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Main Bearings

Posted: 09 May 2010, 11:32
by KWM_gbr
I am just in the process of trying to reassemble my engine after a main bearing failed.

I have the new bearings from LT but one seems to be loose. The part numbers are also different.
One is simply marked 63/28 and I have fitted this in the left crankcase.
The other is marked 63/28C3 and I am reluctant to install this as it seems to be more worn than the old one that came out.

I have searched for information on the parts and it appears the C3 is something to do with clearance.

Does anyone know what clearance this refers to (does it explain the looseness) or should the bearings feel the same and I just have a poor tolerance item.

Thanks

Keith

Re: Main Bearings

Posted: 09 May 2010, 11:42
by fallenmikethebike
C3 bearings are, generally an engineering type application, so could be worth checking you have been supplied with the correct item.
http://simplybearings.co.uk/shop/p45932 ... _info.html.
Mike

Re: Main Bearings

Posted: 09 May 2010, 11:47
by knackeredMk1
See - http://simplybearings.co.uk/shop/p146/6 ... _info.html.

Run the mouse over the 'C3 explained' for explanation ;) . I would think that both or neither would be suitable but maybe not a mix :?: . Don't really know :? .




EDIT - Second thoughts - 'It says don't replace non-C3 bearings with C3 bearings'. So it's the wrong bearing definitely.

Re: Main Bearings

Posted: 09 May 2010, 11:51
by KWM_gbr
Thanks Mike, that is an useful website. Their explanation on C3 confirms that they can feel loose until running at temperature, I now wonder if the other would benefit from being a C3 as well.

Keith.

Re: Main Bearings

Posted: 09 May 2010, 11:56
by KWM_gbr
Hi Knackered

I shall have to postpone the job and call LT tomorrow to see if they will exchange it for the standard bearing or if they suggest I install it anyway.

Keith.

Re: Main Bearings

Posted: 09 May 2010, 12:05
by knackeredMk1
C3 Text -

Image

Re: Main Bearings

Posted: 09 May 2010, 17:33
by fallenmikethebike
"I shall have to postpone the job and call LT tomorrow to see if they will exchange it for the standard bearing".
I would agree with that part of your statement.
Mike

Re: Main Bearings

Posted: 09 May 2010, 17:39
by knackeredMk1
+1

Re: Main Bearings

Posted: 13 May 2010, 13:57
by Jonorow
i was told to replace the mains with C3 so to avoid any heat seizures

Re: Main Bearings

Posted: 13 May 2010, 21:26
by KWM_gbr
When I called LT they confirmed that they install C3 normally, the standard item I received was an error in their stock. Since I had already installed one 63/28 I sourced a second locally and returned the C3 for a refund. Since a 63/28 came out I assume it is an acceptable bearing for the application, time will tell.