Does anybody know if JBP's Cross drilling the crankshaft is worth it? -It says it helps increase oiling of the bearings, I was wondering if anybody has purchased this mod yet and if so what they had noticed about it. Is it just a simple widening of the oiling hole in the crank?
Cross drilling is a technique use on high RPM motors to ensure the oil gets to the rod bearings at those higher RPMs. When I say higher RPMs, I'm talking upto 7000rpm +. This is typically done in conjunction with lengthening the main bearing oil groves in the bearing saddle and drilling more oil feed holes in the main bearings. This type of mod is typically done with a dry sump oiling system or a very well engineered wet sump system. This would typically be overkill for a J-Body motor using a stock PCM and the stock rev limits.
Yes, I used the word "typically" alot here, but there are always exceptions to the rule! These exceptions would be a motor running higher levels of boost or larger amounts of nitrous and races this motor regularly.
A good mod for the 2.4L TC, would be the 2.3L Quad4 HO oil pump conversion. You could also do what is called lead-in groves. These are groves that are .125" wide X .200" deep, starting at the oil feed hole in the crank, extending forward in the direction of rotation of the crank and tapering out to approximately .500" to .750". It will also help to radius the turn going from the lead-in groove to the oil feed hole. Another mod to help here would be to drill 2 additional oil feed holes in the main bearing between or on each side of the existing feed holes, depending on where the main bearing saddle oil feed grove extends. The crankshaft
must be polished, turning in the direction of rotation, after this proceedure has been done.
Even this is more than what alot of people really need.
^^^ Very good post.
-Aaron
www.TurboTechRacing.com
Performance Parts For Cavalier, Sunfire, Cobalts and More!!!
My 1st question would be what engine?
TC and Quad cranks are crossdrilled from the factory.
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