CLONE
TECHNICAL MANUAL
AND RULES
For information on the Box Stock Project LLC contact
Jimmy Sims @
office 386
-
938
-
4211 or cell 386
-
249
-
0122 Email to
sims1@windstream.net
.
Box Stock Project
LLC
Box Stock Project Engine Rules
For Use In Box Stock Project Classes
Box Stock Project yellow engine: 6.5h
p OHV 196cc must have
the stamped
“Box Stock Project” on the front of the bloc
k
.
All Engine parts must be stock OEM parts unless otherwise spelle
d out. All
gaskets must conform to stock configuration. Using more than one gasket
for side cover clearance is acceptable. Allow plus or minus .005” tolerance
on all measurements
except for stated minimum,maximum or no
-
go
dimensions when compairing to a
stock oem part.
Fuel will be gasoline. 87
-
93 octane maximum. No aftermarket coatings of
any type are permitted on any part of the engine.
Fuel tank must be removed from engine for safety reasons.
Floor mounted fuel tank can be pulsed from crankcase o
r valve cover. Any
pulse type fuel pump permitted.
Carburetor: Huayi or Rui*ing allowed. All stock carb gaskets must be
present. One extra gasket must be used with restrictor plates. Choke
assembly must be functional. Choke bore must be cast. Venturi .6
15” No
-
Go. Back carb bore .751” No
-
Go. Emulsion tube (E
-
tube) must remain
stock .064” No
-
Go. Main jet Non
-
Tech. Low Speed idle jet .019” No
-
Go.
After market air filter
is OK for use
(
K&N style filter) maximum length:
1.375.
Block must remain stock. Ma
ximum bore is 2.685”. Stroke is 2.123” plus or
minus .005”.
Governor and governor components are non
-
tech.
Use of multiple gaskets is okay (gaskets must be stock configuration).
Combustion chamber minimum: 26.5cc with piston at TDC. To be
measured using pr
escribed technique.
Block may be welded for repairs as long as the repair does not constitute a
functional modification to the block. No welding to block above
cooling
fins
.
Cylinder Head:
No porting, grinding or modification. Valve seats
must
have
two
angles: single 45° bottom and single 30° top. Head gasket must be
stock configuration.
Valve train will remain stock. No polishing. No grinding. No Alterations.
Stock 1:1 ratio OEM rocker arms only. Stock valve springs only. Maximum
spring wire diameter is
.0705”. Maximum spring pressure is 10.8 lbs. at an
installed height of .850”.
Springs must be wound in same direction as
compared to known Box Stock spring
Stock rod only; no modifications. Stock crankshaft only; no modifications.
Stock piston only. Stoc
k rings only.
Camshaft:
Maximum running lift on exhaust is .242” taken on valve spring
retainer with zero lash. Maximum running lift on intake is .238” taken on
valve spring retainer with zero lash. Camshaft base
circle measurement
:
.865”
-
.005 “+ .01
0”.
(.860
-
.875)
Duration check for Intake and Exhaust
lobes. Intake duration of 218.5 degrees
max.
at .050 lift/85.5 degrees at
.200 lift. Exhaust duration of 221.5 degrees
max.
a
t .050 lift and
96.5
degrees
max.
at .200 lift. (All checks will allow
+2 degrees for wear and
gauge variances.)
Flywheel and ignition coil must be stock. NO alterations, NO machining.
Timing must be stock with stock flywheel key. Plastic fins must remain
stock.
Header and Muffler. Maximum length on header and muffler is 14
” and
minimum length is 10”. Header must be single stage maximum .750”
outside diameter. Muffler must be the Weiner type, part #89966 (Rotary
stocks these mufflers, also can be purchased at most lawnmower shops).
Muffler must be screwed on and unscrewed fo
r technical inspection.
Muffler must be stock and unaltered.
Pull starter must be present and remain stock. You may rotate pull starter
for a better angle to crank from.
Engine oil recovery system mandatory (oil catch can).
The above rules are written wit
h the idea of simple tech in justifying the
winner and runners up.
Do Not Read Into The Rules What Is Not There!
Jimmy Sims, BSP