my bravo outdrive gear experiment
#161
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Keep posting you progress please.
Putting in a 540 ci 850 hp whipple motor in my Hallett 270 step.
xr drive with shower and a -2 imco lower.
going with a 30-32 inch 4 blade pending speed runs outcome.
Maybe(vif you let me
) over the winter I can send you my lower gears or complete lower assy to have you put your magic gears in.
The drive is a stock XR besides the -2 imco lower
Boat should have no problem runnig in the low to mid 90's
Putting in a 540 ci 850 hp whipple motor in my Hallett 270 step.
xr drive with shower and a -2 imco lower.
going with a 30-32 inch 4 blade pending speed runs outcome.
Maybe(vif you let me
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The drive is a stock XR besides the -2 imco lower
Boat should have no problem runnig in the low to mid 90's
#162
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Smitty, just lunched the new Imco, 4 decent passes and a little cruising. Hopefully the gears you're sending will last a bit longer. Do you have any 1.35s for my spare drive?
#163
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#166
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When I have had people look at them that know more than me there consensus is there is obviously surface contact where the extreme pressure has forced the oil from between the 2 surfaces allowing the metal to contact and wear thru the hardened outer surface. I have never had a problem with the gears spitting or shearing a tooth right off,just the surface flaking away until the softer metal underneath starts to errode quickly.
Good luck!
Michael
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The first thing I would do is look at your lubricant. You say in a later post you are using 85/140. A multiviscosity oil will give you less protection in high shear situations that even a straight weight 85 oil. That's because the viscosity index improver has very low shear strength, and "replaces" some of the straight weight oil. While it makes the oil thicker at higher temperatures than a straight weight oil, it doesn't have the protective properties. The only way to fix this problem is to reduce the gear loading (lower the input torque or use larger gears), or use a lubricant with higher sliding friction strength which means higher viscosity. I would try a 140 straight weight oil. I would look into a synthetic, since it has more stability at higher temperatures, which some people are experiencing with their drives.
Good luck!
Michael
Good luck!
Michael
#168
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Michael
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Smitty, just to clarify, you can't detect "viscosity breakdown" visually. It has to be tested. Also, I wasn't referring to viscosity breakdown per se. I was referring to oil film breakdown between gear teeth in high shear situations, which is helped by higher viscosity oil. It sounds like you have already tried this. I could be wrong (and I hope I am), but you may be fighting a losing battle, with such small gears.
Michael
Michael
I think its called breneailing[sp]??? Like Dean at the Bravo shop said theres nothing you can do about it, theres only one tooth touching at a time,Thats why there trying to get a helical style gear in the foot.3 teeth sharing the load.
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The Only Time You Have To Much Ammo Is When Your Swimming Or On Fire.
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The Only Time You Have To Much Ammo Is When Your Swimming Or On Fire.
#170
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Smitty, just to clarify, you can't detect "viscosity breakdown" visually. It has to be tested. Also, I wasn't referring to viscosity breakdown per se. I was referring to oil film breakdown between gear teeth in high shear situations, which is helped by higher viscosity oil. It sounds like you have already tried this. I could be wrong (and I hope I am), but you may be fighting a losing battle, with such small gears.
Michael
Michael