bravo failure

[Griff]

Have't done it myself but I've seen people put studs and spacers on the top cap instead of bolts. Makes sense to me!

Thats how my Imco upper was.

 

[Strip Poker 388]

Thats how my Imco upper was.

long time ago I bought a Imco kit, the studs were a larger dia.

Save the old for parts for the next time, sorry

 

[Mr Gadgets]

Rogue,
I normally dont helicoil unless the threads are damaged. I dont like to use larger studs, either, the case is pretty thin in that area and drilling to a larger dia makes it that much thinner. The holding power of the 3/8" studs is sufficient in normal operation of the drive. I like to fill the majority of the threaded hole with stud. I believe it helps stabilize the upper case some. I red loctite them in and use nyloc nut to hold the cap down. Then I install a treaded spacer with bolts in the top to hold the drive shower on. This isolates the top cap fastening from the cap clamping.

If the gears break, it is going to destroy things any way. I have yet to see a top cap come off and cause the gears to break, well when they are studded. In my opinion, I believe the gears break and pop the top cap. But I have never seen one with out streached bolts or undamaged threads. Not saying it doesnt happen, just not seen in in my shop. If the drive is operating properly, I dont see a need to increase clamping load on the top cap.

J.T.
My opinion of the XR gears is not very favorable at present. A few years ago, 1000hp was not an instant drive breaker. Now a days, 650hp in a light boat and the teeth on the driven gears just break off. I had the metal analyzed and no one can match the material up to any common steel offering listed out there. I have also analyzed the Helical gear from Merc and the Bmax upper gear. All very interesting. I am in the process now of attempting to have upper gears made with better material. It is very costly and nothing happens over nite.. We'll see where it takes me.

I have seen a hub seperate from the ring gear (that was what I was refering when I said gear split in two). I have also seen a ring gear break in two, half of it was left on the hub, the other have did some interference machining in the case. All very ugly!

Hope this helps.
Dick

 

[Geronimo36]

I had the metal analyzed and no one can match the material up to any common steel offering listed out there. I have also analyzed the Helical gear from Merc and the Bmax upper gear. All very interesting.

I'd love to know more about your helical gear findings.

I noticed on IMCO's new SCX drive they went with bigger gears like the BMax but they utilize a straight cut design like an XR. It also appears as though they are using a larger cone/clutch. I also heard a rumor that IMCO's lower unit will bolt up to an XR and vice versa but havne't been able to confirm???

From what I was told the helical can disperse the load better having more tooth contact area. I'm no scientist but it seemed to make sense so long as the teeth had enough meat on them.

 

[ROGUE]

Rogue,

I have seen a hub seperate from the ring gear (that was what I was refering when I said gear split in two). I have also seen a ring gear break in two, half of it was left on the hub, the other have did some interference machining in the case. All very ugly!

Hope this helps.
Dick

Yeah, this pinion did some fatal damage when it broke.

 

[Mr Gadgets]

Here is what the XR gear looks like inside. That cavity goes all the way around the gear. That must be where it is welded together and it is a weak point..

 

[boot-e-licious]

the gears were chewed up , the shaft was sheered in two, the upper is trash. the shop that does my work is going to cover all costs, they already ordered a new upper. last month i replacxed the port drive, it was under warranty. not really sure the exact cause, but it was ugly when they broke it down.

 

[MOBILEMERCMAN]

the gears were chewed up , the shaft was sheered in two, the upper is trash. the shop that does my work is going to cover all costs, they already ordered a new upper. last month i replacxed the port drive, it was under warranty. not really sure the exact cause, but it was ugly when they broke it down.

That is good news.

Hats off to your shop taking care of you.

 

[Mr Gadgets]

That is good news!!

 

[Offshoredrillin]

the gears were chewed up , the shaft was sheered in two, the upper is trash. the shop that does my work is going to cover all costs, they already ordered a new upper. last month i replacxed the port drive, it was under warranty. not really sure the exact cause, but it was ugly when they broke it down.

Wow, that is great news... If you dont mind, for doing the right thing, you may want to make a post in the Good bad and ugly section. I'm quite sure that they would love some more business. also let them know that you did it and how much it is appreciated..

Dick, I blew the gears in my starboard lower and am going through both of them now, I would be interested in your gear findings as well...Rob

 

[PARADOX]

Glad to hear your shop will take care of you Lenny.

Good news.

 

[boot-e-licious]

hi guys, the shop is pablo creek marine center and they are very good at what they do. they are here in jacksonville,fl. last year at the jacksonville poker run in june, which is a great run and an area for great boating, a fellow boater in the run blew a water line, still 25 miles from the docks and they met me at one of the docks with the line to bring to this gentleman.

hi pete, how did the surgery go, how's gail? boat will back up next week sometime.