Re: speed w/heavier outdrive oil
 

I'm running 900 plus hp/ft lbs tq thru a single bravo max worx upgraded drive,the upper has 200 plus hours on it (the gears),I have been thru it every 40-50 hours checking for damage and changing bearings because metal from the lower scarred them slightly. Now it hasn't always had that much power put thru it either,the first 130 hours was 750 hp and this is only a 27 ft boat so rough water and no wake zones at cruising speed or idle account for alot of the hours too. The lower gears are a experiment for durability,they are a set of USED gears I bought and had re-heat treated,they have over 20 hours on them now,trying to see what its going to take to get them to live (other than reducing the power). I broke them in on royal purple 80/90 and been running royal purple 85/140,I'm NOT a die-hard royal purple fan by no means,I just can get it locally wholesale (cheap in other words) so its what I'm using in this experiment. I have drained it a couple times in past weeks including changing it out from the 80/90 and I'm not seeing ANY metal in the oil yet,usually by 20 hours (on lower gears) I'm getting a serious amount of metal in the oil changing it every 6-10 hours (every weekend if I see some full boost hard 2-10 minute runs),every other weekend if I only do short wfo burst. Either the thicker oil is helping to cushion the gears and keep them from galling or deeper case hardening is keeping gears from breaking thru hardness or both. I'm not going to switch back to thinner oil just to see if its the oil either as I don't want to buy bearings,gears etc plus breakdown but I am going to tear lower down pretty soon and see how the gears are looking,Smitty

Re: speed w/heavier outdrive oil
 

XR upper gear pics-200 plus hours with 750 and 940 hp blower motor turning them.

Re: speed w/heavier outdrive oil
 

Looks like alot of us will be getting gears treated this winter. Maybe we are on the verge of a beak through in longevity here. :evilb:

Re: speed w/heavier outdrive oil
 

I sorta expected the gears to catastrophicly blow the teeth off the first time I put the boat into boost but it hasn't happened yet and I'm starting to gouge on it pretty hard the last few times out,we'll see how the gears look in a few weeks,especially after a weekend at hardy pond. I have chewed up 4 different sets of lower gears in past couple of years so it won't just be a fluke if they hold up. I specifically used lower gears that were already used in another boat because I didn't want to wreck a brand new set if they were just going to crumble from being brittle or something from deeper case hardening,if they hold up a full season and still look good then I will call this a sucsess, Smitty

Re: speed w/heavier outdrive oil
 

I hope I didn't give you the wrong impression on the xr upper gears but they are just the ones max worxs sells with there upgrade parts,they are holding up with no special treatment other than the bearings,tower and cap they use,blowing uppers apart has never been a issue on my boat. They could be re- heat treated too but you would have to remove the brass parts for the cone clutch somehow,Smitty

Re: speed w/heavier outdrive oil
 

Smitty,

I am not too concerned about the uppers. They seem to be able to hold up. At least, better than the lowers. I not running near the power you are. 680 hp, 660 torque. I ate up a set of lowers last season in 17 hours. However, I think they were just set up wrong. This winter, I set up new gears, bearings, etc, in the drive myself ( well, with help over the phone from Mr Gadgets ). So far, approaching 40 hours of pretty hard running with no issues and clean oil. If I can get the season out of them, I would be happy enough. BUT, if this process works, maybe I can get 2 or 3 years from a set of gears. That would be great. My only concern is the fact that you have to have a slightly used set of gears treated. That complicates things. If thats the way to do it, I guess I will have to get a new set of gears and set them up just before the end of the season to get a few hours on them.
Actually, I am in the market for a -2 Imco lower. I would love to test it out. Hopefully, 1 will surface before the end of the season.

Vinny

Re: speed w/heavier outdrive oil
 

Vinny,I started out with used gears in case they self destructed the first time I leaned on it but I also thought it might be a good idea to use ones that had a little run time on them too. After they were re-heatreated you couldn't tell they were used though. They went on shafts pretty tight too but the max worx shafts I used have always fit tight anyways. I think the heat treating would work on new ones too but I'm slightly concerned if they had no wear whatsoever on internal splines they might not fit,Smitty