Imco extreme advantage
08-12-2009, 03:15 PM
#21
I'm working on designing a new upper gear set for an XR drive.
Should know more in a few weeks.
Should know more in a few weeks.
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08-13-2009, 09:24 AM
#24
They will be the straight gears as used in the XR drives, but hopefully will hold up to at least 800 hp.
And I will be testing them personally with a big heavy boat and 800 hp and 900 ft lbs
And I will be testing them personally with a big heavy boat and 800 hp and 900 ft lbs
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08-13-2009, 12:04 PM
#25
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Smitty,the current XR gears are forged? and made from what sort of metal?
Is/will a billet gear be stronger?
Who do you think in your opinion makes or modifies the best currently available gears?
Does getting "more tooth contact"like the bravo 1 spiral gears as oppose to the XR style help?
I just wonder if the Bravo 1 failures related to HP are attributed to the gears or is it the towers,shafts etc letting them down whereas if a reg Bravo1 was given all the upgrades the XR gets with a huge set of spiral gears.
Is/will a billet gear be stronger?
Who do you think in your opinion makes or modifies the best currently available gears?
Does getting "more tooth contact"like the bravo 1 spiral gears as oppose to the XR style help?
I just wonder if the Bravo 1 failures related to HP are attributed to the gears or is it the towers,shafts etc letting them down whereas if a reg Bravo1 was given all the upgrades the XR gets with a huge set of spiral gears.
08-13-2009, 03:09 PM
#26
My biggest challenge is to get a stronger gear in the same space as the current gear occupies.
Helical gears would be stronger, but the teeth are to narrow now and there is no room to get bigger.
The current rash of failures are due to the quality of the metal used in the gears along with the fact that they are 2 piece gears. That hub that holds the brass ring is welded on.
Billet gears might be stronger but they cannot be CNC'd right now because of the hub.
That's all I can say for now. I am on a mission to get something made that will hold 800 hp and last more than a season !!!
Helical gears would be stronger, but the teeth are to narrow now and there is no room to get bigger.
The current rash of failures are due to the quality of the metal used in the gears along with the fact that they are 2 piece gears. That hub that holds the brass ring is welded on.
Billet gears might be stronger but they cannot be CNC'd right now because of the hub.
That's all I can say for now. I am on a mission to get something made that will hold 800 hp and last more than a season !!!
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Gold Member
08-13-2009, 10:05 PM
#28
Registered
Smitty,the current XR gears are forged? Yes forged.
and made from what sort of metal? 'Corresponds to a case-carburising low-alloy steel equivalent BS970-1955 Grade EN33 ( Aus)'
Is/will a billet gear be stronger? 'A suitable alternative material for the local manufacture of these gears would be a case-carburising steel such as AS1444-1996 Grade X3312(EN36A), case carburised to an effective depth of 0.9-1.2mm'
Who do you think in your opinion makes or modifies the best currently available gears? IMO and experience, I have run cryo'd, cryo'd and polished with no noticable increase in gear life, carefull assembly, ie setting correct backlash in both upper and lower gear housings, correct bearings for the application and proper oil gives maximum life.
Does getting "more tooth contact"like the bravo 1 spiral gears as oppose to the XR style help? My testing is showing this to be to help.
I just wonder if the Bravo 1 failures related to HP are attributed to the gears or is it the towers,shafts etc letting them down whereas if a reg Bravo1 was given all the upgrades the XR gets with a huge set of spiral gears. I believe that for more torque and or horsepower you need larger gears, see BMax, Imco SCX, Konrad upper gears, with proper gear support ie bearings and housings. Straight or helical does not seem to be the issue.
and made from what sort of metal? 'Corresponds to a case-carburising low-alloy steel equivalent BS970-1955 Grade EN33 ( Aus)'
Is/will a billet gear be stronger? 'A suitable alternative material for the local manufacture of these gears would be a case-carburising steel such as AS1444-1996 Grade X3312(EN36A), case carburised to an effective depth of 0.9-1.2mm'
Who do you think in your opinion makes or modifies the best currently available gears? IMO and experience, I have run cryo'd, cryo'd and polished with no noticable increase in gear life, carefull assembly, ie setting correct backlash in both upper and lower gear housings, correct bearings for the application and proper oil gives maximum life.
Does getting "more tooth contact"like the bravo 1 spiral gears as oppose to the XR style help? My testing is showing this to be to help.
I just wonder if the Bravo 1 failures related to HP are attributed to the gears or is it the towers,shafts etc letting them down whereas if a reg Bravo1 was given all the upgrades the XR gets with a huge set of spiral gears. I believe that for more torque and or horsepower you need larger gears, see BMax, Imco SCX, Konrad upper gears, with proper gear support ie bearings and housings. Straight or helical does not seem to be the issue.
Replies above in red.
Also in the report I commissioned, FWIW,
Comments on
"Material Identification of Damaged Bevel Gears'
'Two damaged gears, one a straight bevel gear and the other a helical bevel gear..were submitted for metallurgical examination primarily for material identification purposes.'
'Metallurgial examination has revealed that the bevel gears had both been manufactured from a low alloy case-carburising steel....
Cross-sections of teeth taken from each gear showed that they had been case hardened to an approximate effective case depth of 1.1mm,ie minimum case depth at which the hardness remains above 500HV. Both the material and heat treatment, including the case, is considered satisfactory for this application and not likely to have been contributory in failure.'
Steve
08-13-2009, 10:22 PM
#29
Registered
To answer the OP question,
Year 2000, serial # OM100000 and above was when the X, XZ and XR were introduced.
So a 1998 model would have the old style gears, ie, helical bevel, thinner floor, different bearings and small U-Joint yoke, unless, of course, it has been upgraded.
Steve
08-14-2009, 12:34 AM
#30
Registered
The boat is a 98. I think the drives were originally done in 2000 or so By MMW. They were refreshed in 04 before I purchased the boat. The drives have held up very well behind the 800's, but... the boat isn't very heavy. I do run 1.36 gears and 36p Bravo props, so it does see some serious stress. I did have one issue last year, but it was due to a broken top cap. Knock on wood..... they have been very reliable for me.
Darrell.
