Fabrication at Churchfield Racing

Building for 2019...

 

The Fabricator Page:  This is a mish-mash of tips, tricks and FAQ pages that may solve some problems and help you avoid another DNF...
Index:
Starting with the Body...
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 crankshaft "thrust" 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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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...

There is a home improvement product that might interest you...Ram Board. The product is used by home owners who want to protect floors and interior areas while demolition or construction work is on going.
So what can body builders use it for?? Well this is a sturdy "paper" product that can be used as panel templates. Unlike cardboard, Ram Board is easier to work with and comes in a size perfect for body side panels. A roll of
the product is 36 inches by 50 feet. It can be folded on a break, and is sturdy enough to mock up an entire side of your car prior to working with aluminum sheets. Then...when you are ready to cut that aluminum, lay some RAM Board on the garage floor to protect your investment. You can purchase a roll of rosin paper, but the Ram Board is much thicker and it holds shape much better.
Note: If you have a neighbor or a friend in the stainless steel cabinet fabrication business, these people receive their sheets of material from the manufacturer with a similar paper product that is used to separate each sheet of fine stainless when they are delivered on pallet. This paper product is very much like Ram Board, however it is not quit as strong. But, the good thing, it comes in 4 by 10 sheets. If you know where you can find these "disposable" paper sheets, you can build your panels and save a lot of money.
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