Church-Built by Churchfield Racing
Church's tips for 2019...
The Church Built Notebook:
Starting with the Body...
an Axle End...
Remove a pilot bushing...
Remove a pilot bearing
(3/2/19)Ok here is a tip you might be
interested in. I know, these tips are not really fabrication, but in the grand
scheme of racing, anything you do to prepare a racecar, or upgrade, or repair,
you will need to apply some
form of fabrication. In this case we fabricate
a tool to remove a pilot bushing. This should also work with "bearings", but
if the bearing is really torn up, this removal tip is not going to work for
you. Our simple
tool saves us a trip to Walmart and about 25 bucks. For a
once-in-a-while tool...yeah I can do that.
At the rear of your engine's crankshaft there
should be a pilot shaft bushing inserted to maintain proper driveline to
engine relationship. The pilot bushing is present so the transmission input
shaft maintains proper
alignment with the crank. The bushing must be
inserted properly. That is, there is a stop on the inside of the crank that is
machined to a proper depth. The bushing should be inserted to this stop (or
f I may
let me explain why. The rear main bearing that supports the crankshaft is
known as the "thrust bearing". This bearing actually is designed to move a
short (few thousands) distance to properly load the crankshaft under engine
stress. These bearings are designed to take axial loads when forces are
applied. Such forces include a small movement "back and forth" of your
ctankshaft during rev up and down. Hydraulic forces that we cannot control
will "thrust" the crank forward and backward under normal operation. In a drag
car for example, the amazing thrust placed on the crankshaft during "go
green", is beyond your imagination. Granted there are several ways to un-load
these forces, but your engine oil system is the first element involved. The
same hydraulic pressure that causes your crankshaft to "float" above these
bearings, is required in order to protect the "thrust bearing" al the rear of
your engine block.
Now that we are
beyond "thrust bearings 101", we can continue. For those with big dollars, you
can apply the Perkins system to your race engine. This adapter protects the
crank in a way that allows the
pilot shaft to slide in and out as
the crank moves rearward under acceleration. For the rest of us in Street
Stock, we generally choose a "brass bushing" or a "roller bearing" type
alignment, but too
many of us do not insert the bearing to proper
depth. This is where we make our mistake...not allowing the crank to
move rearward without binding to the pilot shaft, we are damaging the "pilot
pilot shaft and thrust bearing"...which leads to engine
repairs, and transmission repairs. I won't mention possible clutch damage.
Please understand, you guys running automatics, this is not an issue, but
must understand how important the crankshaft thrust bearing is, no matter what
driveline you apply power too!!
So, the best way to check your
installation...pull back your bell housing from the engine. Lay a ruler across
the face of the bell housing and check the depth of the pilot shaft. That is,
measure from the ruler edge to the face of the pilot shaft. Now measure the
distance the crankshaft protrudes beyond the "bell" face of the block. You now
have two numbers, subtract. Now measure the depth your pilot bearing is
inserted into the block. Now measure the length of the pilot shaft from face
to clutch pilot gear. Doing the math as shown here, you should have a deficite
as defined by your crankshaft supplier. That deficite is the amount your
crankshaft will move rearward without binding hard on the pilot clutch gear.
You should never allow the pilot to "push hard" on the pilot gear...for any
reason, this is bad for your crankshaft. Remember...this movement is thousands
of an inch, maybe .003 at maximum, but if the crank is not allowed to move,
the rear main bearing will not live very long.
The tool we fabricated is simple to make on your lathe. Take a 3/4 bar stock
of solid mild steel and turn down the bar to the diameter of your pilot shaft,
less a few thousands to
allow the tool to slide in and out of the
bushing like a piston. Now take any lubricating grease, not your expensive
stuff, and fill the cavity of your crankshaft with grease. Go ahead
the entire cavity behind the bearing. Now push the tool into the pilot bearing
and pump like a piston. You may have to add some grease while the bearing is
moving out, until
the bearing is removable by hand.
simply created a hand pump. Very much like the "grease sleeve" tool that you
can buy on eBAY that allows you to use your grease gun like a pump. These
tools work, but
they are a ball-buster to use. You have to hold the
grease gun, push the handle on the gun and keep the tool in place hoping it
does not pop out before it pushes the bushing
out far enough to grab
with a screw driver...very awkward. Hydraulic pistons work but they must fit
If you want one of these tools made for you...contact us.
Give us the dimension of your pilot shaft and Gary will turn one on our lathe.
The material and labor is about 25.00
to do this for you. Takes
about 20 minutes and saves you hundreds of dollars in aggrevation.
that is how you remove your polit bearing. BTW: Did I mention, you should drop
your pan and check the "thrust bearing" in your engine, if you see any wear on
brass bushing. The pilot shaft will not show much wear, but the
brass bushing will tell the tale. Don't destroy a good engine over a 15.00
Bleed the Hydraulic Systems: (3/12/19)
There is a very
nice tool that you can buy to help you "bleed" your racecar brakes and that
pesky clutch system. The clutch is probably the least desirable hydraulic
system on your racecar.
First, it sits high in the car, almost level with
just slightly below your master cylinder. While some racers still use the
"slave" to manage a mechanical clutch, the proper way is to use a hydrauluc
system such as RAM, Tilton or Quater Master. The ultimate system is a
Bert transmission and you eliminate clutch issues, but we are not all
privledged to use specialty transmissions in our racecar, so we must apply a
single or triple disk clutch using a throw-out bearing. These systems are easy to install
and most all after market bell housings accept the hardware. The triple disk
clutch system eliminates the use of a heavy "flywheel",
they are more reliable and
less likely damaged from track debris. The problem is bleeding these units.
They should be bench bleed prior to installation, but
if you have a blown line and you loose your hyrdaulics,
you must repair and
re-bleed the system. Use a "vacuum bleeder" to do the job. It will be
far easier at the track than attempting to bleed the system by hand.
There are a
lot of these units on the market, but for 20 bucks, the Harbor Freight
"Pittsburgh" (60770) tool works fine. You do not have to spend a lot of money
on one of these tools. To use...plumb the tool as shown in the illustration.
The "cup" should always be in-between the "hand pump" and the system you are
bleeding. Attach the proper tubing "adapter" to the "bleeder" (brake or
clutch), now "top-off" the master cylinder resevoir. Open the bleeder and
pump the tool handle, the vaccum gauge will inform you of system charge and
the tubing should deliver hydraulic fluid from the "clutch (or brake) system"
to the clear plastic "cup".
Note: While these tools are called "vaccum bleeders", essentially they are
a HAND-PUMP that pulls fluid from the resevoir through the entire system.
This works far better than conventional hyrdaulic bleeding. If you have a
"bias" brake adjustment, you cannot bleed front-rear brakes properly, they
are separate circuits, but the bias bar functions with both master cylinders.
Keep an eye on the resevoir and make sure you maintain at least 1/2 the
resevoir during the operation. When you are satisfied, close the bleeder and
"top-off" fluid again. One more tip...if you are using this system to do
brakes, first you should close the calipar piston completely. This clears the
"bubble void" that remains between the bleeder and the piston.
Body Hanging Tips: (2/22/19) There
was a very good article written by Jeff Huneycutt and published on Circle
Track website back in April 2015. Jeff is well known for his highly
opinionated articles that guide racers in the proper
reading the article I began to hang our 2019 Pro Stock body. I decided not to
write an entire article, but instead add my opinions, tips, ideas and basic
simplestic-expertise to the
Hanging an aluminim body -- create a template -- transfer to aluminum
sheet -- bend, fold and bead roll -- mount to chassis -- tab "A" meets tab
"B", now rivet them together -- repeat and repeat!!
have posted the article here on the website. Simply click here
and the .PDF Acrobat file will download for you.
You may need the latest Acrobat Reader. The article is not complete, and
neither is the
car at this point, but the original article by Mr.
Huneycutt is. Afterall that is what you came for...