prop shaft alignment

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jemni
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Joined: 12/16/12
Posts: 17
prop shaft alignment

has anyone done a prop shaft alignment?...new shaft is on order and I'm trying to avoid the $90/hr labor rates

Bill
"Jem'nI
Cat 36 MKII #2004
Annapolis, Md

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2sailaway
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Joined: 7/24/09
Posts: 49

I have read about them a bit and will attempt to do this myself next weekend. One thing I am sure of is that I need to wait until the boat is in the water to finalize the process, being on the hard will not allow for final adjustments to be made. Good luck to you, I'll be keeping an "eye on this thread.

Larry Robcke
MKl Tech Editor S/V  L' Amante #319, 1984 C36
Sailing Long Island sound and the Hudson River

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Wavelength
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Joined: 9/28/11
Posts: 166

I aligned my C30 with no real issues. If you can while on the hard make sure all of the bolts on the engine mounts are freed up. Figure out how you will get to them. Since you are installing a new shaft initial allignment should be pretty good as long as you did not move the engine. Final allignment needs to be done in the water. Follow the steps that are outlined some where in this site and it should work out.

Make SMALL adjustments, and then recheck, tighten down the engine mounts and recheck.
Use a small wonder bar or pry bar to move the engine.

I installed a flexible coupling when I did my C30 ant that absorbed any small alignment issues as well.

Ross & Joanne
Wavelength
Saint John NB
RKYC
C36 #658 TR 1987

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Chachere
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Posts: 826

[QUOTE=Wavelength;17019]... If you can while on the hard make sure all of the bolts on the engine mounts are freed up. Figure out how you will get to them. .. .[/QUOTE]

Ditto to what Wavelength wrote. Its not rocket science by any means; both Nigel Calder's "Boatowner's Mechanical and Electrical Manual" and Don Casey's "This Old Boat" book have good write-ups on the process. It just takes patience and time; if you lack either you may have to opt for someone else doing it, but at $90/hr . . .
The trickiest bolts to reach are those on the motor-mount at the starboard-aft corner; a combination of socket extensions and flex (u-joint) extensions were needed to reach it on ours.

Here is a link to a thread on this site from about 2 years ago when I had some questions about how to do this, and got some good help from other members: [url]http://www.c36ia.com/forums/showthread.php?t=1104[/url]

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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newguy
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Joined: 8/1/11
Posts: 408

Not done one yet on my 36, but did many times on my previous boat. After using wedges and "estimating" when the shaft was in the center of the shaft log at the stuffing box (critical), I came up with a solution. I just used a cutless bearing temporarily inserted into the shaft log at the stuffing box. Now, my shaft did not run through a strut, so I simply used an old cutless bearing. Don't know yet if an old strut bearing would work.

The engine can move around three axis by virtue of the amount of lift supplied by the mounts as well as the slotted mounts moving laterally. To move the engine laterally, you have to loosen the lag bolts and coax the engine side to side with a crowbar. A little bit of silicon spray helps here. Important to also ensure that any lift supplied by the mounts is somewhat equal as you can easily end up with an engine supported by just three mounts and not really know it.

Finally, it requires a lot of making an adjustment and then measuring the effect with a feeler gauge between shaft and transmission mating faces. Be sure to duck you head when exiting the aft after each adjustment. You'll be doing this a lot....

Nick Caballero
Retired C36/375IA Mk II Technical Editor

BudStreet
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Joined: 9/4/09
Posts: 1127

So when you're checking with feeler gauges, are the bolts in the coupler and tightened up or is it just held hand tight?

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TomSoko
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Joined: 2/15/07
Posts: 978

Bud,
The bolts should not be tight at all. Nuts don't even need to be on. Slip the bolts into their holes to line things up, bring the flanges together so they just barely touch, and take your measurements at 12, 3, 6, and 9 o'clock. If you tighten the nuts on the bolts, they will (very very slightly) bend the shaft, move the engine, bring the two flanges together, eliminate any gap you might have had, and you would not be able to get even a 0.00001" feeler gauge in there!

Tom Sokoloski
C36/375IA Past Commodore
Noank, CT

BudStreet
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Joined: 9/4/09
Posts: 1127

Thanks Tom! I suspected that to be the case.

I think my flex plate is on its last legs, getting a more persistent neutral rattle, so this fall I'm going to change it. While it's apart I'll have the trans gone over to find a persistent oil leak at the shift shaft (seal didn't fix it) and general health check on it, and then have the shaft checked for straightness and corrosion, the prop cleaned, pitch checked and rebalanced and put a new coupling on. Never done this alignment before so needed to know for sure how this was done.

I put in a new cutless (cutlass? which is right?) bearing and stuffing box 3 years ago. What else might I "fix" while it's apart?

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