Md2020 engine/gearbox removal in water?

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mattnj

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Sigma 33, md2020, has a few issues, gearbox leaking oil, really poor starting and smoking till warm (head gasket I think)

It has a Volvo type gland.

Question is, can I remove the engine/gearbox with boat in water...I have a crane on pontoon at the club...

Trying to decide on removing gearbox (I guess shaft will push back enough? And head, and do works in situ...or just whip whole lot out and take home for a full refresh at home in my workshop...
 
If you undo the drive flange bolts the shaft cannot slide back. It can most definitely be done afloat, I took my Bukh 20 engine and gearbox out. Lifted it with a Turfer, lowered it onto a skateboard on a plank and rolled it into the saloon.
 
If a Volvo type lip seal gland then I would suggest checking the the section of shaft you will be pushing into the gland is smooth and clean so it does not damage the lips of the seal.

If the seal was a face to face seal then there might be a problem as one sealing face is held in place by compression and leakage could take place once the compression is relaxed to slide the shaft back.
 
hello again, so engine has been swapped out with it in the water, all easy enough, I dropped it back in yesterday (a new engine) and although the rear mounts are undisturbed the front engine mounts have been off/back on cant guarantee 100% in the same place...but they should be pretty close...

It slid in ok and the flange on the propshaft and the rubber coupling on the gearbox all just lined up first attempt and the shaft pushed forward and onto the coupling ok.... do I need to check/adjust/tweak the alignment at all on the engine/shaft, what's the process to do that? I assume it needs to be bang on!

Thanks
 
mattnj said:
hello again, so engine has been swapped out with it in the water, all easy enough, I dropped it back in yesterday (a new engine) and although the rear mounts are undisturbed the front engine mounts have been off/back on cant guarantee 100% in the same place...but they should be pretty close...

It slid in ok and the flange on the propshaft and the rubber coupling on the gearbox all just lined up first attempt and the shaft pushed forward and onto the coupling ok.... do I need to check/adjust/tweak the alignment at all on the engine/shaft, what's the process to do that? I assume it needs to be bang on!

Thanks
Click to expand...
Yes, alignment is critical. First ensure the shaft is central in the stern tube. Ashore use three little wedges, afloat is a bit more of a challenge but not impossible. Then measure the clearance at 90 degree intervals between the shaft and gearbox flanges with a feeler gauge. Adjust the engine mounting screws until clearance is the same all around to within .002"(sorry cannot think these small units in metric!).

Well worth googling as there are hundreds of pages giving more detail
 
mattnj said:
It slid in ok and the flange on the propshaft and the rubber coupling on the gearbox all just lined up first attempt and the shaft pushed forward and onto the coupling ok.... do I need to check/adjust/tweak the alignment at all on the engine/shaft, what's the process to do that? I assume it needs to be bang on!
Click to expand...

Think this covers it - it's about changing feet but also alignment. From the Vetus owners FB page.
https://www.facebook.com/video.php?v=1079405979600196
 
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