PTPA MODIFIED TRACTOR  

NOTE: NEW ROLLOVER PROTECTION RULES FOR 2011

WEIGHT CLASS: 7200 POUNDS

1.  ENGINES:

- ANY CAST IRON OR ALUMINUM 8 CYLINDER AUTOMOTIVE TYPE ENGINE WITH 2 VALVES PER CYLINDER AND NO OVERHEAD CAMS.  CYLINDER HEADS ARE LIMITED TO 1 SPARK PLUG PER CYLINDER.

- A SINGLE STAGE V-12 ALLISON AIRCRAFT ENGINE

ONE BLOWN ENGINE

            MAXIMUM SIZE: BLOWN - 575 CUBIC INCH

            MAXIMUM BLOWER SIZE 8-71 (ROOTS BLOWER ONLY)

BLOWER BELT SHIELD REQUIRED, ALUMINUM BLOWER STUDS ARE MANDATORY AND A BLOWER RESTRAINT IS REQUIRED.

ONE TURBOCHARGED ENGINE

            MAXIMUM SIZE: - 575 CUBIC INCH      

            ENGINE IS LIMITED TO A SINGLE TURBOCHARGER

            TURBOCHARGER MUST BE SHIELDED 360 DEGREES BY .060'' STEEL OR 1/8'' ALUMINUM.

TWO NATURALLY ASPIRATED ENGINES

            NATURALLY ASPIRATED - COMBINED 1100 CU. IN.

            EACH ENGINE IS LIMITED TO CARBURETORS OR MECHANICAL FUEL INJECTION.           

        ONE V-12 ALLISON AIRCRAFT ENGINE

                    ENGINE WILL BE LIMITED TO A SINGLE CARBURETOR SUPERCHARGER MAY HAVE AN SFI TYPE BLANKET OR A STEEL SHIELD. SUPERCHARGER MUST BE SHIELDED AS FOLLOWS: SHIELDING WILL BE THE SAME ON EACH SIDE OF THE SUPERCHARGER.  THE SHIELD WILL START AT THE CENTERLINE AND EXTENT 5 INCHES REARWARD.  NOTCHING WILL BE ALLOWED TO FIT AROUND NECESSARY COMPONENTS.  THE SHIELD WILL RUN 8 INCHES FORWARD OF THE CENTER LINE.  THE FRONT EDGE OF THE SHIELD WILL HAVE A ROLLED LIP THAT EXTENDS INWARD (1) INCH AND BE AT A 90 DEGREE ANGLE.  THE SHIELD MUST BE CONSTRUCTED OF 3/8 STEEL AND BE         BOLTED EVERY (2) INCHES.  THE SHIELD MUST START AT THE BOTTOM OF THE HOUSING AND GO UP AND OVER TOP AND DOWN THE OPPOSITE SIDE.

          TURBINE ENGINE LIMITATIONS

            HORSEPOWER RATING - ANY COMBINATION OF TURBINE ENGINE OR ENGINES TOTALING 1,600 HORSEPOWER AS RATED BY MILITARY.  NO WATER OR ALCOHOL INJECTION PERMITTED.  

            TURBINE SAFETY AND SHIELDING 

            1.  A TURBINE ENGINE THAT EXCEEDS 8000 RPMS ON THE OUTPUT SHAFT WILL NOT USE A CLUTCH/FLYWHEEL ASSEMBLY TO AN AUTOMATIC     TRANSMISSION.

            2.  EXHAUST PIPE MUST EXTEND A MINIMUM OF SIX INCHES ABOVE THE BEND OF THE PIPE.

            3.  NO TURBINE WILL OPERATE BEYOND MILITARY SPECS, TEMPERATURE AND RPM LIMITS.

            4.  ALL AIR INTAKES SHALL BE SCREENED WITH METAL SCREEN HAVING 3/16 INCH OR SMALL OPENINGS.

            5.  TURBINES UNDER 1500 HP MAY USE A STEEL CONTAINMENT SHROUD 3/8 MINIMUM.  1/2 INCH MINIMUM IS REQUIRED FOR OVER 1500 HP.  SHIELD MUST EXTEND A MINIMUM OF FIVE INCHES FORWARD AND TEN INCHES AFT OF THE TURBINE SECTION AND MUST HAVE A MINIMUM OF 3/8 THICK FLANGES.  EXTENDING RADIALLY INWARD FROM THE SHROUD ON BOTH ENDS OF THE SHROUD, WITH A MAXIMUM OF ONE INCH OF ENGINE AND ID OF FLANGE MUST BE MAINTAINED FOR COOLING AIR INSIDE THE SHROUD.   FLANGES MAY BE SCALLOPED OUT TO CLEAR ACCESSORIES, BRACKETS OR TUBING AND MAY BE EITHER ROLLED EDGES OR TUBING AND OR STEEL RINGS ATTACHED TO WELDING OR RIVETING TO THE SHROUD.

            6.  EXHAUST STACK DIAMETER TO BE NO SMALLER THAN ONE INCH OF ENGINE OUTLET.

            7.  TWO OVERSPEED DEVICES ARE REQUIRED ON TURBINE WHEEL.

            8.  GOVERNOR SETTING NOT TO EXCEED MANUFACTURER'S MAXIMUM SPECS.

            9.  OVER SPEED SHUTDOWN CONSISTING OF A SPEED MONITOR ACTIVATING A NORMALLY CLOSED SOLENOID VALVE LOCATED BETWEEN THE FUEL CONTROL AND THE FUEL MANIOLLD TRIP SETTING TO BE LOW ENOUGH TO PREVENT OVERSPEEDIN CASE OF DRIVELINE FAILURE.

2.  ON VEHICLES WITH MULTI-CYLINDER ENGINES USING STARTER RING BETWEEN ENGINES - THE STARTER RING MUST BE 360 DEGREE SHIELDED WITH ¼ INCH STEEL AND HAVE BOTH ENDS ENCLOSED.

3.  MULTI-CYLINDER ENGINES THAT ARE COUPLED TOGETHER THE COUPLER MUST BE 360 DEGREE SHIELDED WITH ¼ INCH STEEL AND FASTENED WITH BOLT.

4.  HARMONIC BALANCERS MUST BE 360 DEGREE SHIELDED WITH ¼ INCH STEEL AND FASTENED WITH BOLT.  SFI APPROVED BALANCERS EXEMPT FROM SHIELDING.

5.  VEHICLES EQUIPPED WITH ANY TYPE OF CLUTCH MUST HAVE STEEL OR ALUMINUM FLYWHEEL AND USE A BLOWPROOF BELLHOUSING HAVING. NO NON-FACTORY HOLES, DRILLED OR CUT IN IT - EXCEPTION OF CLUTCH MAINTENANCE / INSPECTION HOLE AND ONE 1" COOLING HOLE, AND BE EQUIPPED WITH A BLOCK SAVER PLATE OF 3/16" STEEL OF 1/4" ALUMINUM.  NO CAST IRON COMPONENTS PERMITTED.  COMPONENTS DEFINED AS FLYWHEEL, PRESSURE PLATE, FLOATERS/CLUTCH DISC(S).  ALL AUTOMATIC TRANSMISSIONS MUST HAVE POSITIVE REVERSE GEAR LOCKOUT AND A SAFETY BLANKET INSTALLED.  THE BLANKET MUST BE A 7 STRAP SFI TYPE IN GOOD CONDITION AND START AT THE BACK OF THE BLOCK AND RUN TO THE TAILSHAFT OF THE TRANSMISSION.  ALL AUTOMATIC TRANSMISSIONS MUST HAVE A SHIELD AROUND THE TOP HALF OR THE TRANSMISSION OVER THE TORQUE CONVERTER.  THE SHIELD MUST HE MADE OF 3/8 INCH STEEL OR SFI APPROVED.

6.  MAXIMUM LENGTH OF VEHICLE IS 14 FEET FROM CENTER OF REAR AXLE HOUSING TO THE FURTHER MOST POINT OF VEHICLE, THIS INCLUDES WEIGHTS.  VEHICLE MUST HAVE WIDE FRONT AXLES.  FRONT WHEELS MUST TRACK WITHIN REAR WHEELS.

7.  HITCH HEIGHT IS 20" FOR ALL VEHICLES AND LENGTH IS MINIMUM OF 18" FROM CENTER OF REAR AXLE TO HOOK POINT.  NO CLEVIS ALLOWED ON DRAWBAR.  HITCHES MUST BE RIGID, IN ALL DIRECTIONS.  NO MOVEMENT IS ALLOWED WHILE PULLING.  DRAWBARS MUST BE PARALLEL TO THE GROUND.  HITCH MUST BE HORIZONTAL – NOT VERTICAL.  DO NOT CONNECT DRAWBARS AND STABILIZER BARS.

8.  MAXIMUM TIRE SIZE OF 30.5" X 32".  SINGLE CUT OR DOUBLE CUT TIRES ALLOWED.

9.  COMPETING VEHICLES MUST HAVE WORKING REAR WHEEL BRAKES.

10. ALL EXHAUST SYSTEMS MUST DISCHARGE VERTICALLY - VERTICALLY IS DEFINED AS BEING WITHIN 10 DEGREES (ANY DIRECTION) OF “BEING PLUMB”.  HEIGHT SHALL BE A MINIMUM OF 12'’ ABOVE THE BEND IN THE PIPE WHICH DISCHARGES VERTICALLY, MEASURED FROM THE TOP OF THE PIPE TO THE BOTTOM OF THE BEND. 

11. ALL TRACTORS WILL HAVE A DEADMAN THROTTLE THAT WILL AUTOMATICALLY RETURN TO A CLOSED POSITION.  THROTTLES WILL WORK IN A FORWARD TO REVERSE MOTION, FORWARD BEING OPEN.

12. ALL TRACTORS MUST HAVE A STARTER INTERRUPTER SWITCH THAT WILL ALLOW THE STARTER ENGAGEMENT ONLY IN NEUTRAL OR PARK POSITION ON THE TRANSMISSION GEAR SELECTOR.  ALL PULLING VEHICLES MUST HAVE A NEUTRAL SAFETY LIGHT.  A WHITE LIGHT BEING A MINIMUM OF 2 INCHES IN DIAMETER.  THE LIGHT SHOULD BE MOUNTED WITHIN 6 INCHES OF THE KILL SWITCH.  THE STARTER INTERRUPTER SWITCH AND NEUTRAL SAFETY SWITCH WILL BE OPERATED OFF THE GEAR SELECTOR.

13. PULLING VEHICLES MUST HAVE AN AUTOMATIC IGNITION KILL SWITCH AND/OR SHUT OFF.  KILL SWITCH MUST BE MOUNTED INDEPENDENTLY OF DRAWBAR AND/OR WHEELIE BARS.  KILL SWITCH TO BE MOUNTED IN REAR CENTER OF VEHICLE, 48" ABOVE AND WITHIN 6" OFF CENTER OF POINT OF HOOK. KILL SWITCH/SHUT OFF MUST HAVE A MINIMUM 2" DIAMETER SOLID RING, WITH MINIMUM 1/8" CROSS SECTION THICKNESS, ATTACHED.  KILL SWITCH FOR SPARK IGNITION ENGINES THE KILL SWITCH MUST BREAK OR GROUND THE IGNITION CIRCUIT AND MUST BREAK ELECTRIC POWER TO AN ELECTRIC FUEL PUMP(S) IF SO EQUIPPED.

14. PULLING VEHICLES MUST HAVE A SHIELD BETWEEN THE DRIVER AND THE TIRES THAT CONSISTS OF A SOLID BARRIER BETWEEN THE DRIVER AND ANY PART OF THE REAR TIRES.  THE BARRIER MUST BE ABLE TO SUFFICIENTLY SUPPORT THE WEIGHT OF THE DRIVER AND MUST EXTEND A MINIMUM OF 6" HORIZONTALLY AT THE TOP, AND BE A MINIMUM OF 36" WIDE AT THE TOP.

15. ANY TRACTOR THAT HAS THE FRAME BOLTED TO THE TRANSMISSION MUST HAVE THE FRAME BOLTED TO THE AXEL HOUSING.  THE FRAME MUST BE SUFFICIENT ENOUGH TO WITHSTAND THE BOLTS BEING REMOVED FROM THE PLATE OF THE TRANSMISSION OR REAR END AND STILL BE ABLE TO SUPPORT THE WEIGHT OF THE TRACTOR FOR THE CLASS BEING ENTERED.

16. ALL VEHICLES MUST HAVE BE EQUIPPED WITH STABILIZER BARS.  STABILIZER BARS TO HAVE PADS, NOT WHEELS, ON BOTTOM OF BARS. PADS TO BE A MINIMUM OF 5 SQ. IN.  PADS TO BE A MINIMUM OF 32" REARWARD FROM THE CENTER OF THE REAREND HOUSING.  PADS MAXIMUM OF 10" OFF THE GROUND.  OUTSIDE TO OUTSIDE LENGTH OF PADS TO BE A MINIMUM OF 20".  MINIMUM 12" HIGH BUMPER BARS - TOP TO BE FASTENED TO STABILIZER BAR FRAMING.  BARS MUST SUPPORT WEIGHT OF TRACTOR FOR WEIGHT CLASS BEING PULLED.

17. ALL WEIGHT FRAMES AND WEIGHTS MUST BE STATIONARY AND SAFELY SECURED TO THE VEHICLE.  RUBBER STRAPS WILL NOT BE PERMITTED TO HOLD ANY WEIGHTS ON THE VEHICLE.  FRAMES OR WEIGHTS MUST NOT EXTEND REARWARD BEYOND THE REAR TIRES OR EXCEED 12" BEYOND THE WIDTH OF THE REAR TIRES.  NO WEIGHTS ON VEHICLE SEAT OR DECK OR WITHIN 8" OF DRAWBAR HOOK POINT.

18. ALL DRIVE SHAFTS AND UNIVERSAL JOINTS MUST BE TOTALLY ENCLOSED WITH SIX INCH WIDE, 5/16" MINIMUM STEEL OR 3/8" ALUMINUM, ROUND, WITH THE INSIDE DIAMETER NOT GREATER THAN 2" MORE THAN THE OUTSIDE DIAMETER OF THE LARGEST UNIVERSAL JOINT.

19. LEGAL FUELS ARE GASOLINE, DIESEL, WATER, AND ALCOHOL.  ALL FORMS OF NITRO-METHANE, INCLUDING NITROUS OXIDE AND PROPYLENE OXIDE ARE ILLEGAL.

20. ALL MODIFIED TRACTORS ARE REQUIRE TO HAVE 47.1 SFI SPEC ROLLOVER PROTECTION OR BETTER FOR THE 2011 SEASON. 

21. FIRE EXTINGUISHER IS REQUIRED.

22. DRIVER MUST WEAR HELMET, HEAD SOCK AND FIRE SUIT (JACKET AND PANTS) AND GLOVES.  DRIVER MUST WEAR LEATHER BOOTS OR SFI TYPE FIREPROOF SHOE, NO TENNIS SHOES.

21. ALL PULLER’S MUST BE SIGNED UP 30 MINUTES BEFORE PULL STARTS!