2004 BMW Z4 3.0

2004 BMW Z4 3.0

Author
Discussion

g3org3y

15,144 posts

146 months

Saturday 6th July 2019
quotequote all
What a great thread. Well done on being able to do so much of the work yourself. clap

Court_S

2,562 posts

132 months

Monday 8th July 2019
quotequote all
Good work on the brakes, they look fab.

Your thread got me looking at cheap Z4’s the other day. Luckily we don’t have room for a third car. I’ve got a real soft spot for these and think they’ve aged very well.

cerb4.5lee

15,194 posts

135 months

Monday 8th July 2019
quotequote all
Really enjoyed reading your thread and I'd love to be as handy with the spanners as you. I love what you have done with the car. thumbup

Jakg

Original Poster:

2,402 posts

123 months

Friday 19th July 2019
quotequote all
Jakg said:
I've just got to remember that this is supposed to be a cheap entry into the world of convertibles and resist the urge to start modifying it...
This really isn't going well!

It's got standard M-sport suspension, but is 15 years old. It could do with a refresh, but a Bilstein B8 kit is about £600, and OE parts even more so.

I found this on eBay and knew I had to get it.



KW V1 coilovers, about 4 years old - £1,200 RRP! I got them for a fifth of that.

First off, big shout out to my latest toy - a big battery impact gun.



I've tried some cheap Lidl ones and they were... ok. I use a Bosch impact driver a lot but it doesn't have the power to crack stuff off. This thing claims 1600nm of torque so I shouldn't have that problem...

The shock bolt looks looked like it might be a problem, but came out with no effort at all.

In fact getting all the old suspension out was very very easy - way easier than my Megane. Only annoyance was having to remove the rear "parcel shelf" to get to the rear shocks which is very awkward from inside the boot.





Out with all the old stuff.

With the suspension out I also had a look at the rear arm mountings - the thing the socket is on in this picture



They didn't seem to have any play on the car but I changed them anyway.

Officially you need to remove the arm but if you bend back the dust shield (and remove the disc obviously) you can get to them.

I've done this in the past on my MG ZT and really struggled - the threaded rod + washers did nothing and I had to use my hydraulic puller.

This time there wasn't enough access for the puller so I had to settle for my ball joint press - basically a big C clamp. 32mm 12-point socket as a pusher and a bit of tube on the arm itself.

It was a bit of a struggle, ended up using the impact gun to get them in / out and i'm not sure the press would do it again but got them all out.



The upper mountings are ball joints (on the left in the picture).
The lower ones are just rubber bushes (on the right).



The M3 / Z4M uses the ball joints on the lower, too - but the rest of the Z4 / E46 range don't, apparently for cost reasons.

Off the car it was clear the ball joints had a little play and the bushes looked past their best.

I fitted ball joints in both the upper and lower parts, and fitted them using the press in reverse.



Don't look exciting fitted though.

I also fitted rear strut reinforcement plates, although I'm not sure if they are any good



My assistant has a lot to learn



All back fitted



I replaced most of the nuts and bolts I touched, too, as well as the top mounts.

I also had a go at adjusting the handbrake as I had to wind the shoes back when I took the disc off and didn't count how far I'd done it - it's a little better now but it's still rubbish. I think the mechanism on one side might need an overhaul.

Had it aligned and everythings back to where it should be, except the rear camber that won't adjust on one side - I had a go (to try at least put it back to what it was before) when I was putting it together and couldn't do it, either. So I'll get a new eccentric bolt / nut etc and try it again.

I also managed to get into an argument at the garage as apparently the rubber bushes at the back keep moving when they tried to free off the camber bolt.
I explained they are ball joints, but apparently they aren't - they are rubber bushes. They helpfully pointed out ball joints have a ball in them and move around.
What would I know, I only fitted the things...

Ride height wise my aim is basically stock - I've had a go but need to let it settle before finishing it off.

Early days but it drives better - I was expecting horrible stiffness but it rides better than my Megane on stock (refreshed) suspension.

Edited by Jakg on Tuesday 29th October 22:19

Jakg

Original Poster:

2,402 posts

123 months

Saturday 2nd November 2019
quotequote all
Boring update:

When I got the car I used a simple vent mounted phone holder. It was rubbish and fell off all the time.



Fitted a Brodit mount instead - not cheap but holds it perfectly steady.

I also fitted a USB charger in the dash and ran a wire out to charge my phone in addition to the USB socket the previous owner put on the centre console.



Also fitted an LED strip in the boot as the boot light is rubbish.



Also refurbished the DISA valve with one of the kits - not convinced the risk as great as quoted but it wasn't expensive.

Struggled to remove the old plastic parts and ended up drilling them out - pillar drill coming in handy again!


Jakg

Original Poster:

2,402 posts

123 months

Saturday 2nd November 2019
quotequote all
Slightly more exciting update - did my first trackday.

This was at a very wet Snetterton.

Went out on the sighting lap and expected a slow convoy to assess the track - but the pace was quite a lot quicker than expected. So quick, in fact, that I put too much effort on reading the track and ended up spinning. Quite embarrassing...

https://youtu.be/WpevFZe3HYk

For the rest of the day I decided to leave the stability control in the "Dynamic Traction Control" setting as I didn't spinning it again, or worse still wrecking it.

To start off with I found this rather frustrating as you could feel the systems grabbing each corner of the car's brakes and unsettling it, but as the day went on I got much smoother and found the intervention much less. Net result was no crashes - unlike several other drivers on the day.

Car handled the day well, although being wet you would expect to have a much easier time.
Brakes performance was consistent throughout the day and no fade - which is to be expected with a light(wish) car and large front brakes.
Did get a "warped disc" sensation after about 15 minutes on track which went away after the car cooled down each time - I think that perhaps the (unknown brand) rear pads were overheating from the traction control activations? Not sure.

One of my last laps is here - https://youtu.be/rKqoRsTTC5A
In advance, I'm aware it's very slow. I was focusing on getting the lines and flow right (and not spinning!) not setting fast laps. And I didn't gun it down the straight as I didn't see a point.







In hindsight, for the track conditions my Megane would've been a *much* better car to take. There's always next time...

xjay1337

15,000 posts

73 months

Saturday 2nd November 2019
quotequote all
Grats on spinning on a sighting lap lol.
Usually you get sent home for that.
Snetterton is incredibly slippy in the wet. Great fun in the dry though. And lots of run off if you want to do skids. :-)

Jakg

Original Poster:

2,402 posts

123 months

Sunday 22nd December 2019
quotequote all
The car has always used oil, which seemed to be a characteristic of the engine.

Since replacing the rocker gasket and swapping to 5w40 oil, it's been much reduced, but is still there.

The next thing on my list was to swap the CVV - crankcase ventilation valve, PCV, oil separator, breather - whatever you want to to call it.

There are two kits - the "regular" valve and a "cold climate" one that has extra insulation to reduce condensation at low temperatures.
The "cold climate" kit wasn't much more and I bought all the new hoses to go with it, too.

Even from the right angle with the engine at rest you can't see it at all.



After removing the inlet pipework, dipstick, airbox, throttle body & lots of wiring, I removed the old unit using brute force.

Sludging wasn't too bad I don't think, but I'd already destroyed the old one getting it out so onwards



Unfortunately, getting the new unit in was much, much harder.

Not only was it more difficult to delicately install the new part, but the insulation jacket around the CVV makes it much larger.

The guides all said it was do-able with the inlet manifold in situ, you just had to angle it right, so after a couple of hours I tried to be a little more forceful and then, ooops....



Broke the new one!

The guides specifically say if a garage is saying the inlet manifold needs to come off, they are scamming you etc, but I just couldn't do it. So off with the inlet manifold.





Then it was much easier (but still not really "easy) to get the new unit (arrowed) installed. Even if I'd of got it installed in situ, I dread to think how I would've connected the hoses up.



With the inlet manifold off, I needed to think about the inlet manifold gaskets



Not really that bad, although there's some small split on one edge, so they got replaced.



I also cleaned the throttle body and replaced the dipstick o-ring at the same time.

Put it all back together, started it up and after a little hesitation was back to normal. Feeling triumphant, reverse off the drive and the check engine light comes on...

Drove ok but when scanned with INPA had a fault for the tank vent valve and the oil pressure sensor.

When looking online I could see something looked a little different - I'd plugged them in the wrong way round!

Every connector on the wiring I'd removed was keyed differently - except for two sensors right next to each other, with identical connectors.



Swapped it over, cleared the errors and it looks ok so far.

Edited by Jakg on Sunday 12th January 00:15

Jakg

Original Poster:

2,402 posts

123 months

Sunday 12th January
quotequote all
Service history said the aux & ac belt were last changed in 2012 and from above they looked a bit cracked.

Initially was struggling to work out how to get them out, but after removing the undertray and working from below it became pretty obvious.



Belts were actually ok after all, but replaced anyway - dated 2011 so time for a replacement.




g3org3y

15,144 posts

146 months

Sunday 12th January
quotequote all
Jakg said:
Important to keep your energy levels up when you're working on the car. Cocktail sausages FTW. hehe


Jakg

Original Poster:

2,402 posts

123 months

Sunday 12th January
quotequote all
g3org3y said:
Important to keep your energy levels up when you're working on the car. Cocktail sausages FTW. hehe
They're for my assistant. He gets distracted otherwise.


shalmaneser

4,068 posts

150 months

Sunday 12th January
quotequote all


Looking at this pic I reckon a strut brace would really help the stiffness of the chassis! The scuttle is a lot further back than in the coupe - I'm sure there's much more flex.

Enjoying this thread, you're building a lovely car here.

g3org3y

15,144 posts

146 months

Sunday 12th January
quotequote all
Jakg said:
g3org3y said:
Important to keep your energy levels up when you're working on the car. Cocktail sausages FTW. hehe
They're for my assistant. He gets distracted otherwise.

biggrin

d_a_n1979

1,085 posts

27 months

Sunday 12th January
quotequote all
Really good thread OP smile Great to see you doing most of the work.

On both previous E39 530i cars, I’ve removed the inlet mani to do the CCV kit, just makes life easier and it can all be really well cleaned too with it out of the way. Like you, new Elring gaskets fitted and no more issues wink

I did the DISA on my current 530i touring and the thing was hard to get apart, I don’t have the luxury of a oiled drill, so used brute force to get it apart to rebuild it. That plastic cog is a bugger to get off in one piece!

rooflesstyrant

31 posts

73 months

Wednesday 22nd January
quotequote all
Are you still on runflats even after the suspension upgrade and the trackday? Probably need a dry track day or two to wear out those tyres.

Jakg

Original Poster:

2,402 posts

123 months

Wednesday 22nd January
quotequote all
rooflesstyrant said:
Are you still on runflats even after the suspension upgrade and the trackday? Probably need a dry track day or two to wear out those tyres.
I was kind of hoping the track day would've killed them, but it was too wet! I have some fronts in the right size in the shed waiting. I'm sure I can find a way to wear them out...

Mr Tidy

11,344 posts

82 months

Thursday 23rd January
quotequote all
shalmaneser said:


Looking at this pic I reckon a strut brace would really help the stiffness of the chassis! The scuttle is a lot further back than in the coupe - I'm sure there's much more flex.
A great build, but as a serial Coupe owner I really don't think the scuttle is placed anywhere different on an E85 to an E86.

BEN99W

73 posts

194 months

Saturday 25th January
quotequote all
Nice thread. I've always had a soft spot for the Z4 and can relate totally to your initial intention not to modify anything and then end up doing loads. Looks like you've got a decent set of tools which helps.

I really like the brake and suspension upgrades you've done and hope you feel your efforts rewarded with an improved drive. Those Z4 alloys are my favourite wheels fitted to any car and those brakes only help to enhance the looks.

Ben

Jakg

Original Poster:

2,402 posts

123 months

Tuesday 10th March
quotequote all
NorthernSky said:
Oh and as others have said, treat the car to new tyres all round and get them aligned, ditch the runflats. Hopeless on UK potholed roads!
Sticks. said:
I kept my rfts for quite a while. Although getting rid is an improvement, it's nothing like an E46 on mismatched tyres.

Not just tramlining though, the car felt less unsettled my small bumps, more planted, almost lower. In short, like you'd have expected it to.
Braintax said:
Like the earlier poster in this thread, my car's steering would tighten up in the summer and it really, really wasn't pleasant. As others have mentioned, the best thing I ever did was to switch to non-runflat tyres, I went through Falken FK452s and Uniroyal Rain Sport 3s, both of which were pretty excellent and really transformed the car.
CousinDupree said:
Great progress. Can't help but think you are still missing a trick though.

Fitting a new set of good tyres is the most cost effective improvement you can make, especially if you are junking runflats.

It's all a bit of a crapshoot until you do that. A new set of F1 Assym 3s transformed my Z4 3.2. Steering, ride, traction, tramlining....

Not expensive either!
rooflesstyrant said:
Are you still on runflats even after the suspension upgrade and the trackday? Probably need a dry track day or two to wear out those tyres.
Can you sense a consensus?

Runflats have gone, now on a set of Vredestein Ultrac Vorti's. Used Vredesteins for years and really rate them.

Tramlining disappeared, and ride is better - but not great - I think the coilovers are a little too stiff for me.

Getting the tyres fitted was a bit of a disaster, though. I've used the same tyre fitters for years - they used to do decent prices on tyres, but they started quoting silly prices (i.e. £50 a corner more than I could buy online) but were happy to fit ones I supplied. A while ago I went in and the boss served me, who moaned the entire time about how I was supplying tyres and it left a really sour taste. But later they were fine.

Four tyres won't fit in a Z4 (I could get one in the boot, one in the front) so a friend dropped the other two off and I got served by the boss again - as soon as I mentioned I had tyres, he signed and demanded to see the car, see the wheels, see the tyres, moaned about me supplying tyres and was just generally difficult. And then said it'd be £20+VAT a corner - normally it's £10!

If I could've put the tyres back in the car I'd of left then and there but I was stuck so had to put up with it.

2 and a half hours later the cars done, and I immediately notice some damage on the wheel. The boss is a bit evasive about letting me look at the car before paying and when I mention what I've seen, out comes the sighs again

By fluke I had a picture of the wheel from the other day



And now



At the top there's clearly a fresh bit of impact damage that's gone through the lacquer, and then the rest of the lacquer has started to peel.

They couldn't claim they hadn't done it, so then the paint finish on the wheels was blamed. Couldn't really argue the point so now I'm stuck.

Overall, left a sour taste and definitely won't be going back.

Moving on...

MOT failed on a drop link split boot so that got changed

Old one



Probably could just've reseated the boot but I've got this far



Always annoying that aftermarket parts use different sized bolts to standard ones - half way through an 18mm spanner had to be slimmed down to counter hold.



Shiny new one fitted



Got a chip in the windscreen and it turns out I don't have windscreen cover - ooops.

AutoGlass wanted £70 to fix a chip (?!?!) so I'd planned on leaving it but I saw someone mention the cheap repair kits and thought I'd try it.



Difficult to photo the before / after but it's done a fantastic job - the piston pushes the resin into the spider cracks so they disappear and there's only a faint mark visible of the centre of the chip. Not bad for a fiver and 20 minutes.

Scanning with INPA showed a fault code for one of the cylinder so after swapping coilpacks around to diagnose, two new ones were fitted.

Finally, it's got another driveway friend



I now have two very different 6 cylinder BMWs - https://www.pistonheads.com/gassing/topic.asp?h=0&...

Also, you can tell I really need to wash cars more often.

Mr Tidy

11,344 posts

82 months

Wednesday 11th March
quotequote all
That's some impressive spannering OP!

And welcome to the two world of owning two 6 cylinder BMWs. thumbup I've been doing that for just over 5 years now and there isn't anything I would rather have.