I’d be happy to make a specific recommendation. Please contact me off list at firstname.lastname@example.org
. As far as your other question on placement, here’s what I know about oil thermostat installation on the 912. First, the specific placement is not that important, providing you observe some key guidelines: (1) the oil hoses should be routed so that they are not in contact with or close to the exhaust system or where they can rub against other components. If the oil hoses are in contact with any other components, it's a good idea to sleeve them at the point of contact; (2) the hose manufacturer’s rule on minimum bend radius should not be violated. For example, Aeroquip AQP Socketless Hose (FBV0800 or FBN0800) has a minimum bend radius of 5.0”. This sounds like a tight bend, but this bend radius can easily be exceeded if you are not careful. If the minimum bend radius is exceeded, than the cross-sectional area of the hose is reduced (oval cross-section vs. round) and the hose is more susceptible to being collapsed at the bend by the negative pressure (partial vacuum) exerted by the oil pump. I once heard Phil Lockwood say that the weakest point on many 912 installations is the oil hose routing to the oil pump inlet. The 912 is supplied with a straight fitting at the oil pump inlet which can result in a very tight oil hose bend radius at that fitting which in turn can eventually lead to oil starvation as the hose ages, gets softer and progressively collapses at the tight bend. A 90 degree fitting for the oil pump inlet (Rotax P/N 956 585) can be installed to address that potential problem. Another important point to consider is the oil fittings used at the oil thermostat. The most restrictive part of the oil circuit on any 912 is the internal diameter of the fittings used in the circuit. Rotax recommends a minimum ID of 9mm (.354”) for all fittings (SI-912-011) and also recommends that 90 degree fittings not be used unless they are the large radius Rotax-type fittings (Rotax P/N 956 580). Many 912 oil thermostats have been installed with hardware store-type hose barb fittings with unknown IDs. It’s a good idea to use only aircraft quality fittings with known IDs, such as Aeroquip P/N FBM2007 which has an ID of .391” all the way through the fitting or AN840-8 and AN844-8 fittings which have IDs of .400” all the way through the fitting. Hose and hose clamp selection are also important but I think I’ve written enough on this for now. The overall idea is not to introduce potential points of failure into the oil circuit with your choices on thermostat type, fitting type, hose and clamp type and hose routing.