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Discussion Starter #1
Does anyone know the size of bore the crank bearing shells fit in on a 2 Litre? I can find crank dia and I can find clearance info but nothing for the bore size, reason I’m asking is they look a bit worn as if a shell has spun and I’d like to check them before moving forward on engine rebuild
I’m getting 63.69 to 63.67 mm
 

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Discussion Starter #3
sorry for late reply I posted on my phone and have no clue how to answer back
thanks a lot for the info I will add that to my file, what book is that from and is it available?

ok so I have checked the bore of the big end casting with shells removed and if I read the file correct they should be 2.5069 at the top end of spec for a 2 ltr Nord, mine are reading 2.5075 so 1.5 thou over top tollerance should I be concerned?
if this is not acceptable what are my options? or do I chance it order a set of new shells and check with plastigauge that crank to shell clearance is good
I don't really want to continue until this issue is sorted I'm considering spending a lot of money on new pistons etc so would like to know my options
also this Nord is from an Alfeta circa 83 would that change anything?
 

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Can you post a picture of the bearing housings you are talking about? Both in the block and the main bearing caps? Also, what are you using to measure, i.e. how certain are you of your 2.5075" measurement?
 

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Doesn't look like it spun to me. Are you getting the same measurements at 6-12 o'clock and 3-9. Also, did you use a mic to check your id mic? You could be a thou off and not even know it.
 

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Discussion Starter #7
Doesn't look like it spun to me. Are you getting the same measurements at 6-12 o'clock and 3-9. Also, did you use a mic to check your id mic? You could be a thou off and not even know it.
good point will check tomorrow
I believe its bigger 12 to 6 than 3 to 9 but will double check
 

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I would also say not spun, why did you think this? Try 1:30 - 7:30 and 4:30 - 10:30 too. From your pics I would say cleanup and go
 

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That has not spun a bearing.

I'd check roundness of the bore (indeed at 12-6, 3-9 and a few in between), if round within 0,01mm install and measure bearing ID, measure crank journal dia and work out the running clearance. If OK, assemble and forget or do a plastigauge double-check if you want to make doubly sure. Do check your measuring instruments against each other though to ensure you measure the right bearing clearance and not the bearing clearance plus the errors in both instruments....
 

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Discussion Starter #13
thanks Guys
checked the internal micrometer with a reference ring its good also borrowed the digital bore mic but this only gives an average as its three points, 2.5062 was average
2nd photo is using the internal mic as best I can and that's showing .5 thou (0.01 mm) over top clearance at 12 to 6 all others ok
think its worth the risk to order shells and test with plastigauge
 

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I was suspect of Plastigage many years ago, but have come to accept the results. My thought is if the plastigage checks out and the crank spins reasonably smooth when assembled with bearings and oil it will work just fine.

How do the rod clearances look?
 

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Discussion Starter #18
not got around to that yet but crank shaft is within spec for the rods so new bearings should put everything correct, old shells a little worn with a few areas having the white metal worn through will make sure all the oil ways are cleaned out before re assembly
 
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