GCS Mighty Kart Rules

Driver Age requirements

     Age’s 8-16

Minimum Weight with Driver

·            325 Pounds

     Engines allowed: Briggs and Stratton Animal Only Allowed. 

d  Animal engines built to WKA/IKF unrestricted "stock" specs only. Other              O engines may be run, but no points or trophies will be awarded.

·          Alcohol only

·        Dry type clutch only, can be single/multi disc or drum type. No wet clutches or torque converters     allowed.

·        Must have a clutch/chain guard

·           Carbureted only. No injectors or blowers.

·        Must have a pull point at the spark plug that is easily accessible by track officials.

·      

Chassis

·   Production racing chassis, Champ kart type, recommended.

·   Must have full roll cage.

·   Must have front bumper extending beyond the front tires.

·   Must have nerf bars extending at least to the middle of the tires.

·   Must have at least a 5-point approved racing harness, attached to the chassis per manufacturer's

i    instructions.

·       A properly mounted racing seat is required (no tie wraps, please).

·       Must have a live rear axle. Must have snap rings or safety wire on axle ends.

·       No wings.

·       Must be chain driven from the crank to the axle.

·       Chassis must have some type of body that completely covers the driver from the waist down.

·       Any part of the chassis that could come into contact with the driver must have padding.

·       Numbers must be on both sides and on the front that can easily be read and contrast with the karts paint job.

Safety Equipment

·       A Snell M, SA, or SFI 24.1 approved full face helmet with face shield. No bicycle or open-face helmets allowed. Snell SA or SFI 24.1 recommended.

·       An approved, fire resistant SFI rated racing suit is mandatory, SFI 3.2A-5 recommended.

·       Neck collar is mandatory.

·       Gloves are mandatory.

·       Arm restraints and/or window nets are mandatory.

 Gulf Coast Speedway Mighty Class Briggs Animal Engine Tech Specifications


1. Shrouds and covers: Engine shroud and covers and control bracket must be intact and not modified, except control cover may be modified to attach fuel pump. Alternatively, Briggs & Stratton panel #555699 may replace plastic control cover and control cover bracket. Bracket attaching flywheel shroud to control cover bracket may be removed from flywheel shroud. Taping of flywheel screen allowed, Fixed screen must be affixed to shroud to cool air intake area. Cylinder shield may be trimmed for CHT sensor installation and header flange clearance. Cylinder shield may be notched to clear gusset on new block (#555687) which is now legal.
2. Air Filters: Any air cleaner permitted.
3. Carburetor: PZ Model 22 Carburetor only. Must be stock as from the factory except those parts inside the float bowl that can be removed through the float bowl are non-tech items, with the exception of the fuel discharge nozzle height in the venturi. This is a tech item for height only. The end of the nozzle can be modified. The end of the nozzle may not protrude into the venture area more than 0.060”.
4. Throttle Bore: Maximum throttle bore inside diameter is .874” NO-GO. Must be as cast.
5. Choke Bore: 1.149” No-Go. Must be as cast
6. Venturi: Verticle .794” No-Go, Horizontal .615 No-go. No machining allowed.
7. Horizontal Area: A .602” No-Go will be the horizontal check for the narrowest part of venture. May not enter slide area.
8. Air pick off hose: Maximum .062” No-Go
9. Slide: Minimum length top edge of slide to deepest part of cut away 1.142” Must be stock as from factory.
10. Needle jet: shall have an overall length of 1.677” min. to 1.692” max. Taper on the needle must remain stock as from factory. Needle diameter must not be less than .070” at .500” from the tip.
11. Restrictor Plates. None
12. Intake: Stock animal intake as supplied from the factory. No modifications allowed. Length is Max- 1.740, Min- 1.760. Inside I.D. is .905” No-Go Max & .805” No-Go Min.
13. Intake To Block Gasket: Maximum thickness is .070”.
14. Fuel Pump: Auxiliary pulse type fuel pump allowed. Fuel pump must be pulsed only from the crankcase upper oil cap. Pulse line not to exceed 15”. Maximum ID of pulse line is ¼”.
15. Valve Cover: Stock valve cover as from factory.
16. Valve Cover Gasket: Valve cover gasket must meet stock configuration . No sealer allowed.
17. Rocker Arms: Must be stock as from the factory. Minimum length of 2.865”
18. Camshaft: Maximum lift of .252” taken directly off the valve spring retainer at zero valve lash. All cam profile readings must be taken with zero valve lash and degree wheel at top dead center (TDC) of compression stroke. Readings shall be measured from push rods. Set the dial indicator at zero and do not reset during the profile process. Only stock factory camshaft from Briggs & Stratton is permitted, part number 555532 & 555584. Camshaft lobes may be ground but not to exceed 0.870 base circle. Mechanical relief is non-tech. camshaft lobes must remain flat and of original width.
19. Camshaft Profile limits:
Intake

Lift Degrees
.020”………………………....18° to 13° BTDC
.050”…………….……..….0 TDC to 4° ATDC
.100”…………………16° ATDC to 20° ATDC
.150”…………………33° ATDC to 37° ATDC
.175”…………………42° ATDC to 46° ATDC
.200”…………………53° ATDC to 57° ATDC
.225”………………….67° SYFV to 71° ATDC
MAX……………………….…Max. lift is .257”
.225”………………….39° BBDC to 35° BBDC
.200”………………….25° BBDC to 21° BBDC
.175”………………….15° BBDC to 11° BBDC
.150”…………………….5° BBDC to 1° BBDC
.100”………………….12° ABDC to 16° ABDC
.050”………………….28° ABDC to 32° ABDC
.020”………………….44° ABDC to 49° ABDC


Exhaust

Lift Degrees
.020”………………….61°BBDC to 56° BBDC
.050”…………………44° BBDC to 40° BBDC
.100”…………………27° BBDC to 23° BBDC
.150”…………………..11° BBDC to 7° BBDC
.175”……………………1° BBDC to 3° ABDC
.200”…………………10° ABDC to 14° ABDC
.225”…………………24° ABDC to 28° ABDC
MAX……………………….…Max. lift is .257”
.225”…………………78° BTDC to 74° BTDC
.200”…………………64° BTDC to 60° BTDC
.175”…………………53° BTDC to 49° BTDC
.150”…………………43° BTDC to 39° BTDC
.100”…………………27° BTDC to 23° BTDC
.050”..…………………10° BTDC to 6° BTDC
.020”………………..…5° ATDC to 10° ATDC


20. Ball Rocker: As stock from factory. .590” no-go to 0.610” must go.
21. Push Rod: Stock as from factory. .185” to .190” diameter. Length 5.638” to 5.658”.
22. Head Bolts: Stock head bolt must be utilized and four are mandatory.
23. Head Gasket: Must be of stock configuration. .042” minimum thickness measured in four places between head bolts. Measurements to be made from inside of gasket. Measurement to be made with micrometers.
24. Cylinder Head Plate: Must be stock as from the factory. Cylinder head plate gasket must be stock configuration. .060” maximum thickness.
25. Rocker Arm Studs: Must be stock as from the factory. Studs must be installed as per the factory, 90 degrees to the plate surface.
26. Valves: Stock valves ONLY. Must be one angle. Valves may not be polished or lightened. If working area (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. Minimum intake and exhaust valve length 3.372”+ or - .010”.
27. Intake Valve: 45° Intake valve minimum diameter is 1.055” – 1.065”. Depth of dish in valve .99” - .119”.
28. Exhaust Valve: 45° Exhaust valve minimum diameter is .935” - .945”. Depth of dish in valve .084” - .104”.
29. Valve Springs: Maximun valve spring length is 0.930” no go. Wire diameter is 0.103” to 0.107”, measure in three places on spring. Inside diameter of spring 0.615” minimum, 0.635” maximum. Must be identical in appearance to factory part and have 4 to 4.5 coils in stack.
30. Intake and Exhaust Spring: Maximum valve spring length is .930”. Wire diameter .103” - .107”, measured in three places on spring. Inside diameter of spring .615” minimum, .635” maximum.
31. Valve Spring Retainers: Stock as from the factory. .055” - .075” thickness.
32. Cylinder Head: Stock Briggs & Stratton cylinder head part #558. Head gasket surface area may be machined. Bosses on head may be tapped to allow for the attaching of a header brace. Depth of head at shallow part of head .011” minimum. Depth at floor of head .319” minimum. Depth to top of valve seat .360” maximum, .335” minimum.
33. Valve Seats: Must be 45° angle ONLY on valve seats. Stock Briggs & Stratton valve seats are mandatory. Intake seat inside diameter .966” - .972”. Exhaust seat inside diameter .841” - .850”. Exhaust and intake seat 45° angle.
34. Ports: Must have stock configuration. No porting or modifications of any kind allowed. No machining, sanding, buffing, bead blasting or alteration of surface finish or any port dimension.
35. Intake Inlet: .918” No-Go when checking 90° to stud pattern No-Go will be straight, when checking in line with stud pattern No-Go will set on floor of port at bottom and stop at upper edge of port on top.
36. Exhaust Outlet: .980 No-Go
37. Valve Guides: Stock valve guides as supplied by factory. Stock replacement guide part #555645 allowed. Maximum depth from intake cylinder gasket surface to top of valve guide is 1.255”.
38. Deck / Piston Clearance: Machining of deck surface is permitted. Piston pop-up cannot exceed .005” above block surface in the center of the piston. When measuring piston pop-up, it should be accomplished on bar stock on a parallel with the piston wrist pin. In center of the piston, and using a dial indicator, check the piston pop-up in this area.
39. Cylinder Bore: Over boring of .035” allowed. No circular or machined grooving of cylinder is allowed in any position of cylinder. Stock cylinder bore is 2.690”.
40. Stroke: Stroke is 2.204” maximum. Stroke is checked by pushing piston down to take up play of rod clearance. Stroke is checked from bottom dead center (BDC) to top dead center (TDC).
41. Ignition: Briggs & Stratton factory stock coils or B & S PVL 4 legged coil are allowed. PVL coil must be used with the PVL flywheel. No slotting of mounting holes or machining of attaching bolts is permitted. There must be resistance from ground to the plug wire. Spark plug connector must be stock factory type. Rubber plug boot is allowed. Note: Coils may be rechecked for correct ohms reading after a minimum of 10 minutes. Resistance for 2 leg coil from plug wire must be 3,000 ohms minimum and 6,000ohms maximum.
42. Starter: Recoil starter may be retained as produced and intact. Electric may be utilized.
43. Flywheel: Only stock flywheel is permitted. Any flywheel key, or no flywheel key, is allowed. No altering or machining, glass beading, or sandblasting of flywheel is 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, Briggs & Stratton part #555625 is the only flywheel allowed. Fan assembly part #555526, is the only legal fan assembly allowed with no modifications.
44. Weight of Flywheel: 4 lbs. 8oz. PVL flywheel 4 lbs. 1 oz.
45. Crank Case Side-cover: Side-cover must remain stock.
46. Valve Lifters: Stock lifter as supplied from factory. Head of lifter have a minimum .820” diameter, .860” diameter maximum. Maximum length of lifter 1.515”, 1.525” minimum.
47. Connecting Rod: Stock connecting rod only. Connecting rod may not be lighter in weight than known stock component. No under-sizing of connecting rod is permitted. However, rod may be clearanced providing that it is in stock configuration in finish with no dimpling or media-blasting. Rod ends must be concentric with crank case journal and /or wrist pin with no chamfer or breaking of edges. The use of all first and second generation stock rod bolts is allowed. Stock rod length is 2.419” minimum, 2.429” maximum. Measured from bottom of wrist pin to top of crankshaft journal. Oil hold opening new or old style rod is .185” No-Go. Billet rods allowed as long as they meet stock specs for length, weight, etc…
48. Wrist Pin: Wrist pin must not be altered. Maximum inside dimension of wrist pin is .414”. Outside dimension is .624” - .626”. Minimum length 1.901”.
49. Rings: Three rings are mandatory. Compression or top ring chamfer or Zero must face up and must remain as manufactured. Scraper ring must be installed with inside chamfer down and O up. Stock oil ring must be installed as from factory. Ends of ring must remain flat. Excessive end gapping of rings not allowed. Rings must conform to all listed factory specifications and be of stock configuration. Known standards for piston/ring configuration are Briggs & Stratton factory approved parts. No machining of rings allowed. Exception: Lapping and end gapping allowed – Rings must be in one piece when removed from block. Minimum width top two rings .095”. Thickness top two rings .059” - .064”. Oil ring minimum width .065”. Ring groove must be present. Expander ring must be installed. Oil ring thickness .098” - .102”.
50. Piston: Stock, unaltered Briggs & Stratton piston mandatory. Wrist pin hole must not be altered or relocated. Deck above top ring must not be altered. No machining is allowed on piston. Arrow must point toward flywheel. From top of piston to wrist pin bore .658” minimum measurement. New style circ clip piston allowed. Minimum piston length is 1.762”.
51. Crankshaft: Stock factory crankshaft mandatory. Stock factory timing gear mandatory and must be installed properly. Lightening, polishing of counter-weights, addition of metal or other material is not permitted. Offset crankshafts are not permitted. Shims if used must be installed as from factory. Crankshaft journal diameter is 1.094” – 1.100”.
52. Block: Block must be as produced with no alterations except repair from broken rod damage. One coil post is allowed as long as the remaining post is factory and unaltered. No knurling of guides allowed. Latest Briggs and Stratton cylinder block part #555655 is allowed. No welding above cooling fins upward.
53. Welding: No welding can be done to an engine. The only welding permitted is to repair damage from a broken rod.
54. Clutches: Dry clutches are mandatory.

 

Interpretation of these rules is to the discretion of the tech official. The tech official reserves the right to disqualify any car or driver as he deems necessary.