S50B32 Grinding noise...

[Danger 31]

Ok so I changed the oil/filter in my M3 last week. Decided to go with Valvoline VR1 Synthetic in 10W40.

As of a couple days ago I now have a slow grinding noise somewhere in the front of my motor.

Its not a particularly rhythmic noise, just grinds away at what seems to be a slower pace than the RPM. Very obvious when I turn the car off.

Took valve cover off yesterday and its dead clean and very fresh inside. Timing chain seems tight?

Car has 100 miles on it

 

Any ideas? Vanos? Chain tensioner? Or worse?

Edited September 11, 2016 by Danger

[Danger 31]

Previously it had a dead spot/ stutter/miss around 2-3k rpm as well

[euroriffic 607]

Should probably be running 10/60. Did you run a flushing product through first? And did you replace the vanos filter? 

But could just be a belt idler going bad

[Danger 31]

I wasn't aware there was a vanos filter. I read 10/60 but that seems hell of a thick for something with the complexity of vanos.

Got seals coming from beisan systems so will give the vanos a birthday and check the tensioners etc.

[Rubix 434]

Use Castrol edge 0w-60 or 0w-60 TWS.
I'd replace oil ASAP if I were you. My old car is a testament to using the right oil. ~470,000km S50b30 on Castrol edge 0w-60. 10w-40 is too thick.

[KwS 2425]

i ran 5w40 in my S50B30 without an issue, but this whole oil issue has been beaten to death.

Can you identify where in the engine the noise comes from? Is it in the vanos? My chain tensioner made a weird rattling/whirring noise at about 1800rpm before i replaced it, but the B32 tensioners are a better design than the B30 ones (hence why B32 tensioners are a common replacement on B30)

[M3AN 4016]

10 hours ago, Rubix said:

Use Castrol edge 0w-60 or 0w-60 TWS.
I'd replace oil ASAP if I were you. My old car is a testament to using the right oil. ~470,000km S50b30 on Castrol edge 0w-60. 10w-40 is too thick.

No, I'm afraid this isn't correct. At operating temperature an (x)w60 will be significantly thicker (higher viscosity) than an (x)w40. And unless you're regularly experiencing -30*C temps a 0w oil is doing you no benefit. Furthermore the bigger the gap between the kinematic viscosity numbers (0 and 60, 10 and 60, 5 and 40 etc.) the less stable the viscosity is over it's operating range and more stability is always more desirable (because it affects temps and pressures).

Ultimately you need three things in motor oil:

1. A "winter" (w) viscosity to suit your climate. In the south of the South Island a 20w is probably fine (-15*C), in the north of the North Island you could get away (easily) with a 25w (-10*C).

2. A HTHS (High Temp/High Shear) rating of no less than 2.9 cP. HTHS is the modern, accepted measure of how "good" an oil is at lubricating under load.

3. The lowest possible kinematic viscosity range (the difference between the "winter" viscosity and the operating viscosity).

In a good synthetic oil the operating viscosity, as long as it's 30 or above, is irrelevant unless specified by the manufacturer (e.g. S54 engines). Age has nothing to do with it.

As long as the 10w40 you're using has a HTHS of 2.9 cP or higher (and this can be difficult to find data on) then it's a much better choice than 0w60 or 10w60 for your engine. Some oil manufacturers publish HTHS for some or all of their oils but many do not (yet).

S54 owners got jipped when they were required to start using 10w60 because it's a real compromise oil. It has a massively high HTHS (over 5 cP I believe) to prevent abnormal wear but a massive operating range (less stable) and a huge operating viscosity (less efficient). An engine that requires such a high HTHS is almost unheard of (2.9 cP to 3.7 cP is "normal").

 

Edited September 14, 2016 by M3AN

[Rubix 434]

Understood - thanks for the info. I was under the impression a lower weight when engine is cold (i.e 0w as opposed to 10w) would be more ideal to reduce engine wear upon startup, but forgot to factor in climate - most of my reading is from USA forums where they obviously experience a huge range of climates.

Is there a specific reason BMW recommend Castrol TWS 0w-60/10w-60  over a higher cP HTHS but lower viscosity range for s50/s52/s54?

Edited September 13, 2016 by Rubix

[M3AN 4016]

1 minute ago, Rubix said:

Is there a specific reason BMW recommend Castrol TWS 0w-60/10w-60  over a higher cP HTHS for s50/s52/s54?

Yes, but not for S52 or S50, only S54 (because bottom end bearings were designed or manufactured poorly).

The reason is that at the time, and even still today, HTHS is not a headline value on oil packaging and in some cases can't even be found, consumers might have a hard time getting the correct data to make their decisions. Since a quality 60 weight oil is guaranteed to have a (very) high HTHS rating it's also assured of being in a very safe range. I somewhat doubt a 60 weight oil or a HTHS of over 5 cP is required for the S54 but it's considered "safe" by BMW and I'd not recommend against it when it's advised by the manufacturer.

 

[Olaf 3317]

hey, I'm impressed with 470,000kms, Dion!

[Rubix 434]

Gotcha, cheers Dave. Makes sense.

[Danger 31]

Yeah i felt a synthetic 10w40 was a safe option. Found and cleaned the vanos filter this arvo thanks for the heads up. Was fairly clean as is the rest of the engine. Will go ahead and rebuild the vanos for piece of mind and try get a look at the timing chain guide while i have it out. If the problem goes deeper than that it can be parked up for a while.

[*Glenn* 854]

If you haven't, and / or someone else hasn't diagnosed what the actual noise or problem is, do you think it's wise to start blindly pulling things apart without knowing what the fault is ?? You may find you start introducing more costly repairs by not having the experience or tools to carry out this work to a reasonable standard. 99% of a successful repair is diagnosing accurately what the problem is first before you pick up a tool to repair the fault.

Edited September 14, 2016 by *Glenn*
add on

[M3AN 4016]

To be fair Glenn, a S5x VANOS overhaul isn't a risky or complex procedure and if you don't do the rattle kit then there are no timing implications. The only thing you really need to be careful of this the valve cover bolts. However simple though it's a time consuming job so the cost/benefit/risk equation doesn't really lead itself to a shop job in this case (I've not seen it quoted for much less than $1,000 + parts and consumables).

I totally get where you're coming from, if you want a professional job take it to a professional but I also think that committed and careful enthusiasts with the correct tools can do a simple job perfectly adequately. A non rattle kit VANOS job is very simple on these engines. I'd certainly suggest your recommended approach to anybody who wasn't committed and careful!

Which reminds me @Danger, I have the tools you need if you're going to do your VANOS, send me a PM when the time is right.

[*Glenn* 854]

I understand what you are saying Dave, but the "actual" fault is yet to be diagnosed properly. At this stage it's an undiagnosed noise, which in my opinion is only a guess by "Danger" as to the actual problem

Edited September 14, 2016 by *Glenn*

[M3AN 4016]

True that Glenn, hunting in the dark is difficult and I see that's your point when I re-read your original post. I support your diagnostic advice.

Nevertheless, he's going to have to do the VANOS eventually so jump on in I say, might get lucky with the noise!

[Danger 31]

The way I see it, i'm delving into what appears to logically be the problem area while completing some preventative maintenance along the way.

I've shown the car to 2 mechanics for their opinions on the noise and spent hours reading threads detailing various s50b32 issues.

I've then posted this thread seeking additional advice.

With all due respect i've worked on plenty of engines before and i'm hardly "blindly pulling things apart"

[Danger 31]

45 minutes ago, M3AN said:

Which reminds me @Danger, I have the tools you need if you're going to do your VANOS, send me a PM when the time is right.

Thanks for the offer, do you mean the cam locking bridge? I was just going to make one if i could confirm the locking pins are just 90° perpendicular to the bridge.

[M3AN 4016]

26 minutes ago, Danger said:

Thanks for the offer, do you mean the cam locking bridge? I was just going to make one if i could confirm the locking pins are just 90° perpendicular to the bridge.

Crank locking tool, timing check bridge (it's not a lock) and rattle kit tools, yes. It looks like 90* but I've never found any specs to confirm that.

[Danger 31]

Thanks. I'll see how i get on.

[Danger 31]

Well, im regretting doing the rattle kit proceedure as it was quite time consuming and now i have the exhaust cam out. The bearings seemed ok anyway..

I struck a big issue with the nut on the end of the intake piston rounding despite using all the correct tools. Had to file it off which has scored the top of the piston a little however this isnt a wear surface.

Inspected the vanos oil pump and managed to fire a spring off into some part of my 110m2 workshop so todays job will be attempting to find that..

All in all, i would recommend not doing the rattle kit unless you observe excess play once you've removed the vanos unit.

[M3AN 4016]

34 minutes ago, Danger said:

All in all, i would recommend not doing the rattle kit unless you observe excess play once you've removed the vanos unit.

Yep.

Once you find that spring (and you'll need to for obvious reasons) then do all assembly and disassembly of the pump disk in a plastic bag so when (not if) the springs fire out you catch them in the bag. To assemble do two opposing springs and pistons, assemble that in the ring then, with the ring holding those two in, spin the disk a little in the ring to expose the two remaining hole and then fit the springs and pistons to those.

Good luck! Need those tools?

[Danger 31]

Yeah i found it and all back together. Yes ill be needing the bridge and crank locking pin thanks. Nothing obvious with regard to the mystery noise, chain guides look good and everything is extremely clean.

[Danger 31]

Well I'm pretty confident I've located the mystery noise. Noticed before that the no.1 cam journal on the exhaust cam is badly nipped up.

Not exactly what i wanted to see..if anyone has a b32 cam tray or exhaust cam please get in touch

[Danger 31]

Decided what I'll do is remove cam tray and see if I can get the journal machined oversize then get the cam metalsprayed and ground to suit.