How to find correct alignment?

[k. michael marquardt]

Disregard the shaft seal. you want to align the engine to the shaft bearings and not to the seal.
In any way it pays ta have a flexible coupling between the transmission gearbox and the shaft because the alignment will vary with engine load, annealing of engine mounts and wear on your bearings.


The 'feeler gauge' procedure will give you the indication that the flanges are parallel.
It does not imply that the transmission drive and shaft axis are in flush bearing. For this you need to put an engineers rule across the flanges and determine the height of the flanges by a feeler gauge. A proper alignment will show no gap between both flanges up down and both stb & port. The more precise method is to rotate a flange with a microclock against the other.

[Cheechako]

Your shaft will not fall out. The coupling is on it. I've never experienced one that would slide out even if the coupling wasn't on it. Also, may boats it wont come out due to rudder interference anyway. The feeler gage method works fine. Can be a little frustrating adjusting the motor mounts but just take your time and take a break now and then!

[artisanmach]

Pump alignment is the same as aligning your prop shaft and engine/transmission. it is even more critical because centrifugal pumps spin much faster than the typical propeller.
there is a ton of information on the web.

[artisanmach]

using feeler gauge is a very accurate way of finding angular misalignment but you need a dial indicator or depth micrometer to measure concentric misalignment. on a 4" flange .003" = .1° .00035" =.01°

[Cadence]

I think I lost a post? Remember you are dealing with three axis not two. Shims and a crowbar. If your not gray or bald you will be.

I think Terra Nova had it pegged on determining the shaft position in the gland.

Best of luck.

[Lake-Effect]

Originally Posted by artisanmach

using feeler gauge is a very accurate way of finding angular misalignment but you need a dial indicator or depth micrometer to measure concentric misalignment. on a 4" flange .003" = .1° .00035" =.01°

As I recall, the only couplings I saw were all self-aligning for concentric alignment, due to the mating stepped section I mentioned earlier. Different sorts of couplings?

[Terra Nova]

No need for dial indicators or depth micrometers in doing an ordinary engine/shaft alignment.

[artisanmach]

keep a space between flanges while checking for co-axial alignment.

[Cheechako]

Originally Posted by Lake-Effect

As I recall, the only couplings I saw were all self-aligning for concentric alignment, due to the mating stepped section I mentioned earlier. Different sorts of couplings?

Me too, never had one that wasnt self aligning. I pretty much quit using feeler gauges, instead I use a nice drill bit. Put it in the gap 4 places to determine where it's at. You get a feel for it. .005 or less is readily determined with eyesight or feel.

[coastalexplorer]

hello

I am located on the upland at a marina that deals primarially with power boats. (They are not allowed to dredge because of the oysters) The service manager of the yard has told me that the only way to accurately align the inboard engine with a standard propeller shaft is with the boat afloat. because blocked up on the land the hull can be twee-eked in a different position to the natural support it receives while floating.

The vessel I am working on had two previous engine installations both with a PYI dripless seal. (The rubber was perished, and the spring rusted to a point of ineffectiveness) There was a wear mark on the inside top of the stern tube at the four O clock position.So theoretically it would seem that it is possible to push and wear the cutlass bearing out of alignment with the stern tube, and for the shaft at the inboard end to wear right through the tube over time?

So far I have installed a new cutless bearing out board, a stave bearing inboard and a new PYI dripless. I am assuming that this will give a stable point of reference, I also have a R&D marine of England flexible shaft coupling 103-037 11 x 57 910-019 to fit between the flanges. To this I will match a MS2b Volvo transmission on 2003 series Volvo penta.

For those boat owners who still use 2000 series engines. Next Wave marine systems Inc located on Vancouver's Island, Canada have developed a bolt on kit that can be shipped anywhere in the world to protect against the splined shaft to damper failure problem. Installation is with simple tools and does not require any machining. It can also be fitted to a damaged shaft. I have the prototype. FYI...check out the video.

https://www.dropbox.com/s/eixuwb7c85...drive.mp4?dl=0

I represent a non profit organisation, and have no business dealing with them beyond paying them for their work...so this is not a commercial plug. If you are interested in more information contact them directly.
Barbara Mark
NextWave Marine Systems Inc.,
5-3125 Van Horne Road,
Qualicum Beach. BC Canada
V9K2R3
email: bmark@suredrivemarine.com
NextWave Marine Systems Inc.
250 752 1790 Telephone
250 752 2791 Fax

I assume that aligning my engine with feeler gauges will be simplified once the vessel is afloat.

[TurninTurtle]

https://www.youtube.com/watch?v=m_IrCYRtVvU

Note that for saildrive (any boat drive line) the shaft may exit at a downward angle so the foundation may not be level.

[dick sargent]

The goal is to align the engine to the shaft, not the other way around. This is best done in the water. The shaft has to be centered in the shaft tunnel first. I use a piece of plywood with a saddle cut-out and clamp it somewhere in the engine compartment. After centering the shaft both up and down and side to side in the shaft tunnel, I secure it with the plywood jig. Next, I mate the transmission and prop shaft flanges to .003 of an inch or less using a knife type feeler gauge. Hopefully you have adjustable engine mounts. My engine weighs 1500# so I use s make-shift chain-fall to lift the engine slightly to easily adjust the mounts, either side to side or up and down. It will save the transmission and the engine will run more smoothly. I have heard of misaligned prop shafts sinking boats due to tearing up the shaft tunnels. Alignment, if properly done will save you a lot of grief.

[pcmm]

I like the use of a R&D Drive saver to handle some of the "misalignment" once you've got it as close as possible.

[Scaramanga F25]

If you are concerned with the shaft sliding out ( possible on some models particularly in reverse ) clamp a zinc anode on the shaft inside the boat between the coupler and the stuffing box.

[JOHNMARDALL]

The problem is that with a typical small boat installation, the only bearing is the cutless in the strut or at the outboard end of the shaft log. Even when that cutless bearing is new, there will be a lot of shaft movement at the other end from the bearing, at the gearbox coupling, so the shaft M ust be centered in the shaft log and alignment performed before a dripless shaft seal, with a flexible rubber hose boot is installed. A low tech method of centering the shaft is to wind masking tape around it until that collar fills the inside of the log tube, thereby centering the shaft. Alignment of the gearbox flange and shaft flange, with feeler gauges can then proceed.
Even then, alignment must be performed with the boat out of the water, and the hull will flex after she is launched, so a flexible coupling such as a Vetus Bulflex is always a good idea to take up hull flexing and engine movement on the flexible engine mounts
John Mardall
Shameless Commerce Division
Vetus Grouo