XR Swept Backs
 

I just did an upgrade to my 37 with motors and drives, motors will be 640-650HP NA's. I just bought some XR's to upgrade from B1's ,is there anything on those that I need to watch out for, or anything I can do to help them out a little bit,any good secrets out there.
thanks

Drive showers are a must. I recommend draining the oil after 5hrs, then 10 more then 15 more. The XR upper and lower gears are net forged and during break in create a lot of metalic glow to the oil. This is metal dust that goes through the tapered bearings and causes damage. The more often you get the oil changed in the begining the cleaner that oil will be. After about 25hrs, the gears are done with their initial metal producing period. After that, you take a chance with the teeth snapping off the driven upper gears.. Then when they are at life's end, metal chunks will start to come out of the surface of the teeth.. Any chunks or flakes on the magnets is an indication of the process. In the last few years the gears Merc is making are not as good as they used to be..
Hope that helps.
Dick

If you're under the 550 - 600 hp range are you better off using the helical type gear sets right now?

The owner of my local shop had two XR drives off the back of a one year old Fountain. You could clearly see stress fractures in the gears. He recomended running anything from a stock 525 and up its a good idea to inspect them each season. He will tear them down, inspect, and put them back together for $200 per drive. I can tell you from here on out I'm a believer. It's much cheaper than repairing one.

I'm running 580 hp motors and baby the XR's out of the hole and try not to air them out too much. One was rebuilt less than 15 hours ago and the other one is off the boat being repaired right now......:(

The helical gears are doing more than they should be. I have a friend that has upgraded bravos with X gears on a 38 Formula with 575hp per side, NA and on the fourth season, if I remember correctly. I have been recommending the X gears for some time in certain situations. I have a lot of friends with the same build and are having good luck with them.
PM me if you want more specifics..

Dick

Thanks guys, I have a friend of mine that has a Cryo Machine, I have heard some people talking about doing the gears on XR's, anybody have experience in that or have heard of it.What Drive showers out there work the best for Swept backs?

I had 2 new sets cryo'ed a couple years ago.

After 1 season, 1 set started falling apart
( chunking out) and the other set is still
doing ok.

I don't doubt the process.....I doubt the quality
of the gearsets made in the last 5 or so years.

WHat does Merc have to say about the quality of the gears. Buy More?