S50 B32 blue and red bearing shells.

[UweM3]

In the process of changing the bearing shells on my S50B32.

Can anybody explain the difference between blue and red bearing shells?

Please no theories (have a lot myself), the facts please if you know them.

[ajay]

Im also interested in the awnser to your question,i will be inspecting mine as i do the arp rod bolt upgrade,if necesarry i may have to get a new set.

[DanThe]

One colour for the top side the other for the bottom, cant remember which way off the top of my head

[UweM3]

One colour for the top side the other for the bottom, cant remember which way off the top of my head

Is this something you know for sure? The two bearings look absolutley identical. Why would one be top?

Not doubting you, just want to know it exactly. If one get's something wrong in this department.......££££££

[DanThe]

Yes defo, its the same with other BMW engines

[UweM3]

Yes defo, its the same with other BMW engines

thanks, so now we have to find out which is which.

[e21Jason]

I rember speaking to one of the kumho racers about this and the info is in the TIS, i believe the reason was the top bearing was a different hardness which is common on the jap turbo stuff

Jason

[UweM3]

I rember speaking to one of the kumho racers about this and the info is in the TIS, i believe the reason was the top bearing was a different hardness which is common on the jap turbo stuff

Jason

I have been told that the BLUE one is harder then the RED one. This would make sense with what you have posted. Thanks.

[GermanGorilla]

Hi,

I am not so sure this is correct.

My understanding was this,

Red shells are for warmer climates etc
where std oil or normal oil temps
are acheived.

Blue shells are for colder climates
where the oil temps are on the low
side and thus a harder shell is required
as the oil temp can be lower and not offer
the normal protection.

A shell or bearing is designed that the rotating
mass runs on a film of oil, it would make no
sense to alter the 'friction' of the shells, by having
surfaces that conduct the friction into heat from
a common rotating mass, differently.

Reason being is that a bearing/shell is held in place
by 'pinch', not the little lugs on the rear, so why would
you want a differing rate of shell / bearing expansion
when they are both heated by a common rotating mass.

The conrod or crank rides on the oil film in the
shell/ bearing.

You would have a differeing rate of expansion.

What the Jap guys do I do not know, but I do know
that some of the high end revvy Jap stuff runs very
narrower bearings/shells in order to reduce friction
ie ''Heat''.

Check with BMW and they should confirm that Red shells
are for normal, and blue are for the colder climate.

When I ordered the BMW M62 shells for a Merc project
I was asked if I wanted red or blue, ie it was not
8 red and 8 blue, it was either 16 red or 16 blue.

That is my understanding.

Regards,

The Gorilla.

[UweM3]

Thanks Gorilla,

I have heared that version as well.

I have also been told some other stuff which I didn't have time to check out yet.

Will post my final findings as soon as I know.

[ajay]

checking mine on the s54 i don"t see any colour on the shells just corresponding numbers for top and bottom,bottom perfect top the coating seams to have worn in the middle.

[GermanGorilla]

Hi,

Seems I was wrong but only on
certain BMW Engines.

As example M42 has red and blue shells
for top and bottom whereas S62 and
M62 you either use blue or red.

E34 S38 seems to be red or blue, where as
it can also depend on Crank size.

Some engine have blue as standard and then
red are oversize for regrinds, pending size.

So while what I was told for the M62 is correct it
would not apply to say a M42 or S38 engine.

All same colour shells are also denoted for
global regions pending climate.

Then just to confuse some more, some are
coloured 'stripe' ie] blue or red, and then some
have the colour denoted via a dot on the rear of
the shell/ bearing.

Then just to confuse totally, I have a new set
of BMW supplied S54 B/E shells here which are
clearly marked for a std size journal and have a
red dot on both halves.

BMW confirm these are correct.

Then you read the BMW recall Paper for the S54
Bearing issues, where it clearly states that the
Rod shells top is red, and the bottom is blue.

The same paper also states that the S54 running
with the M11 Rod bolts are to be re-used !!! and the
later engines with the M10 ones are to be replaced.

I know of several S54's that have been used for
some light Track work, that are no more due to
rod bolt failure on both M10 and M11 B/E bolts.

I do not think you could have made it more
complex and prone to error if you had tried.

Regards,

The Gorilla.

[Jhonno]

So it seems the situation is clear as mud.

[DanThe]

Maybe best to rebuild the engine using non BMW parts then just to be safe

[fixedwheelnut]

We did enough bearing shells on a recall for these at work
Blue = top half
Red = bottom half

I always remember sky blue for up and red baboons bottom

[UweM3]

We did enough bearing shells on a recall for these at work
Blue = top half
Red = bottom half

I always remember sky blue for up and red baboons bottom

Brilliant!
Jhonno posted me a link to TIS and it was stated there one blue and one red but NOT in which order.

[fixedwheelnut]

We did enough bearing shells on a recall for these at work
Blue = top half
Red = bottom half

I always remember sky blue for up and red baboons bottom

Brilliant!
Jhonno posted me a link to TIS and it was stated there one blue and one red but NOT in which order.

The text in TIS actually says they both go in top but the graphic picture shows blue top and red bottom, and the recall bulletins back that up

[UweM3]

We did enough bearing shells on a recall for these at work
Blue = top half
Red = bottom half

I always remember sky blue for up and red baboons bottom

Brilliant!
Jhonno posted me a link to TIS and it was stated there one blue and one red but NOT in which order.

The text in TIS actually says they both go in top but the graphic picture shows blue top and red bottom, and the recall bulletins back that up

your help with this is much appreciated. Hell I must be blind, will have another look.

[GermanGorilla]

Hi,

Uwe- are you sure that the S50 B32
is ''Blue'' up and ''Red'' down ?

Thwe BMW Recall paper on the S54 which
is the last variant of the S50, is ''Red'' up
and ''Blue'' down ?

But as I alrteady said, I have a set of std
replacement shells for the S54 and they
are ''all'' Red dot.

Regards,

The Gorilla.

[UweM3]

Hi,

Uwe- are you sure that the S50 B32
is ''Blue'' up and ''Red'' down ?

Thwe BMW Recall paper on the S54 which
is the last variant of the S50, is ''Red'' up
and ''Blue'' down ?

But as I alrteady said, I have a set of std
replacement shells for the S54 and they
are ''all'' Red dot.

Regards,

The Gorilla.

Danny,

I am not sure about anything in this regard. I will pop both combinations in with plastigauge and see if there is any difference to start with.

The TIS I have says nothing about the orientation of blue or red.

IF (and that is a big IF) the blue and the red have the SAME lining material methinks it won't matter which way the go as it's just for bearing clearance.

But if they are DIFFERENT, then the debate is open again about orientation.

I also haven't found any colour coding on the crank as stated by TIS but have to admit I didn't look kvery hard. Next time round I will use a 500W flood light!