New Engine Prep (Animal Senior & Junior Classes)

By following along with this page I will walk you through the preparation and the steps that goes into making your new F.C.H.P. engine run up to it's full potential and become a winner.  Rebuilds are done in the same manner except machine work already performed by other shops will only be checked to ensure it meets the current sanctioning body rules and the standards set by F.C.H.P.  Please realize some of the steps and/or processes may be skipped or not detailed in the description below due to some of the items/steps/processes are not "public knowledge" and may be what we use to set F.C.H.P. apart from the rest.  However, I will try to be as detailed as possible so you get an idea of how much work goes into "creating" your new masterpeice.

Animal Engines

• First thing that is done to all new engines as soon as they come out of the red box is to check the internal clearances to make sure they are all in line and nothing is missing from the factory.
 
• During the initial inspection, all the "as-cast" items from the factory that can not be machined or altered are inspected and checked to ensure they are legal.  Once all the "as-cast" areas are checked we move on.
 
• Ok, all the factory specs are verified, all the parts are as they should be and up to the level required to make a "good" engine, now we do the WORK that makes it a REAL race engine.
 
• First we build the bottom end.  Briggs has now given us a very strong bottom end to work with.  First we put together the sidecover & block with our dummy shaft installed through the main bearings.  Then this assembly is chucked up in our milling and boring fixture that is a one of a kind fixture that ensures the block is align bored, head surface, and motor mount surface ALL decked/bored inline with the crankshaft centerline.  By doing this ALL internal and external mis-alignment from the factory is corrected and ensures the bottom end is all as true as it can be to obtain all the HP that is possible by reducing as much mis-alignment friction as possible.  In this fixture the block is align bored, decked, and mount surface decked.
 
• After everything on the bottom end is verified or machined true, the bottom end is assembled.  We have built Animals from the very beginning when they were available so we know what internal clearances work and don't work for reliability and horsepower.  We have a special process we do to the rings that allow us to still obtain ring seal and reduce friction.  I know by seeing other builders motors come through here, not many are doing this.  And we verify ring seal on our dyno with a blow-by gauge.  Once the rings have been gapped, trued, and setup for the class being run, the bottom end is assembled.
 
• Now, with the bottom end assembled, we move to the head & carb.  Now, most guys just lap the valves in the factory seats, throw an alky kit in the carb and call the topend done..... WRONG!!!!  Not if you plan on getting the most HP out of each engine.  Others will tell you there is not anything you can really do to the head or carb and stay legal.... WRONG!!!!
 
• Let's go over the head first.  First thing we do is pull the factory seats and install seats that seal better to the valves, flow better than the factory seats, and don't beat grooves into the valves.  The factory exhaust seat is so hard it literally beats a ring into the face of the exhaust valve.  Not every shop is setup to do this.  It takes custom precision machinery and tools to perform this job.  It is even more complex than replacing seats on the Raptor engine.  It takes time to do it right, and one simple slipup will ruin the head.
 
• Once the seats are installed they are cut and trued with precision seat grinding equipment to ensure maximum valve seal.
 
• Next the head is checked on the Superflow SF-60 to ensure the head flows as it should.  And there are a few tricks we do in in the head to pick up flow that can not be listed here.
 
• The valve spring setup comes next.  The class in which the motor will be run dictates how the springs will be setup.  Yes, a motor can be setup to run in different classes, but to take FULL advantage of the horsepower available the springs must be setup for the class, track, and weight the motor will actually be used for.  We have a wide variety of springs available to use for us to "customize" a spring selection for your motor.  Once the head is done it's bolted to the block and the indicators are bolted on to the head to roll the cam/rockers/valves through and ensure we are at the MAXIMUM legal limit set by WKA and not giving up even .001" in valve lift.  There are shops that tell you this does not make a difference or there is no way to adjust this... and they are DEAD WRONG!!
 
• The carb is next in line for the "personal" touch.  Since by the rules you are not supposed to do any machining on the carb, I will not post here what we do, but I will say our carbs flow a lot of air :-).  The fuel metering jets and nozzles are reamed (not drilled) and the size is determined by the class to be run and how the carbs fuel signal shows on the flowbench.  A LOT of on track and dyno testing is used to determine the proper hole size for the class and type of racing.   Once the carb is assembled it goes to the flowbench for several test.  Not only is each carb checked for max air flow at full throttle they are also run through the full fuel throttle range to check the fuel curve.  The carb work alone can be as little as 30 minutes if it all falls in line the first time or as much as 3 hours.  Basically there is not one area we do not "adjust" or "work" in the stock Walbro carb.
 
• The proper header is installed for the most performance for the class and track being run.  Once the header is installed all the sheetmetal is installed and it's headed off to the break-in stand.
 
• On the dyno the engine is run at varying loads and heat cycles which will seat the rings and is monitored to see when the proper leak-down is achieved.  Once the proper leak-down and crank case pressure is established the dyno runs start.  Generally several pulls are made to fine tune the carb.  Once it comes off the dyno the engine is ready to bolt on the kart and race, no break-in time needed.