Help Please - 912ULS Low differential pressure on Cyls 1 & 4

500 ml oil consumption for 20 hours is excessive.  Most 9-series engines use very little oil.  Its not uncommon for 912 to use less than 500 ml before oil change.  So instance...  my RV-12, 912ULS w/ 825TT, uses about 1 liter oil in 100 hrs.  This is with lots of take-off's at full power setting and 5500 rpm cruise at near gross wt.  

500ml in 100 hours is a lot.  Most don't use any oil. In 1500 hours on my engine I never had to add oil in between oil changes.

As for the original post I would have those cylinders (piston and head) with all that crud cleaned and re-built by a Rotax service center, 65  psi is way too low. The normal psi drop is 1-5 psi.

Hi Sam, I'd say the cylinder looks fine.  Do you perhaps mean the piston ?

Roger Lee wrote:

500ml in 100 hours is a lot.  Most don't use any oil. In 1500 hours on my engine I never had to add oil in between oil changes.

As for the original post I would have those cylinders (piston and head) with all that crud cleaned and re-built by a Rotax service center, 65  psi is way too low. The normal psi drop is 1-5 psi.

Thanks Roger, we are leaning towards that conclusion as well.   Although 80/65 is within operational specs, I'd also like to see all pressures about the same.  Does anyone have an idea as to the cost to get the piston and heads re-built ?  Or perhaps replaced with reconditioned if that's an option with the 912.

Be very cautious about the instinctive jump to the the costly solution.