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Post by Candyman on Mar 13, 2008 11:17:14 GMT -8
Non-turbocharged: 150 hp @ 5,600, 162 lb-ft @ 4,000
Bore and Stroke - 3.44" X 3.98"
Fuel Delivery System: Sequential Multipoint Fuel Injection
Compression Ratio - 9.5:1
The engine uses balance shafts to reduce vibration, as the 2.5 liter engine did before it.
Revisions include:
Cylinder head. Reshaped ports and redesigned cooling passages, reduced exhaust valve diameters to increase cooling of the spark plugs and exhaust valve seats.
Pistons. New aluminum alloy pistons have a new crown configuration to improve charge motion for improved idle stability.
Camshafts. A redesigned exhaust cam optimizes performance and idle quality in conjunction with the redesigned exhaust ports and valves in the cylinder head.
Intake Manifold. Refined manifold runner and plenum configurations help provide a broad torque curve with abundant low-speed torque. The intake manifold configuration also helps minimize low-speed wide-open throttle induction noise (called rumble). Ribs molded into the top surface of the manifold provide rigidity and minimize radiated engine noise.
As usual, returnless sequential fuel injection isi used, though the fuel pressure was increased to 58 psi for better warm weather driveability. A larger air cleaner reduces resistance, while a tuning chamber lowers noise.
A Double Start Override feature prevents starter operation when the engine is running and automatically disengages the starter when the engine reaches operating speed to prevent excessive overrun. The alternator charging rate, fuel injection rate, and spark advance, which vary with temperature, are computer controlled. An electronic engine idle speed control provides a low nominal idle speed.
The manual transmission includes a gear brake for reverse, so it is easier to shift into that gear. Other changes were made to increase durability of the gears and clutch. The self-adjusting mechanism maintains a consistent clutch spring orientation as the disc wears, where the spring orientation changed with prior mechanisms. Hydraulic clutch actuation provides pedal isolation from power train vibration and noise and provides a positive feel.
The cable operated transmission has a 3-plane shifter and these gear ratios:
1st - 3.50
2nd - 1.96
3rd - 1.36
4th - 0.971
5th - 0.811
Reverse - 3.42
Final Drive - 3.94
Overall Top-Gear - 3.20
For the four speed automatic:
1st - 2.84
2nd - 1.57
3rd - 1.00
4th - 0.69
Effective Final Drive - 3.910
Overall Top Gear - 2.694
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Post by Candyman on Mar 25, 2008 0:09:31 GMT -8
PT Cruiser 2.4 Turbo complete Engine Specs:
Dimensions
Displacement --148.2 in(cubed)(2429 cm (cubed))
Bore -- 3.44 (87.5)
Stroke -- 3.98 (101)
Bore-to-stroke ratio -- 0.87
Block length -- 16.43 (417.3)
Block height -- 9.36 (237.8)
Rod length -- 5.94 (151)
Connecting rod L/R -- 2.99
Compression ratio -- 9.4:1
* All dimensions are in inches (millimeters) unless otherwise noted.
Heads
The cylinder head is a low profile aluminum casting with pent-roof combustion chambers that house four valves per cylinder. The valve included angle is 48 degrees, allowing large valves.
Dual camshafts run in six bearings with removable caps that are machines in the head base material. Powdered metal valve seat inserts and valve guides are pressed into the head. Spark plugs thread into the center of the combustion chamber through wells cast into the head.
Ports from each valve merge in the head, leading to a single branch (runner) in their respective manifolds. To provide turbulence in the cylinders that contributes to the rapid combustion necessary for low emissions and efficient operation on regular-grade gasoline, the ports cause incoming air to "tumble" from top to bottom of the cylinders. The degree of tumbling action was balance against the conflicting need for high air flow to obtain high power output.
Made of die cast aluminum, the cylinder head cover features an isolated mounting with an O-ring type, silicone perimeter gasket. The DIS coil- mount is built into the cover. The PCV system is also integral with the cylinder head cover.
Manifolds
The one-piece, cast aluminum intake manifold used on first-generation cloud cars has a runner length of 15.7 inches (400 mm). The intake manifold combines tuned individual runners for each cylinder with an integral plenum chamber. Made of thin-wall cast nodular iron, the exhaust manifold has a four- into-one runner design. The four-bolt outlet flange mates with a sealed flex coupling flange on the exhaust pipe.
Later vehicles used a plastic intake manifold. The PT Cruiser has a unique intake designed to fit within the confines of its teeny engine compartment.
Valves (standard, non-turbocharged, early-introduction version; turbo engines are different)
Dual overhead camshafts actuate four valves per cylinder. Valve diameters are 1.40 inch (35.5 mm) intake and 1.20 inch (30.5 mm) exhaust. All valves have 0.24 in. (6 mm) chrome plated stems. Valves have a 48-degree included angle. The exhaust valves are on the right (rearward) side of the head. Each valve is operated by an end-pivot rocker arm that has a 20 mm roller cam follower to reduce low speed friction and cam wear. Rockers pivot on inboard-mounted, fixed hydraulic lash adjusters. Barrel-shaped single valve springs provide control of valve actuation to 7200 rpm.
Camshafts of post-hardened nodular cast iron provide a 236 degree intake duration and a 240 degree exhaust duration. The intake cam centerline is 113 degrees ATDC, the exhaust is 110 degrees BTDC, with 15 degrees of overlap. Intake valve lift is 0.33 inches (8.25 mm) and exhaust valve lift is 0.26 inches (6.5 mm).
Camshaft drive is similar to the 2.0-liter SOHC engine but the intake and exhaust cams have separate drive sprockets. A three-piece molded plastic cover, with inspection plate, completely encloses the belt to prevent damage from foreign matter.
Pistons and rods
Cast aluminum, single-size pistons have pop-up tops with valve cut outs allows broken-belt valve clearance. Piston pins are held in place by press fit to the connecting rods, which differ from those in the 2.0 liter engine only in length.
Crankshaft
Cast of nodular iron, the lightweight crankshaft has eight counterweights and a 75 percent balance ratio. Counterweights straddle each crank pin to balance the bearing loads for smooth, quiet operation. Counterweights straddling each crank pin also allow smaller, narrower bearings. Smaller diameters reduce friction and, therefore, increase fuel economy and power. main bearing diameter is 2.36 inches (60 mm), rod bearing diameter is 1.97 inches (50 mm). The crankshaft main bearing journals are 1.0 inch (25.5 mm) wide for low friction.
A torsional vibration damper is used. The damper has two poly-V pulleys that drive accessories.
Balance shafts
The 2.4-liter engine operates very smoothly because of a system of counter-rotating balance shafts which counteract second-order unbalance, the predominant reason for four-cylinder engine vibration.
The two counter-rotating, eccentric balance shafts, interconnected by gears, are driven by a short chain from the crankshaft. They turn at two times engine speed to offset the reciprocating mass of the pistons and connecting rods and to achieve the desired balancing effect. The balance shafts are enclosed in an aluminum housing mounted beneath the crankshaft in the oil pan. The housing is bolted to the bottom of the main bearing webs of the bedplate and rest in the oil supply. When the engine is running, the balance shafts pump oil out of the housing to minimize parasitic drag which could occur if the shafts spun in the oil.
Bearings
The camshafts need no bearing inserts. They operate directly in the cylinder head. Main and rod bearings have bi-metal inserts.
Lubrication
The powdered metal gerotor oil pump mounts in the front of the block and is driven by the crankshaft.
The system that returns oil from the head is designed to prevent aeration during high-rpm running. The block is inclined to the right (rearward in the car) to allow the oil to drain from the head along the right face of the clock. The crankcase is ventilated through and opening on the left side of the head. Oil capacity is 4.5 quarts plus filer. SAE 5W-30 oil, grade SG/SH is recommended. A half-quart oil filter mounts horizontally to an extension of the oil pump body providing easy access for service.
The oil pan is stamped of a sound-deadening metal-plastic-metal laminate material to minimize transmission of noise. A windage tray, integral with the oil-pan gasket, minimizes aeration of the oil.
Cooling
To reduce complexity, the base of the water pump housing is part of the block. The body of the pump is die cast aluminum, bolted to the front of the block. The pump is driven by the timing belt. The thermostat, radiator nipple, cooling system filler neck and overflow nipple are combined in a single unit.
Fuel Injection
The returnless, sequential multi-port injection (SMPI) uses four dual-spray injectors to provide balanced fuel delivery to all cylinders. Sequential injection improves throttle response and overall driveability compared to single-point injection. The returnless fuel injection system, which is similar to that on the 2.0-liter engine, is less complex than customary systems.
PCV
To minimize oil pullover at high rpm, the crankcase ventilation system includes an oil separator in the cylinder head cover. The separator has baffles that inhibit the flow of oil to the intake manifold. Oil drains out of the baffling on a long, narrow plate pinned to the inside of the cover.
Ignition
The 2.4-liter engine features a direct ignition system (DIS), without a distributor.
The PCM determines idle speed. It actuates a stepper motor and valve in the throttle body to change idle air flow. An idle speed control sensor has been added to signal loads from the power-steering system. A switch on the power steering high pressure hose detects an increase in hydraulic pressure from steering action and increases idle speed when the steering wheel is turned.
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Post by soonercruiser on Aug 20, 2008 10:29:36 GMT -8
WHEW! I'm getting dizzy reading this.... 
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Post by monzaguy on Mar 11, 2010 9:31:28 GMT -8
good write up. I took the balance shafts out and replaced them with a windage tray.Shaved over 20 lbs from the front end and most likely gained 5 horse in the process. Also added a much needed catch can that the factory kind of forgot to put into the PT/GT.
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