66k mile S50B32 maintenance

[nick325xit 5spd]

Is there anything that I should do to this motor before shoving it into a car? Rod bolts, rod bearings? Something along that line?

[Impulsed7]

Is there anything that I should do to this motor before shoving it into a car? Rod bolts, rod bearings? Something along that line?

I hear that the rod bolts and bearings dont fail as much on these as the s54's, but its mainly a factor of RPM. If its going in a race car, I would do it.

Also the balancer's seem to fail on these from race use. VAC just came out with a new race balancer, but its not on the website yet. They were showing it off at MPACT. Its next on my list of things to do.

[nick325xit 5spd]

It's just a street toy. I guess the answer is leave it alone and revisit later.

[nick325xit 5spd]

For the record, this appears to have been a mistake.

[Jim E.]

For the record, this appears to have been a mistake.

What happened? Do tell.

[nick325xit 5spd]

What happened? Do tell.

Spun rod bearing, like you probably guessed. I think I've sourced a crank, so it'll be getting a light refresh and reassembled.

[Jim E.]

Spun rod bearing, like you probably guessed. I think I've sourced a crank, so it'll be getting a light refresh and reassembled.

That stinks. Especially that you couldn't even salvage the crank and needed to source another one. S50B32s are not known for killing bearings. I know you've probably taken this into account but make sure your oil pump is in perfect working order including the oil pressure valve that goes on the side of the block.

Is this a stock engine?

[nick325xit 5spd]

That stinks. Especially that you couldn't even salvage the crank and needed to source another one. S50B32s are not known for killing bearings. I know you've probably taken this into account but make sure your oil pump is in perfect working order including the oil pressure valve that goes on the side of the block.

Is this a stock engine?

Stock engine.

Also, I am not convinced that the S50B32 is actually less prone to spinning rod bearings than the S54 (now that the S54s with defective bearings have either been fixed or blown up). I've come across a *lot* of S50B32 rod bearing issues. I think that we just don't hear about it because it's happening elsewhere.

I think that the crank *could* be repaired. However, the cost and timeframe for crank repair made it worth looking at replacement. (The journal is enough out of round that I'd probably want to have it welded rather than just ground down.)

I have an oil pressure gauge and didn't have any pressure issues, but I may replace the pump anyway. Certainly I'll replace the CPV - it's too easy not to replace it with the block on a stand.

[Mr M3]

The secret is to properly warm the engine up before you go heavy with the right foot. Make sure the oil comes to full operating temp, not so much the water temp. I know this is difficult because it doesn't have an oil temp gauge. Just exercise common sense.
Do regular oil changes and only use the correct synthetic oil. I use The Castrol 0w-40 A3B4 in my S50. Vanos seems to like it too.

[nick325xit 5spd]

The secret is to properly warm the engine up before you go heavy with the right foot. Make sure the oil comes to full operating temp, not so much the water temp. I know this is difficult because it doesn't have an oil temp gauge. Just exercise common sense.
Do regular oil changes and only use the correct synthetic oil. I use The Castrol 0w-40 A3B4 in my S50. Vanos seems to like it too.

1) I have an oil temp gauge. I also have an oil pressure gauge.
2) I always allow the oil to come to temperature, and ensure that the oil is up to temperature.
3) I change oil at least annually with quality synthetics. More if I drive it a lot. Typical oil change interval is under 3,000 miles due to (lack of) use.
4) The idea that rod bearings only spin because people didn't warm the engine properly is a stupid myth.

[nick325xit 5spd]

Back in the car with a "new" crankshaft. Hopefully it runs this weekend.

[nick325xit 5spd]

OK, didn't quite get to fire it this last weekend, but it fired Monday. No more knocking!

[MParallel]

For the record, this appears to have been a mistake.

Well you say that 10 years after that previous post, so can't really say it was a mistake.

Doesn't take away it sucks now.

[MParallel]

I have no numbers on SB50B32's with spun shells, so I can only add that in the past I have hardly every heared this was an issue of this engine. Only after it became a known problem on the S54, it was somehow applied retrospectively to the S50b32.

Well obviously it does happen. But what is the failure rate compared to S54's? I have no idea. From someone I knew who apparently knows alot about it (an engineer) he once told me that the harmonic balancer isn't ideal on prolonged high rpm's and that the imbalances that then accure can result in this.

Personally I have never been really worried about it, but mainly because I drive it like nanny most of the time, which can me seen a shame, but that's just how I drive.

Nick, out of interest, do you know the milage on the engine?

[nick325xit 5spd]

I have no numbers on SB50B32's with spun shells, so I can only add that in the past I have hardly every heared this was an issue of this engine. Only after it became a known problem on the S54, it was somehow applied retrospectively to the S50b32.

Well obviously it does happen. But what is the failure rate compared to S54's? I have no idea. From someone I knew who apparently knows alot about it (an engineer) he once told me that the harmonic balancer isn't ideal on prolonged high rpm's and that the imbalances that then accure can result in this.

Personally I have never been really worried about it, but mainly because I drive it like nanny most of the time, which can me seen a shame, but that's just how I drive.

Nick, out of interest, do you know the milage on the engine?

Less than 100k. I made it about 30k miles.

Also, you have to bifurcate the S54 rod bearing issue. The rod bearing issue that the S54 became famous for was a simple defective parts issue. BMW had wrong size bearing shells enter the parts chain, and a lot of motors blew up as a result. Fortunately, pretty much all of these motors either blew up or were fixed under warranty.

Long term, the S54 is actually pretty reliable (for what it is). Rod bearings should be changed every 100k or so. From what I have seen of the S50B32, the rod bearing wear rates are pretty similar to the long term S54.