Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 18-02-2013, 23:01   #1
Registered User
Chrisc's Avatar

Join Date: Aug 2006
Location: Whangamata. New Zealand
Boat: H28
Posts: 210
Engine alignment question

I have just replaced my gearbox and rebuilt the engine beds so need to do a complete realignment of the engine/gearbox to the tail shaft. The two are connected via a R & D flexible coupling. According to the instructions that accompanied the flexible coupling, all that is necessary to to align the gearbox flange and the tail shaft flange with reasonable accuracy and then install the flexible coupling between. One of the bolts connecting the coupling to the flange has a cone shaped head, and you check the clearance between it and the flange at north, south, east and west positions by rotating the shaft. If all are within 0.25mm of each other then the engine is correctly aligned to the tail shaft. I have done this to 0.1mm.
The question is this : I understand the rationale behind this, ie by doing so you assure that both flanges are in the same plane (within 0.1mm) but I do not see how this ensures that the engine and tail shaft are in the same line fore and aft. In other words, the two flanges are parallel to each other but possibly the gearbox output shaft is not in the same line as the tail shaft, or am I missing something here?


Chrisc is offline   Reply With Quote
Old 19-02-2013, 07:56   #2
Registered User
Fishspearit's Avatar

Join Date: Jan 2006
Location: FL
Posts: 576
Re: Engine alignment question

If you check all four corners as you described, then rotate the shaft 90 degrees, check all four corners again, than I believe you have checked both planes.

Fishspearit is offline   Reply With Quote
Old 19-02-2013, 08:12   #3
Registered User
sww914's Avatar

Join Date: May 2009
Location: Punta De Mita
Boat: Vagabond 39 Hull # 1
Posts: 1,842
Re: Engine alignment question

You're right, they can be parallel and not in the same line. My coupler and tranny flange have the same OD so it's easy to tell if they're simply parallel but still eccentric.
sww914 is offline   Reply With Quote
Old 19-02-2013, 08:33   #4
Senior Cruiser
AfterHoursNLCT's Avatar

Cruisers Forum Supporter

Join Date: Nov 2010
Location: Quaker Hill, CT (just above the US Coast Guard Academy)
Boat: Silverton 34 Convertible
Posts: 196
Re: Engine alignment question

Hope this helps...LL
Frequently Asked Questions -
AfterHoursNLCT is offline   Reply With Quote


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 07:12.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.