E30 Zone

hi all how do you tell from the crank what shells are needed when you come to doing a new build when you dont have the old shells to look at ???
they are obviously pricey to buy and i dont want to get the wrong ones ,iv brought a used 2.8 crank thats in good nick but now i need to start buying the components i.e :big end shells etc and i noticed that they are colour codes for different ones

sorry its more advice for me but i just want to be sure
thanks

First get the crank measured to make sure its journals are round, or if it needs a regrind ect.
The shells that are colour coded are the crank mains, there are three sizes of journal; standard, -.25mm and -.5mm, Within each of these three sizes there are a further 3 sizes which are denoted by dots on the crank counter weights (yellow, green or white). These colour coded bearings can only be found at main dealers and are quite expensive. Non genuine ones can be had for about £60-70 but they only come in the three main sizes they are quality items though (Federal Mogul Glyco).

The difference between the coloured dot grade sizes is literaly a gnats cock or .06mm, 6/100th of a mm.
I have built engines with both types without issues, but it is BMWs over-engineering style to have 3 size grades within another, I have had an original engine presumably with the dot bearings in run to well over 300,000 miles and still be within tolerance, it had FSH to 260,000 though. The choice is yours the BMW ones are twice as much as good aftermarket ones.

The big end ones are not dot coded, so just three sizes as the main journals instead the red and blue refurs to it being for the rod or the cap

HTH Maggs

of so i need a digital measure to see if they round ,and by the size they read ,use the right colour code SHELL to suit ?!? in simpleton terms

Jaff take the crank to a MACHINE SHOPand get done properly
BTW your pistons and rods are getting picked up friday by courier
Remember i have a crank that will be very useful to you if you decide not to go 2.8 route

yesim going to do that i think ! ,thats great fowler thanks for that