S54 Rod Bearing Journal Widening Kit Including Crankshaft Journal Modification
The Lang Racing crankshaft modification kit addresses the issue of the undersized rod bearing on the S54. What we did is actually quite simple and is very similar to what we've done on some of the stroker engines we engineered in the past. We chose a rod bearing that was a significantly wider than the S54 stock bearing but also slightly smaller in diameter. This allows us to take damaged crank journals and have them re-ground to accept our wider bearing. Once the crankshaft is modified we then heat treat, plasma nitride, and dynamically balance it.
This modification has many benefits, both in engine reliability and in economics. Most obviously the wider rod bearing will increase rod bearing/rod journal surface area. This change between the bearing and journal provides increased protection against crankshaft journal to rod bearing contact and prolong the overall life of the rod bearing. This also allows the bearing to handle more potential torque from the piston, a good idea if you are considering forced induction, high compression, or racing. The remaining benefits have a lot to do with the economics of rebuilding an S54 engine. The cost of OEM BMW parts have always been high, but we chose rod bearings and rods that don't have a long lead time to manufacture and in most cases we will have all these items in stock. Secondly, there is a very quantifiable advantage is in weight savings. The S54 rod with bolts weighs in at 668 grams while our custom designed H Beam Carrillo rod weighs in at just 477 grams. That is a weight savings of 191 grams (23.5%) per rod.
This package is sold as a combination of crankshaft, rod, and rod bearing combination. The rod we choose is a very important part of our package. We believe if you can't use a part that's better than OEM then it shouldn't be used. Our rods are manufactured by Carrillo rods here in Irvine California using high quality forgings. We've designed our kit to utilize the OEM rod length compensating for the change in rod bearing. This means that the end user has many "off the shelf" options when it comes to piston choice. If your engine has good pistons you are able to reuse those, or purchase new pistons. We recommend and can supply JE, CP, and Mahle Motorsport pistons and are available as separate product on our website. This kit does require that you provide a core S54 crankshaft, one with spun rod bearings is typically acceptable, there is an extra 200 dollar charge if the mains need to be ground. We use Clevite bearings in this kit that are commonly available.
For an additional charge we also do complete bottom end or complete long block assembly in house and international shipping is available. Our assemblies come complete with build sheets including all clearances and weights of the components used.