Let's talk oil pumps and harmonics

So, I'm getting ready to buy an E46 330Ci (big step up from an auto 325i, not sure how it'll compare to my rev happy AP1 S2000) and started reading about common mods and problems. Much to my dismay I find that extended RPM use above 6K can lead to backed off oil pump nuts, gear shearing, and engine destroying goodness. This is no bueno my friends. But why I ask? The general consensus seems to be crankshaft harmonics which made me dig a little deeper...

Lets look at some other inline 6's aside from the M54B30:
Toyota 2JZ-GTE: totally square motor 86mm bore x 86mm stroke. Nice beefy internals and can take 7.5K all day (the HEAD internals being the limiting factor).
BMW S54B32:Undersquare (.96) at 87mm bore x 91mm stroke. 8K redline.

Now the M54B30: Only slightly more undersquare than the B32 (.94) at 84mm bore x 89.6mm stroke. Likes to massage itself apart above 6k...

So what gives? What are the physical similarities and differences between the B30 and B32? Bore spacing, deck height (rod angles)?
Are the factory oil pumps/dampers interchangable?
Does either motor have a girdle?
Hell, what about crankshaft ventilation: does the M3 have more/beefier provisions?
No matter how you slice it; the $2k oil pump offered or the $200 kit are just band aids (or a cast) for an underlying problem...

Originally Posted by SH4DY

So, I'm getting ready to buy an E46 330Ci (big step up from an auto 325i, not sure how it'll compare to my rev happy AP1 S2000) and started reading about common mods and problems. Much to my dismay I find that extended RPM use above 6K can lead to backed off oil pump nuts, gear shearing, and engine destroying goodness. This is no bueno my friends. But why I ask? The general consensus seems to be crankshaft harmonics which made me dig a little deeper...

Lets look at some other inline 6's aside from the M54B30:
Toyota 2JZ-GTE: totally square motor 86mm bore x 86mm stroke. Nice beefy internals and can take 7.5K all day (the HEAD internals being the limiting factor).
BMW S54B32:Undersquare (.96) at 87mm bore x 91mm stroke. 8K redline.

Now the M54B30: Only slightly more undersquare than the B32 (.94) at 84mm bore x 89.6mm stroke. Likes to massage itself apart above 6k...

So what gives? What are the physical similarities and differences between the B30 and B32? Bore spacing, deck height (rod angles)?
Are the factory oil pumps/dampers interchangable?
Does either motor have a girdle?
Hell, what about crankshaft ventilation: does the M3 have more/beefier provisions?
No matter how you slice it; the $2k oil pump offered or the $200 kit are just band aids (or a cast) for an underlying problem...

ati super damper for 700 shipped brand spanking new is a permanent solution for you check it out

OP, the problem lies in the block.

The BMW M54B30 is an Aluminum Alloy block, it simply gets a harmonic resonance in it at higher RPM. Kinda like a tuning fork. Apparently the oil pump is the weakest link in the chain. The three things that can be done to alleviate this problem are 1) ATI Super Damper $800 2) TC Kline / vaio76109 Super Oil Pump $750 3) S54 Timing Chain Tensioner $160.

I've personally had a high RPM motor failure because of this, I believe the three items listed above are necessary for sustained high RPM usage.



Good luck,
Rob.

Originally Posted by steven747

ati super damper for 700 shipped brand spanking new is a permanent solution for you check it out

Steven, it has NOT been proven that the damper alone is "a permanent solution".

Originally Posted by Rob43

The three things that can be done to alleviate this problem are 1) ATI Super Damper $800 2) TC Kline / vaio76109 Super Oil Pump $750 3) S54 Timing Chain Tensioner $160.

For clarity, Rob is suggesting that the best results are achieved using all 3 items together and not that any one of the 3 would suffice.

Thanks for the list of fixes (or things the factory didn't do right) Rob but that's still not really what I'm after...
Doesn't the S54 also have an Aluminum block? That's why I'm interested in the physical differences between them and peripherals like girdles and how the mains are secured (2 bolt, cross bolted, etc).
Or is is the crank itself? Are there significant differences between the M54 and S54 cranks besides stroke? Journal sizes, counterweights, overall weight...
Anyone ever put the rotating assemblies on a scale?

I'm just curious... it seems like there could be so much potential but much like a viable end user flashable tuning solution there's nothing out there.

Also, Rob: I see we're pretty much around the block from each other. Are there any BMW meets in the Mid-A coming up? I'd like to head to VIR at some point this year.

Originally Posted by SH4DY

Thanks for the list of fixes (or things the factory didn't do right) Rob but that's still not really what I'm after...
Doesn't the S54 also have an Aluminum block? No. That's why I'm interested in the physical differences between them and peripherals like girdles and how the mains are secured (2 bolt, cross bolted, etc).
Or is is the crank itself? Are there significant differences between the M54 and S54 cranks besides stroke? Journal sizes, counterweights, overall weight...
Anyone ever put the rotating assemblies on a scale?

I'm just curious... it seems like there could be so much potential but much like a viable end user flashable tuning solution there's nothing out there.

Also, Rob: I see we're pretty much around the block from each other. Are there any BMW meets in the Mid-A coming up? I'd like to head to VIR at some point this year.

I'm no S54 guru, there are many other E46F forum members way smarter than me on that subject, but to the very best of my knowledge it's a cast iron block, not an aluminum alloy like the M54 motor.

As to VIR: The May 12-13 SCCA Double MARRS (Mid Atlantic Road Racing Series) Race #2&3 (VIR), well I'll be in Hawaii on my Honeymoon.

Rob

If you are very serious about getting this issue solved I recommend speaking directly to Adam (PEI330) on here. He probably knows more about these engines than anyone else. However I believe Rob has covered most of the important stuff.

Totally random and hilarious but May 10th-13th I'll be in Vegas for my bachelors party congrats on tying the knot by the way Rob.

I'll see what Adam has to say about all of this. Thanks for the input guys.

The M54 and S54 are just fundamentally different motors. The M54 probably has more in common with the S52 than the S54, as the m54b30 uses the same crank as the older S52. Like the S54 though, the S52 also used an iron block.

Originally Posted by steven747

ati super damper for 700 shipped brand spanking new is a permanent solution for you check it out

Its about 800-850 shipped...

It can't just be the aluminum block. The m52tu's are aluminum block engines and there have been no reports of the same thing happening that I've found.
If I'm right and they aren't affected. I still think a 328 makes a better track car. Hell I'm pushing the same kind of power as a stock 330 now and I feel much safer about the engine out on the track when I'm up hanging out at redline.

Originally Posted by jared_wiesner

It can't just be the aluminum block. The m52tu's are aluminum block engines and there has been no reports of the same thing happening that I've found.
If I'm right and they aren't affected. I still think a 328 makes a better track car. Hell I'm pushing the same kind of power as a stock 330 now and I feel much safer about the engine out on the track when I'm up hanging out at redline.

No, you are correct in that you can't just blame one component of a system for an issue like this. I think what most are saying is that it's the combination of the crank used in the 330 (this is the rotating component and thus the source of vibration) combined with the aluminum block (Al is more ductile than Fe and thus the crank isn't "pinned" as rigidly at the bearings) which creates the harmonics that lead to the failure of a weak oil pump design.

Since the 328 doesn't use the same crank as the 330 and also isn't known to experience this harmonic issue (at least in the < 7k rpm range these motors are typically run), there is legitimate justification for feeling the 328 has the better high rpm motor (ie, the better track motor).

Most people with a b30 don't want to tackle trying to modify the crank or block but that still leaves several avenues for attacking this harmonic problem. Anything that alters the vibration characteristics of the crank are obvious solution candidates. Hence we have the development of things like the ATI Super Damper and recommendations to stick with the stock dual mass flywheel (as a LW single mass flywheel doesn't dampen crank vibrations as effectively as the dual mass). The use of the S54 timing chain tensioner has also been suggested, and although I am running this myself, I'm not sure the effect has ever really been quantified (in theory, it could make things better or worse - all I can say is that I notice less chain rattle). Making the oil pump robust enough to withstand the level of vibration experienced is the other logical solution (or band-aid depending on your point of view) and there have been a number of different attempts at making the oil pump more robust (some seem to work, others still experience failure). Due to the general lack of research and long term usage data, it would seem the safest approach would be to attack the problem on all fronts hence the recommendations to upgrade the crank damper, oil pump, and chain tensioner.

TxZHP04,

Very well written, I'm glad we have Engineers on board.



Rob.

There is also a final solution. If its a track car, just keep a spare motor....

I think that while the aluminum block is a factor in harmonic amplitude, it's not the cause. That still comes back to crank design...in this case the 89.6mm piece which was originally designed for the iron block USA S52 engine.

The 2.8L cranks seem to have less issues...especially on higher HP builds.

I seem to just like throwing $$$ at any and all problems....so I'm probably not the most economical person to have a discussion with on this topic.

At least you're honest... and you have good taste in parts.

Originally Posted by PEI330Ci

I think that while the aluminum block is a factor in harmonic amplitude, it's not the cause. That still comes back to crank design...in this case the 89.6mm piece which was originally designed for the iron block USA S52 engine.

The 2.8L cranks seem to have less issues...especially on higher HP builds.

I seem to just like throwing $$$ at any and all problems....so I'm probably not the most economical person to have a discussion with on this topic.

Originally Posted by aggieE46

At least you're honest... and you have good taste in parts.

Haha ya, don't get me wrong. What you have done with your car is nothing short of phenomenal PEI330Ci. A 330 is capable of more ultimate power than a 328... I get people that want to extract that power and doing what it takes.

I guess I'm at a settling stage in my life where I feel like where I used to want the biggest baddest when it came to just about everything.
I now want the easiest to live with.

That and I have to justify my car to make up for my size envy...

uhh...About displacement size

Bookmark

Sent from my ADR6300 using Bimmer App