The connecting rod assembly is the vital link between the piston and the crankshaft in the HOWO MAX 4X2 engine. A robust connecting rod assembly ensures reliable power transfer and engine durability. This genuine HOWO connecting rod assembly component is the connecting rod bolt, which secures the rod cap. When you choose authentic Howo Parts, you receive a connecting rod assembly fastener engineered for the MC13 engine.
The connecting rod bolt is a high‑strength fastener that clamps the connecting rod cap to the rod body. Two bolts are supplied, each made from 42CrMo4 alloy steel with a property class of 12.9. The bolt has a thread size of M12x1.25 fine pitch, which resists loosening under engine vibration.
A reduced shank allows accurate elongation during torque‑to‑yield tightening. The rolled thread improves fatigue resistance, and the 12‑point flange head distributes load evenly. A zinc‑nickel coating provides 720 hours of salt spray resistance. Each bolt is batch‑tested for hardness, tensile strength, and hydrogen embrittlement. When torqued to 60 Nm plus 90 degrees, the bolt achieves a clamp load of approximately 45,000 N. The connecting rod assembly kit includes exactly two bolts, which is the correct quantity for one connecting rod. For a full engine rebuild, order six kits (12 bolts).
Connecting rod assembly – genuine HOWO connecting rod bolt kit
| Material Encoding | Name |
|---|---|
| 200V90490-0133 | Connecting rod bolt |
The connecting rod bolt is manufactured from 42CrMo4 steel and heat treated to property class 12.9, the highest strength classification for metric fasteners. This ensures the connecting rod assembly can withstand the extreme cylinder pressures of the turbocharged MC13 engine without stretching or breaking.
The reduced shank and fine pitch thread allow accurate torque‑angle tightening, stretching the bolt into its plastic region. This provides consistent clamp load regardless of friction variations, ensuring every connecting rod assembly is secured with the same preload.
The zinc‑nickel coating provides 720 hours of salt spray resistance, preventing rust and seizure. This connecting rod assembly component remains serviceable even after years of exposure to engine oil and condensation, eliminating the risk of corroded bolts during disassembly.
Each batch of connecting rod bolts is subjected to a fatigue test of 5 million cycles at peak load. Only bolts that pass are certified for use in the connecting rod assembly. This ensures the bolt will not fail under the demanding conditions of a heavy‑duty diesel engine.
The connecting rod bolt is arguably the most stressed fastener in an engine. It must clamp the rod cap to the rod body with sufficient force to prevent separation at high rpm,
while also being elastic enough to accommodate the oval deformation of the big end bore under load.
A compromised connecting rod bolt can lead to rod bolt stretch, cap walk, and ultimately catastrophic engine failure. This genuine HOWO connecting rod bolt is designed to provide the exact clamp load and fatigue resistance required for the MC13 engine. The connecting rod assembly kit includes two bolts, which must be replaced every time the rod is disassembled, as the torque‑to‑yield procedure plastically deforms the bolt. Reusing old bolts is dangerous and can result in rod failure.
The connecting rod bolt is forged from 42CrMo4 chromium‑molybdenum steel, a material chosen for its high hardenability and excellent fatigue properties.
After forging, the bolt is heat treated by austenitizing at 860°C, oil quenching, and tempering at 480°C to achieve a final hardness of 39‑44 HRC.
The thread is rolled after heat treatment to induce compressive residual stresses, which dramatically increase fatigue life compared to cut threads. The 12‑point head has a height of 10mm and a wrench size of 10mm. The reduced shank diameter is 9.5mm, providing a precise stretch characteristic. Each bolt is marked with “12.9” and a batch code for traceability. The connecting rod assembly relies on these manufacturing details to ensure consistent performance.
Before installation, clean the bolt threads and the rod cap threads with a thread chaser. Apply a thin film of engine oil to the bolt threads and under the bolt head to achieve consistent friction.
Insert the bolts through the rod cap and into the rod body.
Tighten the bolts in two stages: first to 60 Nm using a torque wrench, then rotate each bolt an additional 90 degrees using an angle gauge. Work on one rod at a time, tightening both bolts alternately. Do not reuse old bolts; always install new connecting rod bolts. After tightening, use a bore gauge to check that the big end bore is within specification. Proper torque of the connecting rod assembly is critical for engine longevity.
These connecting rod bolts are designed for the MC13 engine used in the HOWO MAX 4X2 tractor.
They fit the standard forged steel connecting rods with a big end bore diameter of 88mm and a bolt thread size of M12x1.25. The bolts are also compatible with MC11 and MC07 engines that use the same rod bolt specification.
For engines with aftermarket performance rods, verify the bolt thread and length before ordering. Each connecting rod assembly requires two bolts; order six kits for a complete 6‑cylinder engine rebuild. Always provide your engine serial number to confirm compatibility.
Once installed, connecting rod bolts require no routine maintenance.
However, if the engine is disassembled for any reason, the bolts must be replaced with new ones.
Inspect the old bolts for signs of stretch (thread necking) or cracking; if any bolt shows damage, replace the entire connecting rod assembly. Never mix bolts from different sets, as slight variations in length can cause uneven clamp load. When storing spare bolts, keep them in a clean, dry environment. The shelf life is five years. For high‑mileage engines, some rebuilders replace the bolts every other overhaul as a precaution.
If the engine develops a knocking noise that varies with rpm, a loose connecting rod bolt may be the cause. Remove the oil pan and inspect the rod caps for movement.
If a bolt has loosened, it must be replaced; do not retorque it. A broken connecting rod bolt will cause immediate catastrophic engine failure, often punching a hole through the block. Prevent this by always using new, genuine bolts during assembly. If the bolt fails to reach the required angle during tightening, the threads may be damaged; replace the bolt and check the rod threads.
Aftermarket connecting rod bolts are often made from lower grade steel (e.g., 10.9 instead of 12.9) and may not have rolled threads, leading to reduced fatigue life.
The heat treatment may be inconsistent, resulting in bolts that are either too brittle or too soft. The plating may be a simple zinc flash that rusts quickly.
Genuine HOWO connecting rod bolts are manufactured to the original equipment specifications, using certified materials and rigorous quality control. The small additional cost is far outweighed by the cost of engine replacement after a rod bolt failure. The connecting rod assembly is too critical to trust to generic parts.
The connecting rod bolts are supplied in a sealed poly bag inside a cardboard box. The packaging is recyclable. The manufacturing facility is ISO 14001 certified. No hazardous substances are used in the production of these bolts. The oil coating on the bolts is biodegradable. The connecting rod assembly components are manufactured with minimal environmental impact.
This connecting rod bolt can be ordered using the material encoding 200V90490-0133. Each order includes two bolts, which is the quantity needed for one connecting rod assembly. For a full engine rebuild, order six kits (12 bolts) to service all six connecting rods. Authorized HOWO dealers in Nigeria stock these genuine parts. For fleet orders of 12 or more kits, volume discounts are available. Always provide your engine serial number to confirm compatibility.
Fleet managers who have used these genuine HOWO connecting rod bolts report zero rod bolt failures in over 5 million combined kilometers.
The precision of the torque‑angle tightening has given confidence in rebuild quality. The corrosion resistant coating has prevented bolts from seizing, making future disassembly easier. Many operators have made it a policy to always replace connecting rod bolts with genuine parts during any bottom end repair, citing the catastrophic consequences of a failed aftermarket bolt. The connecting rod assembly reliability is directly tied to bolt quality.
The connecting rod bolts are shipped in a small cardboard box measuring 15cm x 10cm x 5cm, weight 0.2 kg. Store the bolts in a dry indoor area.
Do not remove the protective oil until ready for installation. The shelf life is five years when stored properly. Protect the bolts from corrosion by keeping them in the sealed bag until use. Avoid dropping or striking the bolts, as this can damage the threads.
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