Remote Mounted V-Drive (Walter)

[TheIntern36]

How hard is it to get perfect alignment on the shaft between the V-Drive and the cutlass bearing?  What methods have you found successful? 

I may remove mine for a checkout and possible rebuild, and want to make sure it's perfect when it goes back in.  The shaft and propeller were balanced last year.  It seems to run true at cruising speeds, and docking speeds, but has a small whip in between high and low RPM.

Any advice on this system would be greatly appreciated.  Most of the folks out there can't get past the idea the engine sits backwards when I ask them for advice.

Sam

[S/V Deo Volente]

Here is some reading for you.
http://www.pearson365.com/forum/index.php?topic=392.0
http://www.pearson365.com/forum/index.php?topic=1328.0
http://www.sailingseadragon.com/Manuals/Walter_V%20_Drive.pdf

[PeteW]

Not sure what your question is. But it sounds like you are talking about the alignment of the shaft to the centerline of the cutless bearing in the strut which is something I have wondered about while aligning the V-drive to the shaft. I know that this shaft does have a small amount of motion up down left right. My solution has always been to place the shaft as close to center of the shaft log. If the stuffing box is installed I lift the shaft a small amount to offset it weight from gravity.

All that being said, how far out of center to the cutless bearing is that. The bigger question I can't answer is how much misalignment is too much for a cutless bearing,  It's made of rubber so it can give a little. Doing some quick trigonometry on a 50" some inch shaft that's within 1/8" of centerline works out to 0.14 degrees. Probably OK for a rubber water lubricated bearing.

If you're asking how to align the v-drive, its part art and a fair amount of science. In short you align the v-drive to the output shaft, with the input shaft removed, to within .003" with a feeler gauge at the coupler. That trigs out to less than 0.07 degrees of misalignment max. The v-drive has a slotted swivel plate with lifting screws on either side. If they are all rusted you are going to have a rough time of it.  Note: do this part with the input shaft removed.

You are now done aligning the v-drive and its locked down. Next (2) you align the motor/tranny flange to the v-drive input shaft center line to within 3 degrees.  Then you (3) reduce to angular error on the u-joint yoke in 2 axis to less than 2 degree overall of misalignment. That's were the .125" yoke delta measurement comes from ( from the Walter instructions). You will need a dial caliper to do this measurement. I have roughed it in very close by dropping some perpendiculars with a square and some string off the flange surface of the input tube on the V drive to the flange on the transmission while the shaft is removed.  So once I measure my error by using  large right triangles and trigonometry, I can calculate my error with very high precision to 3 decimal places.  I can then calculate how much to adjust each of the 4 motor mounts up or down. Without doing these calculations there will be a lot of trial and error going on.   But typically the rear mounts establish the centerline on the shaft and the front mounts establish the angle on the u-joint. But there is a lot of interaction.

And don't ignore the initial horizontal alignment of the motor. The slots in your motor mounts affect this part which can be a real bear especially if its way off. You can slide the motor with a bottle jack. You will note that the motor has the same offset in degrees as the output shaft which clears the skeg.

Its complicated and you might as well shoot for 0 degrees of misalignment on all three components done in the correct order.

[SVJourney]

Nice write-up Pete.  Thanks much!