Cracks you don't want to see from your S63

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[email protected]

Jul 24, 2018
This S63 candidate arrived to receive our built S63 treatment. During each build we tear each engine and thoroughly inspect it for any inconsistencies or abnormalities. This S63 arrived with a spun rod bearing and possible bent rod and was mentioned to us prior to receiving this candidate. Little did we know what else we would find.

We found the engine to be extremely clean inside and out. It almost looks brand new. Clearly we thought there was a mistake. Removing the heads and working our way to the bottom end the engine was clean with little to no oil staining. After removing the oil pan and the connecting rods we soon found the spun rod bearing and signs of excessive heat that was generated by the loss of oil lubrication.

Once all the connecting rods and connecting rod bearings were removed we further inspected the crankshaft, crankshaft main journals and bearings. During our inspection we found traces of excessive heat around the rear main journal with the rear main bearing showed an excessive amount of heat as well. Once we removed the crankshaft we found a crack in the rear main journal at the oil passage going down the side of the journal on the engine block. Unfortunately due to this flaw the engine block will not be able to meet our quality control and be used for the build. Even with what happened internally there were visual signs of failure on the cylinder walls or outside the block.

When it comes to these high caliber builds we are very stringent and look for ways to improve upon the factory parts/ design to promote longevity and reliability. One of these items is rod bearings. BMW has been known to use bearings with tight tolerances which cause excessive wear and the need to replace them frequently. With the spun rod bearing being the route cause of this issue, for our S63 builds we spec our own rod bearings that can handle the abuse of higher horsepower and reduce the risk of running into a spun rod bearing. We have built multiple S63's and with one having well over 30,000 miles, each one is still going strong.

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Feb 23, 2018
Wow, really cool to see these threads. Must be fascinating to tear into these motors and discover the reason for failure!

[email protected]

Jul 24, 2018
Thank you :)

It is pretty cool to disassemble them and investigate cause of failure. They may all look the same from the top end but the bottom end usually holds some different stories. Just taking the time to investigate and check the condition of the block can save us and the customer a lot of headache in the long run.


Platinum Vendor
Apr 8, 2017
If you need help sourcing a replacement block let me know! Would love to start a friendly relationship with another engine building shop.


Oct 18, 2016
Dang, such a small thing can really mess everything up. Its good to see that you're being incredibly meticulous.

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