World Formula Modified Tour Rules
The rules and regulations set forth in this booklet are intended to provide for uniform guidelines for World Formula Modified Tour competition. They are not intended to establish, provide or maintain any safety standards of any type. No express or implied warranty or representation is made as to the safety and suitability of these rules and regulations to protect the participant, spectator or official from injury and/or death. Each participant assumes full liability and holds the World Formula Modified Tour, including its officers, managers, officials, and volunteers, harmless from any injury and/or death resulting from any cause, including negligence, sustained in connection with any racing event organized by the World Formula Modified Tour. The safety of the car, its engine design, fabrication, maintenance and operation are the sole responsibility of the car owner, driver and/or participant. Items in red are additions or changes to rules and supercede all prior versions.
1. Dimensions :
A. Length measured from bumper to bumper, not including exhaust pipe.
B. Wheelbase measured from centerline of front axle to center line of rear axle.
C. Width measured at widest point of car.
D. Height measured from the ground to the highest point of the body.
|
Dimensions |
Minimum |
Maximum |
|
Length |
78" |
96" * # |
|
Wheelbase |
52" |
67" |
|
Width |
37" |
48" |
|
Height |
30" |
42" |
*excluding muffler
# additional length considerations will be allowed for rear engine cars using a World Formula engine that may not be able to meet hte maximum length requirements.
2. Minimum Weight:
A. 200 lbs. (Car only, wet, no ballast)
B. 450 lbs. (Car & Driver)
C. Removable ballast must be painted white and safely secured to the welded chassis or other welded part of the car with bolts and cotter keys/safety wire.
3. Frames:
The chassis main frame must be made of a minimum of .065" wall thickness, 1 inch round or square steel tubing.
4. Roll Cage Requirements:
5. Bumpers:
A. All cars must have front and rear bumpers.
B. Bumpers will be made with a minimum of .065" wall thickness, ¾ inch steel round or square tubing, or minimum .100" wall thickness, one (1) inch round aluminum tubing.
C. Bumpers must be three (3) to five (5) inches from the ground to the bottom of the lowest rail and at least six (6) inches from the bottom of the lowest rail to the top of the highest rail. They must have a minimum of three (3) connecting bars and at least one (1) must be in the center of the bumper.
D. All bumper ends must have looped or boxed ends and must be of double rail design.
E. The rear bumper must cover at least from center to center of the rear tires but cannot extend past the outer edge of the rear tire/wheel combination.
F. The front bumper must be a minimum of 15 inches and a maximum of 24 inches wide, centered between the main frame rails where they attach to the front of the main frame.
6. Nerf Bars:
A. Nerf bars (or rub rails) are mandatory on all cars. They must be made of a minimum of .065" wall thickness, ¾ inch round or square steel tubing, or a minimum of .100" wall thickness, one (1) inch aluminum tubing, and extend to within eight (8) inches of the front tires and four (4) inches of rear tires.
B. Double rail nerf bars are mandatory and must be a minimum of half the length of the wheelbase.
C. Nerf bars must extend to at least half of the width of the rear tires, and cannot protrude more than ½" outside the respective rear tire.
D. All welds must be complete.
7. Fire Wall:
A. All cars must have a minimum of .030" thickness metal fire wall which completely shields the driver from the fuel supply and the engine compartment.
8. Flooring:
A. All cars must have a minimum .030" thick metal floor pan with no openings between the driver and the ground. Must cover the full underside of the car from nose to the rear end of driver's seat, to shield driver's body from the ground.
B. Any openings between the floor pan and body must have ½ " screening or a protective covering to prevent debris from entering the driver compartment.
9. Fuel Lines and Fuel Tanks:
A. No fuel lines or fuel tanks are allowed in the driver"s compartment.
B. Fuel lines must be three (3) inches from the exhaust pipe or shielded by metal
C. Fuel tanks must be an approved type fuel cell. They may not extend outside of the car, and they must be protected from impact with a steel bar.
D. External fuel tanks must have a shut-off valve and fuel lines must be clamped or safety wired.
E. A spill proof cap must be used to prevent leakage of fuel in the event of a rollover.
10. Exhaust System:
A. Exhaust outlet must be a minimum of three (3) inches from any tire and is not included in measurements of the overall length of the car.
B. Exhaust outlet must not be in an enclosed space and must extend a minimum of 3" behind the rear-most part of the axle.
C. A strap or cable must anchor the exhaust pipe so that breakage of the normal exhaust mounting will not result in pipe falling off the car.
11. Tires and Wheels:
Maximum Diameter
|
Wheel |
6" |
|
Tire |
15" |
12. Steering:
13. Brake System:
A. Foot pedal operated brakes are mandatory.
B. Hydraulic disc brakes only.
C. Minimum of two-wheel braking required.
14. Ignition Kill Switch:
A. Car must have a safety kill switch that will shut off the ignition to motor, and be clearly labeled "ON & "OFF".
15. Rear Axle and Hubs:
A. Rear axles must be of one-piece design. No two-piece axles allowed.
B. Both rear hubs must be solidly mounted to rear axle.
C. No slip or idler hubs.
16. Bodies:
A. Aluminum, polycarbonate, fiberglass or similar materials are the only materials allowed. No steel bodies.
B. Bodies must resemble a Dirt and/or Asphalt Modified Stock Car or traditional sedan or coupe style body.
C. No sharp edges, corners, or points.
D. Window openings must be large enough for emergency access to driver.
E. Must have a closed roof with a latch that can be opened from both inside and outside
F. No external wings allowed.
G. Any bars within reach of the driver's helmet must be padded.
H. Body panels may not be secured by Velcro only.
17. Windshield:
A. The entire windshield area must be covered by metal screening with a maximum spacing of ½" x ½" , or clear Polycarbonate with a minimum thickness of 1/8 inch.
B. No glass anywhere on the car
18. Mirrors and Radios:
A. No mirrors or radios are allowed in cars.
19. Seats:
A. Molded seats with an opening to allow seat belts to pass through are required.
B. Seats must be bolted using a minimum of 5/16 bolts with load spreading washers.
C. Seat must be attached to the chassis with a minimum of four (4) Grade 5 bolts. Two bolts shall be installed at the bottom of the seat not more than three (3) inches from the outside edge, and two bolts shall be installed at the two most practical widely-spaced points at the top of the seat rack.
D. Vehicles with metal seats do not need required straps, but do require larger washers at each bolt.
E. It is recommended that all seat edges be padded. Also flat sides of the seat should be padded with at least 1" of foam in any area that may contact a driver"s rib cage.
20. Safety Belts:
21. Headrest:
A. All cars without an integrated high back seat must have a headrest centered behind the driver's head, with a minimum size of 4" x 4" and a two (2) inch thick padding.
B. Cars with a high back, racing style seat may use that manufacturers seat padding where the helmet meets the seat, or that same area must be padded with a minimum of a one (1) inch thick pad.
22. Oil Catch Can:
A. A catch can must be mounted inside the body such that oil blow-by cannot leak onto the track.
B. Blow-by from the engine breather system must be routed to the oil catch can.
C. The oil catch can must be vented to outside air only.
D. No connection to carburetor permitted.
23. Drive Train Clutch:
A. Centrifugal dry engine clutch and chain drive only.
B. No belt drives, torque converters, axle clutches, or variable ratio allowed.
C. The use of 219 sprockets and chains are not allowed.
D. Clutch/chain guards are mandatory.
24. Batteries:
A. Batteries must be secured and shielded to prevent leakage in the event of a turnover.
B. The battery shall be enclosed by a marine-style box, covered and secured to the vehicle as to not allow movement of the battery.
C. Battery box is not mandatory if battery is mounted outside of drivers compartment. If a battery box is not used, all bolts must be safety wired or cotter pinned.
25. Car Identification:
A. Cars must be numbered for scoring purposes. Minimum sizes are as follows: (Larger sizes are recommended)
B. If track officials request that a number be changed for legibility, driver must comply.
C. No duplicate numbers. Numbers are available on a first come, first serve basis. Drivers having registered a number the prior season will have the first rights to that number.
D. Number and letter combinations are allowed.
E. No three digit numbers.
|
Body Area |
Minimum Size |
|
Left Side |
10" |
|
Right Side |
10" |
|
Rear |
6" |
|
Roof |
10" readable from right side |
F. The World Formula Modified Tour decal must be displayed somewhere on the car in order to receive winning payout monies and/or award contingencies.
Transponders
A. At any track that utilizes electronic scoring transponders, the mounting location shall not be any further forward than the front downtube of the rollcage.
A. Drivers must wear a one-piece fire resistant suit, and flame-retardant gloves covering their bodies, arms, legs and hands. The material used in this clothing must be approved by the Race Track Administrator before participating in any racing event. Noncompliance is a penalty.
B. Fire resistant underwear tops and bottoms are recommended.
C. State and track regulations may supersede this rule.
2. Helmets:
A. Drivers must wear a full face safety helmet with a Snell SA 2000 rating or newer.
3. Head, Neck & Arm Restraints:
A. All racers must use a head-and-neck restraint device (neck collar, HANS, Hutchins-type device).
B. Arm restraints are also mandatory to prevent driver's arms and hands from reaching outside the cage.
4. Other Equipment:
A. World Formula Modified Tour reserves the right to modify or add safety equipment pursuant to the racing regulations as required by the State or the track itself.
5. Vision Aids:
A. Prescription lenses noted on the participant's driver's license must also be worn during a racing event.
6. Age:
A. Participants must a minimum of 13 years of age in the calendar year to compete in any racing event.
B. Participants under the age of 15 must display a red ribbon or bumper decal on the rear of car.
7. Driving Privilege:
A. World Formula Modified Tour has the right to revoke the privilege to compete or participate in any racing event at any time.
8. Rookies:
A Rookies must display a yellow ribbon or bumper decal on the rear of car for the entire season. Rookies with no prior racing experience will start in the rear of heats and features for the first three events. Rookies with prior racing experience will use the standard line up procedure.
9. Registration & Fees:
A. All drivers must pay a fee of $40.00 for the season for a full registration for one car. Drivers running multiple cars will be required to pay an additional $10 fee for a second car. A temporary, one day, driver registration fee will be $15.00. After the purchase of 3 temporary licences, the registration will be considered a full registration.
A. All drivers must comply with safety rules, safety dress codes and requirements, both World Formula Modified Tour and state regulations.
B. No fueling is permitted with the engine running.
C. Smoking shall not be permitted in any area where fuel is being transferred or stored.
D. The use of welding or acetylene torches is not permitted in any area where fuel is being transferred or stored, unless a fully-charged fire extinguisher is on site.
E. No driver shall compete in any event with his head or arm extending outside of the windows or roll cage.
F. World Formula Modified Tour reserves the right to modify or add safety rules pursuant to the racing regulations as required by the State or the track itself.
A. All drivers must understand Flag and Race Procedure rules and obey them.
B. During a race, any car brought back to the pits will not be permitted to re-enter that race.
C. Any driver exiting his vehicle during a race, unless instructed by the race director, shall not be allowed to complete that race.
D. Failing to come to an immediate safe stop and shutting off the engine under the RED if required by track rules, for any reason, disqualifies a car from completing that race. The car will be scored from that position at the end of the race (number of laps completed).
E. If track officials see any problem with any car, that car will be black-flagged, and the flagged car must proceed to the infield.
F. The Black Flag when given to any driver must be obeyed immediately. The starter may use this flag, not only for disqualification for infraction of the rules, but also for some mechanical trouble with the car which the driver may not be able to see, which in the opinion of a race official makes the car dangerous. In such event, the driver shall raise hand, avoid interference with other cars and safely pull off the track immediately.
G. All on track decisions made during the running of any race will be made by the track officials only. The track official's decision will be final. Video replays can be used if available, to help determine any on track decisions.
H. Any driver exhibiting detrimental conduct: rough riding, fighting, foul language, etc., will be subject to a drivers meeting on the incident. The drivers in the race at issue will discuss the incident and determine the action to be taken by simple majority vote. The driver in question does not vote.
I. Upon completion of a race, the top three finishers will move their cars directly to the Tech area for post-race inspection.
J. If a driver and/or car fail to show up for post race Tech inspection, the car and driver will be disqualified for the race event.
K. In the event of raindates/postponments/rescheduled events, the driver qualifies, not the car. If a driver changes cars in the course of an event or at a make up feature due to a postponment, they must notify the race director and will start at the rear of the field. If an event is postponed after the heat races are run, only drivers that were signed in on the original race date will be eligible to run a make up feature.
A. Fields of up to 11 cars will pay back five (5) positions, fields of up to 15 cars will pay back six (6) positions.
B. Sponsored events will adhere to the same purse distribution, unless requested by the sponsor.
C. Payouts are based off of competitor registration fees from each event, less any fees payable to the track. The World Formula Modified Tour can retain a percentage up to, but not to exceed 50% of the registration fees after expenses for operating expenses and end of year awards. The following payout schedule shall be used for all events.
Up to 11 cars
|
Position |
Percentage of purse |
|
1st |
35% |
|
2nd |
25% |
|
3rd |
20% |
|
4th |
10% |
|
5th |
10% |
Up to 15 cars
|
Position |
Percentage of purse |
|
1st |
35% |
|
2nd |
25% |
|
3rd |
20% |
|
4th |
10% |
|
5th |
5% |
|
5th |
5% |
D. Every effort will be made to have a payout at each event. Payout amounts can vary due to car count fluctuations. In the event of a low car count a 100% payback of registration may be used.
.
A. All cars, engines, and fuel are subject to inspection at any time at the discretion of the Chief Tech Inspector and must meet specifications and be in safe racing condition.
B. No compensation will be given to a car owner as a result of any inspection and/or tear down.
C. Technical Offense: A technical offense is a technical violation of the rules, such that in the opinion of the Tech Inspector, no possible speed or performance benefit resulted, and the race outcome would not have been affected by the violation. There is no penalty, but the problem must be corrected before the next race.
D. Major Offense: A major offense is a violation of the rules such that in the opinion of the Tech Inspector, speed or performance benefit could have reasonably resulted, or the race outcome could have been affected by the violation. The penalty for said offense is that the car and driver will lose all points, awards, and money earned for that race, and will be subject to a re-inspection of the violation when returning to race in a subsequent event.
E. Engine Offense: If the World Formula engine has been tampered with, i.e. broken seal, the penalty will result in the loss of all points earned for the entire season, forfeiture of awards and money received for that race meet, and suspension from racing in World Formula events for the remainder of the season.
F. Cheating will not be tolerated. Any driver and/or car owner refusing to permit an inspection of the engine, or to have the fuel checked, will automatically lose all earned points for the current year and be subject to suspension.
G. The Tech Inspector's decision is final. No appeals.
A. Only cars taking the green in the feature will receive points. There are no points for qualifying heat races. The following points will be awarded:
1st Place 100 points
2nd Place 96 points
3rd Place 92 points, etc.
B. ALL cars & drivers that are registered, signed in and able to compete in the days race event will receive 10 attendance points. Attendance points are NOT subject to points drop.
C. Bonus points may be awarded to cars and/or drivers for special events.
D. Race events that are "Twin Feature" events will award regular feature points in each feature.
E. Best 12 out of 14 point shows count for year end awards. (Notwithstanding the above, in the event the race schedule is modified, the throw-away allowance shall be equal to two (2) race events
F. Must attend ten (10) World Formula Modified Tour point events to be eligible for year end awards.
G. In the event of a disqualification, that event cannot be used as a points drop.
Heats: Lineups for the heat race(s) will be determined by a blind draw at sign-in.
Feature: The feature race line ups and handicapping will be determined by the following procedure:
a) The field will be lined up according to the heat race finishing order. In the event that 2 heat races are necessary, the finishing order of heat 1 will be the "inside" row, and heat 2 will be the "outside" row.
b) The winner of the last heat race will draw a number to determine the invert for the feature race line up.
c) Feature draw: There will be chips numbered 2 through 8, one chip will be labeled "all", and one chip will be labeled "zero" (no invert). The feature race line up will then be provided to the track officials
Protests
All protests involving a particular race must be in writing, specifying the matter of protest, signed and submitted by a race participant or car owner tothe Tech Inspector no later than 15 minutes after completion of that race.
1. Protest Fee: $150 CASH must accompany protests of engines / fuel. The fee will be divided as follows:50% (or $75) to JC Specialty regardless of outcome, with the remaining 50% (or $75) going to either the protestor or the car owner whoever is found to be correct in the disputed issue.
2. Engine and Fuel: Both engine and fuel may be protested for a single fee.
3. Location: Teardowns will only be performed at the end of the full race program. All engine tear-downs will be performed off-site by JC Specialty. Engine will be removed from the race car at the track, packaged and shipped to JC Specialty.
4. Who can be present: Only the following persons will be permitted to attend the tear-down / protest:
· The Tech Inspector
· The car owner or driver (or his representative)
· The protestor (or his representative)
5. Fuel: Fuel will be analyzed using the standard World Formula test. Fuel may be protested and a sample taken at any time during a race event. Fuel may be checked by any means.
The Tech Inspector will decide if specifications have been violated. His decision is final.
GENERAL SPECS
•Model/Type: 124435 8101-01
•Displacement: 12.48 Cu. In 200 cc
•Slant, 30 degree Overhead Valve Design
•Dual ball bearing Cylinder
•Dura-Boretm Cast Iron Cylinder Sleeve
•Bore: 2.6875/2.6885 in.
•Stroke: 2.2 in.
•Compression Ratio: 9.7 to 1
•Factory Timing: 28 degrees BTDC
•Recommended Oil capacity: 20 ounces
RACING SPECIFICS
• Dual ball bearing block
• Electric start
• Specially cam ground, barrel-faced,
moly coated domed piston
• Chrome-faced top ring
• Dual valve springs
• 3-piece automotive-style keepers
• Dished valves
• Nitrided exhaust valve
• Cast aluminum manifold with rubber mounting flange
• Racing designed combustion chamber
• Green air filter
• D-shape intake port
• Premier clutch with quick change
sprocket set (16-17 tooth)
• Billet aluminum rod
• Walbro round slide carburetor
ENGINE RULES
The engine is to be run in stock form, with the exception of the following which applies to recent B&S factory updates:
1 Rev Limiter - Rev limit is 7100 rpm +/- 50 rpm. Rev limiter may be checked at any point in the race program.
2 Coil - Unaltered stock B&S coil or B&S PVL 4 legged coil is legal. PVL coil must be used with PVL flywheel. Attachment bolts must not be altered. Spark plug connector must be stock factory type. Rubber plug boot is allowed. Coil air gap is non tech.
3 Flywheel - Stock cast iron flywheel or B&S PVL flywheel is legal. PVL flywheel must be used with PVL coil. No machining, glass beading, sandblasting, painting or coating of flywheel is allowed. Minimum factory overspray is allowed. Chipped fins due to poor casting are legal. Completely broken fins are not allowed. Stock flywheel key is required.
Seals must be on engine at all times. No alterations of any kind are permitted, except as otherwise stated herein. Disqualification is at the discretion of the tech inspector.
SEALING OF ENGINE
All engines MUST be teched and sealed by JC Specialty. Cylinder head, side cover, and shroud will be sealed. Engines not purchased at JC Specialty will be teched and sealed at JC Specialty for a fee of $50.00. Any tampering of engine or seals in any manner will result in immediate disqualification. In the event a repair is necessary that requires removing the seal, the seal can be removed by the WFMT tech official, the repair made and the seal replaced at no additional cost. This can be done at the track or through appointment with the WFMT tech official. All seals will be numbered and the numbers recorded at the time of inspection. Every effort has been made to ensure the timely inspection, sealing and return of engines. If for any reason, JC Specialty cannot return the motor in a timely manner, it should be brought to the attention of a WFMT official.
UNSEALED ENGINE ELIGIBILITY
Any unsealed, stock World Formula engine will be allowed to compete in one race event. At the conclusion of the nights racing program, the motor is to be removed by World Formula Modified Tour tech officials, packaged and shipped to JC Specialty to be teched and sealed for a fee of $50 + $30 shipping. All awards and points are to be held until said engine is deemed to be legal and all fees are paid in full. If the competitor refuses to have their motor sealed, they will forfeit all points, awards and/or payouts for that event.
Begining in 2012, all motors MUST be sealed to compete on the World Formula Modified Tour.
AIR FILTER
Any type filter that meets stock specs is permitted. Air filters requiring an adapter are not allowed.
VALVES
Valve lash adjustment is permitted. (Lash is non-tech).
Valve cover vent tubes are non-tech.
EXHAUST
1 Any exhaust allowed.
2 The use of header wrap is recommended.
The only approved Exhaust Silencer is the RLV 4106. Any tampering, altering, or removal of silencer will result in immediate disqualification. Muffler must be on the car at the end of the event.
STARTER & BATTERY
The stock engine starter & battery must be in place and functional at all times. Only dry or gelcel batteries (SLA sealed lead batteries) are permitted. Recoil starter and cup may be removed and replaced with a started nut as a back up in the event of a battery/starter failure.
CLUTCH
Any dry centrifugal is allowed.
FUEL
Standard pump gasoline shall be used. No additives or enhancers of any sort are permitted. Failure of fuel test will result in disqualification.
CARBURETOR & INTAKE MANIFOLD
Carburetor must remain in complete stock condition (Stock Walbro PZ26 carburetor only). The only changes that are allowed are:
1. To change the main carburetor jet. Any size jet is allowed.
2. To change the needle height by moving the clip. Stock needle and clip must be utilized.
3. Carb bowl overflow must be attached to catch can.
4. The use of aftermarket fuel pumps is allowed.
Only the stock World Formula manifold may be used. No alterations of any kind are permitted.
The above specifications are subject to change to accommodate continuity with other organizations in an effort to allow more competitors the opportunity to race this class at multiple tracks and/or events.
CONTROLLED STOCK FLATHEAD ENGINES
The use of controlled stock engines will be permitted up to the 2011 racing season. All engine specifications must comply with the last published WKA controlled stock rules. The use of a Tillotson carburetor is permitted, 357 B only with matching manifold.
1 Minimum weight for car and driver shall be 450 lbs.
2 Muffler: The use of Exhaust Silencer RLV 4106 is allowed.
3 Fuel: Alcohol (Methanol) fuel only for this engine type. No additives or enhancers of any sort are permitted.
4 Fuel Tests: Fuel will be analyzed using the standard Methanol & Water Test. Using a clean glass bottle and distilled water, a mixture of equal parts (50/50) of the competitor's fuel and distilled water will be combined and shaken. The mixture should clear top to bottom within three minutes to be deemed legal. The presence of additives or contaminates will cause the mixture to remain cloudy and will be considered a failure of the fuel test resulting in disqualification
5 Engine Protests: In the event of a protest, all engine tear-downs will be done by JC Specialty or the track technical inspectors when available. . The fee for such protest shall be as provided herein
WKA CONTROLLED STOCK ENGINE SPECS
24.0 BRIGGS & STRATTON CONTROLLED STOCK
NOTE: All parts must be Briggs & Stratton factory production parts unless otherwise specified. No machining or alterations are permitted unless specifically noted. Any parts that are to remain stock are subject to be compared to a known stock Briggs and Stratton part. No reading between the lines. If it's not in the rules, it must remain stock. No titanium parts allowed, UNLESS OTHERWISE STATED ENGINE WILL BE TECHED AS RACED.
24.1 SHROUDS & COVERS: Engine shroud and covers must be intact and not modified, except Scatter Shroud made by W.E. Chapps may be used. This includes flywheel shroud unless there are no holes in block for it to be used. Taping of shroud housing allowed. Tape on block disallowed. Fixed screen must be affixed to shroud cool air intake area. Any bolt utilized to secure sheet metal, shrouding, etc. with the exception of sheet metal secured by the head bolts, may be replaced with large diameter bolt(s).
24.2 HEADER/SILENCER: Exhaust pipe/header must extend beyond gas tank be a minimum of 3" from rear tire and have no exposed sharp edges. Header/exhaust pipe MAY NOT PROTRUDE inside of exhaust port so as to alter port configuration for performance gain. Studs allowed for header pipe attachment to block. Exhaust may protrude past the rear bumper by approximately 5"
NOTE: WKA In events where silencing device is MANDATORY (Divisional, National, etc., points event and where required for non-points, local events), use of RLV 4106 SILENCER IS MANDATORY. Silencer must be utilized as produced, with no modifications or alterations permitted.
MRL allows the use of the RLV part number 4106 muffler.
24.2.1 Gasket and/or Silicone allowed to seal the header.
24.2.2 Header must be of fixed design, NO SLIPPY PIPES allowed. No extra tubes or extra holes allowed except hole for heat sensor probe if sensor is used.
24.2.3 All header pipes must be of continuous length from flange to end of pipe with stages or butt welds permitted (no chamber, infusers or covers of any type allowed on muffler etc.) Silencer must be visible when viewed from any angle. Header tube and silencer only legal parts.
24.2.4 Extra HEAT SHIELD above chain guard IS ALLOWED.
24.2.5 A header support brace and safety wiring of header bolts is MANDATORY to assure header bolts remain tight. It is recommended that the safety wire wrap around pipe to insure that bolts remain with pipe in case they are stripped out of block. Silencer must be tight, secure and completely intact on the header throughout the entire event. Silencer must be clamped to header tube and no welding of silencer in any area.
24.2.6 The use of exhaust block saver is allowed. It must be round with a 0.75 inches min. and 1" maximum thickness and be made of ALUMINUM. Must have a straight bore with a 1.005 MUST GO ID. Bolt holes must have stock cord diameter.
24.2.7 WKA Silencer Baffle holes .1285" maximum all baffles.
24.3 AIR FILTER: Any air cleaner permitted that is installed in a safe manner. Filter may not be used as an air ram and must filter from all areas as raced. Any open areas in filter must be covered with a filter sock. (No open areas allowed).
24.4 FUEL TANK: Tank cap MUST be stock and in the stock position. Brace on tank bracket IS permitted. Stock gas cap must be utilized. No overflow tube is allowed. Acceptable cap is stock Briggs & Straton domed cap with single vent hole and stock gasket or old style cap with metal insert (See Fig. 701.4). Cap splash shields are not permitted. Bungee-type strap may be used in ALL CLASSES to wrap around engine and fuel tank to prevent loosening of parts from vibration. One of two gaskets allowable on carburetor/tank joint. Only one gasket allowed Carb to tank with Blue Print-O-Seal is used in pick up cup of fuel tank, however an open a lot must be visible at the top of the pickup cup. (Min. distance of .062") (See Fig. 701.4)
NOTE: INSTALLATION INSTRUCTIONS FOR TANK REPAIR KIT: (See Fig. 701.4)
CAUTION: Fuel cup insert may have sharp edges, handle with care.
1. Remove fuel tank from engine and remove old gasket.
2. Roll fuel cup insert into a coil 1" in diameter or less with tab on outside of coil and insert into the fuel cup in tank, Fig. #1.
3. Tab should rest against edge of fuel cup. Push on insert at both sides of steam until seams butt against each other, Fig #2.
4. Reinstall tank and new gasket on engine.
24.5 FILTER ADAPTER: Filter adapter may not be funneled or tapered. Top of filter adapter must be flat. Adapter may not be run without an air filter. No sealer between carb and filter adapter allowed.
24.5.1 Adapter may have rolled edge not to exceed .250" from top.
24.5.2 Maximum thickness of filter adapter is .250", measured from the top of filter adapter to carb air horn mating surface.
24.5.3 One Briggs and Stratton stock gasket may be used under filter adapter, maximum thickness 075".
24.6 CONTROLLED CLASS CARBURETOR: Must be Briggs and Stratton stock appearing carburetor and must have stock dual pick-up tubes. No material can be added to inside or outside of carb. No additional holes can be drilled in the "body of" carb. "Area behind jet no a tech item". Both pick up tubes must work. Air must enter carb at air horn ONLY. One or two gaskets allowed. Only one gasket allowed when Blue-O-Print gasket is used. No sealer allowed on carb to block. Any attempt to bypass, gasket, bolts or bolt holes is prohibited. The butterfly must be held in place on throttle shaft with a screw. No other way of attaching is allowed.
24.6A CONTROLLED CLASS ALTERNATE CARBURETOR: Tillotson model number 357 B with matching manifold (part number EC-440) , Fuel pump and external tank to be accepted as an alternate to the stock Pulse-a-jet carburetor.
24.6.1 Maximum bore at .715". (Full-length of bore) The carb bore is from the recess on the flange end (end that bolts to block) of the carb to the backside of the throttle shaft. Must be able to see some of the lip at between the recess area and the bore.
24.6.2 Diaphragm side CANNOT be used to create a pressure fuel feed. Diaphragm side of carburetor parts MUST be installed as supplied from the factory. Diaphragm cover plate MAY be surfaced to ensure a proper seal. No silicone or other material may be applied to diaphragm side of gaskets. After-market diaphragms, (including Teflon pumper diaphragm), allowed as long as it is of similar material and configuration of Briggs & Stratton diaphragm.
24.6.3 Breather tube must be removed from carburetor. The hole in the carburetor may be plugged.
24.6.4 A tab to reinforce a broken tank bolt on the carburetor-to-tank flange of carburetor is allowed.
24.6.5 No after-market coatings are permitted.
24.6.6 Remote mechanical carb adjusters legal in all stock classes.
24.6.7 Holes left after removal of choke and threaded hole at floor of air horn may or may not be plugged so long as plugging does not protrude into air-horn area.
24.6.8 Felt or foam washer must be on carb shaft under lever. Rubber seal must be in proper location in carb body for air seal around throttle shaft.
24.7 HEAD BOLTS: Any stock head bolts may be utilized and eight are mandatory. Head bolt with stud allowed.
24.8 CYLINDER HEAD: Stock Briggs & Stratton 5HP cylinder head required. Head cannot be machined below the flat cylinder portion of the head. Machining of two pockets for valve clearance or a single, continuous relief area from side-to-side across valve area is permitted. In no instance may the relief area touch either the back or sidewalks of the head and should be done in a manner not to affect airflow. Head may not be O-ringed. Recess at deepest point of cylinder head must be a minimum of .400° (from gasket mating surface).
24.9 HEAD GASKET: Briggs & Stratton production head gaskets are approved and aftermarket gaskets of general stock configuration (accommodates all head bolts, follows general stock pattern; does not extend to form "heat sink," etc.) are acceptable. Gasket sealer must NOT be utilized o head gasket. NO aluminum or Copper gaskets allowed. (See Fig. 701.9)
24.9.1 Head gasket must be a minimum of .043" thickness at four points between head bolt holes, front, near and both sides.
24.10 CYLINDER BORE: No circular or machined grooving of cylinder is allowed in any position of cylinder (See Fig. 701.14.1)
24.10.1 Stock cylinder bore is 2.5625" and overbore is permitted providing it does not exceed 2.6025" (approximately .040" overbore).
24.11 CAMSHAFT: Cam can e of the type centered on each weld. Maximum running lift .265" no visual tech on lobes. Gear must remain as cast.
24.12 BREATHER VALVE: Crankcase breathers are allowed.
24.13 VALVES: Stock valves ONLY. No Stellite type valve allowed, as found in industrial style engines. Must be one angle ONLY. Valves may not be polished or lightened. If working are (that portion of the valve stem translating with the valve guide area) of valve stem is cleaned, no material may be removed, such as linear grooves, cross hatching, etc. (See Fig. 701.11)
24.13.1 INTAKE VALVE: 30 degrees. Intake valve minimum diameter is 1.115".
24.13.2 EXHAUST VALVE: 45 degrees. Exhaust valve minimum diameter is .990".
24.13.3 Minimum thickness of valves between top (flat area) and seating surface to be minimum .035" (no "knife edging" of valve allowed). Valves will be checked with a NO-GO gauge for head thickness and legality will be determined by that gauge.
24.14 VALVE SPRINGS: Optional, including retainers. Back facing of upper portion of valve chamber to stabilize valve spring retainers and prevent spring bind is allowed.
24.15 VALVE SEATS: Valve seats must meet stock specs and can be replaced. Seats must have one angle only, 30-degree intake and 45 degree exhaust. Seats MAY NOT PROTRUDE above block casting or deck surface. PIN PUNCHING may be used to tighten a loose valve seat. No more than eight approx. evenly spaced pin punches per valve seat (see fig. 701.13 for locate and placement of pin punches). When re-facing valve seats it must be understood that if the tool for checking valve seat height enters valve seat, legality will be determined by that gauge.
24.15.1 Intake seat inside diameter, 1.004" (NO-GO).
24.15.2 Intake seat maximum thickness .215". Minimum thickness .199".
24.15.3 Exhaust seat inside diameter, .880" (NO-GO).
24.15.4 Exhaust seat maximum thickness .215". Minimum thickness .199".
24.16 DECK/PISTON CLEARANCE: Pop up not a tech item except Decking of the block cannot extend into the aluminum at rear of block (top of tin.)
24.17 IGNITION: Briggs & Stratton factory stock coils are MANDATORY and must be utilized in unaltered form (see photo). NO slotting of mounting holes or machining of attaching bolts is permitted. New style composite ignition is allowed. There must be resistance from ground to the plug wire. SPAR PLUG CONNECTOR must be stock factory type. Rubber plug boot is allowed. May be run with or without air vane (See Fig. 701.18).
NOTE: Coils may be rechecked for correct ohms reading after 2 minimum at 10 minutes.
24.17.1 Resistance from plug wire must be 2,000 ohms MINIMUM and 6,000 ohms MAXIMUM.
24.18 STARTER: New style recoil starter may be retained as produced and intact, however, if new style coil is removed, starter cup must also b removed. Old style recoil starter must be removed. If removed, crankshaft may be cut-off to facilitate any style nut and use of electric starter.
24.19 FLYWHEEL: ONLY stock, 5HP flywheel is permitted. Any flywheel key or NO flywheel key is allowed. Painting and coating of the flywheel (other than minimal factory over-spray) is not permitted. No machining, glass beading or sandblasting of flywheel is allowed. Chipped ins because of poor casting are allowed. However, completely broken fins are NOT allowed. Any screen or guard that fully covers the flywheel fins is allowed EXCEPT NO revolving screens. All screens must be bolted to blower housing. Flywheel washer must be stock
24.19.1 Weight of flywheel shall be 6lbs 4ozs MINIMUM.
24.20 CRANKCASE SIDE-COVER: Side-Cover must remain stock EXCEPT block and side-cover may be pin-punched to help prevent side-cover gasket failure and stub for governor may be removed and hole plugged to prevent leakage. Crankcase breather allowed.
24.20.1 After-market gaskets approved, however, must be same size and material as stock gasket(s). Up to three crankcase gaskets are allowed. Block and side-cover may be pin-punched to help prevent side-cover gasket failure. Fel-Pro Multi layer crankcase cover gasket is allowed for all classes.
24.21 VALVE LIFTERS: Optional. No titanium lifters allowed.
24.22 VALVE SEAT HEIGHT: Install a .500" rod in place of the cam and replace side cover. Measure through the valve guide from top edge of .500 rod to the top of the surface of the intake or exhaust valve seat. Minimum 5.485" / Maximum 6.520". Aluminum may be removed from top of seal to check seat height. Lifter bore and valve guide bore must except seat height gage rod.
24.23 CONNECTING ROD: After-market connecting rod may be used, but must meet stock specs No .020 undersize rods allowed. No under-sizing of connecting rod is permitted. However, rod may be clearanced providing that it is in stock configuration and finish with no "dimpling" or media blasting. Rod ends must be concentric with crankshaft journal end/or wrist pin with no chamfer or breaking if edges. Raptor III rod & dipper is legal: Dipper on Raptor III rod may be broken. However, it must be a natural break with no grinding, polishing or bead blasting visible. Old style rod (after market dipper) is a non-tech item in all classes.
24.23.1 Stock rod length is 3.120" minimum , 3.1333 maximum. Measured from bottom of wrist pin to top of crankshaft journal.
24.23.2 Oil hole opening. Raptor 3 or old style rod, is .185" NO-GO. New style cast Briggs & Stratton Raptor connecting rod approval (Part #555207). Oil hole and Chamfer no-go size to be established.
24.24 WRIST PIN: Wrist pin must not be altered and must be stock Briggs and Stratton pin.
24.24.1 Maximum inside dimension of wrist pin is .290".
24.24.2 Maximum outside dimension of wrist pin is .290".
RAPTOR IN WRIST PIN SPECS
24.24.3 Maximum inside dimension of wrist pin is .291".
24.24.4 Maximum outside dimension is .490".
24.24.5 Length 1.732 + OR .490".
24.25 RINGS Three rings are MANDATORY. Compression or top ring, if chamfered, may have either a beveled or chaffered inside face and must remain as manufactured. Scraper or second ring may only have an external circumference relief area. End of rings must remain flat. Mandrel check is no longer required. New factory rings from Briggs & Stratton without bevel on top ring and with relief around circumference of second ring are permitted. Excessive and gapping of rings not allowed. New style, beveled top compression ring (factory produced) is approved. Rings must conform to all listed factory specifications and be of stock configuration. Known, standards for piston/ring configurations and Briggs & Stratton factory approved parts. No machining of rings allowed. Exception; lapping and end gapping allowed, Shrinking of oil ring and low tension ring allowed. Rings must be in one piece when removed from block. With the exemption of the Raptor III oil ring, all broken pieces must be present in the ring land, if not the ring will be illegal. If stock rings are used they must meet the following specs.
24.25.1 Top two rings, .105" minimum width (for wear).
24.25.2 OIL RING must have minimum .085" width (for wear). Grove and six oil relief slots MUST be present on oil ring Groove must measure .083" minimum, regardless of condition of ring.
24.25.3 End gap with rings compressed on ring gauge cannot exceed .500".
24.25.4 Top ring cannot exceed standard Briggs and Stratton ring land width of .084 maximum.
RAPTOR III RINGS SPECS
24.25.5 Minimum width top two rings .090".
24.25.6 Thickness top two rings .058" + OR -.005".
24.25.7 Oil ring minimum width .070", ring groove must be present.
24.25.8 Oil ring Thickness .100" + OR - .005".
24.26 PISTON: After-market piston and stock rings may be used. No excessive cleaning oil top or skirt of piston allowed Piston Pin must be Briggs and Stratton Stock. Wrist pin hole must not be altered or relocated, minimum honing of wrist pin hold allowed, NO matching is allowed on piston. If stock piston is used it must meet the following specs.
24.26.1 From top of piston to wrist pin bore .937" minimum measurement
24.26.2 Minimum piston length is 1.869".
RAPTOR III PISTON SPECS
24.26.3 From top of piston to wrist in bore .937" minimum measurement.
24.26.4 Minimum piston length is 1.671".
24.26.5 Top two-ring land width .0603" .0612".
24.26.6 Oil ring land width .1020" .1032".
24.27 CRANKSHAFT Stock factory crankshaft mandatory. Stock factory timing gear mandatory and must be installed properly. Lightening, polishing of counter weights, addition of metal o other material is not permitted. Hardening of stock crankshaft is permitted in all classes to reduce premature journal wear. The power takeoff journal of a sleeve-bearing cranskshaft may be machined (turned-down concentrically) to permit its use in a ball bearing block. Offset crankshafts are not permitted. After-market bearing of non self-aligning type, with or without shield, is permitted. NO STROKER CRANKSHAFTS ALLOWED. (Se Fig. 701.28).
24.27.1 Minimum crankshaft journal diameter is .990".
24.27.2 Crankshaft may be clearanced to a minimum dimension of .775" to permit easier removal of the bearing.
24.27.3 STROKE: Stock stroke is 2.4370" plus .007" or minus .010" for wear. Stroke is checked by pushing piston down to take up play of rod clearance. Stroke is checked from bottom dead center (BDC) to op dead center (TDC). (See Figure 701.16).
24.28 PORTS: Porting Allowed. Ports surfaces are non-visual tech item. NO ADDITION OF MATERIAL ALLOWED. Block MAY NOT be machined or altered on intake or exhaust port "gasket mating" surfaces. NO GRINDING is allowed on underside of valve seat. No HOLES in ports allowed. If port is pin-punched, it may not be done in a manner to prevent entry of a NO-GO into port area. (See Fig. 701.29).
24.28.1 Intake port .880" NO-GO.
24.28.2 Exhaust port 1.005" NO-GO.
24.29 BLOCK Must be as produced, with no alterations or reworking, except block can be relieved for red clearance. Blocks repaired from broken rod damage, cracked lifter area, etc., are permitted providing that repair does not constitute a functional modification of original block. Porting of intake and exhaust ports allowed but block may not be machined on intake or exhaust ports gasket surfaces (See fig. 701.29). No bushings of any kind allowed except for bushings approved in this Tech Manual. DU Bearing may be installed in conventional block on flywheel side. Extra oil hole, 1/8" in diameter, may be drilled on flywheel side of block at crankshaft bushing to better lubricate crankshaft (applicable to all classes). Sleeving of cylinder block is permitted in all Briggs and Stratton engine classes. Regular ferrous sleeves only, with no coatings or plating, such as NicaSil, allowed. The repair of one coil post is allowed, as long as the remaining post is factory and unaltered. Valve guides may be replaced. Aftermarket valve brass or bronze guides allowed as long as they meet stock requirements. Valve guides may be stacked, No KNURLING of guides allowed. Minor grinding of block behind seal in a double bearing block where crank goes through block is allowed (to prevent crank from seizing). Chaffering at bottom of lifter bore for clearance purposes only allowed. Diameter of chamfer cannot exceed .500 and will be checked with a .505 no-go gauge, which measures .505. This applies to stock blocks that have been welded for strengthening purposes. No Undercutting of lifter bore permitted. (See fig. 701.30)
24.30 WELDING: No welding can be done to an engine from the cooling fins upwards except minor welding to lower exhaust bolt hole is allowed for repair (weld cannot protrude into exhaust port). The only welding permitted is to repair damage from a broken rod or cracked lifter bore. Welding of lifter bore for reinforcement or breakage allowed. Installation of bushing guide to help reinforce lifter bore area allowed.
RACE DAY EVENT JOB DESCRIPTIONS
Pit Steward Has full authority - controls and coordinates all activities going on in the pits. Will be responsible for car and driver sign-in sheets, setting up and posting race line-ups and the racing schedule, organizing and setting up a driver's meeting prior to the heat race, and lining up cars in the staging area.
Assistant
Pit Steward Works with Pit Steward in the staging and infield areas. Is responsible for observing cars for rules violations, safety issues, and advising Pit Steward, Flagger and/or Tech Inspector of conditions which require attention. Must have knowledge of kill switch location, and operation of roof latches on all cars.
Tech
Inspector Makes a thorough inspection of each vehicle and driver safety requirements, and is responsible for enforcing all vehicle and engine specifications. Completes a written vehicle checklist record for each car participating in the race event. These records will be maintained and held by the World Formula Modified Tour. The Tech Inspector shall follow up with previously noted illegal vehicles to ensure that they have complied with the standard specifications set forth in the rules. Additionally, the Tech Inspector must have access to all necessary tools for inspections. Tech Inspector must also remain at the track for at least 30 minutes after the race event has been completed. In the event the head inspector is not present, the assistant tech inspector will assume his responsibilities.
Promoter Responsible for promoting races at all tracks. All races must be arranged and booked through the Promoter.