Formula Atlantic complete 4ag parts list and specs

[gda03subaru]

i found this list, even includes factory part numbers for a trigger wheel, pick up sensor and what not, may be helpful.

(p.s. dont even bother calling a toyota dealer for these or trdusa for that matter(already tried) you would have to call toyota of japan directly)


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

[mooreofit]

cool part numbers!!!


they run them motors loose!!! .0025 to .0030 on the oil clearance on the bearings!!!!! doesnt make much sense. i run .0015! i ran .0025 on my piston to wall clearance! nice and tight! no piston slap on the forgies either! wiseco recomends .003 at the minimum but thats just a little c.y.a. winters coming and i didnt have any problems with the pistons heating faster than the block during the last cold snap but we will see what it looks like when its 30* outside.


p.s. formula 1 motors are built so tight that they are basically ceased below 80*f these motors are built for revs. the least amount of slack the less deflection you will get at high rpms so this whole loose thing has me confused.

[gda03subaru]

i found it a bit strange as well, but they have to have a reason, but im willing to bet the actual motor specs are hush hush, this spec sheet is probably for public use not race use

[mooreofit]

i bet its cause the motors are pulled and reasambled after every race as far as trd is concurned but that loose bearing spec still doesnt seem right.

[86boy]

BROUGHT BACK FROM THE DEAD!!!

I had this explained to me when I was doing my GZE rebuild from a guy at the machine shop. He told me if I go to the loose side of things the parts when they expand actually tighten up when being pushed to the limited due to the difference in metals. My valve clearnaces are not to far off from this formula atlantic engine in my GZE. My intake valves are at 0.011" and the exhaust is 0.013". Also the bearing clearances to allow more oil through with a higher flowing oil pump totally makes sense.

80-90 psi is crazy especially with that bearing clearance! kinda makes sense to let more oil through and up the flow rate of the oil pump. Maybe this guy here actually knows wtf he's doing.... hahaha!! The loose side of things is more for endurance. that guy told me drag cars will build towards the tight side since they generally rebuild between runs. Where as endurance engines are built a little loose to handle the high rpm for longer periods of time. Same goes for the the clearances on the rest of the engine... piston rings etc. After seeing those specs it really makes me think a little more about my setup and how it was kinnnddaaa on a similiar style build just different parts.