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Opinion on bearing condition
https://www.ausmini.com/forums/viewtopic.php?f=2&t=99598		 Page 1 of 3
Author:  Morbo28 [ Mon Jan 13, 2020 6:12 pm ]
Post subject:  Opinion on bearing condition
Hi everyone,

I have removed the crank from my 1275 to get a bit of machining done on the primary gear surface.

I took a pic of the condition of the main and conrod bearings and thought I'd post it here. Let me know if you have any opinions on the condition of the bearings. Pic is below - I know it's big, I did this so you can see some level of detail.

Image

Engine runs like a dream, do these bearings look all good? Engine has done maybe 5k kays.

Given the engine was professionally built, my default plan is to touch as little as possible to leave it as the builder left it. Crank out, grind the nose of it, then replace exactly as I found everything.

Thoughts?
Author:  TK [ Mon Jan 13, 2020 6:24 pm ]
Post subject:  Re: Opinion on bearing condition
look ok to me
Author:  drmini in aust [ Mon Jan 13, 2020 6:31 pm ]
Post subject:  Re: Opinion on bearing condition
No 4 rod bearing looks scored, so I would replace the rod bearings.
Mains look OK.
Measure all the crank journals for ovality and check for scoring.
Author:  Morbo28 [ Mon Jan 13, 2020 7:00 pm ]
Post subject:  Re: Opinion on bearing condition
Thanks guys!

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Author:  Morbo28 [ Mon Jan 13, 2020 8:23 pm ]
Post subject:  Re: Opinion on bearing condition
What would be your recommended bearing brand?
Author:  timmy201 [ Mon Jan 13, 2020 8:29 pm ]
Post subject:  Re: Opinion on bearing condition
ACL
Author:  Morbo28 [ Mon Jan 13, 2020 8:35 pm ]
Post subject:  Re: Opinion on bearing condition
Sorry one more question! What is the big end conrod bearing clearance I am after? I couldn't find it on a search. I would just use this to triple check my measurements with plastigauge to confirm fit.
Author:  TOZOOM [ Tue Jan 14, 2020 5:29 am ]
Post subject:  Re: Opinion on bearing condition
ACL heavy duty bearings are pretty good.
Author:  Morbo28 [ Tue Jan 14, 2020 6:11 am ]
Post subject:  Re: Opinion on bearing condition
Thanks guys. Two for ACL, and I noticed on GRs website one of the brand's he recommends is ACL Duraglide. Il go will ACL ta.

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Author:  drmini in aust [ Tue Jan 14, 2020 5:34 pm ]
Post subject:  Re: Opinion on bearing condition
Your old bearings look like they are aluminium tin. Were used standard in Morris 1100S etc.
ACL Duraglide are copper lead indium, most people prefer this type for heavy duty, or racing use.
You could replace the mains too, but they look fine to me.
Author:  Morbo28 [ Tue Jan 14, 2020 5:36 pm ]
Post subject:  Re: Opinion on bearing condition
Ah. It is an 1100S block, would the non-S 1275 bearings be the right choice?

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Author:  drmini in aust [ Tue Jan 14, 2020 5:40 pm ]
Post subject:  Re: Opinion on bearing condition
Doesn't matter really, for mains. They do look to be well bedded in, looking lovely. :)
Author:  Morbo28 [ Tue Jan 14, 2020 8:38 pm ]
Post subject:  Re: Opinion on bearing condition
Great :) crank is at the shop. I just replace a big end cap and measured the ID of the big end with the existing bearings in place. I used one of those only-semi-reliable digital calipers. Measured 1.600" or 40.65mm.

Does anyone know if that suggests I have standard crank journal diameters or whether they require +.010 etc?

EDIT: Google seems to indicate std is 1.625" So 20" under plus ~005 for clearance plus error suggests I should get +0.020 bearings, would anyone agree?
Author:  timmy201 [ Tue Jan 14, 2020 8:48 pm ]
Post subject:  Re: Opinion on bearing condition
Standard is 1.625”. The bearings should have the size stamped on the back?

Or your engine guy can measure them properly
Author:  Morbo28 [ Tue Jan 14, 2020 9:00 pm ]
Post subject:  Re: Opinion on bearing condition
timmy201 wrote:
Standard is 1.625”. The bearings should have the size stamped on the back?

Or your engine guy can measure them properly


Yes of course!

This says .010 which means I guess the crank journal is now 1.615 but seems strange I got the measurement of 1.600" using the admittedly crappy (but repeatable) calipers.

Good advice I will get the machine shop to check.

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