HERCULES QXLD3 SPECIFICATONS
The information contained in this document has been derived from the following sources:
1) Operation and Maintenance Manual for QX Series Engines (1956) Hercules Motors Corporation, Canton, Ohio.
2) “A New Standard of Excellence: Diamond T Improved Super Service Engine” (undated brochure), Diamond T Motor Car Company, Chicago, Illinois.
3) “Motor’s Truck Repair Manual” (1948) 2nd edition, Motor, New York, New York.
4) “Motor’s Truck and Tractor Repair Manual” (1951) 4th edition, Motor, New York, New York.
5) “Suggestions for the Care and Operation of Diamond T Trucks” (undated) Diamond T Motor Car Co., Chicago, Illinois
When different specifications are given, I indicate both specifications with the source.
MAJOR ENGINE SPECIFICATIONS for HERCULES QXLD3 ENGINE
Cylinders: six
Bore and stroke: 3 7/16” x 4 1/4″
Displacement: 236 cubic inches
Compression Ratio: 6.5 to 1
Torque: 190 ft. pounds @ 1400 RPM
Horsepower: 91 bhp @ 3200 rpm
Rotation: clockwise, looking at cranking end
Firing Order: 1-5-3-6-2-4
Block, material: Nichrome iron
LUBRICATION
Forced feed gear pump
Pump capacity: 4.9 gallons per minute
Oil pan capacity: 6 quarts
Oil Filter: Purolator L30034 or Wix 51006
MISCELLANEOUS
Timing drive: Helical gears
Water-pump type conventional
Pump capacity: 50 gal. Per minute
Air-cleaner: Oil bath
Engine mounting: Cushion-cradle
CRANKSHAFT AND MAIN BEARINGS
No. of bearings: seven
Bearings, type: precision (insert type)
Bearing Length:
Front 1 1 5/16”
Center 4 1 15/16”
Rear 7 1 15/16”
Int. 2, 3, 5, 6 1 7/32”
Overall bearing length: 10 1/16”
Journal hardening: Tocco
Journal Diameter:
Standard: 2.497-2.498”
.020” 2.477-2.478”
.040” 2.457-2.458”
.060” 2.437-2.438”
Main Bearing Clearance:
Motor’s Truck Repair Manual gives a clearance of .0015-.002”
The Hercules Operation and Maintenance Manual gives the following clearances:
Babbitt lined shell: .002-.003”
Hi-lead bronze shell: .0035-.004”
Crankshaft thrust clearance: .002-.004”
CONNECTING ROD and CONNECTING ROD BEARINGS
Connecting Rod material: heat treated nickel chrome molybdenum steel
Journal Diameter:
Standard: 1.987-1.988”
.020” 1.967-1.968”
.040” 1.947-1.948”
.060” 1.927-1.928”
Rod bearings, type: Precision (insert)
Connecting Rod bearing clearance:
Motor’s Truck Repair Manual gives a clearance of .0015-.002”
The Hercules Operation and Maintenance Manual gives the following clearances:
Babbitt lined shell: .001-.0015”
Hi-lead bronze shell: .0015-.002”
Connecting rod side clearance: .005-.010”
CAMSHAFT
Camshaft Journal Diameter: 1 ¾”
Length of bearings:
Front and rear: 1 1/32”
2 and 3: 9/16”
Camshaft bearing clearance: .0015-.0025”
Camshaft gear back lash to crankshaft: .000-.002”
Oil pump gear back lash to camshaft: .008-.010”
VALVE DATA
Valve arrangement: L-head
Inlet valves: 1 ½” Nichrome Steel
Exhaust valves: 1 ¼” Aust. Al. steel
Valve seat diameter – exhaust 1 ¼”
Valve seat diameter – intake 1 3/8”
Face of valve seat – exhaust 3/32 – 1/8”
Face of valve seat – intake 3/32 – 1/8”
Valve stem clearance in guide:
Motor’s Truck Repair Manual gives a clearance of .001-.0015”
The Hercules Operation and Maintenance Manual gives a valve stem clearance of .002-.0025”
Push rod or tappet clearance in guide: .00075 – .001”
Valve tappet clearance:
Intake (running, hot) .008”
Exhaust (running, hot) .010”
Valve seat angle degrees (exhaust and
intake): 30 degrees
Average valve spring pressure: 41 lbs. @ 1 9/32 ”
PISTONS AND RINGS
Piston material: aluminium alloy
No. of rings: three
Piston pins: 7/8” carburized
Piston ring gap: .015-.020”
Piston ring land clearance – top: .0035-.005”
Piston ring land clearance – other rings: .0015-.003”
Piston pin clearance (aluminium piston): hand push fit
Piston Clearance (for aluminum pistons):
Motor’s Truck Repair Manual gives a piston clearance of .0025”
The Hercules Operation and Maintenance Manual gives a piston clearance of .003-.0035”
MISCELLANEOUS CLEARANCES
Bellhousing clearance on chamfer: .012-.025”
Accessory or water pump shaft end thrust: .002-.003”
Idler bearing (shaft) clearance: .00075-.001”
TORQUE WRENCH TENSION:
Foot pounds
Cylinder head screws – with washers (all) 100
Cylinder head screws (8-10-12-14-15-17-18-20-22-24) 80
Cylinder head screws (all others) 90
Cylinder head stud nuts 60
Connecting Rod bearing caps: 39
Main bearing caps (front and intermediate) 70
Main bearing caps (center and rear) 60
Prepared by: Allan Garber
10914 – 125 Street
Edmonton, Alberta
Canada
T5M 0L6
