Bravo Upper Gears - Shimming?
04-08-2007, 11:01 AM
#11
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Pettem,
I take it you are trying to install new thick floored gears in a drive that did not have them previously? If so, the upper shaft doesnt need to be changed, but the cone clutch, shift fork, tower races, all need to be changed. That is if you are trying to install new X (thick floored gears) in an OL drive..
Hope this makes sense..
And all the bravo's need to be shimmed, just what thickness is the trick question. To do it properly, you need to measure the lash on each gear. The cases are different, the top caps are different, and the pinion depth will be different. A properly setup drive is essential for long life..
Just my .02 on the subject.
D*ck
I take it you are trying to install new thick floored gears in a drive that did not have them previously? If so, the upper shaft doesnt need to be changed, but the cone clutch, shift fork, tower races, all need to be changed. That is if you are trying to install new X (thick floored gears) in an OL drive..
Hope this makes sense..
And all the bravo's need to be shimmed, just what thickness is the trick question. To do it properly, you need to measure the lash on each gear. The cases are different, the top caps are different, and the pinion depth will be different. A properly setup drive is essential for long life..
Just my .02 on the subject.
D*ck
What are you using for a backlash number ?
Do you have a different # between XR gears and
the standard helical ?
What are your thoughts on checking tooth
contact patterns ?
04-08-2007, 12:23 PM
#12
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All backlash numbers are different according to ratio it's all in the tech service manual. The 16/19 xr gears have a .009 to .015 backlash spec after you shim the pinion at .025 using the shim tool.
04-08-2007, 10:34 PM
#13
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Mike,
clutch is 52-865344A01
Yoke and cam assy is 806552A1
You will also need to replace the races on the towers. 31-861791. You will need two of them. One for the cap and one for the tower in the case. They have to be installed with the proper driver to set them at the proper height on the tower. You can wing it if you understand the concept. But you should at least have the tools for a normal race, in order to install the race properly. Do you have any tools to do that? You might want to take it to someone that does, to have the old races removed and the new ones installed. Give Sterndrivespec a call for parts. 315-623-7642.
Setup, I feel, is dependant on a lot of things. I use the manual as a guide. I change things depending on whether the drive will see 500hp or 1400hp. It is also dependant on type of gear and how well they are made. The helical gears are pretty consistant, but the netforged gears are all over the place. The process I use to setup gears is from the book, with several adustments to the proceedure. I have modified the process with respect to results found on the drives I have built, for different situations. I guess we'll call it experience. I am not ready to give out any secerts at this point. Maybe when the video is done, I will,
. I have some very large boats with moderate horsepower and some kinda small boats with very large horsepower to get feed back from. And I do lot of it by feel, depending on how the numbers come out while setting it up. I would hate to make any recommendations and have some one misinterpet what I am saying.
If you go by what the manual says, you wont go wrong. As far as using tooth contact, well I am not very good at that. I will admitt that. With slight variations, I cant see the overall differences. I have tried all kinds of tracer die, or grease or prussian blue. And I have tried several pairs of glasses.. I find that what I am doing, is working so far, so why complicate the process.
I dont know it all, just been having decent luck at setting them up. I told my customer with the 1400 hp.. that it would break the first time he put that power to it.. After 15 hard passes, I did an inspection tear down and things looked pretty good inside!! So it should last another 5mins, or till he gets it on plane. Any more than that, is considered living on borrowed time for that drive with that kind of power.
Hope this helps..
D*ck
clutch is 52-865344A01
Yoke and cam assy is 806552A1
You will also need to replace the races on the towers. 31-861791. You will need two of them. One for the cap and one for the tower in the case. They have to be installed with the proper driver to set them at the proper height on the tower. You can wing it if you understand the concept. But you should at least have the tools for a normal race, in order to install the race properly. Do you have any tools to do that? You might want to take it to someone that does, to have the old races removed and the new ones installed. Give Sterndrivespec a call for parts. 315-623-7642.
Setup, I feel, is dependant on a lot of things. I use the manual as a guide. I change things depending on whether the drive will see 500hp or 1400hp. It is also dependant on type of gear and how well they are made. The helical gears are pretty consistant, but the netforged gears are all over the place. The process I use to setup gears is from the book, with several adustments to the proceedure. I have modified the process with respect to results found on the drives I have built, for different situations. I guess we'll call it experience. I am not ready to give out any secerts at this point. Maybe when the video is done, I will,
. I have some very large boats with moderate horsepower and some kinda small boats with very large horsepower to get feed back from. And I do lot of it by feel, depending on how the numbers come out while setting it up. I would hate to make any recommendations and have some one misinterpet what I am saying. If you go by what the manual says, you wont go wrong. As far as using tooth contact, well I am not very good at that. I will admitt that. With slight variations, I cant see the overall differences. I have tried all kinds of tracer die, or grease or prussian blue. And I have tried several pairs of glasses.. I find that what I am doing, is working so far, so why complicate the process.
I dont know it all, just been having decent luck at setting them up. I told my customer with the 1400 hp.. that it would break the first time he put that power to it.. After 15 hard passes, I did an inspection tear down and things looked pretty good inside!! So it should last another 5mins, or till he gets it on plane. Any more than that, is considered living on borrowed time for that drive with that kind of power.
Hope this helps..
D*ck
04-09-2007, 01:49 PM
#14
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I have a couple of different Bravo repair manuals
from over the years ( 2005 is the latest), and I've never seen anything about checking backlash in the uppers.
The only adjustments they list is the pinion bearing preload,
and the thrust bearing race/ case matching #'s.
It does have proceedures for checking backlash in the lowers
though.
Does Merc have a customer service manual, and a dealer
service manual, with the dealer service manual having
more info in it than the customer service manual does ?
The several that I've had apart are still going strong,
( knock on wood) but, the set up proceedures listed in my
manuals seem very basic, compared to set up proceedures
for a differential in a car, truck, or in our case, a forklift.
I like to check tooth contact, just to see where the
teeth are riding.
I have the upper gears out of my XR's getting cryo treated,
when I reassemble these I'll check backlash and see where they come in at.
from over the years ( 2005 is the latest), and I've never seen anything about checking backlash in the uppers.
The only adjustments they list is the pinion bearing preload,
and the thrust bearing race/ case matching #'s.
It does have proceedures for checking backlash in the lowers
though.
Does Merc have a customer service manual, and a dealer
service manual, with the dealer service manual having
more info in it than the customer service manual does ?
The several that I've had apart are still going strong,
( knock on wood) but, the set up proceedures listed in my
manuals seem very basic, compared to set up proceedures
for a differential in a car, truck, or in our case, a forklift.
I like to check tooth contact, just to see where the
teeth are riding.
I have the upper gears out of my XR's getting cryo treated,
when I reassemble these I'll check backlash and see where they come in at.
04-09-2007, 02:13 PM
#15
Charter Member #601
Charter Member
The new procedure was in Supplement #28 ( I believe). It is the new procedure for the new style, new design upper case. And they look for .009-.015" @ .025 pinion depth, as AT said. Several tools are needed to measure it. The Supplement explains it well.
Hope this helps..
D*ck
Hope this helps..
D*ck
04-09-2007, 04:54 PM
#16
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The new procedure was in Supplement #28 ( I believe). It is the new procedure for the new style, new design upper case. And they look for .009-.015" @ .025 pinion depth, as AT said. Several tools are needed to measure it. The Supplement explains it well.
Hope this helps..
D*ck
Hope this helps..
D*ck
04-09-2007, 07:22 PM
#18
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JaayTeee and Mr Gadgets:
Trick about that Supplement is right on. I only found out about it when a new Bravo upper case was ordered and it had NO case matching number to recommend shim thickness.
Pettem, sorry to hear you did not get the whole kit in one shot, I kinda wonder how you got JUST the gears alone. Did you try too hard to get only what you wanted? Or was it Aftermarket?
Trick about that Supplement is right on. I only found out about it when a new Bravo upper case was ordered and it had NO case matching number to recommend shim thickness.
Pettem, sorry to hear you did not get the whole kit in one shot, I kinda wonder how you got JUST the gears alone. Did you try too hard to get only what you wanted? Or was it Aftermarket?
04-09-2007, 11:28 PM
#19
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Wrench01, I purchased the gears I have now off ebay. I was just taking my drive apart this winter to check on things when I found one of my driven gears had a tooth missing? My drive being a 2000 and the cross-over year (OL to OM) I ended up getting the new style gears. I'm not sure if you can purchase the gears without the clutch, shims, bearing races etc... but, I didn't get any of that.
Mr. Gadgets, i'm sure you will be able to answer this for me and anyone else in future who finds this thread. My drive, a pre OM drive does not have to be shimmed and checked. (Standard 400HP or less application) Any drive with the older style gears being converted to the newer style only needs the .091, .094 or .097 shim removed and the corresponding .040 thinner shim but in it's place. (E.g. .051, .054 or .057) Obviously the housing/cap modification, clutch and shifter fork assembly need to be replaced along with the gears but the shimming is not required on the pre OM?
Mr. Gadgets, i'm sure you will be able to answer this for me and anyone else in future who finds this thread. My drive, a pre OM drive does not have to be shimmed and checked. (Standard 400HP or less application) Any drive with the older style gears being converted to the newer style only needs the .091, .094 or .097 shim removed and the corresponding .040 thinner shim but in it's place. (E.g. .051, .054 or .057) Obviously the housing/cap modification, clutch and shifter fork assembly need to be replaced along with the gears but the shimming is not required on the pre OM?
04-10-2007, 10:23 AM
#20
Charter Member #601
Charter Member
Well that is correct, Merc says that you dont have to check lash on that upper case. But through the years, it has been found that the lash can be excessive. It took Merc a lot of years to come to that conclusion and hence the new design/style case, with their procedure. I check the lash on all the drives I set up. Very rarely do I even look at the numbers stamped on the case. If you measure the case, they do vary from one to another. In most low hp cases, just putting them together will work. But I cant sleep well, not knowing exactly where the lash lies. I have measured too many cases and found measurements all over the place. So I cant afford to "not know" when I set a drive up for a customer.
When you started this thread, you were pretty general about what you were doing, and I figured that you might be talking a stock setup, but didnt want to make any general statements. So in your case, you should be good to just install the new gears, shims, etc and it will be good....
But then there is the reason that a tooth was missing!!!??? Was it due to loose lash? or something else.
Another thing I have found is that when teeth break off, it can egg shape the tower in the case, so it should be checked.
The longevity of a Bravo drive is relative to the shape of the case the parts are in. If something is off by a couple of thousands, it can have a detrimental effect.
If you need more detail, give me a call. I can guide you as to what might be a problem or not.
Hope this helps...
When you started this thread, you were pretty general about what you were doing, and I figured that you might be talking a stock setup, but didnt want to make any general statements. So in your case, you should be good to just install the new gears, shims, etc and it will be good....
But then there is the reason that a tooth was missing!!!??? Was it due to loose lash? or something else.
Another thing I have found is that when teeth break off, it can egg shape the tower in the case, so it should be checked.
The longevity of a Bravo drive is relative to the shape of the case the parts are in. If something is off by a couple of thousands, it can have a detrimental effect.
If you need more detail, give me a call. I can guide you as to what might be a problem or not.
Hope this helps...
