Linning up prop shaft with velvet drive

guglielmo6160 · Post by **guglielmo6160** » Tue Jan 18, 2011 7:27 pm

besides using common sense, any tricks to doing this? seems the flange on the end of the prop shaft moves a little and can be brought to meet the rear of the drive,
any tips, or advice?
thanks

Paul · Post by **Paul** » Tue Jan 18, 2011 8:41 pm

What do you mean by "moves a little"?

guglielmo6160 · Post by **guglielmo6160** » Tue Jan 18, 2011 10:37 pm

well, just as I said, you can take the flange that is on the prop shaft and there is a little movement in it, should there not be? besides the cutlass bearing under the boat, what else should ther be besides the rubber boot, that the stuffing box is clamped to? Im assuming there would be some play to align the flange that comes out of the stuffing box to the back of the velvet drive, which will act as another anchor point for the shaft? is this not correct, ?

captainmaniac · Post by **captainmaniac** » Tue Jan 18, 2011 11:12 pm

If you mean you can move the top end of the shaft (with flange attached) a bit, then ok. If you mean the flange moves on the shaft, that ain't right.

To do the alignment, you actually should be using a feeler gauge (like for spark plug gap) to measure distances between the two halves of the flange (the one on the shaft, and the one coming out of the tranny). If things are out of spec or uneven as you measure at different points around the flange, you need to change the position of the engine to get things to align. That might mean raise the front and lower the back, or raise or lower the whole thing, or 'twist' it one way or the other in teeny tiny increments until you have identical tolerance all around the flange. Then you are in alignment. (Ain't as easy as hooking up an engine/tranny to a drive shaft in a car because you don't have any universal joints on the boat - its gotta actually line up or you get vibrations and potential damage).

When I needed mine done, I decided to pay the mechanic for an hour or so to fart with moving a half ton of iron to the precise position it needed to be in (besides - he outweighs me by about 100 pounds so he can move the engine easier than I can). He didn't want the job, but wanted the money more. And if it ain't aligned right, both me and he know who's paying (or absorbing the cost) to do it right, as well as pay for any damage caused!

guglielmo6160 · Post by **guglielmo6160** » Wed Jan 19, 2011 5:48 am

ok, well in this case I agree, as I mentioned the flange is keyed and bolted to the shaft, so any play in that would not be acceptible, what I was referring to is that once that assembly is together, (I mean the flange, the prop shaft, stuffing box rubber boot etc etc. and you pull it through the cutlass bearing from inside the boat to meet the trans flange, it should mate up by moving the engine around,
ok, agreed.

rbcool · Post by **rbcool** » Wed Jan 19, 2011 7:01 am

A VERY small amount of play is due to the rubber at the shaft log. But alignment MUST be perfect. I've seen mis-alignment blow a tranny. If I remember, this is the boat that has all the new stuff?? Doing this in the water will make it harder to align properly as there are easy things you can do on the hard. I think if you do a search for Cutlass bearing there was some good advice on alignment awhile back.

Ron

ready123 · Post by **ready123** » Wed Jan 19, 2011 9:17 am

rbcool wrote:Doing this in the water will make it harder to align properly as there are easy things you can do on the hard.

I understood that doing the alignment in water was the preferred method as blocking often does not support the hull and gear in the same attitude as water. Am I incorrect in this view

captainmaniac · Post by **captainmaniac** » Wed Jan 19, 2011 9:32 am

You could do a rough alignment on the hard, but should recheck and adjust while floating. The hull and bottom are likely to flex a bit while on blocks compared to how everythign sits while in the water, so a perfect alignment while on blocks may well be out while in the water ... and proper alignment while in the water is more important (for obvious reasons).

rbcool · Post by **rbcool** » Wed Jan 19, 2011 9:45 am

ready123 wrote:
rbcool wrote:Doing this in the water will make it harder to align properly as there are easy things you can do on the hard.
I understood that doing the alignment in water was the preferred method as blocking often does not support the hull and gear in the same attitude as water. Am I incorrect in this view

Doing a full alignment in the water is fine, if you have a trained mechanic down in the bilge while underway.
On a new install I like to start the alignment on the hard because its a lot easier to check it by the prop shaft and the prop itself. Mis-alignment shows up much better at the prop since its farthest away from the tranny. .030 at the flange shows up almost to the naked eye at the prop. I do fine tuning in the water, both in the slip and under load at 1500 rpm.

Ron

mr elevman · Post by **mr elevman** » Wed Jan 19, 2011 9:59 am

rbcool is rite on as i repowered last year i was heled in the slings for 2 hrs to check alinment and tighten shaft packing witch was allso replased

summer storm · Post by **summer storm** » Wed Jan 19, 2011 2:53 pm

I saw you posts on craigslist, I guess you are going to fix her up.
I will add one more thing, although it is OK to have movement at the shaft packing gland you need to check to see if the shaft is centered (or close) where it enters the boat. If it rides on the the bronze fitting it will score the shaft. I just went through this on the 40ft Topaz and it was very expensive to fix.

jav · Post by **jav** » Wed Jan 19, 2011 4:31 pm

Boys- unless I'm in an alternate universe- all this talk of alignment being easier on the hard and refining alignment while in motion is misleading and downright dangerous.

A true "shaft aligment" must be done in the water- after the hull has been afloat for a few days and after any compliant engine/tranny mounts have been loaded and settled.

Yes- rough alignement can be done on the hard but it is NOT required. Further - only when a new strut is fitted, or if the mounting surface of the strut has been compromised (by hull damage or removed for rebedding) is a rough alignment required. BUT- this is an alignment of the "strut" in order to set the "bearing bore" in line with the shaft log. Once this is done, the shaft alignement should be done as previously stated- wet and stationary.

rbcool · Post by **rbcool** » Wed Jan 19, 2011 6:43 pm

Well I guess opinions are like................

Ron

Allen Sr · Post by **Allen Sr** » Wed Jan 19, 2011 6:50 pm

rbcool wrote:Well I guess opinions are like................

Ron

C'mon Ron, don't keep me hanging like this you know my heart can't take much more.............'like WHAT??????...........'

hmc · Post by **hmc** » Wed Jan 19, 2011 7:41 pm

The only right way is in the water , you get is close on land with a feeler gague but need to recheck in the water with feeler gage .