Is running Alyson Less than zero weight bad for a lake river boat in the gearcase.

**FMP** · 04-19-2017, 08:23 AM

For what it's worth I've used Royal Purple for years, holds its properties and protects. They changed weight slightly with a new product this year but 75/ 90 works for me.

**Ted Stryker** · 04-19-2017, 09:28 PM

Truth is most any lube will work, long as is clean and free of water.. the differences in performance between a quality lube and what is the most awesomest super goo will be very minimal.. many manual trans use atf and it will work in a gearcase too, again provided its clean and changed reasonably often.. outboard short blocks survive on a mist of barely lubed fuel, a gearset operates in a bath of oil, difficult to cause wear under those conditions.. you may break something that's caused by impact, slung blade, broke shaft etc but it won't be the oil's wrong doing..

**FORBESAUTO** · 04-19-2017, 09:54 PM

As long as it can handle the heat of packing a 2200 plus lb boat with the whole bullet above water not being able to get cooled and turning a 27 pitch prop above 80 mph for 20 plus miles without breaking down and loosing its lubricating abilities it'll be just fine. These lowers get extremely hot and just any old oil ain't gonna cut it.

**olboatman** · 04-20-2017, 05:56 AM

Originally Posted by FORBESAUTO

As long as it can handle the heat of packing a 2200 plus lb boat with the whole bullet above water not being able to get cooled and turning a 27 pitch prop above 80 mph for 20 plus miles without breaking down and loosing its lubricating abilities it'll be just fine. These lowers get extremely hot and just any old oil ain't gonna cut it.

Thats how I look at it.....you can compare it to NASCAR that pushes their rear gear sets to the max for 500 mi or so. They use oil coolers to keep the temps down where my truck can run the interstate at 75 for hrs with no problems. When runnin the LU that high for that long has anyone used a "shower" to keep the temp down as they have on I/O LUs ? Just wondering. Gary

**Ted Stryker** · 04-20-2017, 06:13 AM

Water exits through the bullet and helps

**FORBESAUTO** · 04-20-2017, 06:21 AM

Think about the amount of pressure we are putting on a tiny set of high ratio gears with less than a quart of oil compared to 8-13 inch ring gears with much lower ratio and multiple quarts of oil turning much less rpms. We expect a lot out these things and it's no different with oil. It has to be some good stuff! For short spurts any old lubricant and any old viscosity will go just fine, but for the long haul you better know you got the right stuff with the right additives that can handle the job in there.

**FORBESAUTO** · 04-20-2017, 06:24 AM

Originally Posted by Ted Stryker

Water exits through the bullet and helps

Not through bullet. It exits with exhaust and that's all behind the gear sets, no help at all for cooling.

**olboatman** · 04-20-2017, 06:53 AM

Originally Posted by FORBESAUTO

Not through bullet. It exits with exhaust and that's all behind the gear sets, no help at all for cooling.

So if this is the case then the best rig would have the exhaust exiting out the mid before the LU and the water dumps directed down into the bullet ahead of the gear sets and NO exhaust allowed thru the bullet. Loud but effective ? Gary

**largecar91** · 04-20-2017, 07:38 AM

I have run it in my raceboats for years. The proplem with the synthetic is like was stated before is water intrusion. The water will mix with dino oil and still provide some lubricating properties were as synthetic will not.

**Mr. Demeanor** · 04-20-2017, 10:26 AM

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**Ted Stryker** · 04-20-2017, 12:04 PM

I'll try to remember if I've ever hurt a set of gears and post back

**Tcatrett** · 04-20-2017, 12:43 PM

I run the Alisyn 0w in all my lowers. Good stuff. Seems to last just as long as the Merc hi per oil. I lost a seal once it mixed with the water and made like a grease. Every thing was good. Was a mess to wash out lower. I have pics somewhere. Maybe I was lucky.

**Ted Stryker** · 04-20-2017, 12:43 PM

cranking one in gear to prevent shavings, a straight prop shaft and a well balanced prop goes a long way too but that's getting outside the orig question

**FORBESAUTO** · 04-20-2017, 01:46 PM

Like I stated before I'm not saying allisyn is responsible for bearing and gear wear. Propshaft breaking at thrush washer was just fatigue of an old shaft. I was a firm believer in the allisyn and even convinced a few people to switch over to it. I ran it for a few years with no noticeable problems. When I drained fluid to tear down lower to replace propshaft and reseal, fluid was clean. It concerned me when I found the wear on pinion and reverse gear. Appeared to be damage from overheating. I switched back to Mercury oil in case(never had any internal failures with it). Gonna run it and see how much life I get out of lower. If I loose another gear or bearing going back to allisyn and take it that it's just part of the price you pay to play. If no failures then this rig is staying on Mercury oil. Just wanted to share my experience. And as far as any lubricant will work just isn't true. These are the best two oils I've used, just think allisyn better for race applications and Mercury best all around. I'll let ya now in few years (hopefully) how the Mercury oil held up. This is also a non hypo coned lower that I'm putting through the ringer and may be just the way it is with either oil, were soon to find out.

**Ted Stryker** · 04-20-2017, 03:58 PM

maybe another ingredient is what kind of use will the gearcase see.. will it be cruising mostly with short to moderate burst, or the throttle crammed against the stop for miles and miles on end.. ..

not to create confusion, when I mention any oil my thoughts are in regard to known quality oils.. merc, evinrude, Yamaha, pennzoil, Mobil, klotz, redline etc.. known quality oils, in a healthy case, shimmed correctly, fluid fill changed reasonably often