Excess 'play' In Upper Gearcase

Author Message   Mike Member Username: mike77cj Post Number: 100 Registered: 06-2007 Posted on Monday, April 28, 2008 - 08:11 pm:    This weekend I dismantled my upper gearcase (280) to inspect / lap the cone clutch. I carefully marked each shim when I took it apart. During disassembly I discovered a great deal of corrosion around the upper and lower bearing housings. I also discovered an area where water was entering the gearcase between the clamp ring housing and the gearcase housing. Before assembling the gearcase I used a Scoth pad to remove the scaled corrosion from the housings. I then rinsed everything with brake cleaner. Upon assembling the gearcase this evening I found a large amount of play in the assembly. I installed each shim in its proper location. I did not replace any bearings, or gears; reusing all the old components. I do not understand why there is so much play now if I did not change anything. Is this a common problem? By 'cleaning' things up did I affect tolerances that bad? Looks like I have to check backlash and set up shims now...   Morten Ringvold Senior Member Username: haffiman37 Post Number: 2675 Registered: 04-2006 Posted on Monday, April 28, 2008 - 10:12 pm:    Since You have the upper apart, don't forget to change the lower brass ring at the vertical shaft. Change both the ring and the two steel halves. Then measure the vertical play of the shaft. The shimming of the shaft vertical play is done by the top nut(links) that comes in different thickness. Shim it in to the minimum, this will reduce the banging when changing gear, and extend the life time of the cone. Lap the cone to the gears by using Carborundum (valve grind paste) at the same time. If the cones in the gears are polished, ruff the surface with some 800 wet paper. If the gear backlash has changed, it is more likely bearing wear than gear wear that causes it. Any axial play in the ball bearings, replace them.   Mike Advanced Member Username: mike77cj Post Number: 103 Registered: 06-2007 Posted on Tuesday, April 29, 2008 - 09:21 am:    Morten, Do you happen to know the thickness of the lower brass ring when it is new? I would like to compare it's specs with the one in my drive. I shimmed the upper and lower drive gear bearings to the upper gearcase housing as described in Seloc. When I torgue the vertical shaft nut there I notice there is still play between the bearing and gearcase housing. Is this normal?   Morten Ringvold Senior Member Username: haffiman37 Post Number: 2682 Registered: 04-2006 Posted on Tuesday, April 29, 2008 - 08:48 pm:    I do not know the thickness of the wear-ring. I had it as normal procedure every second year to lift off the upper gear case and measure the play. In almost every case (V8 and diesels), running hours 80 -100/year, the play was too big. Changing the wear-ring brought it back to nominal play. In some cases I've even experienced the primary shaft go like a rocket through the upper cover as the ring has broken. The more play, the more sledge hammer effect it gets when shifting, and the cost of the ring is next to nothing. To properly measure the play, the upper has to be 'clean'(no oil films) and held up-side down and nut torqued to specs.   Mike Advanced Member Username: mike77cj Post Number: 106 Registered: 06-2007 Posted on Tuesday, April 29, 2008 - 09:08 pm:    Thanks Morten. Per Seloc the allowable play is between 0.004 - 0.020". The play in my gearcase is 0.022". I currently have the standard size nut on the top of the shaft. Can I get away with replacing the standard nut with a thicker nut (2.37 mm as opposed to 2.00 mm)? A new nut is $4 as opposed to $52 for the brass collar. Also is it normal for there to be 'play' between the upper and lower gear bearing housings and the gearcase housing? I have shimmed them per the manual. Thank you.   Morten Ringvold Senior Member Username: haffiman37 Post Number: 2685 Registered: 04-2006 Posted on Tuesday, April 29, 2008 - 11:36 pm:    I would NOT change the nut without having changed the ring. I do not remember all of the shimming. I always had the manuals at hand when performing. Outboards, Hurth's, Volvo's. ZF's -too much to remember. Some You shim with 'play' some with press-fit.

Administration Log Out   Previous Page Next Page

Home / Directory | Engine Manuals | Engine Parts | Discussion Board | Free Classifieds | Orders / Shipping | Contact Us | View Cart

About Us | Terms of Use | Privacy Policy MarineEngine.com, 184 Jones Dr., Brandon, VT 05733 USA Phone: 802-247-4700 FAX: 802-301-1034 info@marineengine.com Copyright © 2000 - 2007 by MarineEngine.com, Inc. All rights reserved

Traduca Traduisez Traduza Traduca Ubersetzen