The main symptom my engine had was typical: corroded lifters and cam lobes. Two lifters were definitely not airworthy:
The source of the metal found in the filter was mainly from the lifters. When reading this article about lifter destruction stages, it is pretty evident that these were in stage #3 and had to be replaced.
Since the cam was not in good shape neither, it also had to be changed. Took the opportunity to switch to a high performance cam (different lobe shapes that modify the lift and duration to optimize valve timing and increases combustion efficiency)
This engine only has 500h since new. The cylinders were inspected at the shop and were found in good condition so it was worth taking this opportunity to proceed with porting/polishing of their induction and exhaust tracts as well as carry out a flow balancing on them. This allows a higher volume, to flow with greater efficiency to and from the combustion chamber, hence producing more power.
While the cylinders were getting ported, the crankcase and oil sump got completely cleaned and painted:
The reassembly was also initiated:
Once the cylinders were back, they went for honing, but this revealed an unpleasant surprise: the inside of the cylinder walls were also affected by corrosion:
The solution for this was to oversize the cylinders by 0.010". This howevers means new, oversized pistons and rings. Here's a shot with the cylinders painted and the new pistons followed by pictures of the final assembly:
Once the final assembly was done, the engine got installed on a test bench with a dyno. They ran it for a few hours and checked twice the oil filter for metal. Thank God nothing was found this time! Testing on site is is nice because the break-in of the engine is actually done at the shop. Dyno results were also interesting: with the high performance cam and ported cylinders, the engine produces about 10% more power at 2700 rpm.
The engine is still in the shop of Aerorecip in Winnipeg; it will be shipped right after the new year! Been working on a new firewall in the meantime which is going to be the topic of my next post.
Happy holidays to all of you my readers! I hope 2018 will be full of happiness and interesting projects for you!
