ORIGINAL: rlmcnii
1. A Saito can spit no more oil out than it takes in. For that matter, neither can any other four-stroke.
Sounds reasonable.
ORIGINAL: rlmcnii
2. All of the oil that goes into a Saito, or any other four-stroke, must come out. Or, is this not correct? Do four-strokes, other than Saitos, somehow make their oil vanish? I ASSUME that they do not. I could be wrong. Is it possible that the other four-strokes are just taking in less oil than a Saito? My personal experience with other four-strokes is too limited to know. I recently helped an older friend set up a Magnum four-stroke and with the needles set, per instructions, for the initial running that engine was taking in much less fuel...and oil...than any Saito with which I have had experience.
Some of the oil is burned or vaporized, especially the synthetics used in model fuels. I use 8% Klotz synthetic oil in my FS-52 and the exhaust has very little oil in it. The engine is being lubricated adequately. I run 20%-25% castor oil in my four stroke diesel conversions and the exhaust is very dry. I would have to say a good part of the castor must be burning, but then again, the engines use less than half the volume of diesel fuel than glow fuel.
ORIGINAL: rlmcnii
3. New Saitos (I believe hs said his was new) have their LS needles set very rich. And, exhaust large amounts of oil, both in the exhaust and through the crankcase breather, until the LS needle is properly set.
Yes, this is typical for break-in procedures.
ORIGINAL: rlmcnii
4. For some reason a lot of folks are reluctant to properly tune their Saitos. That is, they are reluctant to sufficiently lean the LS needle. Probably because they usually require what seems to be an inordinate amount of turning to get them properly set.
Saito carbs low and high needles tend to interact. If you don't know this then you will constantly chase settings and never come to a good tune. Saito engines in general have much higher compression ratios than other engines and in my opinion must be run rich in order to prevent preigntion and or detonation.
ORIGINAL: rlmcnii
5. Could it be that the engine under discussion here, since it has the crankcase effluent running back into the intake track, is being impeded in its operation just because of the amount of non-combustible oil (and other by-products of combustion from the blow-by gasses) being dumped into the intake track? Perhaps it needs a little finer tuning.
No, I don't think so. The crankcase recirculation idea is not new. OS has been using it for more than 15 years on various engines. Besides, he tested the engine with the vent disconnected from the intake and found the same problem. The volume of oil compared to the volume of methanol is small. Do the math figure out how many BTU we are talking about estimate engine efficiency and give a theoretical power figure. And this figure will only be correct if the suspended oil is not burning at all. If the oil that is suspended and not in contact with metal engine parts is burning, and some of it is, it is also contributing to power. A simple test would be to run an engine for a few minute on straight alcohol. There will be enough oil in the crankcase to prevent damage for a minute of so. I know most of you won't risk an engine like that but I will. I'm running 8% oil now. I might go to 5%. I've heard about people running 2% in Saitos and running hundreds of hours. Four stroke lubrication is different than two stroke even though they are both total loss.