670 Rotax

[TY2068]

Dave & Bluebird

My research (yeah I read stuff on the internet lol) indicates that using 30W (or other weight motor oil) in the Rotary systems originated with the racing-recreational Snowmobile guys. After repeated failures of the brass gear and/or seals on the Rotary shafts they started experimenting with better lubrication than 2-cycle oil provides. Evidently much better results were seen in the high temp-stress-rev racing and recreational environments. At some point a few guys in the UL-Exp-PPC and Watercraft worlds caught on to this and started using various motor oils (30W, 20-50 and even heavy gear lube) also. I have yet to determine for sure that new motors from the factory do indeed come with motor oil or 2-cycle oil that "looks" like motor oil. It was said (Here) that new motors are shipped with 30W. I have a gut feeling that's not correct and they are shipped dry or with honey colored 2-cycle oil as was mentioned here.

One thing I do know for sure is that my engine had motor oil in the Rotary system bottle and I wanted to know why. It was not possible for me to ask the pevious owner of the plane about it. Thanks to this forum and the guys whom provided initial information I now have a better understanding on the subject.

[TY2068]

Well Mr. NLappos the apology is accepted and I'm glad you were able to get further info. I probably could have worded my posts differently or explained things a bit more clearly.

I'm a bit puzzled as to why Rick doesn't explain about the Rotary oil a little better to customers when he sends an engine out. Personally I think using 30W or synthetic 20W-50 (High Zinc content and anti-foaming properties) will do no harm and/or actually be beneficial. Any internal leakage or oil usage at some point would signal a return to using 2-cycle pre-mix oil however. Many would see no point in using motor oil and it is not standard advised procedure anyway. Maybe being that TBO is only 300hrs on 582's for example Rotax calculates that 2 cycle pre-mix is sufficient.

As far as me being anonymous anyone can send a private message at any time if they what personal info or private contact with a member. Me..I'm just another guy out there who's been interested in flying since the Stork flew me in. I'm PP licensed, high time Ultralight pilot and a Low time Kitfox pilot/mechanic

[nlappos]

Just finishing my installation of the 670 in the former 582 mount on my Avid Mk IV, serial number 1174D. Will post photos tonight. Overall, it was cake, the Rotax Rick engine slid right into the 582 mount. The two upper brackets fit perfectly, the 670 case had been touched up where the interferences were, so there was 1/8" clearance.
I used a Harbor Freight hydraulic lift table, and mounted the engine solo
The Mike Hair exhaust fits well, and stays inside the lateral confines of the cowl, as shown, but the muffler hangs below the lower OML, so I must trim the cowl bottom to fit.
The cooling system fits perfectly too. I retained the two nose radiators, and have a belly rad waiting in the wings for summer to come around.
I put 170 main jets in because I am at 6000 feet here in Utah.
I fitted an EGT system, and also will install the HACMAN mixture control that I had on my 582 (and which worked quite nicely).
I have to install a Facet electric pump to boost the fuel flow, since the old flat Mitsumi pump is only 9 GPM, and the 670 draws up to 11 GPM at full throttle. The two pumps in series should exceed that by quite a bit.
I hope to fly late next week.

[Bluebird19kf]

Are you planning on running AVgas or auto fuel?

[nlappos]

I plan to run on High Test auto fuel (ethanol mix) and Amsoil 40:1 mix.
"Rotax Rick" says this works fine. The ethanol actually helps the octane, and my tanks are ethanol OK.

[Bluebird19kf]

Thats wierd he told me to only run avgas and that is what his website says too.

[nlappos]

Not really. He says 100LL is great, and don't sweat the lead. He also says that old car gas is a real problem, since the octane drops in just a few weeks. That is why he does not recommend non-ethanol car gas, it can't be trusted. He does recommend fresh ethanol high octane car gas.

Here is EXACTLY what his web site says:

"Fuel and Engine Oil
CAUTION

This information is for all aircraft that have metal, poly or non-fiberglass tanks (WITH EPOXY RESIN), not Polyester resin:

Buy fresh Ethanol premium gas preferred from Chevron, BP and Sunoco.
Use either Amsoil Interceptor OR Quicksilver PWC oil (any of the 3 types of Quicksilver is fine)
Run Premix at 40:1 ratio. (16 ounces for every 5 gallons of gas)
DO NOT EVER USE NON ETHANOL GAS (other than 100LL Avgas which is acceptable). Rotax has a warning that it is “old stale gas.”............
Fuel life is 2 months, depending on the amount of moisture it’s exposed to. You can add Stabile to the fuel if you know your flying may be limited.
AvGas 100LL is the very safest gas you can ever use. I have rebuilt 100+ engines that used it 100% of the time. Don’t listen to the know-it-alls."

https://rotaxrick.wordpress.com/fuel/