Engine rebuild after spun bearing

[JayDD007]

Final engine assembly was completed and after some extensive diagnostic work on an intermittent cylinder 5 misfire the engine has been running great. 1200 mile break in service has been done and I’ve been having an absolutely blast with the car.

Haven’t driven either of my m3’s aside from one needing state inspection since this June. The clutch has been the most different from anything I’ve driven as far as pressure required, grab point and grip. But besides the lack of cup holders it’s now the choice of vehicle of my wife

Hope you all enjoy the final photos and thanks for the comments.

*The cylinder 5 misfire was one of two cam followers popping off the lifter due to a weak spring retainer. So due to the Valvetronic spring tool not fitting between the frame rail and cylinder head the engine came back out for a 5 minute repair.

[M5Rick]

Originally Posted by JayDD007

Final engine assembly was completed and after some extensive diagnostic work on an intermittent cylinder 5 misfire the engine has been running great. 1200 mile break in service has been done and I’ve been having an absolutely blast with the car.

Haven’t driven either of my m3’s aside from one needing state inspection since this June. The clutch has been the most different from anything I’ve driven as far as pressure required, grab point and grip. But besides the lack of cup holders it’s now the choice of vehicle of my wife

Hope you all enjoy the final photos and thanks for the comments.

*The cylinder 5 misfire was one of two cam followers popping off the lifter due to a weak spring retainer. So due to the Valvetronic spring tool not fitting between the frame rail and cylinder head the engine came back out for a 5 minute repair.

S@cks that the engine had to come out again just for that spring retainer but it's nearly always a tight fit with this F10 set up.

[cloverfield]

Originally Posted by D4T

Not sure if it's significant here or not but I recently watch a youtube video that had an M5 that'd basically been driven around a bodyshop for 18 months whilst it had extensive repair work done. Once finished the owner then noticed excessive oil consumption and poor running. The long and short of it was that fuel had contaminated the oil which was assumed to be caused by the rich running when cold and it never got up to proper temperatures.

I'm wondering if lots of these failures are somehow related? I.e. lots of short journeys which result in reduced oil quality which then goes on to lead to failures.

Or is my train of thinking flawed?

Trying to understand this - is the thinking that the cold start/rich conditions/short drives over time would cause unburned fuel to get past the rings and into the oil?

Is there a certain oil temp range that helps get rid fuel in the oil? I've heard short drives can cause water condensation to build up and if the oil temp doesn't get past 100C/212F then it never evaporates, but how does this work if there's fuel in the oil as well?

[SCD-1983]

Originally Posted by cloverfield

Trying to understand this - is the thinking that the cold start/rich conditions/short drives over time would cause unburned fuel to get past the rings and into the oil?

Is there a certain oil temp range that helps get rid fuel in the oil? I've heard short drives can cause water condensation to build up and if the oil temp doesn't get past 100C/212F then it never evaporates, but how does this work if there's fuel in the oil as well?

If there is fuel in the oil, you will see white smoke and smell it too. A small amount will not cause an issue, but if your injectors dump too much fuel and the motor is running too rich for extended periods of time, the oil will be diluted and loses its protective characteristics. It can cause the bearings to seize, if not changed soon. Therefore, I monitor my engine and change the oil latest after 3000 miles.

[D4T]

Originally Posted by cloverfield

Trying to understand this - is the thinking that the cold start/rich conditions/short drives over time would cause unburned fuel to get past the rings and into the oil?

Is there a certain oil temp range that helps get rid fuel in the oil? I've heard short drives can cause water condensation to build up and if the oil temp doesn't get past 100C/212F then it never evaporates, but how does this work if there's fuel in the oil as well?

That's my understanding of it, startup enrichment etc causing fuel to get past the rings. It seemed to also cause excessive oil consumption for this particular owner which I know people think is a thing with these engines despite mine personal not burning a drop ever after 3 track days now. But maybe I'm lucky! 🤞

I don't see how contaminated oil would cause the engine to burn oil but I'm not a professional here - maybe someone else might have an answer for that.

[D4T]

Originally Posted by SCD-1983

If there is fuel in the oil, you will see white smoke and smell it too. A small amount will not cause an issue, but if your injectors dump too much fuel and the motor is running too rich for extended periods of time, the oil will be diluted and loses its protective characteristics. It can cause the bearings to seize, if not changed soon. Therefore, I monitor my engine and change the oil latest after 3000 miles.

I always thought white smoke was water ? But like you I'm a 3000 miles oil change guy

[cruella_M5]

I plan on doing my rod bearings myself, been dealing with bmw’s for about 12 years, first time doing a job dealing with the internals of the engine. I’m mechanically inclined, how ever my question is will i have to remove the oil pump to access the bottom end to remove the bearings, if so what replacement hardware will i need to complete this job. Also if anyone have a complete list of replacement bolts for the oil pan, that would help me out tremendously, i also plan on making a post and uploading pics of the job.

[TinCanSailor]

Originally Posted by cruella_M5

I plan on doing my rod bearings myself, been dealing with bmw’s for about 12 years, first time doing a job dealing with the internals of the engine. I’m mechanically inclined, how ever my question is will i have to remove the oil pump to access the bottom end to remove the bearings, if so what replacement hardware will i need to complete this job. Also if anyone have a complete list of replacement bolts for the oil pan, that would help me out tremendously, i also plan on making a post and uploading pics of the job.

Hit up the folks at 5150autsport as they can help you with rebuild parts etc. If you can afford the time and expense either rebuild your oil pump or just buy a new one. Check out this fellow Floridan's recent work on his M5's ro bearings. He had some other stuff he did along the way. He is a good presenter but the content should not be used as a how to. https://www.youtube.com/@Yes_Way_Jose/videos

[INFURNO]

Originally Posted by JayDD007

Figured I’d share the journey with everyone of my recent rebuild of an s63tu...

Great thread - thanks for posting this. @161k miles here but I always take it easy for the first 2-3 minutes. 4 minutes in, I'm usually doing 65, then let it loose once the temp is off the peg.

JayDD007 Now that you've completed this project and what you've learned - how many labor hours would you estimate if you had the same repair on another m5?

[JayDD007]

Originally Posted by cruella_M5

I plan on doing my rod bearings myself, been dealing with bmw’s for about 12 years, first time doing a job dealing with the internals of the engine. I’m mechanically inclined, how ever my question is will i have to remove the oil pump to access the bottom end to remove the bearings, if so what replacement hardware will i need to complete this job. Also if anyone have a complete list of replacement bolts for the oil pan, that would help me out tremendously, i also plan on making a post and uploading pics of the job.

Yes the pump needs to be removed before removing the upper pan. Replacement of the pump may be something to consider as well since it’s a bit of a mystery why these engines spin bearings. (In my opinion)

There is a mechanical chain tensioner that needs to be removed to slacken the chain before removal, then 3 bolts to remove the pump.

Your local parts department will have the list of the “in conjunction with” parts. If you don’t plan on going through them I can provide them for you, it’s just quite a large list of bolts and gaskets.

[JayDD007]

Originally Posted by INFURNO

Great thread - thanks for posting this. @161k miles here but I always take it easy for the first 2-3 minutes. 4 minutes in, I'm usually doing 65, then let it loose once the temp is off the peg.

JayDD007 Now that you've completed this project and what you've learned - how many labor hours would you estimate if you had the same repair on another m5?

Very hard to say since it was a month or so long project before and after work. I would estimate at least 6 hours removal of the engine itself, 3-4 for removal of accessories and harnesses, then maybe 5 for full tear down of the engine itself. Plus 3-4 hours of cleaning then reassembly. I wouldn’t be surprised for over 50 hours total.

This obviously varies heavily on experience and attention to details.

[M5Rick]

Sure helps with gradual warm up with low revs (while driving re the oil pump) and yearly oil changes to prolong PU life.