BMW 330Ci Coupe M54B30 engine rebuild

[LunarOne]

So I have a 2001 330Ci Coupe at 210k miles which until a couple of years ago was my daily driver. I've owned the car from new and always loved it which is why I've never sold it. Over the years I've replaced my own brake pads and rotors, the thermostat, the power steering pump, the fuel pump and the alternator myself, but recently, the coolant expansion tank cracked, the engine overheated and I have a feeling that the head gasket has gone bad. Having replaced the expansion tank, the engine starts and runs normally, but after a while it starts to misfire badly before returning to normal. I'm not exactly sure what's causing the misfire, but if water or oil is getting into the cylinders then that would explain it. For the last 50 to 60 thousand miles, the engine has been using a lot more oil than normal, so I'm now considering a rebuild.

Now if this was a cheap car which I'd bought used with many miles, I'd be thinking of selling it for scrap. The nearside front suspension balljoint was flagged up at its last MOT although it passed, and the rear arches are beginning to rust, so it's not a car I'd consider buying even as a shed, but since I bought the car new and have owned it for nearly 20 years, I'm pretty emotionally attached.

I gather it's not a particularly cheap endeavour, and I'd be removing the engine and transmission from the car to do the work, so I'd have to get hold of an engine hoist and stand as well as a number of tools. In fact the prospect of getting more tools is the most exciting bit! It's not that I'm expecting the car to last another 20 years, but I'd love to have a go at rebuilding the engine from scratch. Last time I worked on engine internals, I was 15 years old, helping to build motorcycle engines for hovercraft racing. That was a good 30 years ago! I've watched videos on the subject by 50skid and Welshdrive. There's also great information on this e46fanatics thread.

What say you PH? Am I completely crazy?

[g3org3y]

LunarOne said:

So I have a 2001 330Ci Coupe at 210k miles which until a couple of years ago was my daily driver. I've owned the car from new and always loved it which is why I've never sold it.

...

What say you PH? Am I completely crazy?

Given you've had it from new, I'd say no, not completely crazy.

Since it's not your daily driver you can have it as a weekend project to busy yourself with. Am sure you'll learn lots on the way and any excuse to buy new tools and equipement.

Good luck!

[helix402]

I wouldn’t bother with a head gasket. The threads tend to pull out of the block. Better off with a used engine.

[d_a_n1979]

Not crazy at all, always good to learn and get new toys to do that too

But I think a replacement engine would make life a lot easier and it’s be cheaper too.

Unless you really want to rebuild the engine (it has its own issues if the head comes away unclean) then an engine swap would be much more straight forward

[LunarOne]

helix402 said:

I wouldn’t bother with a head gasket. The threads tend to pull out of the block. Better off with a used engine.

Most of the rebuilders seem to rethread the block and insert some new threads - are they called helicoils? Your username is so apt!!

[LunarOne]

d_a_n1979 said:

Not crazy at all, always good to learn and get new toys to do that too

But I think a replacement engine would make life a lot easier and it’s be cheaper too.

Unless you really want to rebuild the engine (it has its own issues if the head comes away unclean) then an engine swap would be much more straight forward

Swapping the engine would certainly be much easier, but it wouldn't give me the rebuilding experience. I'm also on the lookout for an interesting collector car which might need some work, so I'm considering this a practice run. After all, I've already got the car for free so it won't cost me much to try. And if I get inside and discover that things are beyond repair, then I can always get hold of a replacement engine at that time.

[LunarOne]

g3org3y said:

Given you've had it from new, I'd say no, not completely crazy.

Since it's not your daily driver you can have it as a weekend project to busy yourself with. Am sure you'll learn lots on the way and any excuse to buy new tools and equipement.

Good luck!

I actually have a lot more time on my hands than just weekends at the moment. So part of this is giving myself something to get my teeth stuck into. And I've been looking for an excuse to buy an air compressor and perhaps an ultrasonic parts cleaner, even if those probably aren't 100% essential.

[Touring442]

Rebuilding will be expensive. The threads in the block for the head bolts WILL have weakened. So, the block will need skimming and the bolt holes drilled out and fitted with Timeserts- like Helicoils but not crap. Don't even attempt to get away without Timeserts. It will go spectacularly wrong.

The crank will probably be perfect requiring just a polish. The pistons likewise, needing new rings. If the bores are worn (fairly unlikely) then throw the block away and find a better one.These are alloy blocks with steel liners pressed in although you could have new ones pressed in.

[8Tech]

Pull the engine, strip it and cost up what it needs. If it is financially viable, you will be able to reseat the valves, port the heads, rethread the block and maybe balance the internals. Depending on budget, you could uprate the cams and replace the timing chains and tensioners.

At least if you strip it first, you will know what route to take.

https://store.vacmotorsports.com/je-pistons-forged...

https://store.vacmotorsports.com/schrick-camshaft-...

87mm pistons will give you 3.2 litres.

Edited by 8Tech on Tuesday 16th June 22:18

[LunarOne]

I plan if at all possible to strip and rebuild all the way down to the bottom end, so that I end up with a stock M54B30 within factory tolerances. The idea being that not only will I learn how to do something like this, but if I document everything I've done, the engine should have a resale value well above that of a used M54 that's just had the top end done.

I haven't decided if I will do anything about restoring the car itself. Having bought it new, I specced it myself and added £10k worth of options. These won't be worth anything in terms of value, but it makes it still a nice car to drive. I remember the salesman at Heathrow BMW (as it was called then) thinking I was crazy to want both the glass sunroof AND the climate control. He said the system was set up so that I could have one or the other. I insisted on both. I think the only options I didn't specify were the through-loading ski-hatch, and the automatic transmission. The same salesman told me that as far as he was aware, I was the only customer not to have specced an autobox.

Sadly my 330 was an early one with a 5-speed manual. If I can find one in good condition, I'm considering swapping it for the 6-speed unit. I know the first 5 ratios are exactly the same, but the one thing that always bugged me was the lack of an overdrive gear for cruising. I doubt I'll ever be doing long distance driving in that car, but if I can get the gearbox cheap, then why not?

[LunarOne]

8Tech said:

Pull the engine, strip it and cost up what it needs. If it is financially viable, you will be able to reseat the valves, port the heads, rethread the block and maybe balance the internals. Depending on budget, you could uprate the cams and replace the timing chains and tensioners.

At least if you strip it first, you will know what route to take.

https://store.vacmotorsports.com/je-pistons-forged...

https://store.vacmotorsports.com/schrick-camshaft-...

87mm pistons will give you 3.2 litres.

I am definitely reluctant to install upgrades as I'm a fan of everything being as original as possible but thanks for the links - that's a very interesting site! Who knows. Maybe there's little point in trying to remain original in what will likely never be a collector's car.

[aka_kerrly]

Nothing crazy about your plans!!!

LunarOne said:

I plan if at all possible to strip and rebuild all the way down to the bottom end, so that I end up with a stock M54B30 within factory tolerances. The idea being that not only will I learn how to do something like this, but if I document everything I've done, the engine should have a resale value well above that of a used M54 that's just had the top end done.


Sadly my 330 was an early one with a 5-speed manual. If I can find one in good condition, I'm considering swapping it for the 6-speed unit. I know the first 5 ratios are exactly the same, but the one thing that always bugged me was the lack of an overdrive gear for cruising. I doubt I'll ever be doing long distance driving in that car, but if I can get the gearbox cheap, then why not?

Whilst it is true the gear ratios on 1st to 5th on a 5speed an 6speed are very close, the 1st an 2nd gear are slightly shorter on a 6speed but hardly noticeable. The best improvement is to change the final drive to a shorter one an combine it with a ecu map to increase the rev limit.

With the increase in oil usage have you inspected the CCV - crank case breather system that can get clogged up an cause excessive oil consumption an it maybe that the engine is in a better condition than you think. My first port of call would be to get a code reader on to see if the ECU is registering the misfire and then performing a compression test & a sniff test done as that will give you a much clearer idea if the HG has failed and the condition of the engine.

I'd also consider perhaps buying another engine and doing a rebuild on that whilst you can still use your car then when the engine is built you can remove the accessory parts and do the swap much quicker. I also like the idea another guy posted of using this as an opportunity to price up some cams/headwork /6 branch manifold an getting some extra power from a fresh motor.

[8Tech]

LunarOne said:

8Tech said:

Pull the engine, strip it and cost up what it needs. If it is financially viable, you will be able to reseat the valves, port the heads, rethread the block and maybe balance the internals. Depending on budget, you could uprate the cams and replace the timing chains and tensioners.

At least if you strip it first, you will know what route to take.

https://store.vacmotorsports.com/je-pistons-forged...

https://store.vacmotorsports.com/schrick-camshaft-...

87mm pistons will give you 3.2 litres.

I am definitely reluctant to install upgrades as I'm a fan of everything being as original as possible but thanks for the links - that's a very interesting site! Who knows. Maybe there's little point in trying to remain original in what will likely never be a collector's car.

I completely understand where you are coming from, and of course there are budget considerations, but if the bores are worn, a piston kit is a really good option.

I always find it disappointing to carry out a shedload of work on my car and end up with the same as I started with. I always like to be able to stand back and say to myself that all that time, effort and cash went into actually improving something.

If it was a proper classic, then I am with you 100%, but as a car you want to use and enjoy, I would always make it better than it was.

[Zener]

IMO they only pull block threads if over heated muchly the ali can soften) if in doubt fit a set of ARP studs that way your stressing the stud and far less so the block threads as the stud remains static/parked and the ARP studs thread further into the block threaded holes anyway , not a cheap engine to build correctly TBH unless you can get away with top and tailing only

[LunarOne]

aka_kerrly said:

With the increase in oil usage have you inspected the CCV - crank case breather system that can get clogged up an cause excessive oil consumption an it maybe that the engine is in a better condition than you think. My first port of call would be to get a code reader on to see if the ECU is registering the misfire and then performing a compression test & a sniff test done as that will give you a much clearer idea if the HG has failed and the condition of the engine.

I'd also consider perhaps buying another engine and doing a rebuild on that whilst you can still use your car then when the engine is built you can remove the accessory parts and do the swap much quicker. I also like the idea another guy posted of using this as an opportunity to price up some cams/headwork /6 branch manifold an getting some extra power from a fresh motor.

I know that the CCV system is shot, because a few years ago I gave the car to a garage to do oil seals because it was leaving oil on my drive. A few months after getting it back (and with no improvement) I noticed that one of the CCV hoses (connected at the firewall on the left hand side of the car) was dangling loose down by the power steering pump, and I could never figure out where it was supposed to go. Then months later while looking at the engine bay with another "mechanic", I remembered the dangling hose and pointed it out to him. He said, "Oh, I can fix this in a second!" so I let him have a go. Only for him to snap the fitting on the firewall. That hose (along with the piece that is supposed to be on the firewall) is still in the boot of the car. At the time I thought it was something to do with emissions and had no idea it might impact oil consumption, so I just let it be. Yes, I do get codes that suggest a vacuum leak on and off, and I've just cleared them and carried on.

The car also mostly has nowhere near the power it once had. Sometimes the power comes back miraculously, but most of the time it feels like 100bhp have gone AWOL. The car is still perfectly driveable and doesn't hesitate, but something is clearly up. Even at times when no codes are generated. I've become convinced that it's a software thing rather than anything mechanical, but again I plan to rebuild the VANOS and replace all the hoses and plastic parts that have aged, along with the entire CCV system.

As for the head gasket - I borrowed a coolant system pressure tester from my local garage where I have a friendly relationship with the head mechanic. The result from that, plus the bubbles visible in the coolant, suggest HG failure. But there's no evidence of coolant/oil mix, so that's a bit weird. I was expecting to see some sludge under the oil filler cap but the oil looks clean and uncontaminated.

[BFleming]

aka_kerrly said:

Whilst it is true the gear ratios on 1st to 5th on a 5speed an 6speed are very close, the 1st an 2nd gear are slightly shorter on a 6speed but hardly noticeable. The best improvement is to change the final drive to a shorter one an combine it with a ecu map to increase the rev limit.

Let's get some 330i ratios written down for some perspective:
5 speed/6 speed
1st: 4.21/4.35
2nd: 2.49/2.50
3rd: 1.66/1.66
4th: 1.24/1.23
5th: 1.00/1.00
6th: --- / 0.85
Diff: 2.93/2.93

So pretty much identical all the way through, except a 6th gear that's a reasonable amount taller than 5th.

The US 330i ZHP models had a 1:3.07 final drive (diff) ratio for better acceleration, but this means more revs when cruising. From memory, my own pre-facelift 330i was crying out for a 6th gear, which of course they addressed from 2003.

On oil consumption, mine was really bad at the end. 500 miles between top-ups if I was lucky. No leaks, no blue smoke, CCV and all pipework changed, but it only ever got worse. Allegedly it's down to different piston rings being used in the M54 engine over the M52TUB28 that preceded it. Revert to the older ring design & the problem gets a lot better.

[Zener]

If its the oil control rings causing the problem rather than a clogged/broken CCV its that the rings carbon up causing the issue they didnt leave the factory using oil problem not helped by the silly extended oil services , I am on 180k miles with an M54 2.5 my oil use in 4k intervals is minuscule and this engine as not been apart during its life (have owned for over 5 years and its consistent) I have all the history its also my occupation so I would know otherwise , I also maintain another M54 3.0 high miler he uses about a litre every 2k miles howeve I have known at least a few examples of these engines use obscene amounts of oil , they dont all use oil but most do due to the above IMO

[LunarOne]

BFleming said:

Let's get some 330i ratios written down for some perspective:
5 speed/6 speed
1st: 4.21/4.35
2nd: 2.49/2.50
3rd: 1.66/1.66
4th: 1.24/1.23
5th: 1.00/1.00
6th: --- / 0.85
Diff: 2.93/2.93

So pretty much identical all the way through, except a 6th gear that's a reasonable amount taller than 5th.

The US 330i ZHP models had a 1:3.07 final drive (diff) ratio for better acceleration, but this means more revs when cruising. From memory, my own pre-facelift 330i was crying out for a 6th gear, which of course they addressed from 2003.

Forgive me if I'm wrong but didn't the ZHP pack only come out on facelift cars? So all ZHP cars had 6-speed boxes. Comparing cruising RPMs with non ZHP 5-speed cars shows that 0.85x3.07 gives total cruising ratio of 1:2.61 vs 1.0 x 2.93 = 1:2.93. So even with the higher ratio diff for better acceleration on ZHP models, the 6th gear cruising RPM will be lower than the 5th gear cruise on a non-ZHP car. In other words, ZHP cars get better acceleration and still have a lower cruise RPM than a 5-speed car. Sounds like a good upgrade, but getting a ZHP diff in the UK might be tricky and expensive, while getting a 6-speed gearbox alone might be more realistic if not easy.

[BFleming]

LunarOne said:

Forgive me if I'm wrong but didn't the ZHP pack only come out on facelift cars? So all ZHP cars had 6-speed boxes. Comparing cruising RPMs with non ZHP 5-speed cars shows that 0.85x3.07 gives total cruising ratio of 1:2.61 vs 1.0 x 2.93 = 1:2.93. So even with the higher ratio diff for better acceleration on ZHP models, the 6th gear cruising RPM will be lower than the 5th gear cruise on a non-ZHP car. In other words, ZHP cars get better acceleration and still have a lower cruise RPM than a 5-speed car. Sounds like a good upgrade, but getting a ZHP diff in the UK might be tricky and expensive, while getting a 6-speed gearbox alone might be more realistic if not easy.

Yes indeed , you're spot on with your assumptions there.
In the back of mind I seem to recall you need the 6 speed gearbox and the propshaft for the conversion (if you go down that route).
The 3.07 diff does indeed seem to be a rarity, part of the Performance Package (option S767A).

[4rephill]

Zener said:

If its the oil control rings causing the problem rather than a clogged/broken CCV its that the rings carbon up causing the issue they didnt leave the factory using oil problem not helped by the silly extended oil services , I am on 180k miles with an M54 2.5 my oil use in 4k intervals is minuscule and this engine as not been apart during its life (have owned for over 5 years and its consistent) I have all the history its also my occupation so I would know otherwise , I also maintain another M54 3.0 high miler he uses about a litre every 2k miles howeve I have known at least a few examples of these engines use obscene amounts of oil , they dont all use oil but most do due to the above IMO

Technically, they did leave the factory using some oil to one degree or another - They always will until the piston rings and cylinder bores are properly bedded in.

(Also: [pedant] They all leave the factory with running-in oil in the engine, so that should get "used" when the car has it's running-in service [/pedant] )

Talking with a few BMW mechanics and service guys over the years, I was told that a major reason for the variation in oil consumption with the M54 engine, was down to how the car was driven when brand new.

BMW's specified break-in procedure was (From the owners manual) :

Engine and differential

Up to 1,200 miles (2,000 km):

Drive at varying engine and road speeds, but do not exceed 4,500 rpm or a speed of 100 mph (160 km/h):

Obey your local and state maximum speed limits.
Do not apply full throttle and avoid pressing the accelerator beyond the kick-down point.

Once you have driven 1,200 miles (2,000 km), engine speed and vehicle speed can be gradually increased.........

Some original owners ignored the break-in procedure completely, often because they were only going to own the car for a year or two anyway, so any damage done to the engine was not going to be their problem. They would happily hit the red-line, and hold high revs for long periods of time, without a care in the World.

Other owners went the other way with their break-in procedure, and refused to allow the engine to rev anywhere near 4,500rpm, thinking they were doing the engine a favour. Instead they would trundle along changing gear @ 2,000rpm, and cruising at a constant 2,500rpm.

What they failed to realise was, the M54 engine needed some variation in revs, up to 4,500rpm, in order to bed the piston rings and cylinders in properly, and evenly. By failing to let the engine rev a bit, they were doing more harm than good.

So:

Some engines were subjected to excessively high revs and red-lining during the break-in period = High oil consumption later on in the cars life.

Some engines were broken in as BMW specified (or close to it) = Minimum oil consumption later on in the car's life.

Some engines were subjected to too low revs during the break-in period = High oil consumption later on in the car's life.


When my Dad bought a new Ford Focus, he asked about the engine break-in procedure, and they told him pretty much the same as BMW specify - Do not exceed 4,000rpm for the first 1200 miles, vary the revs whilst driving, avoid prolonged driving at a constant engine speed where possible, etc., etc.

When I spoke to him, and asked about the engine break-in procedure, he said to me: "They were talking complete b0II0cks about breaking the engine in! - Everyone knows you don't exceed 2,000rpm for the first couple of thousand miles!"

I tried to explain to him that that was wrong, and bad for the engine, but he wouldn't have it - He knew more about breaking engine's in than the Ford engineers!