When you are pushing the limits of an air-cooled Volkswagen engine, the stock connecting rods quickly become the weakest link in your rotating assembly. These EMPI I-Beam Connecting Rods are engineered specifically for high-performance builds that demand superior strength without the excessive weight of a heavy H-beam. Forged from high-grade 4140 chromoly steel, these rods offer a massive upgrade over original equipment designs. By utilizing a 5.5-inch length, these rods are slightly longer than the standard 5.394-inch stock length, making them the ideal choice for builders looking to optimize their rod-to-stroke ratio. This increased length reduces the rod angle at the midpoint of the stroke, which significantly decreases side-load friction against the cylinder walls, leading to a cooler-running engine and a longer lifespan for your pistons and rings.
Precision is everything in a performance flat-four, and EMPI has delivered with a set that is balanced to within exacting tolerances. These rods feature the popular 2.000-inch Chevy journal, a standard in the world of stroker crankshafts, allowing you to build a larger displacement engine while maintaining a slim rod profile for better internal clearance. To ensure these rods stay together under the most grueling conditions, they are equipped with heavy-duty 3/8-inch rod bolts featuring a 200,000 psi tensile strength. Whether you are building a high-revving street car, a weekend drag racer, or a rugged off-road rail, these I-beam rods provide the structural integrity and high-RPM stability required to keep your crankcase from becoming a scrap metal bin. When you buy from Appletree Automotive, you are getting the peace of mind that comes with decades of air-cooled expertise.
These connecting rods are designed for performance Type 1 based engines utilizing a crankshaft with 2.000-inch Chevy journals. Please note that these will NOT fit stock VW journal crankshafts. They are compatible with the following models provided the appropriate stroker crank is used:
1. Verify Camshaft Clearance
When you are installing 5.5-inch long rods on a stroker crankshaft, the physical "swing" of the big end of the rod is wider than a stock setup. It is absolutely critical to perform a "dry fit" of the rotating assembly to check for clearance between the rod bolts and the lobes of the camshaft. In many high-lift performance builds, you may need to use a clearanced camshaft or slightly "clearance" the rod bolt heads to ensure there is no interference. Always maintain at least .040-inch to .060-inch of clearance between moving parts to account for heat expansion and high-RPM harmonic stretch. Don''t skip this step, or you will end up with expensive metal shavings in your oil on the first startup!
2. Proper Torque and Lubrication
The 200,000 psi 3/8-inch bolts included with these rods are precision fasteners that require exact torque specifications to maintain their clamping force. Never install these dry. You should use a high-quality assembly lubricant or Moly-based thread grease on the threads and under the head of the bolt to ensure an accurate torque reading. We recommend torquing the bolts in three equal steps to reach the final specification. If you have access to a rod bolt stretch gauge, that is the gold standard for high-performance assembly, as it measures the actual tension of the bolt rather than just the friction of the threads. Never reuse rod bolts if the engine has experienced an over-rev or a catastrophic failure.
3. Understanding Rod Ratio and Deck Height
Using a 5.5-inch rod instead of the stock 5.394-inch rod changes your engine''s geometry. Because the rod is longer, the piston will sit higher in the cylinder at Top Dead Center (TDC) if you don''t compensate for it. You must calculate your deck height carefully and use the appropriate cylinder shims (spacers) at the base of the cylinders to achieve your desired compression ratio. The benefit of the 5.5-inch rod is "piston dwell time" at TDC, which can improve combustion efficiency and allow for more aggressive ignition timing. If you are building a 2110cc or a 2276cc engine, this rod length is often the "sweet spot" for balancing internal clearance with long-term reliability.