question regarding grinding alpha

mercs4mark

Petty Officer 2nd Class
Joined
Dec 19, 2010
Messages
141
i just read the post regarding the grinding alpha and they were talking about replacing the top bearing on the driven gear top shaft to top cap, my question is could you replace this bearing alone with success? i mean how would you get an accurate rolling torque with an old bearing on the driven gear, oil seals in place and a new bearing on top. unit is junk anyway but just wondering
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: question regarding grinding alpha

my question is could you replace this bearing alone with success?
yes, i did that. but i didn't have the tools to do the deed. took it to my local mercruser store and they did it. R&Red the top brg. in the cap only.
i mean how would you get an accurate rolling torque with an old bearing on the driven gear, oil seals in place and a new bearing on top
guess, i don't quite understand that question. when i replaced mine, yes, i did check the rolling torque. again with the help of my local mercruiser store. i didn't have a used drive shaft from a lower, but they did. modifiied with a nut welded onto it so you could drive it with a wrench. put the drive gear shaft in the upper, w/o the drive gear in place. torque the cap down and then drive the driven gear shaft with the modified lower drive shaft. use a dial indicator type in./lb. torque wrench to check rolling torque. which my dealer had and i didn't.
ya can see, i needed some special tools to do this which i didn't have. the mercrusier store did have hence going to them to do the deed in my case.
 

mercs4mark

Petty Officer 2nd Class
Joined
Dec 19, 2010
Messages
141
Re: question regarding grinding alpha

well i guess my question is what rolling torque value did the mercruiser dealer use...2-4 in. lb for used bearings or 6-10 in. lb. for new bearings? replaceing only one bearing you would have one of each a new and an old.
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: question regarding grinding alpha

ah, seems like a reasonable question and good point.
well, if i remember right, i came in at about 5 or 6 in. lbs. kinda half way in between the two specs. my mercruiser tech said that was ok. i felt it was likely ok too. i've run my boat maybe 50-75 hrs this season. no issues. side benifit seems to be that the white chalky stuff (minerals from hard water) don't seem to come on as fast as they used to. i'm assuming the old brg. was getting hotter than it should have due to it having rust on it along with pits. hence the reason for replacement.
also. from memory. the in/lb torque wrench used was a quality tool but even then. there isn't much deflection of the needle @ 4-10 in/lbs. so personally, i can't hardly think that the reading is totally accurate. the reading is at the very bottom of the scale (the needle hardly moves). not half way into the capabilities of the tool used where i would think it's most accurate at.
 
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