Shells for bottom end of an m52b28

[tomislav]

Hey people. I'm building an m20b28 engine and i need to replace the main bearing shells and conrod shells for the build.

Gonna use genuine bmw items but i've hit a stumbling block. They want to know colours of the old ones but i dont have any old ones.

Does anyone here know how the hell i can get the right ones?

There are 3 choices on the bmw parts computer, some guidence here would appreciated.

Thanks

[jimmyspeed]

get the crankshaft measured at an engineering shop

[tomislav]

That wont help cos even on the bmw computer 2 of them come up as having texactly the same measurements!

[jimmyspeed]

this might help

http://www.e30zone.net/modules.php?name ... shell+main

[tomislav]

Oooh handy, cheers. I best get looking

[Ant]

"red" uppers with " blue" lowers iirc.

[tomislav]

Ant, god havent seen you on here for a while.

This 2.8 is the one i spent 2 hours talking to you about when i bought some wheels off you about 2 years ago.

STILL not built! But making good progress, just need the shells.

Do these red uppers and blue lowers kinda go across the board as long as the crank hasnt been reground?

It was you who advised me to use m52 shells funnily enough due to crank material i believe.

(Ant, PS, i'll still need your mapping when i finally get this engine in)

[fixedwheelnut]

I always remembered it as Sky blue upper and red baboon bottoms when we did the M3 recalls so unless they have changed it on later engines double check

[tomislav]

oh great, two conflicting answers!!!!

Such is life, looks like more digging required

[fixedwheelnut]

Double checked today M20 engine is Blue upper & Red lower
M52 engine is Blue Upper & Red lower as well

[Simon13]

This red and blue lark only applies to the Big ends. I can't see BMW changing the colours round on a later engine. They keep it all the same unless they have to change it. This is asking for trouble!

The mains come in 3 colours in each size. Each colour is a different size again. If you can find a bentley manual it will tell you everything you need to know about sizes. measuring for the right shells etc.

[fixedwheelnut]

Yeah sorry only the big ends, mains are coded to size but can still differ in colour upper and lower.

Realoem gives a clue to the sizes here http://www.realoem.com/bmw/showparts.do ... g=11&fg=20

[DanThe]

Yeah sorry only the big ends, mains are coded to size but can still differ in colour upper and lower.

Realoem gives a clue to the sizes here http://www.realoem.com/bmw/showparts.do ... g=11&fg=20

No, that just gives you the colour references/part numbers. The size difference there is for ground cranks/undersize shells

[tomislav]

Right, here's a bit more info then.

Firstly i've very stupidly had the crank lightened and balanced so there are no colours! However can i assume from the information above that for the big ends i need to use blue uppers and red lowers on a standard m52b28 crank that hasn't had a grind?

Second, the crank is going off to the engineers 2moro to have all the various bearing mating surfaces accurately measured. Will this actually help me?

Last, anyone in Kent got a bently manuel?

Cheers for your help so far people

[DanThe]

Just found this for the crank -

Yellow - 59.984-59.990mm
Green - 59.977-59.983mm
White - 59.971-59.976mm

These are the standard sized shells so order them according to what measurements you get back

[Simon13]

i can look up the big end specs for you also as dan has kindly listed the main end sizes.

TBH i've never stripped an engine and been able to tell the paint colour thats dabbed on them from new. Even the shells have a lick of colour on them. Its long gone on a 20 year old engine though

[tomislav]

Yeah 22 years and 213000 miles, they're done for lol, although the crank is m52b28 so hopefully less miles than the block had on it!

Anyways, danthe, i assume i wait for my measurements to come back next week. Then, lets say for instance, that no. 1 main bearing on the crank is measured as being 59.980mm then i'll need a green upper and lower for that one yeah?

I know i seem to be taking this on board slowly but this is my first 'proper' engine rebuild and i wanna make damn sure its riight. Three years in the making this bloody engine has been!

[tomislav]

Hey people, i wanna bump this.

I've now got all my measurements but i have no info for the con rod bearing shell sizes/colours.

Thanks to danthe for the main bearing sizes, i've got them sorted.

Anyone with the conrod size colour info? Please?

[DanThe]

No paint colour size on these, the red and blue is just to identify top and bottom shell.
Only 3 sizes, standard, +0.25 and +0.5

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