Doug G. Posted August 11, 2012 Report Share Posted August 11, 2012 I have had contradicting info regarding Sport 4 oil. One pilot and A & P ho has quite q bit of experience with Rotax in his Kitfox said it is really good stuff. Another person said a mechanic he talked to didn't think it was very good and said to use motorcycle oil. Anyone aware of issues with Sport 4? Doug Link to comment Share on other sites More sharing options...
rookie Posted August 11, 2012 Report Share Posted August 11, 2012 Doug, I've been using it for a little over two years with no problems and haven't heard of any. Seems like some guys use Sport +4 which is a semi synthetic and prefer the full synthetic. Rotax.com has a video reviewing the attributes of both. We'll see what Roger weighs with, he's seen more 912s than most guys. al meyer, P.S. Do you have your plane yet? Link to comment Share on other sites More sharing options...
rookie Posted August 11, 2012 Report Share Posted August 11, 2012 Doug, Correction, I meant to say " and some prefer the full synthetic". not much of a typist al, Link to comment Share on other sites More sharing options...
Admin2 Posted August 12, 2012 Report Share Posted August 12, 2012 There is a good article here on the forum about oils. It was written for the Rotax-Owner.com forum for a tech article and re-printed here. This will explain most things for our application. http://ctflier.com/index.php?/blog/3/entry-16-oils-a-fluid-discussion/ Link to comment Share on other sites More sharing options...
Runtoeat Posted August 12, 2012 Report Share Posted August 12, 2012 Here's an older post by Roger Lee. Roger put in a link for the Amsoil comparison with other oils including the 3 ball friction test but this link doesn't seem to work anymore. This was a really nice test comparison done by Amsoil. Here's the post: http://ctflier.com/i...rch__1#entry339 FWIW, I have been using Mobil 1 Racing 4T full synthetic (motorcycle oil for wet clutch). I'm switching over to Amsoil 10-40 full synthetic motorcycle oil this next oil change. Link to comment Share on other sites More sharing options...
Roger Lee Posted August 12, 2012 Report Share Posted August 12, 2012 Hi Doug, The mechanic that said to use a motorcycle oil doesn't really know oils evidently because the Aero Shell is motorcycle oil just packaged for Rotax under the Aero Shell name. It has the same additives that other motorcycle oils have. There are a few good oils out there that meet our needs well. You can use a full or semi synthetic. The full synthetic use is for 91 Oct unleaded fuel only. The full synthetic won't suspend the lead and it will fall out in the crankcase and gearbox and other places you don't want it to stay. A semi syn will suspend a good party of the lead, but not all and it's best to use a lead scavenger like Decalin and run higher cruise rpms like 5300-5400 to help keep the lead out. Run low rpms in the 4000's with 100LL and you absolutely will fill your engine with lead. Then it will be an early tear down and cleaning time. If you run enough 100LL you can pull the oil tank reservoir and look down in the bottom and actually see all the lead. The same holds true for the gearbox slipper clutch. Nothing low lead about 100LL. Now here is the other issue. We need motorcycle oil because like a motorcycles our gearbox uses the same oil as the engine and it needs special additives that car oils don't have any more. Especially ZDDP (Zinc Dialkyl Dithio Phosphate). It is a zinc phosphate additive and is used as a sacrificial metal coating for the gears, flat tappet lifters and close tolerance high rpm parts. You want to have between 1400-2000 ppm in the oil you use. Actually the higher in this case the better. That said there is a point of no return and that is around 2100ppm. Car oils had this additive back in the day with flat tappet lifters, but now days it isn't needed any longer and it trashes catalytic converters. Old antique type cars still need it. The other issues with some oils is they foam too much. This is one reason Rotax raised the oil level in the reservoir tank 30% years ago. So it would not foam and suck air into the system. bad news. There are viscosity issue too where some oils will loose viscosity in high rpm close tolerance engines. Then we have foaming, acid build up, moisture issues, wear issues ect... Motorcycle oils all have these additive packages. Do not use a car oil or a straight petroleum oil or you will damage your engine. Same brand oils made in different countries have different additive packages so one brand made here will be different if also made in Europe. Aero Shell Sport Plus 4 was developed in England and that is the only place it is made. That means the formula is consistent. Of course you can use a semi synthetic oil with either fuel. Here are a few oils that have proven themselves over many years. 91 Oct unleaded fuel: (full synthetic) Amsoil motorcycle oil it's a 10-40W (the best anti foaming oil on the market that is easy to come by) Mobile One Racing 4T 10-40W Mobile One V-Twin 10-40W (another high ZDDP motorcycle oil) 100LL (semi synthetic) Aero Shell Sport Plus 4 10-40W (it basically is a motorcycle oil and can be used in one) Golden Spectro 4 10-40W (The highest ZDDP ( levels at around 2100ppm) These 5 oils are all motorcycle oils. There are of course a few others that can certainly be used and of course not all brands are available around the world. Remember this is not a Continental or Lycoming and if you think of it as a motorcycle engine you will already be ahead of many mechanics. While you're thinking along these lines also think of it as a left engine and right engine. So things need to be in balance to one another. I hope this helps. Link to comment Share on other sites More sharing options...
Roger Lee Posted August 12, 2012 Report Share Posted August 12, 2012 p.s. The best place I have been able to find Aero Shell Sport Plus 4 is here. http://www.oil-store.com/ If you find a better place let me know. Link to comment Share on other sites More sharing options...
Doug G. Posted August 12, 2012 Author Report Share Posted August 12, 2012 Thanks Roger, is there any disadvantage to Sport 4 when you are only running mogas? (Oil-store was where I purchased the case I have.) Doug Link to comment Share on other sites More sharing options...
Doug G. Posted August 12, 2012 Author Report Share Posted August 12, 2012 Oh, and having spent last winter getting my LS certificate flying a Skycatcher with a Continental O-200, I am very aware of the differences...and not only in the engines! Link to comment Share on other sites More sharing options...
Roger Lee Posted August 12, 2012 Report Share Posted August 12, 2012 Hi Doug, There are no disadvantages. Most of this at times just boils down to personal choice. Link to comment Share on other sites More sharing options...
chanik Posted August 12, 2012 Report Share Posted August 12, 2012 With no tax and free ship, seems to be about the same price as 4T from Amazon http://www.amazon.com/Mobil-98JA11-Racing-10W-40-Motorcycle/dp/B004U8JH84/ref=sr_1_1?ie=UTF8&qid=1344804742&sr=8-1&keywords=mobil+4t Link to comment Share on other sites More sharing options...
Adam Posted September 18, 2012 Report Share Posted September 18, 2012 As of March 2012 here is the "Recommended Fluids" for all Rotax 912 Series Engines... Note : Shell Aerosport Plus 4 is the recommended oil for MoGas or AvGas. Good enough for Rotax, good enough for me Latest Rotax Fluids.pdf Link to comment Share on other sites More sharing options...
Jim Meade Posted September 18, 2012 Report Share Posted September 18, 2012 Adam, Thanks for the attachment. It was good to review it. Obviously, one can not quarrel with an oil that Rotax tested and released as OK. I use Shell Aersoport Plur 4, myself. It is interesting to read the list of oils that Rotax mentions as being recommended by distributors for both mogas and avgas, along with the discussion of when their use may be indicated. Rotax does us a favor by providing this interesting discussion of when we might prefer to use an oil they do not endorse but do not oppose. Link to comment Share on other sites More sharing options...
Adam Posted September 18, 2012 Report Share Posted September 18, 2012 Time for one of our scientist guys to look at that list and then tell us if we can all lower our oil temps in the climb by 10 degrees because the formula for one dissipates heat better than another! Link to comment Share on other sites More sharing options...
chanik Posted September 18, 2012 Report Share Posted September 18, 2012 It is very unlikely you will see a difference. The oil is just a heat carrier but the difference in specific heat from one oil to another is tiny and since it is flowing well to the oil cooler, it wouldn't matter that much if there was a difference. Link to comment Share on other sites More sharing options...
Adam Posted September 19, 2012 Report Share Posted September 19, 2012 I was being facetious Link to comment Share on other sites More sharing options...
GlennM Posted September 20, 2012 Report Share Posted September 20, 2012 Another interesting forum that discusses oil is on www.bobistheoilguy.com. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 20, 2012 Report Share Posted September 20, 2012 No mystery about oils. There are some better ones and some to stay away from, but the ones that are usually talked about may boil down to a personal preference. Ther are reasons to use semi synthetic over a full synthetic. Thishas been posted here on the forum a couple of times. Read the Rotax blog below. http://www.rotax-owner.com/rotax-blog/item/8-oils-a-fluid-discussion Link to comment Share on other sites More sharing options...
Doug G. Posted September 20, 2012 Author Report Share Posted September 20, 2012 So, does the use of Decalin make any difference in the choice of oil? I know Rotax approves its use, but doesn't say if it is sufficient if using avgas with full synthetic. I know it scavenges lead, but to what extent? I guess a related question would be, is it a good idea to use Decalin when you are using a semi-synthetic? Doug Link to comment Share on other sites More sharing options...
FredG Posted September 20, 2012 Report Share Posted September 20, 2012 I would like to see a study of the protective properties of these oils (especially synthetic vs semisynthetic),after they have been in use in a 912 for 40 -50 hours. My interest is in the relative loss of lubricating properties after repeated heat/cool cycles and mechanical shear. The oil temperature we observe on our gauges is the lowest temperature in the system. How do the various oils stand up to the higher temperatures that exist inside the engine? Link to comment Share on other sites More sharing options...
Roger Lee Posted September 20, 2012 Report Share Posted September 20, 2012 Hi Fred,With only 50 hrs. The oils should be top notch. The only way to really test the oil would be to send to a lab for a complete analysis, but 50 hrs is nothing. As far as shear that is the reason we use motorcycle oils for the shear protection among other special properties over car oils. The high mechanical action and close tolerances will cause a car oil to loose some of its protection. They have been using these oils in motorcycles and many of the large cruisers get 150k mi. on them. For our purposes the difference between full and semi synthetic should be very marginal if any thing at all. Link to comment Share on other sites More sharing options...
Runtoeat Posted September 20, 2012 Report Share Posted September 20, 2012 I recently changed oil and went from Mobil 1 Racing 4T to Amsoil synthetic motorcycle oil. Both are 10W-40 weight. My oil pressure was consistently running low with the Mobil oil. Many times I saw pressures down at or below 30psi. during steady cruise. After changing to the Amsoil, I'm showing a steady 40psi or better during cruise. I have determined that my gage reads low and suspect that it is not consistent so this just may be the gage deciding to act correctly or perhaps the Amsoil is the difference? I have more Mobil 1 oil so I'll change back to this next oil change and see if my pressure drops. Link to comment Share on other sites More sharing options...
FredG Posted September 20, 2012 Report Share Posted September 20, 2012 Dick, interesting observation. Hard to know without a high degree of confidence in the pressure on the gauge. I would think it odd that two oils of the same indicated weight have such different viscosity that they have different oil pressures. But, that thought is not based on much evidence. I am considering switching from Aeroshell Sport 4 to either Mobil 1 4T or Amsoil synthetic motorcycle oil given the occasional tendency of the 912 to run high oil temperatures. I look forward to the results of your observations! Fred Link to comment Share on other sites More sharing options...
Roger Lee Posted September 20, 2012 Report Share Posted September 20, 2012 Hi Dick, I have used the Amsoil motorcycle oil for many years, especially in my Honda 1800 Goldwing. We have been using it I the Rotax for many years too.There are some other good oils out there. That Rotax article That was posted in the other thread has a few listed. Link to comment Share on other sites More sharing options...
Runtoeat Posted September 21, 2012 Report Share Posted September 21, 2012 Roger, I'm suspicious of my pressure gage as the cause for my increased pressure since both the Amsoil and Mobil oils are the same viscosity. I did put a mechanical gage on my engine a while ago and it showed my instrument panel gage reading about 15psi low. I'll change back to the Mobil oil next time and this will provide a good way to see if there's any difference between the two oils. Thanks for the heads up regarding the info on the other thread. You have provided a lot of good information on engine oils and I've picked my favorite ones using this info. The Amsoil looks to be one of the best. Link to comment Share on other sites More sharing options...
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