Main Bearing Color Codes Blue, Red, Yellow and Black

[Kevin C]

Has anyone ever figured out what the size difference is between color codes?



Lower
Blue *06B105591001 (B)
Red *06B105591002 (R)
Yellow *06B105591007 (G)
Black 06B105591010 (S)

Upper
Blue *06B105561001 (B)
Red *06B105561002 (R)
Yellow *06B105561007 (G)
Black 06B105561010 (S)

[Theiceman]

I didn't during my build of my 8.5 , they but the colours in a 2d barcode and printed it on the block and crank .. so I just left them .. thanks Audi.

[aluthman]

Kolbenschmidt bearings have been fine on all 3 engines I’ve built with them at .0015-.002” clearance.

[Kevin C]

Kolbenschmidt bearings have been fine on all 3 engines I’ve built with them at .0015-.002” clearance.

Thanks for the recommendation on bearings. I'm pretty confident that I will get the proper clearances. I'm mostly curious to understand Audi's select fit bearing scheme and how closely they target their tolerances. I try and hold a .0004 bearing to bearing tolerances. I did just find a table that shows a shell difference of about .00024" color to color for another audi engine, I'm assuming that the 2.0T is the same.

https://www.motorgeek.com/viewtopic.php?f=10&t=47499

[aluthman]

I would assume the sizing order still applies, but the thicknesses may be different. I was never able to find sizes either, which is why I went with aftermarket bearings. I’ve also never seen any color markings on any of the bearings I’ve taken out of stock engines.

[Kevin C]

All the uppers on mine are red and still readable (the rear main is very faint but still you can make out that is was red). It also corresponds to the block being stamped RRRRR. The crank is marked BBGGB. The blue making were still readable, the one that were supposed to be yellow marks were not. The bearing edges all have a coat of varnish and its reasonable that light colors would disappear.

Another find: http://www.engineprofessional.com/TB/TB063017-1.pdf AERA tech bulletin on the color codes. It's for the newer engines but should still apply. It is nice to know that this is an option. Same with the rods, I have found performance bearings at +- .025mm.

Having dealt with tolerance stackup issues on blocks that I have had line honed and cranks that I sent out for ion nitriding (the nitriding grows the crank a few tenths) it's nice to know what options are out there before I start putting the engine together.

I measured the rod journals and they are all within .0002", pretty amazing for a used crank. Audi definitely did a good job on hitting dimensions, the crank may be more accurate than my 30 year old set of mikes.

[Theiceman]

All the uppers on mine are red and still readable (the rear main is very faint but still you can make out that is was red). It also corresponds to the block being stamped RRRRR. The crank is marked BBGGB. The blue making were still readable, the one that were supposed to be yellow marks were not. The bearing edges all have a coat of varnish and its reasonable that light colors would disappear.

Another find: http://www.engineprofessional.com/TB/TB063017-1.pdf AERA tech bulletin on the color codes. It's for the newer engines but should still apply. It is nice to know that this is an option. Same with the rods, I have found performance bearings at +- .025mm.

Having dealt with tolerance stackup issues on blocks that I have had line honed and cranks that I sent out for ion nitriding (the nitriding grows the crank a few tenths) it's nice to know what options are out there before I start putting the engine together.

I measured the rod journals and they are all within .0002", pretty amazing for a used crank. Audi definitely did a good job on hitting dimensions, the crank may be more accurate than my 30 year old set of mikes.

thats a great post with great results. on my 8.5 motor at least the rods all used yellow so there was no variation.. so i slapped in new rod bearings...

how do you like this marking for the lowers ?

[Kevin C]

Agreed, the bar code seems impossible to read. Oddley, the back of my crank had both.

20190918_200029.jpg

Also, I picked up a ball tip for my micrometers and measured the used shells. The blue shell was about .0002" thinner than the yellow. Small sample size and used bearings, definitely a very small difference.

[Van Black]

My block had the bearing size stamped on the oil pan mating surface IIRC. RRRRR - it means Rott(red) on all five mains

[Kevin C]

The block stamping is for the upper shells, the lowers are marked on the crank.

[Theiceman]

Yup.
I had a 2d barcode their too. The bastards.

The block stamping is for the upper shells, the lowers are marked on the crank.

Sent from my SM-G973W using Audizine mobile app

[Kevin C]

Another thing I noticed between the 1.8T design and the 2.0T is the main caps changed design. The 2.0 look to be powder formed (similar to the rods) vs cast for the 1.8T, they also look pretty beefy. The change that caught my eye was the 2.0 on uses one thrust bearing per side (the 1.8 gets 2) and the main cap is not machined for one.

Have thrust bearings been an issue for anyone running an upgraded clutch?

[aluthman]

Another thing I noticed between the 1.8T design and the 2.0T is the main caps changed design. The 2.0 look to be powder formed (similar to the rods) vs cast for the 1.8T, they also look pretty beefy. The change that caught my eye was the 2.0 on uses one thrust bearing per side (the 1.8 gets 2) and the main cap is not machined for one.

Have thrust bearings been an issue for anyone running an upgraded clutch?

Only the early fsi engines had the powdered metal main caps. 07 and up (IIRC) had cast caps. I know Derrek recently had issues with thrust bearings where his block and crank were trashed.

[Kevin C]

Thanks for the feedback. The donor car for my engine was a 2007, so it seems that some engines from that year had the PM caps. I have had no luck figuring out why Audi changed back over. I may upgrade the clutch side thrust bearing to a dual.

[aluthman]

Thanks for the feedback. The donor car for my engine was a 2007, so it seems that some engines from that year had the PM caps. I have had no luck figuring out why Audi changed back over. I may upgrade the clutch side thrust bearing to a dual.

Every BWT I’ve opened had cast caps, but ya, Audi seemingly decides at random when to switch parts and sometimes then they switch back.

[Kevin C]

I ordered a few sample main bearings and took a few measurements to put together a table to help choose select fit main bearings. I need to order a red lower shell to complete that table.

Highlights: Glyco 1.8t mains are going to add an about .001" of clearance compared to your typical factory bearings. On the factory select fit parts, so far it looks like the yellow gets you the most clearance and a black shell the least. If you need to dial in your mains this can help guide you to optimizing the clearances. The total selection range from the thinnest to thickest (Glyco to Black shells) should be about .0018" (assumes upper and lower shells at max and min). The same numbers should work on the uppers as well.

Disclaimer: I only got a single sample of each color. Each bearing was measured three times at the thickest section (90° to the parting line). Measurements were made using a ball adaptor that was zeroed before and checked after each shell was measured. The zero point did not vary over the measurement session. Observed measurement repeatability was better than .0001" Some variation in shell thickness was noticed on the blue shell (.00005 -.00007").

Location	Type	Part #	Shell Thickness in	Shell Thickness mm	Code
Lower	GLYCO	H084/5 STD	.0981	2.492	NA
Lower	Yellow	06B105591007	.0985	2.502	G
Lower	Red	06B105591002	No Data	No Data	R
Lower	Blue	06B105591001	.0987	2.507	B
Lower	Black	06B105591010	.0990	2.515	S

[Kevin C]

I got a sample of the red bearing it measures very close to the yellow and was about .0001" thinner. This is similar to what I got on used reds and yellows.

[JFHI]

I was recently looking up bearings for my 07 (BWT) A4 2.0 s line quattro tip,
Found this info on bearing/color sizing,

Main & Rod bearing color code Sizing,,,


Bottom of my Block is Stamped RRRRR
My Crankshaft end is Stamped BBGGG

———————————————-
Crankshaft bearings/
4-cylinder/
petrol eng/
BFB,ALT,BGB,BUL,BWE,BPG,BWT,BYK,BPJ/
1.8/2.0ltr

———————————————-

Part # 06B105561
Upper crankshaft bearing 1-5

Part # 06B105561010 black 2,496-2,500
Part # 06B105561002 red 2,500-2,504
Part # 06B105561007 yellow 2,504-2,508
Part # 06B105561001 blue 2,508-2,512
Part # 06B105561011 white 2,512-2,516

———————————————-

Part # 06B105591
Lower crankshaft bearing 1-5

Part # 06B105591002 red 2,500-2,504
Part # 06B105591007 yellow 2,504-2,508
Part # 06B105591001 blue 2,508-2,512
Part # 06B105591011 white 2,512-2,516
Part # 06B105591010 black 2,516-2,520

———————————————-




HERE : ilcats.ru/audi/usa-model/vin

[Kevin C]

I know its been a while. I finally got a nice set of undamaged OEM select fit mains. I measured the mains using the factory select recommendations and ended up adjusting one selection looser on #3 and one selection tighter on 2 and 4. That got all the mains to within .0002" of each other (I went for a nominal .0014"). The select fit shells were then sent out for coating. It's nice to finally start putting the lump together. As best as I can tell that's what the factory targeted for clearance. Some will shot for a bit looser, this has worked for me (as well as the factory). Looser mains reduces what's available to the rods, and they see a lot more abuse. That's my story.

[Kevin C]

A quick update on my 2.0T bearing adventure. I got the center cap back from the machine shop today that has been modded to add a second thrust bearing on the side that sees a load when you press the clutch. The 1.38mm deep groove works perfectly and the machinist did a great job. The two ears keep both bearings from rotating. The bearing is modified by cutting the tangs down and adding a chamfer on the leading edge. Not quite a full addition of 180° in thrust surface but an improvement. The end play came out at .004" (0.102mm).

20200319_161601.jpg20200319_161511.jpg

[Van Black]

A quick update on my 2.0T bearing adventure. I got the center cap back from the machine shop today that has been modded to add a second thrust bearing on the side that sees a load when you press the clutch. The 1.38mm deep groove works perfectly and the machinist did a great job. The two ears keep both bearings from rotating. The bearing is modified by cutting the tangs down and adding a chamfer on the leading edge. Not quite a full addition of 180° in thrust surface but an improvement. The end play came out at .004" (0.102mm).

20200319_161601.jpg20200319_161511.jpg

That is very smart! I wonder if the same can be done with the stock bearing caps.
I just fitted mine last Saturday. I went with ACL race bearings.
My block asked for RRRRR block and YYYYY crank. The play I measured with plastigauge on the ACL was just about at
the top range of stock play, maybe one was a little bit over. To be fair, the crank journals are also just about at the minimum
size for stock, so the larger play makes sense.

[Kevin C]

That is very smart! I wonder if the same can be done with the stock bearing caps.
I just fitted mine last Saturday. I went with ACL race bearings.
My block asked for RRRRR block and YYYYY crank. The play I measured with plastigauge on the ACL was just about at
the top range of stock play, maybe one was a little bit over. To be fair, the crank journals are also just about at the minimum
size for stock, so the larger play makes sense.

Thanks.

Unless I'm misunderstanding, the caps I used are stock caps but they are the sintered steel instead of cast iron. What engines got them seems to have varied. The same thing can be done on the cast iron caps. The side to side dimensions will vary but the one taken from the centerline should be right.

[Van Black]

Thanks.

Unless I'm misunderstanding, the caps I used are stock caps but they are the sintered steel instead of cast iron. What engines got them seems to have varied. The same thing can be done on the cast iron caps. The side to side dimensions will vary but the one taken from the centerline should be right.

Those look like aftermarket caps My oil pump assy is not in yet, I still have time to do this mod if I find a reputable machine shop

Cheers for the drawing, but could you upload a larger version? The numbers aren't very clear

[Van Black]

Looks like someone went for the 1.8T thrust bearings

[Kevin C]

Looks like someone went for the 1.8T thrust bearings

I have seen that photo and wondered how they made it work in the block.

Possibilities:

1: Too much clearance
2: Offset thrust faces
3: Thicker Bearings ( over sized)
4: I was sent the wrong part ( too thin)

I would be great to figure it out.

[Van Black]

here's the link to the conversation: https://www.facebook.com/groups/5294...0771176388766/
maybe you can ask that guy how he went about doing it?

[Kevin C]

here's the link to the conversation: https://www.facebook.com/groups/5294...0771176388766/
maybe you can ask that guy how he went about doing it?

I asked, nothing solid but the thrust bearings in his photo look thicker than the ones I have. Something is different.