oil %'s

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moparbarn

Well-Known Member
Joined
Apr 25, 2007
Messages
7,930
with all the threads here and elsewhere dealing with turning car fuel into boat fuel, i'm wondering about a "proper" oil percentage for boats. how do the cars get away with 10 or 12%? they run hotter, & i would imagine the shock loads are higher (on & off the throttle & landing from jumps), temps are generally higher, also - 240 degrees isn't uncommon. how much will recommended % vary by engine size? or roller bearing rods vs plain bearings? more or less nitro? i've heard don ferrette mention too much oil can cause bearings to 'skid/slide', not turn/roll....... what is everyone running? what type of engine? i'm mainly interested in .21's, k&b's in my case. but any info you can share will be appreciated by all, i'm sure B) . i'm getting ready to blend some fuel, want to run less oil, if i can. running 18% now, how low can i safely go? less oil means more methanol at a given nitro %, & even i know there's more power in alcohol than oil :rolleyes: . also, please specify if you run all synthetic, all castor, or a blend. if a blend how much of each. i can imagine oil type would affect what a "safe" % might be.
 
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well i run 60% with 1 percent castor and 14% oil

and 70 percent with 1 percent castor and 14% oil.

i mixed up a gallon of 60% with 12 percent oil and 1 percent castor and to be honest.. it made ZERO difference speed wise. the only thing i seen was that the motor sounded different. that was it.

chris
 
I am no expert....but for running around the pond, I run 18% 14+4... for running with other folks and racing, I run 15% 13+2.

Whether I am extending my engine life by running 18% when I am not racing...I dont know...but it makes me feel better about running 15% other times...LOL ;)

Sean
 
I mix

60%-60,20,20

66%-66,16.5,16.5

40%-40,40,20

Oil is the last digits. I run Klotz 80 synth/20 castor.

Mike
 
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70% w/ 12% oil for the 21's and 60% w/ 15% oil all others, 100% synthetic oil in both blends. B)
 
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I do the same as Don, 12% oil in the 21 (65% Nitro), and 15% in all others(50~57.5% Nitro). I use only synthetic, but I split it 2/3 UCON LB625, and 1/3 Morgan Blue. Works for me.
 
i'd like to take an old motor and test in decreasing amounts of oil, to see where the bottom would be. something that always bothers me is the amount that 2 stroke outboards get by with compared with what we run. somethiing like 2.5 ounces to the gal. and we run up to 25. some one tell me why
 
Steve , I believe the answer might lie in Area of surfaces to be lubricated vs rotational time ( RPM )available that the lubricants have to be dispersed . My 2.5 280- HP Mercury motors will always get 32 : 1 Mix = 4 OZ Per gallon . If you get a mental pic of the insane speeds of model engines and port opening and closing , thrust loads on the rod , crank etc ....it's crazy . !!1
 
Steve , I believe the answer might lie in Area of surfaces to be lubricated vs rotational time ( RPM )available that the lubricants have to be dispersed . My 2.5 280- HP Mercury motors will always get 32 : 1 Mix = 4 OZ Per gallon . If you get a mental pic of the insane speeds of model engines and port opening and closing , thrust loads on the rod , crank etc ....it's crazy . !!1


AND I WOULD LOVE TO DRIVE THAT 2.5 280 HP MERCURY POWERED HULL .
 
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Steve , I believe the answer might lie in Area of surfaces to be lubricated vs rotational time ( RPM )available that the lubricants have to be dispersed . My 2.5 280- HP Mercury motors will always get 32 : 1 Mix = 4 OZ Per gallon . If you get a mental pic of the insane speeds of model engines and port opening and closing , thrust loads on the rod , crank etc ....it's crazy . !!1
got to agree, tom. our "little" engines put stupid crazy demands on oil that full size ob's can't imagine. but i think better water jackets/temp control help a bunch on the full size ones, also ;) . say hi to the suwanee river for me, man i miss that end of fl.
 
Steve , I believe the answer might lie in Area of surfaces to be lubricated vs rotational time ( RPM )available that the lubricants have to be dispersed . My 2.5 280- HP Mercury motors will always get 32 : 1 Mix = 4 OZ Per gallon . If you get a mental pic of the insane speeds of model engines and port opening and closing , thrust loads on the rod , crank etc ....it's crazy . !!1
got to agree, tom. our "little" engines put stupid crazy demands on oil that full size ob's can't imagine. but i think better water jackets/temp control help a bunch on the full size ones, also ;) . say hi to the suwanee river for me, man i miss that end of fl.
I run 14% synthetic in everything 12,21 45. I mix my own fuel, I play with cars and airplanes and use 14% in these also. :)

Walt Barney
 
on my 90 boat i run 80% alcohol and 20% oil (80/20 syn/castor) oh, and 4 cap fulls of GONZO GRAPE.

on my 21 motors i run the 60% o'donell with 18% oil.

i also run EVERYTHING on the rich side and all my motors have lasted for many years. (bearings excluded of course.)

when i was Flying F3A in competition overseas i ran 40% nitro 6% oil and the rest alcohol.

carl
 
Thanks for posting this thread MOPARNBARN. I've been wondering about this since I read the thread on the MPH increases as nitro was increased and someone mentioned that lowering oil% was as significant to to adding MPH as increasing the nitro. <_< One more factor to equate.... :ph34r:
 
i just want to thank everyone for posting the info so far. nice definitive answers, & no pissing matches over what's best! very positive responses, & that's what i'd hoped for. keep it coming.
 
on my 90 boat i run 80% alcohol and 20% oil (80/20 syn/castor) oh, and 4 cap fulls of GONZO GRAPE.
And the residual haze of grape-smelling smoke once the heat is over is amazing and brings a whole new meaning to "when the smoke cleared"! :lol:
 
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