I Apologize Again For Getting This Out So Late - GR

GR-RRR 8’R
Wichita Pontiac Club’s
Monthly
Publication
July 2013
Indy Pace Cars – All of them
Piece of auto history
http://indymotorspeedway.com/v1/500pace.htm#TOP
These are pretty interesting and worth a look! But not one
GTO. How disappointing.
I apologize again for getting this out so late. A dear friend of
ours, Eric Schottler, passed away on Monday, July 8th from
cancer so it’s been a pretty crazy month so far. Please see page
3 for a tribute to him and his life.
Meeting at the zoo, had a great turn out. Discussed items of interest
for our POCI Convention in 2014.
 T-shirts will be ready to take to Dayton
 Need to get article of things to do in Wichita to be submitted to
POCI
— Restaurants, museums, entertainment (Bill Burton will
cover this)
 Design for trophies was discusses. Dan Jones will get art work
and check on prices
 Club is on schedule for convention. Need to work on sponsorship
funds.
Got one renewal, Joan Kennedy.
No July meeting (I, Deanna, got permission for a short August
newsletter)
Upcoming Meetings:
August 18th—Tim Mahoney
September TBA—Cap and Robin Proffitt
October 19—Poker Run
Schottler, Eric, 56, former Boeing Toolmaker and Schottler Engine
Service Owner, passed away Monday, July 8, 2013 from cancer. He
was preceded in death by his father, Glenn Schottler and mother,
Wanda Smith. He is survived by his wife, Deanna Houston Schottler;
brothers, Kirk (Joyce) Schottler and Mark (Bev) Schottler; nieces,
Marcie and Megan and nephew, Marshall. A memorial service was
held at 3:00 p.m., Friday, July 12, 2013, at DeVorss Flanagan-Hunt
Chapel. A memorial has been established with Wounded Warrior
Project, PO Box 758517, Topeka, KS 66675. For the service, in
memory of Eric, he asked everyone to wear your favorite car or
shooting sports t-shirt to help celebrate his life. Condolences may be
offered at www.devorssflanaganhunt.com
We lost a long time member and supporter of the club. He had a love
for Pontiacs, racing, and endless stories about anything and
everything. Another
of his favorite pastimes was competitive shooting matches
and he shared that
love with his wife
Deanna Schottler. He
will be missed by
many.
Eric and his father Glenn at Schottler Engine
Service
How to Choose the Right Driveshaft - (Submitted by Art Meadows)
In the excerpts I will present from this article in Hotrod & Restoration Magazine, I will steer clear of the
more exotic materials and concentrate more on setup and balance of those more normal to our collector
cars. For those interested in additional technical detail the entire article is available at http://
www.hotrodandrestoration.com/engine-drivetrain/how-to-choose-the-right-driveshaft/attachment/markwilliams/ Posted By Mike Mavrigian, November 19, 2012 in Engine & Drivetrain, How-To-Articles
Driveshafts are often treated as a necessary evil in order to finish a build. There’s much more to driveshaft considerations than making one physically fit and painting, powdercoating or polishing it for the
sake of appearance. In this overview, I’ll touch on what you need to consider in order to make an informed choice. After investing a lot of money and countless hours of blood, sweat and tears to create a
masterpiece, it doesn’t make any sense to slap in just any piece of tubing that merely completes the connection from the transmission to the final drive, only to discover that you have a vibration or, worse, experience a catastrophic failure that destroys the belly of the vehicle.
Choosing Materials
While mild steel has been the norm seemingly forever, today’s offerings include assemblies that feature
shafts made from mild steel, aluminum, chromoly and carbon fiber.
Mild steel shafts made from seamless drawn-over-mandrel (DOM) tubing remain popular and are perfectly applicable to any restoration/custom/street rod target. This type of construction is the least expensive, averaging in the range of about $150–300.
Aluminum shafts, by the nature of the alloy, offer lighter weight, which is a factor in competition applications. The nice thing about aluminum shafts for street rod and custom builds is the ability to perform a full
polish of the shaft for the sake of appearance. Aluminum shafts are typically made from 6061-T6 DOM,
with aluminum tube yokes. Prices range in the $300–400 neighborhood.
Yokes are traditionally MIG-welded to the shafts. Mark Williams Enterprises has introduced its “AccuBond” process that adhesive-bonds the yokes to the shaft with a patented process that’s 50-percent
stronger than welding, according to the company, and is similar to the method used for certain aerospace
applications.
Chromoly is a bit lighter in weight compared to mild steel, with extra strength (usually made from 4130
tubing) and is a good choice for high-horsepower applications in the 1,000-plus horsepower range. Highperformance chromoly shafts are generally rated for around 2,800 lbs./ft. of torque. Prices are in the $400
range.
Carbon fiber driveshafts offer substantial weight savings as compared to metal shafts (typically a 50percent-plus weight reduction). More information on these is available in the complete article.
In short, there’s nothing wrong with using a traditional mild steel shaft, but, depending on the appearance
you want, the ponies you plan to pump out, the size of your budget and the application (street, race or
street/race), you have choices. Of course, if you’re performing a true restoration, a mild-steel-as-original
will likely be your only choice.
Naturally, as with most component choices involved in a street rod, resto-mod or custom build, the bragging-rights factor can also influence your buying decision.
It’s important to note that for transmissions that feature an overdrive, it’s highly recommended to use a
lighter-weight shaft material, such as aluminum or carbon fiber, because the overdrive portion is much
more sensitive to frequency inputs created by U-joint operating angles. A lighter-weight shaft reduces the
energy that’s fed back to the transmission, transferring less harmonics.
Achieving Proper Balance
The driveshaft is subject to radial forces (and a degree of axial forces due to shaft angle) during operation, so
the shaft must be properly balanced. If you’re building a shaft, be sure to have the shaft balanced once it’s
assembled. When a new aftermarket shaft is purchased, it should already be balanced by the manufacturer.
Even if the shaft has minimal imbalance, a vibration at a certain speed range can often fool you into thinking
that you have a driveline angle problem, so eliminate the balance variable at the very start.
If the driveshaft features excessive runout, it won’t be possible to achieve balance. Check for proper centering of the front and rear yokes (yoke-to-shaft). The yokes may have been slightly off-center when welded to
the shaft.
Granted, you could experiment by securing weights to the shaft with worm-drive clamps and road testing,
but this is a hit-or-miss approach that could take days or even weeks to finalize. Save time and aggravation
by paying a driveline shop to balance the shaft.
As Denny Bringhurst of Denny’s Driveshaft in Kenmore, New York, noted, most local driveshaft shops
are accustomed to building and servicing driveshafts for heavy equipment (dump trucks, etc.). Their driveshaft balancers may be designed to only spin the shaft at around 1,500 rpm. That may be OK for a bonestock grocery-getter, but for a high-dollar, high-horsepower setup, this will not work. Shaft balance may look
fine on an old stroke-light 1,500-rpm balancer, but when the shaft is installed in a 500-plus horsepower application, you may experience a driveline vibration that’ll have you scratching your head (since you assume
the shaft is OK because you had it “balanced”). The driveshaft for a high-performance application should be
balanced at the anticipated engine speed (for example, 6,000 rpm). Spend the dough for a quality performance driveshaft that’s built properly and balanced accordingly.
Determining Driveshaft Length & Runout
Here’s a very simplified method for determining shaft length, provided by the folks at Inland Empire
Driveline Service of Corona, California. With the vehicle at normal ride height (suspension loaded, don’t
support the vehicle on stands with the wheels hanging), and with the shaft disconnected from the pinion
yoke, push the shaft forward until it bottoms out into the transmission. There should be enough clearance to
drop the rear shaft U-joint past the rear yoke by hand. As much as 3⁄8-inch clearance is acceptable. If you
have more clearance, the shaft is too short. If you can’t easily drop the rear of the shaft free of the pinion
yoke by hand, the shaft is too long. Either condition will cause vibrations. If the shaft length is modified,
make sure that it’s re-balanced.
With the vehicle on a lift, check shaft runout at three locations: at the center of the shaft length and within 2
inches of each weld (front and rear). The official (Spicer) suggested tolerance is 0.010 inches maximum allowable runout at the ends and 0.015 inches maximum allowable runout at the shaft center. In reality, you
should shoot for tighter tolerances of 0.008 inches at the ends and 0.010 inches at the center. If runout is excessive, your best bet is to replace it with a new shaft tube.
Note: If runout is found at the pinion end, remove the shaft from the yoke, rotate the shaft 180 degrees and
reinstall, and perform another runout check. As noted by Inland Empire Driveline Service, driveshaft runout
should either improve or worsen, since splined yokes can be off-center by as much as 0.005 inches when
new, and the retaining tabs of the yoke are subject to wear over time and may loosen. To correct this condition, replace the worn or off-center pinion yoke or pinion flange.
With regard to shaft length, it’s important to note that length is a factor in determining tube diameter. Basically, the longer the shaft, the bigger the diameter. For example, a 3-inch diameter shaft may work for a
Camaro application, while a longer shaft for an El Camino might require a 3-1⁄2-inch diameter. With regard
to diameter, ask your high-performance shaft supplier for their recommendation.
Perfecting Driveshaft Angle & Phasing
The angle of the front and rear U-joints must be equal (ideally within 1 degree).
U-joints are designed to individually handle an angle of 1–3 degrees (2 degrees is considered optimal for
street use). If the U-joints centerlines are too severely angled, the U-joints will operate at different velocities, which will create a vibrational problem.
You cannot measure shaft or joint angles with the suspension unloaded. The vehicle must be at normal ride
height and with the suspension compressed (as normally loaded). With the vehicle on a drive-on hoist,
measure the angle of the engine/transmission and the angle of the pinion.
Using an inclinometer or a digital level (Anglemaster, see sidebar on page 28), check the installed angle of
the engine at a machined surface such as the starter mounting boss or the block’s oil pan rail, if the oil pan
is removed. Check pinion angle at the machined surface where the U-bolt holes are drilled. These two angles should be equal and opposite, for instance, engine angle down and pinion angle up.
Next, check the angle of the installed driveshaft tube. Subtract the shaft tube angle. Ideally, the resulting
joint angle should be 3 degrees or less. For example, if the transmission output shaft is 3 degrees down and
the pinion angle is 3 degrees up and the driveshaft angle is 2 degrees, then 3-2=1 degree joint angle at eac
Transmission output shaft-to-driveshaft and driveshaft-to-pinion shaft angles are compared to determine
joint angles.
Cautions
If you’ve changed the angle of the transmission output shaft (due to fitting to a custom build, using a different transmission that forces the angle to change due to fit/clearance to the body, etc.), don’t focus your
efforts only on the driveline. If the transmission now angles further downward, for instance, the engine oil
level in the pan will change its surface angle. Depending on if your engine oil pan is front-sump or rearsump, and depending on where the dipstick is located, you can end up with erroneous oil level checks on
the dipstick. In severe cases you might also starve the engine of oil, depending on the sump and oil pump
pickup location. By the same token, if you fiddle with the rear axle pinion angle, you need to verify where
the proper axle lube level needs to be to prevent input shaft bearing damage.
Don’t overtighten the U-bolt nuts at the joint locations. Overtightening can distort the bearing shells, resulting in bearing drag, vibration and bearing failure. Proper torque for 1-1⁄16-inch and 1-1⁄8-inch caps is
14–17 lbs./ft. and 20 lbs./ft. for 1-3⁄16-inch cap diameter, according to Inland Empire Driveline Service. If
you can’t access the nuts with a torque wrench, the company suggests using an approximation by tightening until a new lock washer flattens out, plus an additional 1⁄8-inch turn.
The U-joint bearing caps must fit snugly in the pinion yoke. If there’s a gap between the caps and sides, the
caps are too small. If you find a gap between the caps and base of the yoke bearing seat, the caps are too
large in diameter. Correct cap diameter, once seated in the yoke, should feature no gap whatsoever.
Isolating the Vibration
When chasing a mystery driveline vibration, consider temporarily taking the driveshaft out of
the equation. With the vehicle on a lift, remove the driveshaft. Place a cap/plug at the transmission output and run the engine and transmission. If you still feel a vibration, the driveshaft isn’t
the problem. Suspected areas may include flywheel balance, flexplate imbalance, improperly
installed converter, off-center engine block to transmission mounting or transmission shaft
damage. If the vibration is eliminated with the driveshaft removed, check for driveshaft joint
angles, driveshaft runout and balance.
Don’t ignore the possibility of a vibration being caused by the engine itself. For example, if the
customer purchased an engine kit or cobbled an assembly together, the possibility exists that he
may have an unbalanced rotating assembly, the result of installing a weighted damper and/or
weighted flywheel onto a crank designed for internal balance, or by installing zero-balanced
damper/flywheel onto a crank that requires external balancing. In short, if he self-assembled an
engine without having the crank balanced by a skilled shop, you may be facing another variable
in your search for the cause of the vibration.
Naturally, the wheel/tire assemblies need to be properly balanced. Note that in some cases, certain tires may feature a phenomenon known as radial force variation, where a portion of the tire
construction features an inconsistent construction thickness and/or carcass hardness area that
may not be revealed during a conventional dynamic balancing job. A notable radial force variation problem won’t show up until rolling load is placed on the tire. There’s much more involved
in this subject, but if you suspect this condition, have the tire/wheel packages checked on a road
force machine. (Hunter Engineering Co. and other manufacturers offer this equipment). A
cheap and quick alternative is to try another set of wheels and tires during a test drive. If the
vibration disappears, you’ve isolated the problem to the tire/wheel package.
Eliminating Acceleration/Deceleration Vibration
In some cases, everything is fine except during power transitions, such as hard acceleration or
during deceleration. If you experience a vibration only during acceleration, try adjusting the
pinion angle slightly downward by about 0.5 degrees, which will help to compensate for axle
wrap-up. If vibration is felt only during deceleration, try adjusting the pinion angle slightly upward in an effort to compensate for pinion plunge.
My own experience
The entire process of pinion angle adjustment, on my ’64 GTO, was simplified by the installation of adjustable upper control arms at the rear differential. This was accomplished during a
major drivetrain overhaul at Wilhite Automotive and worked out very well.