Re: Stern drive Case Material
What would cause it to self destruct? Am I under thinking this?
I will post pictures of the crack tonight or tomorrow morning.
I am thinking you had a severe enough stike with a foreign object that caused the crack. A crack in the case that is subsequently welded might just cause enough of a mis-alignment inside that would result in an eventual problem.
Most of the time the only successful case welding is only in areas like the skeg or other external areas. You probably don't have a lot to lose........here, to effectively weld , the case would probably need to be completely disassembled because the crack is directly where a bearing is located.
Dissassenbly & reassembly usually requires some rather specialized tools and skills.
Most people don't have have those tools or skills unless they do it for a living.
If you have to pay someone to do it, in addition to the welding (which is not all that hard for aluminum alloys) you will most likley need to replace (add/subtract) shims to reset the bearing preloads etc.
You wouldn't put the thing back together with the old seals so you would need new seals, etc and any other parts that you may not use twice..........
There's also the outside chance that you might need a new bearing or dog-clutch if they're "close".......... (you wouldn't put it back together with worn-out bearings)
So in view of all of the above, it's looking (labor-wise )more like a rebuild................. Doing a rebuild on an Alpha is almost always close (parts and labor) to just buying a new SEI drive with a warranty.
In the case of a Cobra, you have a drive that, while it was excellent in it's day, some parts are simply not available anymore......making it NOT a very good candidate for putting a LOT of money in.
In this case, I might just run the thing until it "blows" and just replace it altogether.
It's up to you. but if you heat that case up enough to "weld" it without taking it apart, you'll have a lot more problems than the crack.....and after you take it apart, you may have the same problems unless you weld it inside and out, put it on a milling machine and line-bore the upper bearing area (where you weld it)
In that event.......it's better to just replace the upper case. I probably wouldn't try to weld the case in a bearing "support" area.
