Author	[Modern View]
buickanddeere 01-31-2013 05:17:31 184.151.61.102 Report to Moderator	A 3.5" journal has 1.361 times more material than a 3.0" journal. [Reply]   [No Email]
Indiana Ken 01-31-2013 19:12:36 66.249.232.131 Report to Moderator	Re: 3 in journel on a stroker crank hold togeather in reply to buickanddeere, 01-31-2013 05:17:31   Quoting Removed, click Modern View to see Yes, this would be correct for cross sectional area. The strength of the journal in tension is proportional to the cross sectional area. However, for a crankshaft, strength in torsion and strength in bending are more important than strength in tension. If I could repeat your calculations for clarity: The cross sectional area is proportional to the diameter raised to the second power (diameter squared). For a 3" journal we have 3^2 = 9 and for a 3.5" journal we have 3.5^2 = 12.25. 12.25 divided by 9 = 1.361; increase in strength in tension. The strength of the journal in torsion and in bending is proportional to the journal diameter raised to the fourth power. For a 3" journal we have 3^4 = 81 and for a 3.5" journal we have 3.5^4 = 150.06. 150.06 divided by 81 = 1.85; increase in strength in torsion and bending. In conclusion the 3.5" journal is nearly double in stength for the more important torsion and bending modes. With all respect - hopefully this adds to your post. Ken [Reply]  [No Email]
buickanddeere 01-31-2013 19:51:37 209.240.120.229 Report to Moderator	Re: 3 in journel on a stroker crank hold togeather in reply to Indiana Ken, 01-31-2013 19:12:36   It's all good with me. Left the torsion and bending out for simplicity. Actually the 4th power is going to take some refreshing and thinking about. It's been a while. Have to wonder with the airflow being limited by valve and and port size along with the short cam timing. Is gaining that last 1/2" to 1" of stroke that requires a skinny cam, 3" journals and a relocated cam really worth it? [Reply]  [No Email]