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Crank and big end shell help!?

Posted: Fri Feb 25, 2011 7:23 pm
by maggspower
Hi there, I'm having a bit of trouble with selecting the above items for an m20 325i. First I must apologise for the quality of the images.

Image

Image

Both pics are of the same part of the crank at different rotations.

Each standard and oversize bearing has 3 other sizes within it, which is denoted by painted spots on the crank, for the main bearings the dots will be either white, green or yellow.

The top one shows the yellow dots for the mains, and the bottom one you can just see red dots on the curve of the crank web. All the journals are within spec and have been polished so all i need are standard size originals.

My conclusion is that I will need the standard size yellow bearings for the mains, but what size big ends? The realoem site seems to say half red and half blue. See part numbers 6+7 on the link

http://www.realoem.com/bmw/showparts.do ... g=11&fg=20

Any one shed some light on this?

Thanks Maggs

Re: Crank and big end shell help!?

Posted: Fri Feb 25, 2011 7:58 pm
by maggspower
I have, its all checked standard size, but for example the 60.00mm main shells have a further three sizes within it which may be 59.999, 60.000 or 60.001 for example but i cant find these sizes. But I know the mains size, 60.00mm standard yellow.

Its the big ends I'm struggling with do I need 2 standard reds or a standard red and a standard blue for each big end.

Re: Crank and big end shell help!?

Posted: Fri Feb 25, 2011 10:52 pm
by baptie0
on my m50 2.8 crank Red is for the con rod cap and Blue for the rod.

Re: Crank and big end shell help!?

Posted: Fri Feb 25, 2011 11:56 pm
by Simon13
ditto big ends aren't so strict in the size. Its a red and a blue you need in either 45mm and then its straight to plus +0.25mm and +0.50mm sizes. Theres no 3 colour scheme for each size if you get me?!

Bentley manual tells you the sizes for plastiguage or measuring the crank. mines not to hand at the moment for exact sizes on the mains. Best to check it i think.

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 8:33 am
by maggspower
Thanks for the help fellas :D I have only used machine shop bearings in the past, But the OCD has kicked in for this one.

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 8:53 am
by Simon13
well prepare to take it hard!! over £10 for the big end shells and ,mains and the thrust washers are £18 each PM sent

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 9:27 am
by maggspower
PM back at ya :D

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 10:21 am
by e301988325i
Is it just - yellow mains - red con rod cap - blue con rod ?

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 10:31 am
by maggspower
e301988325i wrote:Is it just - yellow mains - red con rod cap - blue con rod ?
Yes I think so. I still dont totaly understand the reason for the red dot on the crank, as it seems it can only be a red bearing half and a blue.

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 11:34 am
by Simon13
red and blue for the big ends. One the mains they can be green,yellow and white in each size. Although bentley states sizes for red and blue main ends too! But etk doesn't show these and their sizes are covered by the other 2 colours.

I'll dig the bentley out and post up the sizes

Re: Crank and big end shell help!?

Posted: Sat Feb 26, 2011 11:55 am
by maggspower
pm sent