is complete, and here are the results.
It might have been an easy thing to just hang another vibration dampener/flywheel onto the back of the engine
, but then you are still left with the worn splines on the tranny input shaft, which is likely what caused the whole thing to go bad in the first place. It might bear reminding that in my case, engine was replaced, transmission
would have you replace not only the dampener, but also that shaft, which would entail replacing the entire gearset @ circa $3 grand. Not that much more to replace the whole drive.
So, it takes two mech.engineers and an extremely good machinist, but we have come up with this fix. This is a very abbreviated version. If you want details, I'll have to email. You can get in touch with me via the email link provided in my CF account.
Bore out the splines in the vibration dampener and weld in a splined collar. The splined collar is tack-welded in place to limit the chance of heat damage to the rubber element in the vibe dampener. That process takes quite a bit of time, as you tack in a couple welds, let that cool, then do another couple of tacks. Limit the rubber temp to ca.200F our estimate
As for the input shaft, the machinist put it on a lathe and found that the shaft had about 2000th/inch of runout. The process of machining off the splines included truing the shaft. The prepared spline adaptor was heat-shrunk onto the input shaft. We determined the amount of heat-shrink we could get on the shaft appears to be about 20x the strength of the original splines, therefore we don't have to worry about it slipping.
This fix does not allow you to replace the input shaft seal
, so you need to make sure you have a good seal in place before heat-shrinking on the spline adaptor. Also, we immersed the input shaft housing arrangement/gearset, just enough to cover the seal, as we put the hot adaptor onto the shaft to prevent damaging the seal, so it is imperative to drive out any water
left in the gearset before reinstallation.
I installed this yesterday, and it is shifting smoothly, although the weather
was fairly bad so I didn't take the boat off the dock
. Next time we go sailing we'll find out whether this works, and if it doesn't I'll let y'all know.
This is approximately $200 in parts
(splined stock), enough to do two or three of these, and the machine work was $3-400. If anyone is interested, we can short-cut the engineering work, we'll provide drawings and directions.