I'm looking for an engine oil, that carries a GL4 or 5 rating? If such a thing exists? It's for the engine in my airplane that shares oil with the reduction drive (gearbox).
I emailed AMSOIL and asked if any of their motorcycle oil met that GL rating, and after several emails the rep never would answer the question whether they did, or didn't. All he wanted to know was the application. When I told him it was for an experimental aircraft he told me he wouldn't talk to or help me any further and never responded again. I'm familiar with people getting uneasy when you throw out the aircraft term, but it is experimental and is in a whole different category from certified aircraft. Oh well.
Anyway.. I've done some research and so far I have not been able to find any engine oil with more than a GL1 rating. Rotax worked with Shell to develop a semi-synthetic oil for this application, and it's a good oil, but a high end (group 4 or 5) full synthetic would be better. Apparently full synthetic oil doesn't work well with leaded avgas because it doesn't trap the lead properly. Or at least that is the story. But when I'm not traveling or going to fly-ins with the plane and just out landing on hills and playing (majority of the time) I would like to run a synthetic because I use pump gas most of the time.
The gearbox does get hammered, especially since I installed larger cylinders and 11:1 forged pistons and built he headers, muffler, ram-air etc. to get some more power out of it. I'd really like to find the best quality oil for the application. Rotax actually put out some literature at one point that called for an engine oil with a GL 4 or 5 rating, but I have never been able to find any. I've always felt that Motul and Redline make good oil, along with plenty of other manufactures, but I have no idea on their oils either as far as this goes?
I really do appreciate any help!
I emailed AMSOIL and asked if any of their motorcycle oil met that GL rating, and after several emails the rep never would answer the question whether they did, or didn't. All he wanted to know was the application. When I told him it was for an experimental aircraft he told me he wouldn't talk to or help me any further and never responded again. I'm familiar with people getting uneasy when you throw out the aircraft term, but it is experimental and is in a whole different category from certified aircraft. Oh well.
Anyway.. I've done some research and so far I have not been able to find any engine oil with more than a GL1 rating. Rotax worked with Shell to develop a semi-synthetic oil for this application, and it's a good oil, but a high end (group 4 or 5) full synthetic would be better. Apparently full synthetic oil doesn't work well with leaded avgas because it doesn't trap the lead properly. Or at least that is the story. But when I'm not traveling or going to fly-ins with the plane and just out landing on hills and playing (majority of the time) I would like to run a synthetic because I use pump gas most of the time.
The gearbox does get hammered, especially since I installed larger cylinders and 11:1 forged pistons and built he headers, muffler, ram-air etc. to get some more power out of it. I'd really like to find the best quality oil for the application. Rotax actually put out some literature at one point that called for an engine oil with a GL 4 or 5 rating, but I have never been able to find any. I've always felt that Motul and Redline make good oil, along with plenty of other manufactures, but I have no idea on their oils either as far as this goes?
I really do appreciate any help!