So, you have always wanted to build your 4A-GE to Formula Atlantic specs,
you just couldn't find them.
Well, here they are, courtesy of TRD. I recieved these specs from TRD back
in 1988. Thanks a lot, TRD.
General:
Cylinder Firing Order: 1-3-4-2
Engine Bore: 81mm (3.189")
Engine Stroke: 77mm (3.031")
Oil Viscosity: 40 or 50 weight, depending on air temperature
Fuel Octane Rating: 108 prefered
Operating Oil Temperature: 200º-230º F, above 230º there is power loss
Operating Water Temperaure: 180º-200º F
Oil Pump Operating Pressure: 80-90 lbs
Spark Plug: Champion C55C or C57C
Compression Ratio: 12.7:1 maximum
Intake Camshaft Timing: 102º Lobe Center
Exhaust Camshaft Timing: 102º Lobe Center
Intake Valve Lash (cold): .012"
Exhaust valve Lash (cold): .013"
Ignition Timing: 28º BTDC @ 2,000rpm
Clearances'
Valve Lifter to Bore: .0005" - .0028"
Camshaft Journal: .0014" - .0028"
Piston Ring Gap (#1): .016" - .018"
(#2): .015" - .017"
Piston to Cylinder Wall: .0045" - 0050"
Wrist Pin Diameter: 19mm (.7480")
Wrist Pin: .0006" - .0015"
Main Bearing: .0020" - .0028"
Thrust Bearing: .003: - .006"
Con Rod Large End Diameter: 1.7726" - 1.7716"
Con Rod Bearing: .0025" - .0030"
Con Rod Side: .008" - .012"
Crankshaft Nose Diameter: .9842" - .9834"
Crankshaft Main Journal Diameter: 1.8897" - 1.8892"
Crankshaft Con Rod Journal Diameter: 1.6525" - 1.6520"
Pilot Bushing ID: .678" - .676"
Input Shaft Diameter: .669" - .668"
Cylinder Head Flatness: Within .001"
Valve Spring Height (installed): 1.425" - 1.398"
Valve spring Pressure (installed): 50 psi @ installed height
Final Combustion Chamber Volume: 33.9 cc minimum per cylinder,
including Cylinder Head Gasket.
Bolt Torque Specs
Crankshaft Front Pulley: 60ft/lbs
Camshaft Pulley: 35 ft/lbs
Idler Pulley: 27 ft/lbs
Crankshaft Main Bearing: 47 ft/lbs
Cylinder Head: 43 ft/lbs
Flywheel: 85 ft/lbs
Connecting Rod: 45 ft/lbs
Back to Gunter Automotive Tech Page
