Junk XR gears.
 

I was wondering if there were a batch of gears that were bad or something? I know a guy that is on his 3rd set in 2 years. He said he gets about 25-30 hours out of them with about 650hp.
I think he has a heavy hand, but then again, 3 sets!?!

Jason,
are you talking uppers or lowers?

Uppers, reverse gear of all things.

That sounds wierd to me. Bad shimming or bearings?!

Case has bent tower ????

They are not "junk", 650HP is too much for that gearset always has been. They are not rated for that much power. I always thought 500HP would have been a good place to stop frankly. Sure, John Q Public says "I,ve been running 800HP for years on the same set with no trouble blah,blah. I've seen PLENTY of them break at that level. They were not designed for that abuse. You can "make them last" but you'd be better off upgrading them if you don't want to have to baby them. Would you complain if your one ton truck broke with two tons in it? Sure you could get away with it for a while but, come on be fair. I wouldn't blame it on the boat owner either, the gears just weren't designed for that. Not looking to start a fire but this an old tired subject.

I see you are from Lake George,NY Clustergear, say hello to Nicki Cutro for me.

Sounds like he is shifting F-R/R-F too quickly. That will do it. Does he slam directly from forward to reverse? You really need to pause at neutral to allow the prop to come to a rest, and the internals to come to a rest.

That said; 650HP is a lot for a stock XR, but the tq. number is more important.

I've had my fair share of problems with them.

Had a couple of gears where the teeth material just chunked out.

Had 1 break a tooth off and junk the whole upper out.

Had another gear crack and shear the cone off of the
gear.

I'm not impressed with them.

I am soon to be a member of the Bravo Xr Club. I was running about 600HP very tame on Bravo's and was not having great luck with the drives lasting. I think I had a combo of 15 year old drives rebuilt many times in the same cases and probably had multiple weaknesses. So I upgraded to XR's for long lasting peace of mind. Well I have read many threads on the Xr's and the gear sets wearing and breaking. My peace of mind is leaving me before I even put the boat in the water. What the heck is going on with XR's are these gear sets really that bad. Should I be as concerned as I am.???
What torque numbers are in line with keeping XR's together.\
I want to have a problem free summer.!!!!! Any more thoughts are appreciated.

All my problems have been behind a set of 575's
.....and both drives have had issues.

All I can say is to watch for junk on the magnets,
but that's not 100% either.

Change oil every trip!!

Whatever they make the gears out of now compared to 4 yrs ago is a different formula. The newer gears just break teeth off with no warning. About all you can do is cryo-treat them which helps, but eventually they will fail.

Somebody needs to start making them out of better material.

I would, but then I would have to sell my boat to have the money to do R&D. Vicious circle isn't it:drink:

Working on that Smitty!! Just going to take awhile.. a long while..

rhinoLX
 

rhinoLX ?? Who shound I tell him says Hi. I talk to Nicky almost ever day.

I pm'ed you Clustergear
:ernaehrung004:

Don't mean to hijack tread
 

OK just spoke to Nicky, he said to say and hopes all is well. I hope all is well too haven't seen you in years. Now that you PM me and I know who the real rhionLX is. Any posts from rhionLX about Merc drives and lower units should be taken very seriously, you are not going to find a better source of information.

Are the gears made in china like everything else. Teeth breaking off the steel is to brittle or heat treat is off. Im in the job shop machine shop buss.. Ive made some small gears for high speed heavy duty gear boxes from S7 tool steel. Very tough high wear tool steel hard to chiip or break. Im thinking about giving it a try for XRs on my Black Thunder. Bussniess is slow not much going here.
Bob

BDARCHER, I'm in the die business at GM. We use S7 as our material for trim dies. You are right it is a very tough steel, it's sometimes called chisel steel. Many times, I've thought that S7 would make a good steel for Bravo gears. We heat treat it as an air hardening steel in oven and flame hardening to about 62R. That's probably too much for gears, make them too brittle. Getting the heat treat correct would probably make or break the gears and require some experimentation, $$$.

Do you run the boat hard.??? How long have you had the XR's did they come with the 575's. Not sure of the torque number on 575's?
I hope I'm not floating in the river this summer remembering this thread and thnking they told me so.!!

I'm a little pissed that Merc. does not admit to quality problems like this.

I'm one of those guys ran a stock b1 89 from 90 to 05, skip a year or too and had 420 hp from 03 to 05 then 580hp to 600 until 02 then had 30hours of 650hp. thats stock and its fine. I bought a bravo x drive but never put it on the boat its for sale in the box, I JUST BOUGHT A ACE DRIVE WITH SHORTIE that will handle my new 700 or 1050hp fun motor. I know guys in my area swear by max machine worx running 850hp on a 5500lb single boat and its been fine but he has built a 1100 to 1200hp motor for this summer we will see.

575's come standard with XR's....the boat's a 02'

I'd say it gets average use....I don't baby it......but
it's not at WOT all the time either....and I'm not too
bad on the sticks when the water gets rough.

I too have wondered if merc is having these
gears made in China.

It's sad, but I just put myself in a mindset that it's not
"if" they're going to break, but it's "when" they're going
to break.


My old boat with HP500's and regular bravo's never
had a drive problem in the 6 years I owned it.

Ian, the stock gears are 61R.. I believe, if I remember correctly.

The heat treat is the key. We have a good heat treat shop in town. What material are the Merc gears made from. Any suggestions to try. Ill setup cncs and run a few sets from different materal. $$s for gears not a problem. $$s for broke cases a problem.
Thanks Bob

Right, broken gears always seem to take a lot of other pieces with them. I think I would start by furnace hardening the S7 to 56-58R. They will have a deep hardness most of the way thru the teeth. How will you attach the cone to the gear?

Tool steel would have to be one piece. I dont think you can friction spin weld tool steel. Looks like the teeth can be cut with a gear shaper. If not Ill have to buy them when the tine comes.