Performance engine preparation

Improving reliability

Connecting rods

• tensile loads• reduce reciprocating weight• improve fasteners• aftermarket rods

Performance engine preparation

Improving reliability

Pistons

• light and strong• .200” crown thickness• end gaps with hypereutectic pistons• coated piston skirts• effects of increased clearance?• more cam for less clearance

Performance engine preparation

Improving reliability

Rings

• frictional losses• thin rings reduce friction• Moly rings for less scuff and friction• more end gap for second ring

Performance engine preparation

Improving reliability

Springs

• increased pressure• increased strain on valve train parts• friction dampers generate heat• oil cools springs, but adds to consumption

Performance engine preparation

Improving reliability

Pushrods and rockers

• shafts are more stable than pivot balls• pushrod guide plates• stud girdles help stabilize rockers• increased rocker ratios increase area under curve - also increase wear

Performance engine preparation

Improving reliability

OHC valve trains

• some have rocker ratios• spring pressure much less than OHV

Performance engine preparation

Improving reliability

Oiling systems

• larger pan, windage tray, baffles• high volume pumps to maintain pressure• volume up 5x for 2x increase in clearance

Performance engine preparation

Improving reliability

Bearing properties

• corrosion resistance• strength

• wear• embedability• conformability

Performance engine preparation

Improving reliability

Bearing materials

• Babbitt

Conventional – poor strength Thin – poor conformability & embedability

• Sintered copper-tin-lead

Poor corrosion resistance & wear Metal powders on steel backing

Performance engine preparation

Improving reliability

Bearing materials

• Cast copper-lead

Heavy duty applications Excellent strength & corrosion

• Non-overplated aluminum Wear & corrosion - good

Other properties good

Performance engine preparation

Improving reliability

Bearing materials

• Overplated aluminum

Uses silicon for durability Used by OEMs