S65 Engine Main Bearing Service, Documented

[bigjae1976]

Awesome write up!!! Thx!

[tigermack]

So, like $4000 minimum in labor if you were to find someone to do this?

[pbonsalb]

Probably depends on labor rates.

[deansbimmer]

Originally Posted by tigermack

So, like $4000 minimum in labor if you were to find someone to do this?

At least. We won't do mains in car, and we don't recommend doing them as a preventative measure. So, every main job we've done for a customer has been due to bearing failure, which means the engine is fully disassembled and rebuilt.

[romemmy]

Hey dean,

So here I am finally redoing the timing on all 4 cams, and I noticed something that wasn’t in your write up, and I’m pretty sure I didn’t do on previous go arounds... the TIS actually says you’re supposed to oil the cam bolt threads?!? That’s a huge difference as the torque would be insanely different wet than it would be dry!

https://www.newtis.info/tisv2/a/en/e90-m3-lim/repair-manuals/11-engine/11-31-camshaft/5g1Ql4h

It says in the spec column specifically:

“Screws oiled at threads and heads”

Have you ever oiled the threads before torquing those bolts? The main TIS page doesn’t actually mention it under the procedure itself, but it does point you to the page I linked above for “more details”.

I’m not actually sure how to proceed right now as I’m mid-procedure and wanna close this engine up tonight! The repair instructions can be so frustrating some times!! Oiling the threads will make such a drastic difference in torque that I’m hesitant to do it unless everyone does it.

Thanks!

S.

[romemmy]

I went with oiling them. When I pulled out the old bolts they were covered in oil, so I might have oiled them before (it’s been a while), or they might have gotten oil on them as I pulled them out.

I checked the S85 manual and it says oil them too, so I would recommend adding that to the initial post as it’s somewhat buried in TIS.

Thanks!

S.

[deansbimmer]

Originally Posted by romemmy

I went with oiling them. When I pulled out the old bolts they were covered in oil, so I might have oiled them before (it’s been a while), or they might have gotten oil on them as I pulled them out.

I checked the S85 manual and it says oil them too, so I would recommend adding that to the initial post as it’s somewhat buried in TIS.

Thanks!

S.

Yes, they're lightly oiled. Unless specifically noted otherwise it's almost universally assumed that hardware receives a light coating of oil to achieve consistent torque application.

[Rusty34]

Originally Posted by jcolley

That's a good thing. It makes line honing a block less work if there are thicker bearings available. No decking the block/bedplate, milling a new sealant channel, boring radial seal ODs, etc.

How quickly do those bore sizes increase with just a very small amount of honing? The main bearing shell crush decreases significantly as the engine warms up.

[Rusty34]

Originally Posted by deceneu

hi,

I cannot thank you enough for your contributions to this forum. This is of a real help. There are many people here who are only after profits from these forums and not really contribute much. I cannot thank you enough...
i am in process of rebuilding my S85 and these post is immensely helpful.
I have a question regarding main bearings...i need to replace the main bearings
and tempted to go for Kings because apparently is not need to match them...they are just drop ins... what do you think about it?
If I had to go OEM, considering the crank would be different but same bedplate... would I need to go for "R" mains? In TIS is a big ambiguous as I think when they debate the scenario "used bedplate used crank" they refer
to the same bedplate/crank combination that was originally installed.
What about my scenario where its the same bedplate but different-used crank? do i need to go by the GYV colors or go for "R" if going OEM?

Regards,

Actually no new bearing should be considered a drop-in bearing. It is the job of the person selecting the replacement bearings to measure for the fit and suitability of its use in any assigned position whether a main journal or rod journal. It is true the bearing manufacturers build the operating oil clearance into a given bearing during its design but this just becomes another + or - manufacturing tolerance in the end which must be taken into account along with journal diameters and housing bore sizes.

The color coding system is simply the manufacturers method of sorting and classifying the result of manufacturing variances in order to simplify the selection process. If you didn't have the equipment to accurately measure crankshaft journals and inside diameters of assembled bearings to determine operating clearance you could just take his word for it and select according to color. IIRC putting two reds together will give you the most clearance while putting two blues together would yield the tightest clearance.

Tight will get you in trouble before loose will!

[douglee25]

Good write up. Dean did work on my vehicle while I was transitioning between homes and had no garage to work in. He completed the rod bearing replacement for me and documented every step and measurement. He was by far the most methodical mechanic I've come across. Would definitely do business with him again.

[MPower7]

Great write up. Do you have to replace the 3 timing cover bolts? What is their torque spec?

[Siajoon]

Hold my beer I can do this...




Give me back my beer I didn't sign up for this.

[deansbimmer]

Originally Posted by MPower7

Great write up. Do you have to replace the 3 timing cover bolts? What is their torque spec?

Not sure what bolts you are referring to. Torque to yield bolts must be replaced. Torque specs are listed in TIS. www.newtis.info

[MPower7]

Originally Posted by deansbimmer

Not sure what bolts you are referring to. Torque to yield bolts must be replaced. Torque specs are listed in TIS. www.newtis.info

I've searched through TIS, can't seem to find it.

1) If you look at the diagram below there are three bolts to remove the Timing Cover. However there is no notation to designate the middle bolt. Is the middle bolt a 14 (M6X30-U1) or a 15 (M6X25-ZNNIV SI)?

2) What is the torque spec on these bolts, can't find this information anywhere and am pulling my hair out. Thanks!

[deansbimmer]

Originally Posted by MPower7

I've searched through TIS, can't seem to find it.

1) If you look at the diagram below there are three bolts to remove the Timing Cover. However there is no notation to designate the middle bolt. Is the middle bolt a 14 (M6X30-U1) or a 15 (M6X25-ZNNIV SI)?

2) What is the torque spec on these bolts, can't find this information anywhere and am pulling my hair out. Thanks!

Torque applications for general hardware is listed upstream in TIS. Don't search only under the task description which will direct you to numbers for hardware specific only to the unique component in question. That generic M6 hardware (and others) are listed here (8nm):
https://www.newtis.info/tisv2/a/en/e...ine/1VnYrHsDMb

The realoem diagram answers your question. First, there are four screws per the "qty" column, not three. (2ea x2 cylinder heads=4 total) The drawing does depict which screw goes where. #14 (M6x30) shows applied to the top two holes in the cover. #15 (M6x25) shows applied to the lower two holes in each cover.

The holes on the top of the vanos cover are obviously applied via the valve cover and are unique to the application of the valve cover, so you'll find the torque values in the cover detail. (8AZ here):
https://www.newtis.info/tisv2/a/en/e...th-lid/5VFC6oU

[MPower7]

Originally Posted by deansbimmer

Torque applications for general hardware is listed upstream in TIS. Don't search only under the task description which will direct you to numbers for hardware specific only to the unique component in question. That generic M6 hardware (and others) are listed here (8nm):
https://www.newtis.info/tisv2/a/en/e...ine/1VnYrHsDMb

The realoem diagram answers your question. First, there are four screws per the "qty" column, not three. (2ea x2 cylinder heads=4 total) The drawing does depict which screw goes where. #14 (M6x30) shows applied to the top two holes in the cover. #15 (M6x25) shows applied to the lower two holes in each cover.

The holes on the top of the vanos cover are obviously applied via the valve cover and are unique to the application of the valve cover, so you'll find the torque values in the cover detail. (8AZ here):
https://www.newtis.info/tisv2/a/en/e...th-lid/5VFC6oU

I'm rather paranoid about doing these jobs correctly so thank you. Also, it's interesting the torque for valve cover bolts seems to be 6nm where as most DIYs say to use 10nm.

[deansbimmer]

Originally Posted by MPower7

I'm rather paranoid about doing these jobs correctly so thank you. Also, it's interesting the torque for valve cover bolts seems to be 6nm where as most DIYs say to use 10nm.

The valve cover bolts are a unique component specific to only valve covers on S65 as they incorporate a rubber bushing and shoulder. It makes sense that they would come with a specific torque application.

BMW has specific instructions for a multitude of things that hobbyist DIY's overlook or disregard. But 10nm is typically considered safe for M6 hardware.

[Nick1224]

My apologies, but are the images still available for your Diy?

I can't seem to get them to load.


Thank you

[deansbimmer]

Originally Posted by Nick1224

My apologies, but are the images still available for your Diy?

They are still up, they're visible from our end. There are a lot of them. Viewing on a mobile device may be problematic.

[SYT_Shadow]

I confirm I can see the images

[Nick1224]

I was on a Gov computer....and apparently they blocked them lol

[Scharbag]

Originally Posted by Nick1224

I was on a Gov computer....and apparently they blocked them lol

Well, it is car porn...