M20 oversize thrust/guide bearing shells, where to find and color code confusion

[BertjeConti]

I've searched the internet about oversize thrust bearing shells for a M20 engine but didn't find anything, even BMWFANS/REALOEM didn't show any partnumbers related to oversizes.

My manual describes the axial crankshaft clearance has to be between 0.08 and 0.163 mm, the axial crankshaft clearance is done by the thrust bearing shells, the no 6 main bearing.
Standard thrust bearing shell width is 25.00mm, and the manual describes 2 oversizes for the M20 engine, e.g. 25.20mm and 25.40mm.

does anybody know partnumbers for these oversize thrust bearing shells, or where to purchase them?

Then i have another issue about color coding for the main bearing shells.

The manual describes two color codes, red and blue, if the crankcase has red paint dots the main bearing bores are 65.00-65.01 mm and if it has blue dots these bores are between 65.01-65.02 mm.
If you need new bearing shells you need to get the corresponding color shells as your crankcase shows, e.g. red or blue. In my case my engine had the red paint dots.

Now, BMWFANS/REALOEM shows only bearingshell part numbers in color codes: yellow, white and green, in standard and undersizes, i'm very confused about this as i can't find any bearing shells in red or blue color codes.

clarification needed, thanks

[shadyracer01]

Hi Bertje, This is all info i have without access to parts books, only using e-catalogue to get this far..

For Big end bearings Glyco 71-3419/6 0.25mm

For Main bearings Glyco H023/7 0.25mm

I have seen no info regards colour coding references, perhaps a call to Federal Mogul (glyco parts distributor) Technical dept would help answer your questions

[shadyracer01]

Ok, just looked at realoem, as i understand it, seems red/blue only refers to big end shells , other colours refer to main bearings, so if original std parts inside block then id expect to find either red or blue big ends shells 45mm and then yellow, green or white 60mm mains. Hope this useful to you

[BertjeConti]

Ok, just looked at realoem, as i understand it, seems red/blue only refers to big end shells , other colours refer to main bearings, so if original std parts inside block then id expect to find either red or blue big ends shells 45mm and then yellow, green or white 60mm mains. Hope this useful to you

Thanks for searching, but thats what i dit already and made it so confusing. The manual explicit describes the colors red and blue for the main bearing shells, as also red and blue for the big end shells.

My crankcase has the red color dots for the main bearing shells, the color refers to the bore diameter of the main bearing, thats why you can't interchange the main bearing caps.



But i took a new look into BMWFANS (= REALOEM) and discovered this:
if you chose the main bearing shell yellow in std (60.00) it gives PN 11211706847, digging into this pn refers to an old PN, namely 11211265460, "MAIN BEARING SHELL, RED" tadaa.


If you do the same with the bearing shell green, this one refers to old pn "MAIN BEARING SHELL, BLUE"

and white refers to a old PN also white, but these where since '83, and thats younger as my manual.

i still have the problem with the oversize thrust bearing shells, they seem not to exist.

[shadyracer01]

Yeah, clear as mud...but you deciphered well. If the thrust bearing is the one shown with lip on number 6 journal as per realoem parts diagram then it should come within the replacement main bearing set. Or have i misunderstood?

[BertjeConti]

Yeah, clear as mud...but you deciphered well. If the thrust bearing is the one shown with lip on number 6 journal as per realoem parts diagram then it should come within the replacement main bearing set. Or have i misunderstood?

Yes it does, it comes in the replacement set, but only in standard width (25mm) and i'm looking for oversized thrust bearing shells (25.2 or 25.4 mm in width) as described in my manual, but these apperently seem not to exist

[shadyracer01]

Ok, Ive dug a bit more too and going in circles, I think the phone call to technical best solution maybe, but let us know how it goes please, good luck.

[3771489]

Yeah, clear as mud...but you deciphered well. If the thrust bearing is the one shown with lip on number 6 journal as per realoem parts diagram then it should come within the replacement main bearing set. Or have i misunderstood?

Yes it does, it comes in the replacement set, but only in standard width (25mm) and i'm looking for oversized thrust bearing shells (25.2 or 25.4 mm in width) as described in my manual, but these apperently seem not to exist

Standard size (60,00 mm) thrust bearing is 25,00 mm width,
Size 1 (59,75 mm) thrust bearing is 25,2 mm widht and
Size 2 (59,50 mm) thrust bearing is 25,4 mm widht.

[BertjeConti]

Yeah, clear as mud...but you deciphered well. If the thrust bearing is the one shown with lip on number 6 journal as per realoem parts diagram then it should come within the replacement main bearing set. Or have i misunderstood?

Yes it does, it comes in the replacement set, but only in standard width (25mm) and i'm looking for oversized thrust bearing shells (25.2 or 25.4 mm in width) as described in my manual, but these apperently seem not to exist

Standard size (60,00 mm) thrust bearing is 25,00 mm width,
Size 1 (59,75 mm) thrust bearing is 25,2 mm widht and
Size 2 (59,50 mm) thrust bearing is 25,4 mm widht.

Oh, that sucks, so i also need te regrind the main bearing if i want to use a oversized thrust bearing due to much axial clearance.

Thanks for that usefull information.