Differences between the sixes?

[Sidewaze Samm]

After two months of ownership, our 2.0 SE is going back to the dealer. Permanently.
So a new zed is needed - but this time it will be a 6. But, as my son's car it will still need to be a 2.5 at most

What I can't get to grips with is the different versions of 6-cylinder lumps available in the E85. So if someone could clarify that for me, for the 2.5 and 2.2, it would be greatly appreciated. I know there's si versions, and N-this and M-that engines, with outputs from 170bhp to 218bhp.
But what I could do with is a chronological list of the types and their outputs, and rough dates of when they were used and if any difference between pre and post facelift. And also, given our experiences with the 2.0, which are the most and least likely to give problems.

So, many thanks in advance

PS - and yes, I was indeed told at the beginning of the year, to get a 6 as the 2.0 frequently has more issues.
But the 2.0 was cheaper to buy, and with the insurance costs for my son to consider too...

PPS - When joining the forum we didn't have a zed, and when we got the car didn't post any photos - so better late then never...

Zed.jpg (227.14 KiB) Viewed 1201 times

[mjennings23]

Pre facelift had the M54 engine in 2.2, 2.5 and 3.0 capacities, ranging from around 160ish bhp to 230.

Facelift has the N52 2.5 and 3.0 with 200ish and 260ish bhp respectively.

I think the general opinion is the M54 is a bit simpler and more mechanical, but both engines are very solid and used in a huge range of BMW cars. The M54 tends to have leaky gaskets, not a big job but fairly common, whereas the N52 can develop tappet rattle and the water pumps like to fail suddenly.

These are just some examples, I personally ended up with an M54 due to budget and a well specced example coming up for sale.

[Chris1981]

Glad you've decided to go for a 6 cylinder... they are a lovely drive and sound gorgeous!

M54 engines are pre facelift and N52 engines are facelift... so 2006 or newer gets the N52 series engine, older obviously gets the M54.

Wiki link below will show you the different variants of engines and when they were offered... the N52 3.0i was not offered in the UK as far as i know, but that won't matter if you're looking at 2.5 or lower.

https://en.wikipedia.org/wiki/BMW_Z4_(E85)#Models

[bz4kev]

Maybe worth checking insurance on 2.5 and 3.0 if it’s not much difference I personally would swing more towards the 3.0 m54 depending on budget good look in your search nice smg one with a long list of work done for sale on here Ruskys car I believe well worth a look

[ph001]

Yeh, Chris1981 link tells you most of what you need to know....

Z4 models.jpg (94.1 KiB) Viewed 1152 times

I would add though that the 3.0Si did have a revised engine halfway through it's life with a black cam cover (engine build date Sep 2006 so tends to appear in 2007 cars) known as the N52K and has modifications in the following areas:

• Cylinder head cover
• Camshafts
• Crankshaft
• Stem diameter of exhaust valves increased to 6 mm instead of 5 mm
• Torsional vibration damper
• Crankcase ventilation
• Hot-film air mass meter (HFM)
• Throttle valve
• Digital motor electronics

...full thread with images here... viewtopic.php?f=2&t=105709&start=30

[Chris1981]

I would add though that the 3.0Si did have a revised engine halfway through it's life with a black cam cover (engine build date Sep 2006 so tends to appear in 2007 cars) known as the N52K and has modifications in the following areas:

• Cylinder head cover
• Camshafts
• Crankshaft
• Stem diameter of exhaust valves increased to 6 mm instead of 5 mm
• Torsional vibration damper
• Crankcase ventilation
• Hot-film air mass meter (HFM)
• Throttle valve
• Digital motor electronics

...full thread with images here... viewtopic.php?f=2&t=105709&start=30

Very good point!

I'm uncertain on the timing but only as mine was registered in Jan 2008 but has the earlier silver top engine!? Could be a late registration or replacement engine... although all the mileage adds up

[ph001]

I'm uncertain on the timing but only as mine was registered in Jan 2008 but has the earlier silver top engine!? Could be a late registration or replacement engine... although all the mileage adds up

I think there can be a significant variation in terms of timing between the engines being built and being fitted, and then also you really need to look at your build date as that can be many months before registration date. I suspect it's pretty unusual for an 08 reg car to have a silver top engine though.

[philbo909]

I would add though that the 3.0Si did have a revised engine halfway through it's life with a black cam cover (engine build date Sep 2006 so tends to appear in 2007 cars) known as the N52K and has modifications in the following areas:

• Cylinder head cover
• Camshafts
• Crankshaft
• Stem diameter of exhaust valves increased to 6 mm instead of 5 mm
• Torsional vibration damper
• Crankcase ventilation
• Hot-film air mass meter (HFM)
• Throttle valve
• Digital motor electronics

...full thread with images here... viewtopic.php?f=2&t=105709&start=30

Very good point!

I'm uncertain on the timing but only as mine was registered in Jan 2008 but has the earlier silver top engine!? Could be a late registration or replacement engine... although all the mileage adds up

That's the plastic engine cover, which are random

[Sidewaze Samm]

Maybe worth checking insurance on 2.5 and 3.0 if it’s not much difference I personally would swing more towards the 3.0 m54 depending on budget good look in your search nice smg one with a long list of work done for sale on here Ruskys car I believe well worth a look

I'd certainly like a 3.0si, but it is for my son who is still in early stages of earning his NCD. I don't think the difference is too great, but that would be on top of the difference between a 2.5 and 2.0, which is on top of the difference between a a 2.0 and a 1.2 Suzuki Swift that he's been driving for the last couple of years. So all in all, a 3.0 would be a big increase from what he was paying just two months ago.
And then there's the combination of power, very limited RWD experience, and youth

[Sidewaze Samm]

Thanks for that guys - very helpful.

[Ducklakeview]

One car I'll be glad not to see again

Mike

[Chris1981]

[/quote]
That's the plastic engine cover, which are random
[/quote]

Sorry, should have been more specific, it's the metal cam cover with external ccv... defo the earlier version!

Think I'll look up build date and see if that explains it

[Sidewaze Samm]

One car I'll be glad not to see again

Mike

yeah - but apart from the rough idle issue, oil leak, and intermittent engine issues it was ok - and a nice colour combo.
Oh, and the ABS/DSC issue....
Best place for it...

[mjennings23]

Maybe worth checking insurance on 2.5 and 3.0 if it’s not much difference I personally would swing more towards the 3.0 m54 depending on budget good look in your search nice smg one with a long list of work done for sale on here Ruskys car I believe well worth a look

I'd certainly like a 3.0si, but it is for my son who is still in early stages of earning his NCD. I don't think the difference is too great, but that would be on top of the difference between a 2.5 and 2.0, which is on top of the difference between a a 2.0 and a 1.2 Suzuki Swift that he's been driving for the last couple of years. So all in all, a 3.0 would be a big increase from what he was paying just two months ago.
And then there's the combination of power, very limited RWD experience, and youth

Might be surprised, I went from a DS3 into a 3 litre Z4 for a grand increase of £60, and this was less than 1 month into the policy. Was 26 and 1 years no claims at this point (didn't have a car for a few years due to living in London)

[Sidewaze Samm]

So now I think I've got a handle on the various sixes. I also get the idea that the M54 2.5 might be the safer bet regarding durabilty and reliability, though a bit more expensive on fuel and tax than the N52. And that the choice between M54 2.5 and 2.2 depends on the car it's in and the price - remembering that outright performance is not an issue here.
Anybody concur - or disagree?