So for most transmission replacements you have to move the drive shaft back a bit 1" to 1.5".
How does one do this?
A couple years ago when replacing my cutlas bearing I ended up getting a new stainless drive shaft and sent the prop off to get everything tuned etc. Then added new dripless and coupled against the transmission.
I don't think I can push the shaft back any further because it already looks like the gap between the strut and the prop is at or exceeding the 1" max. So I probably need to cut it. How does one cut this, in place, in the water?
I also need to potentially raise my engine up a bit. How do you do that, I assume some type of shim, but what is that specifically?
Here is a pic of my current coupler. I assume I don't have a 'flexible coupling'. Should I get one? I am worried about not getting everything all aligned after the install and it seems like this may help.
Thoughts?
The red part on the coupler looks like a "Globe Drivesaver". If so you could remove it to get space back. It's not a true "flexible coupling" but more of a shock absorber if your prop hits something. I have one.
Raising the engine should be easy as long as the mounts have enough thread. It looks like you're engine is pretty low so raising it 1/4 or more should not be an issue.
The only way I know of shortening the shaft is to remove it and send to a shop The risk of too long a shaft is prop shaft whipping (which could damage the shaft) if your prop is out of balance . How much vibration do you have today?
How long is too long? Hard to say. You'll find many boats in the yard with"too long a shaft" which have no problems.
This is an excellent article regarding engine alignment: https://www.yachtsurvey.com/Alignment2.htm
If I removed the Globe Drivesaver, that may give me space back but probably not exact. So I would have to still 'move' the shaft back or forward to connect everything. Can you just move the shaft through the dripless PSS? Safely in the water? I have seen something about scratching?
How much vibration do I have? It is sure hard to say because this is my first boat like this.
I have the 'some RPMs' are worse than others but I don't have things in the cabin rattling or I can't feel it in my feet etc.
It seems to have gotten louder (vibration/engine/trans/??) over the last couple years. So I am replacing the motor mounts and insulation during this.
The prop, shaft and globe drivesaver coupler were all machined and balanced 2 year ago.
I have also see this, what does this mean?
QuoteThis maybe a problem if you use the keyway shaft to transmission attachment. If that is a problem change to flexible coupling that doesn't need a keyway -Ron
What is a keyway?
@Kable
I noticed that the anodes might be in a location for "shaft whip." Not the worst (mid-span) but IIWMB I'd place them 2 diameters from the strut and hull.
Thanks, will have the diver do that next time.
Assuming I don't have to pull the boat to make these shaft adjustments for a new transmission.
I guess I am hoping that I can remove the drive saver and coupling. Add in a federal flex and be about the same but then I still have to move the shaft through the PSS and what will that do, can you do it?
Then I still will be left w/ too much post the strut (according to these forums) and now the anodes.
The original length (before I moved to stainless) looks too long as well, but better than my current.
Kyle : What I'd do is get rid of the Driver Saver and get a flexible coupling. I'll guess that when you cut the shaft (so it's 1" space from the from of the prop to the rear of the strut) you'll be out of "keyway" on the shaft. The flexible coupling doesn't need a key way.
I see that you have the original engine mounts - I'd get some new Vetus 75 engine mounts and realign the engine - then you should be OK. That will raise the engine!!
You should be able to do everything in the water. I used a Saws-all to cut my shaft. The shaft should slide along the inside of your dripless gland.
A few thoughts
Ron- you cut a Stainless Steel shaft with a sawzall while in the water and with the engine in place?? "Brave" operation!
Quote from: Noah on July 17, 2022, 11:28:36 AM
cut a Stainless Steel shaft with a sawzall while in the water and with the engine in place?? "Brave" operation!
He didn't have AC to run the saw so he just ran the engine and held the blade against the shaft! :rolling :rolling :rolling
Noah : I never said where I was, but Ken has a new way!!! Even harder to do if you are in reverse!! :shock:
A thought
Sorry for the dumb questions...
So the boat is in the water, I can't see or measure the distance from the prop to the strut (I do have the pics posted but no measurements).
I understand I can remove the drive saver and add the Federal flex coupler and then I will be 'too long' w/ the new transmission. So I could cut off the end (engine side) before adding the couplers etc. If I go this route, I don't need to move the shaft back at all, just cutting the end, right? But this doesn't 'help' the fact that maybe I have too much distance between prop and strut.
So should I go-pro, dive and measure, then pull shaft forward to the engine, then measure (no drive save + fed coupler - new trans) and cut?
Sounds like moving through the dripless isn't a concern, no issues moving through the cutlas? (2 years old)
Ron you have made these cuts in the water, Noah and KWKloeber (Ken?) you joke/pushed back on this idea. What are the concerns/things to consider.
Just trying to learn...
IMO it seems like a risky maneuver to try inside the boat while in the water. Especially if you plan on keeping the cut shaft once cut. A sawzall is not a precise tool and can be dangerous to control in a confined space cutting tough metal. Ideally haul the boat, measure, remove shaft, and cut—either yourself, or preferably take to a machine shop.
The other thing that hasnt been said is that the compression of the bellows on the dripless shaft seal goes away when the shaft isnt connected to the engine risking water intrusion while in the water.
>>>Ron you have made these cuts in the water, Noah and KWKloeber (Ken?) you joke/pushed back on this idea. What are the concerns/things to consider.<<<
Read it carefully, he said YOU should be able to do it in the water. He said only that he cut it in place (not necessarily in the water.)
Even IF IT could be cut in the water, what's Plan B (one ALWAYS NEEDS a B) if things go south?
Quote from: kable on July 17, 2022, 05:55:15 PM
Sorry for the dumb questions...
So the boat is in the water, I can't see or measure the distance from the prop to the strut (I do have the pics posted but no measurements).
I understand I can remove the drive saver and add the Federal flex coupler and then I will be 'too long' w/ the new transmission. So I could cut off the end (engine side) before adding the couplers etc. If I go this route, I don't need to move the shaft back at all, just cutting the end, right? But this doesn't 'help' the fact that maybe I have too much distance between prop and strut.
So should I go-pro, dive and measure, then pull shaft forward to the engine, then measure (no drive save + fed coupler - new trans) and cut?
Sounds like moving through the dripless isn't a concern, no issues moving through the cutlas? (2 years old)
Ron you have made these cuts in the water, Noah and KWKloeber (Ken?) you joke/pushed back on this idea. What are the concerns/things to consider.
Just trying to learn...
Kable and all,
My experience is that the coupler end of the shaft has a keyway and dimples for the coupler set screws. If so, how can the shaft be shortened without extending the keyway and redrilling the dimples? Does the pictured coupler connect to the shaft in a different way?
Regarding zinc placement, make sure the diver doesn't place it so close to the strut that the shaft doesn't slide back far enough to work on.
I was paranoid about losing the shaft out the rear while working on it so I placed my zinc to act as a stopper so the shaft doesn't slide so far back that I can't get it back.
Kyle
Kyle : Re read my post and I said that a Flexible Coupling does NOT need a keyway!!
What I did while in the water was to pull the drive shaft all the way forward so the prop was against the strut, then push the shaft back 1 " !!
A few thoughts
KWKloeber - Yeah, I usually do have plan B and C. In this case, I don't and I don't have enough knowledge of the dripless PSS. My local mechanic that did a great job replacing my cutlas, new stainless shaft, prop etc. really really recommends me pulling it for exactly that. He said he has done it but it is him. Starting to think I should pull it... but then... more "while you are at it projects" will creep in... $$$
I guess I head read that people put a clamp on the dripless when pulling the trans/engine. That keeps things compressed and not much water inflow.
Now, of course I need to pull the shaft foward, hit the strut and move back (thanks Ron). To do this, I need to remove the clamp. I do have helpers, is this something you can hold pressure on by hand while we quickly adjust the shaft? Worst case, plan B, clamp clamp???
Or should I just pull it out?
Now everyone has me scared that how do I know when I re-launch it is not going to flood, since clamping wasn't good enough in the first place. Regardless I guess I need to research the PSS and the set screws that I need to replace etc.
Ugh.....
Going back and forth...
So it sounds like people replace their trany in the water w/ a dripless PSS by installing a clamp (I think to keep the spring tension in place). So I assume when you remove the transmission the shaft is free and that is why you loose the tension in the PSS spring). So they have it clamped, put in the new trany and good to go (maybe there is new setscrews, not sure).
So the difference for me, is that I need to pull the shaft all the way in (hit the prop on the strut) then push back out 1". So to be able to move this I need to remove the clamp, which will cause the spring tension to go away and water to flow in. So can I keep the tension on another way (holding it etc?).
So what would plan B be? For the people placing the clamp, what would their plan B have been?
Not challenging, actually looking for a plan B.
Remember that if you want to get wet you can stuff the outside of the log and control a great amount of flow that will come in around the shaft.
I called Federal Marine Transmission to ask some questions and order their flexible coupler.
https://federalmarinetransmissions.com/contact.html (https://federalmarinetransmissions.com/contact.html)
708-352-2200 (Jim)
He was very knowledgable and provided a lot of history.
It ended up being part # 43A w/ 1" diameter. about $380
https://0201.nccdn.net/1_2/000/000/0d7/d2a/2022--federal-flexible-couplings.pdf (https://0201.nccdn.net/1_2/000/000/0d7/d2a/2022--federal-flexible-couplings.pdf)
The part has to be 'made' which takes about a week.
No mention of a grounding strap.
He said to continue to use the existing old stiff coupler for initial transmission / shaft alignment, then re-install this flexible coupler.
Question/confirmation about the use of a key way.
I said I would be cutting off the front of my shaft and would likely be loosing the key way and that I had heard the key way was not required. He was very adamant that the key way is still required. I mentioned others had success w/ out the key way and he said the only thing he could think of is that they were using the set screws to tighten against the shaft and this wasn't correct. ????
He said the shaft should be pulled, sent off w/ the coupler, re keyed and re-drilled for set screws and fit the new flex coupler to the shaft. He said every shaft is different, like a fingerprint and could be off by a 1K of an inch, etc.
So, now my big concern is the key way. @Ron Hill - I know you have had success, any thoughts?
Now my current thoughts are to get in there and get an exact measurement of my current hard coupler + drive saver. This should be bigger (longer) than the new Federal flex coupler (2 11/16"???). So how much bigger? I need to find 1.5" for the longer transmission. I am guessing I still need to shorten the shaft 1/2".
If I need to pull the shaft and re-cut a key way, I have to for sure pull the boat, cut out the cutlas, pull the shaft back past the rudder, have the shaft properly cut down to account for the prop length behind the strut etc. Reapply bottom paint, etc. (did all this 2 years ago).
Maybe, for now, just simply push the shaft back the 1/2" (making the prop / strut distance worse), but maybe 'this' can be done safely in the water? This would buy me another year (bottom paint, $, time). So thoughts on experiences/safety of just pushing the shaft back a bit while in the water? Or are all the risks the same?
@kable
It's just common sense that a key's purpose it to transmit a certain torque of an axial load while being able to shear if there is a situation where there is possible damage (hit an obstruction.) Setscrews are intended to hold a coupling, etc., on a shaft not withstand the axial load where there's a key or spline (e.g., alternator pulley, crankshaft pulley, crankshaft output shaft, transmission output shaft, etc.) Ask FMT if that's no so.
That's not to say that setscrews don't hold AT ALL, or that they wouldn't work (temporary?) but it's not their purpose.
There are ways to remove the shaft but it takes logistics and careful orchestration. For instance the log can be olugged internally or with a cap. You'll get wet (temporarily? But not sink the boat unless the operation goes south (hence the careful orchestration needed.) it's a gamble that must be weighed.
Kable : I dumped my Driver Saver long ago for a flexible coupling, you definitely don't need both!!! A flexible coupling "clamps itself around a shaft" so there is no need for a key way!!
a few thoughts