Church-Built by Churchfield Racing

Church's tips for 2019...

 

The Church Built Notebook:
Index -
Starting with the Body...
Vaccum Bleeder...
Replace an Axle End...
Remove a pilot bushing...

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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 step).
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 bearing,
 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
 you 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
 fill 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.
 You 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 properly.
 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.
 Anyway, 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 that
 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 part!!!


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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 or 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.

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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
direction. After 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
article.
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!!

I 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...
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