and
his 175 c.i. PRP motor for a sweet metal massage.
With
the motor tied down in the back, we headed out to see Ron Derry at Custom
Balancing & Blueprinting. Ron has been around for many moons and was a
wealth of information. Being strictly a pilot with no mechanical talent what so
ever, it took a few go-rounds for me to catch on but I think this is how it goes.
All manufactured metals contain some amount of
residual/ thermal stress that effects and wears each part in a different way.
Residual internal stress causes your metal parts to change shape over time.
This is what causes so many of the uneven wear marks found on camshafts and so
on. This uneven wear generally hurts the motor’s bottom line.
The main benefits of Stress Relief are said to be
more horsepower, faster times, better throttle response, and greater
durability. In the past Thermal stress relief has been used but it is
expensive, can take days to complete the entire heating and cooling process,
and isn’t 100% effective.
The system used by Custom Balancing is vibrational
stress relief. This system uses non-destructive sub-harmonic vibrations. Ron
has built this special steel table that is vibrated by an electric motor
mounted below. There are numerous threaded holes covering the top so he can
bolt down a number of parts at the same time. It is said that you can do an
entire motor in one piece but we took the heads off and bolted them separately
to the table. He also guarantees us that it will have no effect on the
electrics.
Once all is secured to the table he shakes the whole
deal together. A transducer mounted on the table, feeds the info to a machine
where Ron reads it off in graph form. First he locates the highest frequency of
the part involved. He explains to me that when you see the lady singing and
breaks the glass; that is because she is singing at the same frequency of the
glass. Next he tells me that if he left the table at the highest frequency of
the part/s involved it would eventually crack them.
He is not so much interested in the highest
frequency but more where it is located. Once he has it plotted, he sets up the
table to massage the parts for a ½ hour. After this he plots the graph again to
find the difference. Once the graph peaks in the same spot, your part has been
stress relieved, it is just that simple.
Mick and the boys are off to Phoenix and Vegas in
April, hoping to cut some time off the trip down the strip. The first chance we
will get to see any action north of the 49th is the CMDRA opener at
the end of May in Mission, B.C. I can’t wait to be surrounded by that deafening
roar and subtle fragrance that only burning nitrous can give you. See ya there.
CCRyder
You
can contact Ron at Custom Balancing & Blueprinting, 403-277-0505