Brain fart: Coverting a Z4C to a Z4MC

[shuey]

Ok so firstly - this is not something I'm seriously thinking of doing or even think I would do even I was serious about it - BUT....

Whats peoples thoughts on converting a regular Z4C - with an S54 engine and transmission - basically converting to an unofficial M car?
And yes I know there's steering and suspension and the diff too to consider.

If you're wondering why would even think of doing such a stupid think? Well I already own a pretty tidy Z4C. - and I've always wanted an M.

Yes I know I can probably buy a mint mid-mileage Z4M for 20k ish. But just wondering if I could potentially get a fresher car from a conversion (fresher engine, and new parts) than buying an middle aged Z4MC for the same cost. I assume most of it would be plug and play anyway - not sure about sourcing the steering rack tho... and hypothetically - I'd get a bmw specialist to do the conversion.

Had a quick look on eBay and you can get an S54 - for around 4k for low-ish mileage.

do you guys think it'll cost more than the equivalent of buying another z4mc?

Anyway purely hypothetical... if push came to shove - I actually would just sell my Z4C and buy the M

 

[buzyg]

As a technical project maybe but no. As a cheap way into an MC,. No chance not even if you did most of it your self. Just the parts would cost you a packet. The only way it makes any sense to me would be to simply build a custom Z4C, bbk, S54 sc, LSD, few choice body parts.

Better still find an ///MC, stick a sc, koni's and bbk on it. Fill it with Super. Then just drive.

 

[GuidoK]

Converting your z4c to z4mc will be at least 2-3 times as expensive as trading it in and pay the difference. especially as z4m's cost next to nothing in the uk (compared to mainland europe where they are at least twice as expensive)
And there's no guarantee that you'll get a bug free car.

It's only interesting if you can buy a wreck really cheap that has lots of damage but not to the critical parts (for instance a wreck where a car came in exactly from the side in the door (hoping that the propshaft is still in tact). Even then probably only interesting if you can do the work yourself (only possible if you have a car lift, transmission jack etc)

 

[KevinC]

With enough money, the sky's the limit. But this is a crazy idea. Would cost a fortune, and you'd be left with a "Frankencar" - not really an M car, would never be worth remotely close to how much you'd have to invest. MUCH cheaper, easier, and more practical to simply sell & purchase the real thing.

 

[mmm-five]

Don't forget that the cheap S54 engines you're seeing may not be identical to the S54 in a Z4M, as there are differences between both the earlier S54 in the M3, to the one in the later M3, to the one in the Z4M...even the ECU in the 2 cars are different (MSS50 in the M3 vs MSS70 in the Z4M vs MSV70 in the Z4C).

If the engine has more than about 80,000 miles then you're going to want to check/refresh the rod bearings/VANOS before you fit it, and of course do valve clearances.

...and whatever you do, don't believe the £3k 'supplied & fitted' adverts you see, as they tend to come from an infamous 'engine reconditioning' company in London who claim to do a complete rebuild on their engine, but actually do the bare minimum to get it running and then give it a quick clean.

 

[R60BBA]

Don't forget that the cheap S54 engines you're seeing may not be identical to the S54 in a Z4M, as there are differences between both the earlier S54 in the M3, to the one in the later M3, to the one in the Z4M...even the ECU in the 2 cars are different (MSS50 in the M3 vs MSS70 in the Z4M vs MSV70 in the Z4C).

If the engine has more than about 80,000 miles then you're going to want to check/refresh the rod bearings/VANOS before you fit it, and of course do valve clearances.

...and whatever you do, don't believe the £3k 'supplied & fitted' adverts you see, as they tend to come from an infamous 'engine reconditioning' company in London who claim to do a complete rebuild on their engine, but actually do the bare minimum to get it running and then give it a quick clean.

Differences in S54 for pre facelift M3, facelift M3 and Z4M?

Please enlighten.

 

[GuidoK]

Differences in S54 for pre facelift M3, facelift M3 and Z4M?

Please enlighten.

Different conrods, crank.

But apart from a different ecu in the z4m compared to the m3 you also need 2 or 3 different wiring looms.
And a different speedo compared to the z4c.

 

[mmm-five]

Differences in S54 for pre facelift M3, facelift M3 and Z4M?
Please enlighten.

Between the early and late versions I believe the differences are: rod bearings, rod bolts, oil pump.

Between the late & Z4M versions I believe the differences are limited to mostly ancillaries: sump/oil pickup, dipstick, oil cooler, ECU & engine harness.

 

[R60BBA]

Differences in S54 for pre facelift M3, facelift M3 and Z4M?
Please enlighten.

Between the early and late versions I believe the differences are: rod bearings, rod bolts, oil pump.

Between the late & Z4M versions I believe the differences are limited to mostly ancillaries: sump/oil pickup, dipstick, oil cooler, ECU & engine harness.

Thanks for sharing, I had no idea.

 

[MrPT]

Is the Vanos different? Seem to recall someone saying that we’re at less risk of bolts coming loose (and hence a lower need for the rebuild option).

 

[mmm-five]

Is the Vanos different? Seem to recall someone saying that we’re at less risk of bolts coming loose (and hence a lower need for the rebuild option).

I recall something similar, but wasn’t 100% so left it out.

 

[shuey]

Yeh I thought it’d be an absurd idea... didn’t think about wiring looms, ecu and dials.

Anyway I’m itching I got to get an M now... but have to wait for 3 months before I can seriously start the search...

In the meantime, I’m going to enjoy the low running costs of my z4c

Differences in S54 for pre facelift M3, facelift M3 and Z4M?

Please enlighten.

Different conrods, crank.

But apart from a different ecu in the z4m compared to the m3 you also need 2 or 3 different wiring looms.
And a different speedo compared to the z4c.

 

[BMWZ4MC]

A far better idea would be to fit the S85 V10 from the E60 M5 / E63 M6 :evil:

 

[Capa]

If you're going to that level of effort, do something different.

Basically, as the chap above says: Stick a V10 from an M6 in it.

I do distinctly fancy the idea of like a Z4C... CS though. Keep the standard engine, make a few bits lighter, uprate the brakes, suspension etc. Really with improving the 'feel' of the car rather than necessarily point to point performance...

 

[Jembo]

There was once a guy called JohnnyEssex here with a tidy 2.0 E85 with turbos / engine swaps etc...that if truth be told ended up spending more than a low mileage M Coupe

As a pub beer chat yeah, reality...

 

[BMWZ4MC]

Or as it turned out:

There was once a guy called JohnnyEssex here with a tidy 2.0 E85 with no turbos / no engine swaps etc...that if truth be told ended up spending more than a low mileage M Coupe

...and was still left with a 2.0 :wink:

 

[MrPT]

Or as it turned out:

There was once a guy called JohnnyEssex here with a tidy 2.0 E85 with no turbos / no engine swaps etc...that if truth be told ended up spending more than a low mileage M Coupe

...and was still left with a 2.0 :wink:

He wasn’t even left with it. Someone pulled a fast one!

 

[Jembo]

Or as it turned out:

There was once a guy called JohnnyEssex here with a tidy 2.0 E85 with no turbos / no engine swaps etc...that if truth be told ended up spending more than a low mileage M Coupe

...and was still left with a 2.0 :wink:

He wasn’t even left with it. Someone pulled a fast one!

I thought he got it back eventually... after very painful times

 

[MrPT]

Or as it turned out:

...and was still left with a 2.0 :wink:

He wasn’t even left with it. Someone pulled a fast one!

I thought he got it back eventually... after very painful times

Yeah he got it back, but it was all a bit horrible.

Similar to the emotional trauma of converting a Z4C to a Z4MC, I’d imagine.

 

[Ewazix]

Or as it turned out:

There was once a guy called JohnnyEssex here with a tidy 2.0 E85 with no turbos / no engine swaps etc...that if truth be told ended up spending more than a low mileage M Coupe

...and was still left with a 2.0 :wink:

He wasn’t even left with it. Someone pulled a fast one!

It was a tragic tale, I recall he was lured by some guy working in a barn in the wilds of Norfolk who said he could turbo and trick the 2.0 (which has never been done before) and ended up being b0m raped for several £k, eventually getting his car back in pieces. A sore experience

I'd just trade up to an ///M TBH, it sounds like a FrankenM is going to be a technically difficult money-pit and hard to re-sell.