Originally Posted by aphxero

VeRTigO: You shouldn't make comments if they aren't true. If it was a normal type of crank this wouldn't be so surprising. Remember the 4age is a race engine before it's a production engine.

Maybe you should stick to hondas?

Anyhow, here's a little info from Richard White:

4A-G Crank

The 4A-G crank is by all appearance a high performance piece of hardware. Unlike many production crankshafts which are nodular cast iron, the 4A-G is forged. It is a forged carbon steel, five main bearing, fully counter balanced affair. Each journal is cross drilled for 360-degree supply of oil to the connecting rod bearings, and each hole is chamfered to aid in oil delivery. An additional feature of the 4A-G crank is that each main bearing journal has rolled fillets to improve fatigue strength.



The transition between the main bearing surface and the crank counter weight and rod journal is subjected to very high torsion forces. Compressing the material around the transition, increases the strength and, therefore, the life of the crank. Other performance features include the use of a roller bearing (Toyota p/n 90363-12003) for the transmission pilot shaft (T50 Transmission only) and the use of eight 10mm fly-wheel bolts rather than the usual six that many engines of this size would normally have. This is contrary to Toyota’s illustrations in their own repair manuals typically showing six. And because there are no dowel pins to locate the flywheel position Toyota uses close fitting shoulder bolts. If the flywheel and crankshaft are fitted and torqued properly, all the stress (compression/friction) should be at the interface between the crankshaft and flywheel and the bolt’s shear strength is only needed if something in the system has failed. Rarely do you want a design that uses a fastener in a single shear plane. Bolts are at their best in tension.

Anyhow...