ENGINE BREAK-IN ON BENCH?
10-08-2007, 07:13 PM
#26
Senior Member
My Feedback: (1)
RE: ENGINE BREAK-IN ON BENCH?
There are a lot of good oils, a few of them the same as another one under another name. Mobil, Pennzoil Air Cooled, Belray MC-1 and H1R (different ratios) Motul 800, Redline Racing Oil, and quite a few others. A fair percentage of the natural oils are excellent choices as well if the ratio is watched. I like the way Stihl and Echo oils perform. Too much of any of them increases carbon build up, with the naturals being the fastest. I won't be the one to say which oil is the best because too many are very, very good.
Ratios vary on the weather and type of operations. For 3D with a lot of hovering and stuff I'd use a little more oil. For IMAC, 50 down to 70-1 would work most anywhere. If the ambient is really hot then add more oil. If it's really cold you can go with less. Generally I still run mine at ratios of 70 or 80-1 until it gets hot outside, then it increases to 50-1. If you're goin' racing, more oil is even better. If the engine is tightly cowled and gets little cooling air more oil helps. There are a lot of factors that determine what you need for a mix ratio, the manufacturers recommendation being one of them.
Properly adjusting the carb needles for the oil quantity is also important. Rarely can you change an oil ratio and not need to re-tune the carb.
Ratios vary on the weather and type of operations. For 3D with a lot of hovering and stuff I'd use a little more oil. For IMAC, 50 down to 70-1 would work most anywhere. If the ambient is really hot then add more oil. If it's really cold you can go with less. Generally I still run mine at ratios of 70 or 80-1 until it gets hot outside, then it increases to 50-1. If you're goin' racing, more oil is even better. If the engine is tightly cowled and gets little cooling air more oil helps. There are a lot of factors that determine what you need for a mix ratio, the manufacturers recommendation being one of them.
Properly adjusting the carb needles for the oil quantity is also important. Rarely can you change an oil ratio and not need to re-tune the carb.
10-09-2007, 08:52 AM
#30
RE: ENGINE BREAK-IN ON BENCH?
Mix Bel Ray H1-R at 40:1 and Bel Ray MC1 at 50:1. Use the ratio variables Pat suggested along with the manufacturers recomendations depending on your particular weather conditions.
Karol
Karol
10-09-2007, 03:16 PM
#31
Senior Member
My Feedback: (1)
RE: ENGINE BREAK-IN ON BENCH?
H1R caps out at 50-1 ratios. leaner than that and you need to go to MC1. That can be taken to 100-1 but I recommend against it. Tuning has to be almost perfect and a lean run does in the ring pretty quick at that lean a ratio. Just about all the oils can be run at fairly lean ratios but only you know how good you are at tuning engines, and what to look for in determining how good of a job you did. 40 and 50-1 gives you some room to make mistakes and use your engine the next day instead of sending it in for repairs. Even the best of the best can make mistakes in fuel-air mixtures and oil ratios. I get to see the results of those mistakes every day.
Bottom line is that if you use a good oil, use a reasonable ratio, build simple baffles (mostly on twins) and don't tune for maximum available rpm, your engines will last until you put them into the dirt. Or for many, many years if you don't hit the ground. Synthetics usually have a better film strength than naturals, are more slippery (which is one of the things oil is for) and don't burn away in the combustion process like naturals. Hot running engines develop a hard carbon. Black in color with natural oils, brown in color with synthetics. Cold running engines develop a soft carbo, usually black in color. Engines running super lean and detonating develop a white colored ash on everything. You see that, pull the engine and send it in for repair. It's already toast. In this hobby, that will mostly be found with 3D flyers....
Bottom line is that if you use a good oil, use a reasonable ratio, build simple baffles (mostly on twins) and don't tune for maximum available rpm, your engines will last until you put them into the dirt. Or for many, many years if you don't hit the ground. Synthetics usually have a better film strength than naturals, are more slippery (which is one of the things oil is for) and don't burn away in the combustion process like naturals. Hot running engines develop a hard carbon. Black in color with natural oils, brown in color with synthetics. Cold running engines develop a soft carbo, usually black in color. Engines running super lean and detonating develop a white colored ash on everything. You see that, pull the engine and send it in for repair. It's already toast. In this hobby, that will mostly be found with 3D flyers....
