3.5 Motor Swap DIY and Info

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====Rocker Arm Assemblies==== ====Rocker Arm Assemblies====
-The 3.5 continues to use hydraulic lifters in the rocker arm assembly. Unfortunetly, two solid supports were eliminated in the rocker assembly (as well as the mounting points in the head) and replaced with retaining springs. This design downgrade was most likely due to the lower redline of 3.5 at 5900rpm. Some sort of solid spacers should not be very difficult to machine.+[[Image:Rocker_Assembly_Compare.jpg|250px|thumb|right|3.5RL TOP, 3.2 Bottom]]The 3.5 continues to use hydraulic lifters in the rocker arm assembly. Unfortunetly, two solid supports were eliminated in the rocker assembly (as well as the mounting points in the head) and replaced with retaining springs. This design downgrade was most likely due to the lower redline of 3.5 at 5900rpm. Some sort of solid spacers should not be very difficult to machine.
====Valves==== ====Valves====
The intake and exhaust valves are the same size and part number as used in the Type I Legend. The Type II used a 1mm larger intake valve. The intake and exhaust valves are the same size and part number as used in the Type I Legend. The Type II used a 1mm larger intake valve.

Revision as of 11:14, 18 May 2007

Contents

Engine Block

Block & Displacement Increase

The biggest reason to upgrade to the 3.5RL motor is, of course, for the increased displacement of 3.5 litres (from 3.2 litres). This increase is from a 7mm longer piston stroke from 84mm to 91mm making the block slightly undersquare for low end torque improvement. The same cylinder bore of 90mm was used. Aluminum block casting with cast iron cylinder liners and 6 bolt mains. To compensate for the increase stroke the height of the block deck was raised ??? mm.

Forged Crankshaft

The crankshaft is made of forged steel for bullet proof reliability. Larger main bearing journal supports are used. Journals are microfinished. The bearing surfaces use a pyramidal structure for better oil retention, durability and lower friction. Stroke increased to 91mm.

Forged Connecting Rods

A special block forging method is used for precisely measured and balanced connecting rods.

Full Floating Piston Pins

For engine noise reduction, full floating pins are used. Tolerances between the piston and pin were tightened.

Balance Shaft

A rotating balance shaft helps to damp vibrations inherent to 90 degree V6 motors. The balance shaft, mounted on the passenger's side of the block, is driven by a separate toothed belt and tensioner mounted directly in front of the timing belt. It is theorized that the balance shaft also helps reduce the engine harmonics that cause the well known headgasket failures with the 3.2 block.

Dished Pistons

Since the combustion chamber size (in the head) are the same, and the stroke increased, dished pistons are used to maintain the same compression ratio of 9.6:1.

Oil Pump

The engine oil pump casting is different, the area where the engine oil cooler is on the 3.2 is now occupied by the balance shaft drive and belt.

Water Pump

The water pump no longer has the two auxillary outlets for the differential cooler or engine oil cooler. This area is occupied by the balance shaft drive belt and is now covered by a larger lower timing cover.

Motor Mounts

The motor mount system used on the 3.5RL is completly different from the Legend. The RL utilized an addition set of mid mounts towards the back of the block that are not used with the Legend swap. The Legend's mid mounts are on the the transmission bellhousing. The front motor mount brackets or "legs", are angled in an incompatible way. Fortunetly, the driver's side 3.2 Legend motor mount bolts directly to 3.5 block. The passenger side bracket will not line up and has to be modified. This is due to the balance shaft occupying the area where the mount was before.

Cylinder Heads

Casting

To compensate for the taller deck surface, the location of the intake runners was changed so that the same size and mounting points of the 3.2's intake manifold could still be used

Camshaft

The 3.5 has a lower overlap, "mild cam" which helps to increase low end torque production. Valve overlap is the amount of time (in degrees) the intake and exhaust valves are open at the same time at TDC. The higher overlap cam found in the type II permits better breathing at high RPM sacrificing low end torque production.

Rocker Arm Assemblies

3.5RL TOP, 3.2 Bottom
Enlarge
3.5RL TOP, 3.2 Bottom
The 3.5 continues to use hydraulic lifters in the rocker arm assembly. Unfortunetly, two solid supports were eliminated in the rocker assembly (as well as the mounting points in the head) and replaced with retaining springs. This design downgrade was most likely due to the lower redline of 3.5 at 5900rpm. Some sort of solid spacers should not be very difficult to machine.

Valves

The intake and exhaust valves are the same size and part number as used in the Type I Legend. The Type II used a 1mm larger intake valve.

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