Ghost Engine Rule Book
Core Rule
- The engine must be run “out of the box” with the parts it comes with.
- Any modification of a stock part will result in fines and suspensions.
- Checkered Flag offers the “DNQ” kit for ghost engines.
- This kit is not mandatory.
- All engines will be compared to a known stock engine.
Requirements / Allowances
- Must run RLV exhaust pipe number RLV EXF 5026.
- Must have a muffler installed as per AKRA muffler rules.
- USACK may use 5006 exhaust pipe for clearance issues.
- Fuel pump is open, but must be a small engine diaphragm style pump.
- Air filter is open to the team; the filter may not have any inside fillers and must be open all the way around.
- Header wrap is allowed.
- Carb extension must be the black extension that comes with the engine.
- Throttle linkage is on the teams; however, the option presented by Checkered Flag is preferred.
- Engine spec will be compared to a new engine.
- Sealed engines will be purchased by the series only and will be sold for $100 more than market value.
- Sealed engines will not be able to be claimed.
- Sealed engines will not go through the tech process unless the series deems it necessary.
- Sealed engines that have been tampered with will result in a 1-year suspension and a $1,000 fine.
- Sealed engines get a 20 lb weight break.
- Race-winning engines after tech may be sealed with a red seal to ensure the engine stays as checked.
- The series will supply the bolts.
- 6,350K MAX RPM rule (digitally governed).
- Pump 87 fuel only.
- The series may confiscate parts for inspection purposes or to prevent them from being used again in competition.
Engine Swap / Exchange / Claim Rules
- Ghost engines may be swapped for a brand-new engine if the series sees fit.
- Engine swaps may be executed by the series.
- Teams must run the series engine if asked.
- Claim rule is in place at market price.
- May claim 1 time per year.
- A driver can only be claimed once per year.
- DNQ sealed engines cannot be claimed.
Engine Specs
Below is the uploaded Ghost engine spec data in editable text form.
Cam Basic Profile
- Intake duration @ .050" lift = 212
- Intake duration @ .200" lift = 98.5
- Intake centerline = 104°
- Intake max lift = .254" (+/-.005)
- Exhaust duration @ .050" lift = 212.5
- Exhaust duration @ .200" lift = 104
- Exhaust centerline = 110°
- Exhaust max lift = .255" (+/-.005)
Cam Profile — Intake Opening
- .006 = 58° BTDC
- .020 = 19.5° BTDC
- .050 = 0° TDC
- .100 = 17.5° ATDC
- .150 = 34.5° ATDC
- .200 = 55° ATDC
- .225 = 68.5° ATDC
- Max lift = .254" (+/-.005)
Cam Profile — Intake Closing
- .225 = 38.5° BBDC
- .200 = 26° BBDC
- .175 = 15.5° BBDC
- .150 = 6° BBDC
- .100 = 11° ABDC
- .050 = 28° ABDC
- .020 = 46° ABDC
- .006 = 83.5° ABDC
Exhaust Opening
- .006 = 96° BBDC
- .020 = 58° BBDC
- .050 = 38° BBDC
- .100 = 20.5° BBDC
- .150 = 4° BBDC
- .200 = 16.5° ABDC
- .225 = 30° ABDC
- Max lift = .255" (+/-.005)
Exhaust Closing
- .225 = 72° BTDC
- .200 = 59° BTDC
- .175 = 48.5° BTDC
- .150 = 39° BTDC
- .100 = 22.5° BTDC
- .050 = 5° BTDC
- .020 = 12.5° ATDC
- .006 = 52.5° ATDC
Head
- JT-20-12-251 head
- Head thickness = 2.9125"
- Combustion chamber depth = .488"
- Intake seat diameter = .972" (single 45° angle)
- Exhaust seat diameter = .849" (single 45° angle)
- Intake port horizontal opening = .906"
- Intake port vertical opening = .916"
- Intake bowl depth to lowest point of recessed valve guide = 1.197"
- Exhaust port horizontal opening = .945"
- Exhaust port vertical opening = .941"
- Head gasket thickness = .051" (taken from inside cylinder hole area)
Intake Valve Train Components
- R.I. 6870
- Intake valve head diameter = 27.06 mm (1.065")
- Intake valve length = 3.016"
- Intake valve stem diameter = 5.5 mm
- Intake valve weight = 27.48 grams
- Approx. intake valve margin = .026"
- Intake valve seal flange thickness = .023"
- Intake rocker arm length = 2.646"
- Intake rocker arm weight = 37.72 grams
- Intake pushrod length = 5.785"
- Intake pushrod weight = 14.69 grams
- Intake pushrod diameter = .160"
- Intake lifter head diameter = .928"
- Intake lifter length = 1.436"
- Intake lifter weight = 20.15 grams
- Intake lash cap diameter = .3135"
- Intake lash cap thickness = .139"
- Intake lash cap weight = 1.04 grams
Exhaust Valve Train Components
- R.E. 6870A
- Exhaust valve head diameter = .948"
- Exhaust valve length = 3.017"
- Exhaust valve stem diameter = 5.4 mm
- Exhaust valve weight = 26.45 grams
- Approx. exhaust valve margin = .045"
- No exhaust valve seal
- Exhaust rocker arm length = 2.6465"
- Exhaust rocker arm weight = 37.43 grams
- Exhaust pushrod length = 5.782"
- Exhaust pushrod weight = 14.53 grams
- Exhaust pushrod diameter = .160"
- Exhaust lifter head diameter = .928"
- Exhaust lifter length = 1.437"
- Exhaust lifter weight = 20.07 grams
- Exhaust lash cap diameter = .3135"
- Exhaust lash cap thickness = .138"
- Exhaust lash cap weight = 1.03 grams
Intake Valve Spring and Components
- Intake valve spring length = 1.210"
- Intake valve spring wire diameter = .098"
- Intake valve spring O.D. = .841"
- Intake valve spring I.D. = .640–.645
- Intake valve spring retainer flange thickness = .061"
- Intake valve spring retainer weight = 6.73 grams
Exhaust Valve Spring and Components
- Exhaust valve spring length = 1.196"
- Exhaust valve spring wire diameter = .0985"
- Exhaust valve spring O.D. = .843"
- Exhaust valve spring I.D. = .640–.646
- Exhaust valve spring retainer flange thickness = .0605–.0615 (.010 from one side to the other)
- Exhaust valve spring retainer weight = 6.72 grams
Bore / Stroke / Crank / Piston
- Bore = 2.755" (+.008)
- Stroke = 2.171" (+.005)
- Crankshaft journal = 1.79"
- Cam lobe base circle:
- Intake .867"
- Exhaust .868"
Piston Assembly
- Piston assembly weight with rings = 169.70 grams
- Piston diameter @ bottom of piston skirt = 2.755"
- Piston length = 1.8335"
- Top of wrist pin hole to top of the piston = .575"
- Wrist pin length = 2.1475"
- Outside diameter of wrist pin = .716"
- Inside diameter of wrist pin = .552"
- Wrist pin weight = 44.37 grams
- Connecting rod weight = 118.26 grams
- Top of crank journal rod hole to bottom of wrist pin hole in rod = 2.362"
- Piston overlap will be compared to a stock engine.
Carburetor (PZ22)
- Intake manifold length = 2.194"
- Intake manifold flange thickness = .160"
- Intake manifold I.D. @ head gasket surface = .08635"
- Intake manifold I.D. @ carb gasket surface = .08635"
- Venturi horizontal measurement @ center of carb just before slide area = .609" (+.005)
- Venturi vertical measurement taken just before slide area from manifold mounting side = .765"
- Venturi horizontal measurement taken in bottom half of venturi opening from manifold mounting side = .6125"
- Vertical I.D. measurement of air horn @ transition into venturi = 1.121"
- Horizontal I.D. measurement of air horn @ transition into venturi = 1.117"
- Horizontal I.D. of 1st step on manifold side of carb = .861"
- Vertical I.D. of 1st step on manifold side of carb = .861"
- Idle jet 42 (.0165")
- Small holes in idle jet .033"
- Main jet 85 (.033")
- Main nozzle .102"
- Emulsion tube length 1.046"
- Emulsion tube diameter .196"
- Emulsion tube pass through hole .111"
- Small holes in emulsion tube .021"
- Air pick off hole .097"
- Venturi idle air hole .109"
- Venturi idle fuel hole .039"
- Carb slide cutaway .081"
- Phenolic spacer thickness measured @ front and back mating surfaces = .294–.296