The document is a technical manual for the Chevrolet Performance CT525 Circle Track Racing Engine. It provides detailed information about the engine's design, specifications, installation, and maintenance, specifically tailored for off-road circle track racing applications.
Function Description
The CT525 is a high-performance crate engine designed for circle track racing. It is built to deliver significant horsepower and torque, with features aimed at durability and consistent performance in competitive racing environments. The engine is factory-sealed to ensure integrity and equality among competitors in sanctioned racing programs. It is intended for off-road use only and is not street legal.
Important Technical Specifications
The CT525 engine package (P/N 19434598) is based on the LS3 Gen 4 V-8 engine family, specifically the 6.2L LS3.
- Engine Type: LS-Series Gen IV Small-Block V-8
- Displacement: 376 cubic inches (6.2L)
- Bore x Stroke: 4.065 inches x 3.62 inches (103.25 x 92mm)
- Compression Ratio: 10.7:1 Nominal
- Horsepower: 533 hp @ 6600 rpm
- Torque: 477 lb-ft @ 5200 rpm
- Maximum Recommended RPM: 6,700
- Block: Cast aluminum with 6-bolt, cross-bolted main caps. Deck Height is 9.240".
- Crankshaft: Nodular iron, internally balanced, with a 58X trigger wheel for timing.
- Connecting Rods: Powdered metal, 6.098" long, with ARP P/N 134-6006 rod bolts.
- Pistons: Forged aluminum for 103.25mm (4.065") bores, full floating pins, low tension rings (1.5mm top, 1.5mm second, 2mm oil ring).
- Camshaft: Hydraulic roller design (ASA Camshaft profile, P/N 88958770).
- Lift: .525" intake / .525" exhaust
- Duration (@.050 in): 226° intake / 236° exhaust
- Lobe Separation Angle (LSA): 110°
- Cylinder Heads: LS3 rectangular port, cast aluminum, as-cast with 68cc chambers.
- Valve Diameter: 2.165" intake / 1.590" exhaust
- Valve Angles: 15 degrees
- Intake Port Runners: 260cc
- Exhaust Port Runners: 98cc
- Valve Springs: Bee-Hive style, with a natural color and ivory stripe (latest P/N listed in parts list). Spring pressures are 90lb +/- 13 lb at .525" valve lift.
- Pushrods: 1010 steel, 7.325" long.
- Rocker Arms: Investment-cast, roller trunnion, 1.7:1 ratio. Intake (P/N 12696105) are .200" offset, exhaust (P/N 12681275) are straight.
- Lifters: Stock hydraulic lifters with plastic anti-rotation locator trays.
- Oil Pump: Standard Gearotor design. Normal oil pressures: 15+ lbs at 1100 RPM idle, 40+ lbs @ 5000+ RPM.
- Oil Pan: Steel wet sump, P/N 19243065, 8 quarts capacity, RH kick out, 6 trap doors, 4 1/2" deep.
- Balancer: ATI Balancer, P/N 917279, 6 3/4" diameter, with a 6-rib pulley for 10% slower serpentine system drive. Crankshaft is factory drilled for a 3/16" x .500" pin to secure the balancer.
- Ignition System: Production LS3 coils with an ignition box P/N 19355863. Timing is recommended at 27 degrees @ 3000 RPM for 91 octane fuel.
- Spark Plugs: AC Delco P/N 41-985, gapped to .040".
- Intake Manifold: Single plane 4bbl intake, P/N 25534401, designed for LS3 circle track engine, 4150 style carb flange.
- Recommended Fuel: Premium unleaded - 92 (R+M/2)
- Dry Weight: 415 lbs (approximate)
Usage Features
- Circle Track Specific Design: The engine is specifically adapted for circle track racing with components like a carbureted intake manifold, racing oil pan, ASA camshaft, and specific engine breathers.
- Factory Sealed: Equipped with tamper-resistant seals on the intake manifold, front cover, and oil pan to maintain integrity and ensure fair competition. These seals have unique encrypted codes for verification.
- Carbureted System: Designed to work with a single plane 4-barrel intake manifold and a Holley 4150 series carburetor (Model 80541-1, 650 CFM HP series recommended).
- Ignition Control: Uses a programmable ignition box (P/N 19355863) with production LS3 coils. Programming requires a laptop and data cable.
- Engine Installation: Requires aftermarket brackets to adapt the LS bolt pattern to traditional small block or circle track chassis mounts. The rear bell-housing pattern is similar to small block, but the RH upper bolt boss is deleted. Longer dowel pins and correct metric bolts are needed for conventional Chevrolet bell-housings.
- Accessory Drive: Several aftermarket companies offer accessory drive kits (e.g., KRC Racing) that provide alternators and power steering pumps, compatible with the CT525 underdrive balancer pulley.
- Fuel Pump Requirements: Requires an electric fuel pump with a minimum of 110 GPH, wired with an oil pressure shut-off for safety. Alternatively, a belt-driven mechanical fuel pump can be used.
Maintenance Features
- Break-in Procedure: A detailed break-in procedure is provided for new or rebuilt engines, including oil priming, initial start-up, varying RPM operation, and oil changes. This procedure is critical for engine life.
- Oil System:
- Oil Type: 0W-40 Mobil 1 motor oil (must meet Dexron R specification) is recommended.
- Oil Capacity: 6 quarts without filter (the pan alone holds 6 qts, remote filter and cooler add more).
- Oil Filter: Requires the largest possible filter with a minimum of 10 GPH flow capacity and 25 micron filtration rating (e.g., Fram HP1 or larger). A remote filter adapter and -10 AN lines are mandatory.
- Oil Cooler: A remote oil cooler (minimum 7" x 14" with 10 GPM flow and -10 AN or 1/2" inlets) is mandatory to maintain oil temperatures between 200-270 degrees.
- Oil Temperature Sensor: The oil pan has a 1/2" NPT fitting for an oil temp sensor, highly recommended to monitor temperatures.
- Oil Pressure Gauge: An M-16 x 1.5 metric thread port is located at the left rear of the valley plate, requiring an adapter (e.g., Autometer P/N 2268) for NPT gauges.
- Cooling System:
- Radiator: An adequate radiator is mandatory to keep water temperature within 180-210 degrees.
- Surge Tank: A surge or expansion tank is mandatory and must be properly routed with the LH upper head air bleed line to ensure proper air bleeding from the engine.
- Water Pump: GM P/N 12725009 or equivalent is required.
- Electric Fan: Recommended to maintain optimal engine temperature.
- Spark Plugs and Wires: Recommended spark plugs are AC Delco P/N 41-985. GM highly recommends using spark plug wire heat covers due to close header routing in newer chassis designs.
- Crankshaft Bolt: An ARP bolt P/N 234-2503 is required, installed with red Loctite and silicone sealer, torqued to 235 ft lbs.
- Breather System: The left-hand valve cover is modified with two -16 AN male fittings for breathers. It is critical to set up ventilation tube routings and heights to allow for drain back and prevent crankcase pressure buildup.
- Service Parts List: A comprehensive list of part numbers for various engine components is provided for easy reference during maintenance and repairs.
- Warranty: The engine has no warranty, as it is intended for off-road racing activities only.
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