BMW S54 3.4L / 3.5L Billet Steel Stroker Kit
We believe we've produced the most well thought out solution for gaining 4mm of stroke while keeping this engine reliable. The S54 comes from the factory with 91mm of stroke and we take it to 95mm. This increase has many consequences that we've addressed in our design. Torque is increased primarily due to increased displacement can cause more bearing wear than you would see on a lower displacement S54 engine. For this reason we decided to use a wider rod bearing journal on our crankshaft and chosen a dimension that allows us to use very commonly available Mahle Clevite tri-armor racing bearings, one of the most popular and well tested racing bearings on the market. We believe the increased oil film strength using this bearing will increase engine durability reduce the need to change rod bearings frequently. These bearings also come in +\- .001" size increments which allow us to adjust rod bearing clearances for different applications, something that you can't do with BMW that only come in one size.
The stroker crankshaft is made from billet steel allowing us to shave approximately 2 lbs of weight off our stroked crankshaft compared to the stock forged crankshaft, all without sacrificing strength. All of our crankshafts are dynamically balanced, plasma nitrided, and all journals are micro-polished.
The next step in developing our ideal stroker engine was to work with CP Pistons to come up with an ideal piston design that would allow us to stay as close to the OEM rod ratio as possible. Typical stroker solutions will end up shortening the OEM rod to accomodate the increase in stroke. Shorter rods increase side loading on the piston skirt which can cause excessive cylinder bore and piston wear. We were able to increase the length of the rod we use in our kit. Pistons are made to your specifications of bore and compression ratio. We also all the typical options of side skirt coating, ceramic coated tops, DLC/WPC treated wrist pins.
The last component in this package is the rod. As our standard rod we've chosen to use Carrillo rods due to our history using their rods in racing for many years, and their ability to make low production, very high quality custom rods. These rods are far superior to the OEM BMW rod and allow us to save significant weight in the rotating assembly.
If interested in different strokes or journal dimensions please contact us, custom crankshafts are possible with 2-3 month lead time. We also do full engine assembly in house and have very reasonable shipping rates on long blocks both domestically and internationally.
Designed and Built in California.