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Hi, I'm a newby. Found 5Life after discovering my rotten rear

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#21
Antioxide

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Hello Mark and Garffey,

 

Again, thanks for the welcome. Sad to hear that the crash structure rot is endemic to NC's. What about the front brace bar? I've not yet summoned the courage to tear down the front end.

 

Interested to hear about the alignment. When I bought the car at 6k miles it had a tiny amount of kerb rash on the rims. I assumed that this was the cause of the visibly uneven tyre wear. A 4 corner tracking exercise revealed that the alignment was about the same as a Tesco shopping trolley! I felt vindicated - and had the rims refurbed! Part of the current upgrade project will be to fit 7.5" OZ rims with 5mm hubcentric spacers. The spacers will be necesary to ensure rim/caliper clearance. Yes, I've already checked the security of this change. I'm still getting almost 6 turns on the wheel nuts, obviating the need for extended studs. Although only essential on the front I'm fitting spacers all round in order to maintain matching track width.

 

Antioxide


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#22
Steveti

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Hi AO,

 

I think to say that crash structure rot is endemic to NC's is overstating things a bit, the front and rear bumpers (under the plastic panels) do tend to get some rust on them but I've yet to hear of their actual "crash structure" ergo ability to cope with a shunt being compromised, they are also made of a high tensile mild steel, hence the high pitched ping they produce when tapped with a hammer or similar. Sure they can get a bit rough looking but never yet have I heard of or seen one that has been so rotted that it would crumble in an accident, remember all car manufacturers must design in safety factors to account for ageing and all the associated processes, work hardening, corrosion etc.

 

I have had my own bumper covers off and yes, there was some corrosion present but nothing that removing them, cleaning them up, applying a good rust protector - in my case Dinitrol would quickly stop in it's tracks. Also the location of the bumper units keeps them pretty dry and protected from salt.

 

The NCs main area of concern for serious integrity compromising rot is the area at the front edge of the rear wheel arch and behind the door. As is the case with both the NA & NB there is a fairy complex labyrinth structure behind the panel skin in this area, it's purpose is of course to provide much of the strength of the body due to the lack of a structural roof. This area is the main one to really watch.

 

My own NC was subjected to a full pro Dinitrol treatment at around 3-4 years old and I tend to pop a borescope in various areas, the area mentioned, the sills and a few other sections of the chassis on an annual basis to keep tabs on how things are looking. So far it's all sound but again I tend to load more Dinitrol in there when I do the inspections. For what it's worth a borescope with good enough resolution can be had for under £50 on Amazon or the likes.

 

In many cases what you see on the subframes and other suspension components whilst not pretty and really unacceptable on any modern car does tend to be surface rust and again a proper pro rust proofing treatment will see you alright for a while to come.

 

After my last MOT test in November last year the tester commented that the car was indeed "mint" underneath. It may not look the prettiest after the final black wax treatment is applied but it serves a purpose.

 

Incidentally, the newer treatments should not be confused with old bitumen based treatments that could split and allow moisture to sit in pockets between the treatment and the metal meaning your P&J could rot away unseen, most newer treatments are self healing and actively repel moisture.

 

I hope this helps.


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#23
Garffey

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Hello Mark and Garffey,

 A 4 corner tracking exercise revealed that the alignment was about the same as a Tesco shopping trolley! I felt vindicated - 

 

And quite right too :thumbsup: ....Glad you've 'ticked off' the alignment, and to think many owners just think 'that's how they are'.....a little more corrosion protection and you'll have years of fun!! 

 

Enjoy.


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#24
Antioxide

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Hi Steveti,

 

Thanks for the heads-up. Whilst I've already made a start on some of the treatments that you specify I think I would be better advised to leave it to the professionals. Are you allowed to name the company who sorted your Miata? An endorsement goes a long way! My comfort zone is dealing with the nuts and bolts.

 

Antioxide


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#25
Steveti

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The company I used was called Preserve & Protect just over the other side of Glasgow.
Most if not all of these places are not franchises but rather independent outlets who simy set themselves up in this game. I was recommended P&P by word of mouth, this may be the best way to go for your own area.
A quick Google for vehicle underbody protection specialists should yield results. Go for the likes of Dinitrol or a Bilt Hamber specialist though, Waxoyl and some of the more traditional brands are a bit old hat these days.
Good luck.
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#26
Steveti

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Just spotted that you're considering wheel spacers, 5.5mm too. Never been a fan of spacers for many reasons. That geo set up you have had done will be thrown well out for a start.
My preference and in deference to one of the most highly regarded MX5 tuners, Keith Tanner of Fyin' Miata in the states and his excellent book
https://www.google.c...R6q9dioKG4xP2Ku
Is to go for the 7.5" rims but rather than put spacers in, get a set if wheels with a smaller offset. The standard offset is 55, you can easily go to 45 as I have done, 40 at a push without introducing any odd handling characteristics or tyre rubbing on the arches, this will still widens the track but negates the need for adding in additional components and the obvious extra unsprung mass it will also place less strain on the wheel bearings and suspension components and of course won't take up any of the stud thread.
The geo would of course still need a reset as the car will sit quite differently on a wider track.
It's all personal choice but I personally would never fit spacers when a wheel with a smaller offset will do the same job but a a one piece item and I'd never be pushing hard with spacers fitted.
Just my thoughts after much research for my own '5 and a good read of Mr Tanner's 'Bible' for the MX5.
Hope this is of some use and interest.
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#27
Antioxide

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Hi Steveti. Thanks for the further input.

 

Ahh... I actually bought the 5mm spacers together with a Wilwood 4 piston Little Big Brake Kit from Flyin' Miata! I had planned to get the upgrade (stock diameter) rotors from EBC but they were out of stock so I have drilled/slotted Rotinger rotors instead. Rim clearance with the Wilwoods is allegedly marginal - Flyin' Miata advised at least 3mm spacing but with the planned later change to 7.5" OZ rims I felt that 5mm was 'belt and braces'. The reason for the brake upgrade is twofold... as soon as other work is completed the car will be shipped to BBRGTi for their normally aspirated 200 bhp conversion. Secondly, I have a dislike of single pot caliper systems. Whilst they're fitted as standard to some upmarket performance cars, my E39 included, they're primarily designed for cheapness. Yup, I acknowledge the fact that the geometry will again require attention... so be it.

 

With regard to the Dinitrol protection, I feel that word of mouth personal recommendations are better than random Googling. My instinct is that body protection can be cowboy territory. Can anyone recommend a firm in the Midlands?


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#28
Steveti

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No worries always happy to pass on personal experience.
FWIW I've never found the original brakes lacking even with 260+ bhp on tap. I've had it round Knockhill a few times now and in all honesty even on stock pads and 9-10 laps in and pushing it well into 3 figures before the hairpin, they provided more than enough stopping power with no fade or loss of pedal, that said they we're a tad smoky and smelly after that punishment. As you will know Knockers is a task master of a track and because of it's short length and come corners will show up shortfalls in the brakes. That's not to say I wouldn't go for a nice big brake set up if I felt the need. Interesting that FM are recommending spacers though especially after reading his book but equally each situation can require different solutions. I'm sure BBR also offer Wilwood big brake kits which might have saved you some cash due to duty, taxes etc unless your friends in the states.... gifted them to you :-)

Completely get where you're coming from re rust treatment recimendatons, word if mouth is always the most potent recommendation.

Looking forward to hearing more of how your build comes in.

Lockdown etc allowing i intend taking the GM down to BBR to upgrade the Koni/BBR suspension to the DFV Ohlin kit later this year, that's the plan anyway.

Cheers,

Steve.
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#29
Paulo

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Hi Steveti. Thanks for the further input.

 

Ahh... I actually bought the 5mm spacers together with a Wilwood 4 piston Little Big Brake Kit from Flyin' Miata! I had planned to get the upgrade (stock diameter) rotors from EBC but they were out of stock so I have drilled/slotted Rotinger rotors instead. Rim clearance with the Wilwoods is allegedly marginal - Flyin' Miata advised at least 3mm spacing but with the planned later change to 7.5" OZ rims I felt that 5mm was 'belt and braces'. The reason for the brake upgrade is twofold... as soon as other work is completed the car will be shipped to BBRGTi for their normally aspirated 200 bhp conversion. Secondly, I have a dislike of single pot caliper systems. Whilst they're fitted as standard to some upmarket performance cars, my E39 included, they're primarily designed for cheapness. Yup, I acknowledge the fact that the geometry will again require attention... so be it.

 

With regard to the Dinitrol protection, I feel that word of mouth personal recommendations are better than random Googling. My instinct is that body protection can be cowboy territory. Can anyone recommend a firm in the Midlands?

 

 

I see you plan to have the BBR 200 Bhp conversion done, I have had the said conversion done for the last 5 years now and its never missed a beat. Whilst not giving you that pushback in the seat or torque that the turbo or supercharger can give you it still can put a smile on your face from 5,000 rpm onwards. I would recommend the full exhaust package to go with it, I have the GT back box it gives a great bark when you you give it the beans but at the same time is comfortable on the ears when touring. If noise isn't a problem, then go for the sport back box. I'm seriously  considering having the BBR drive by wire (DBW) billet 45mm DCOE Independent throttle bodies (ITB’s) fitted next year. Not so much for having the extra BHP but for the naturally aspirated sound it will produce. I must be mad really, with the governments plan to do away with petrol cars from 2030 but sod them, I will be a petrol head until I go over the rollers.  :) 


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#30
Antioxide

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Hi Paulo,

Thanks for the valuable info. I'll add the exhaust upgrade to my shopping list. I must say that my choice of the slightly limited BBR 200 package is based upon a couple of prejudices. Firstly, the engine is basically a Ford Duratec and that has a reputation for a rather flimsy crank. Well, it's a Ford, what do you expect? Sadly, I cannot justify a replacement 2.5 or V engine, as encouraged by Flyin' Miata, Good-Win and others! Secondly, I'm not a fan of turbo's on non-oil burning engines - yup, my 3L Invincible came with one! As for blowers, I have a Lysholm on my manual 530i but unlike the Ford, the M54 engine is pretty much bullet proof! The E39 may not have the handling of the Miata but it has all the grunt I need. Indeed, I reckon the 6 pot Beemer M54B30 is one of the best mass production engines ever made. I'm getting on in years so the government threat to see all cars powered by Energisers does not worry me. The Miata and E39 are keepers - with care and love they'll see me out. The big mileage is taken by the throwaways, the Hilux and my wifes 1.2L shopping trolley. Keeping me extra busy are a couple of restoration projects in the workshop, a 325i SE 2 door E30 and a 'two into one' Nissan 100 NX Injection T Bar Pacific build from 2 basket cases.... there are only about 40 left so it should become a collector item... or I'll be out of pocket!

 

Your ride looks lowered, what have you done? I hear conflicting reports about Powerflex or other poly bushes for road use... can you comment?

Antioxide


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#31
boxerdog1

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Hi Paulo,

Thanks for the valuable info. I'll add the exhaust upgrade to my shopping list. I must say that my choice of the slightly limited BBR 200 package is based upon a couple of prejudices. Firstly, the engine is basically a Ford Duratec and that has a reputation for a rather flimsy crank. Well, it's a Ford, what do you expect? Sadly, I cannot justify a replacement 2.5 or V engine, as encouraged by Flyin' Miata, Good-Win and others! Secondly, I'm not a fan of turbo's on non-oil burning engines - yup, my 3L Invincible came with one! As for blowers, I have a Lysholm on my manual 530i but unlike the Ford, the M54 engine is pretty much bullet proof! The E39 may not have the handling of the Miata but it has all the grunt I need. Indeed, I reckon the 6 pot Beemer M54B30 is one of the best mass production engines ever made. I'm getting on in years so the government threat to see all cars powered by Energisers does not worry me. The Miata and E39 are keepers - with care and love they'll see me out. The big mileage is taken by the throwaways, the Hilux and my wifes 1.2L shopping trolley. Keeping me extra busy are a couple of restoration projects in the workshop, a 325i SE 2 door E30 and a 'two into one' Nissan 100 NX Injection T Bar Pacific build from 2 basket cases.... there are only about 40 left so it should become a collector item... or I'll be out of pocket!

 

Your ride looks lowered, what have you done? I hear conflicting reports about Powerflex or other poly bushes for road use... can you comment?

Antioxide

Nice selection of Beemers there , my daily is an F11 530D , last year of the F11's . Have had quite a few 330D's (E46/E91/F31) and a F31 335D X Drive and loved them all. 


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#32
Steveti

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Hi Paulo,

Thanks for the valuable info. I'll add the exhaust upgrade to my shopping list. I must say that my choice of the slightly limited BBR 200 package is based upon a couple of prejudices. Firstly, the engine is basically a Ford Duratec and that has a reputation for a rather flimsy crank. Well, it's a Ford, what do you expect? Sadly, I cannot justify a replacement 2.5 or V engine, as encouraged by Flyin' Miata, Good-Win and others!

Just a bit of info re the engines fitted to the NC's they are not in fact a Ford unit but rather a fully ground up Mazda designed engine that carries the MZR designation as does the 2.5 litre and other variants.

 

https://en.wikipedia...azda_MZR_engine

 

The reason you will see FoMoCo stamped over ancillaries and indeed on the engine internals is that while Mazda designed the MZR engine, this was at a time when Ford held a hefty stake in Mazda and Ford elected to utilise the MZR engine over a large range of their fleet of the time and thus took on the manufacturing of the engines at their plants.

 

There has been this common misconception that the MZR/Duratec engine is soft, the origins of this are really unknown although when Cosworth were developing the supercharger kit, subsequently taken on by Flyin' Miata in the States and BBR in the UK they took the time to develop the software and enable the OEM ECU to be flashed to run with the supercharger with less explosive results. Neil at BBR also told me that there were some aspects of the hardware that also needed rectification. 

 

The MZR/Duratec is in fact a very sturdy reliable unit, I know a few that did run the bottom ends out but this in every case they were being absolutely beasted on track and it is certainly questionable if the oil level was topped up to the full mark potentially causing oil to move away from the pump pickup on the bends causing oil starvation.

 

Further to this from 2008 onwards the 2.0 engine internals were beefed up with a number of forged components to accommodate a raised (+500rpm) and offer a bit more scope for tuning reliably to high BHP. 

 

I think it;s fair to say that the MZR/Duratec has been competition proven for many years and to the best of my knowledge can be tuned to 250bhp + in N/A form, although for the road going F/A is the cheaper route.

 

My supercharged version is 260bhp+ while BBR's current crop of turbos will give between 270-300bhp using standard internals and also offer a massive step up in torque. 

 

Again, I hope this info is of help :thumbsup:
 


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#33
Paulo

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As Steve said, from 2008 the engine internals were beefed up and have handled the SC and Turbo upgrades with no problem at all. Yes my car has been lowered, I'm using Ohlin DFV coil overs fitted by BBR, It was lowered on koni dampers and BBR springs but with the roads the way they are and my back problems i needed a more damped set up. The Ohlins give me that, not cheap but I wanted to keep driving the 5 and this has made it more comfortable for me. My Racing beat ARBs are fitted with poly bushes and I have had no problems with the handling of the car. I'm not doing a lot of mileage so I cant really comment on their long term durability. Steve may be able to give you a better heads up on poly bushes than me.


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#34
Antioxide

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Hello Boxerdog1, Steveti and Paulo,

 

Mea Culpa... I'm guilty of over-reacting to the various web reports of Miata bottom end failure. I must say I'm pleased to discover that my fears and predudices were more or less unfounded. Indeed, It makes the 225 normally aspirated upgrade more attractive! I've not cracked the engine as it is running just fine... is the sump baffled?

 

You may notice a bit of a thread running through my personal car choices (ignore the Nissan project). I'm a firm fan of the rear wheel drive system.

 

The lowering certainly looks the business and presumably means that a front splitter would therefore be too low for practical use? I ask because a front splitter is pencilled on my shopping list as it's claimed to further firm up front turn-in. Your collective thoughts?

 

I'm starting the Rotinger/Wilwood fit this weekend. Can post some snaps if you wish?

 

Antioxide


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#35
Steveti

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The sump is baffled to a degree in as much as there is a baffle plate to contain the returned oil within the lower portion of the sump rather than splash around all over the place. So in theory if the oil level isn't overly low, there should be oil at the pump pick up all of the time.

It may not be a full race baffled sump but it should be more than enough for most uses. I know I've never seen oil starvation at any time even on hard laps at Knockhill.

Without wanting to tell anyone how to suck eggs the obvious route for anyone tracking regularly would be to go to a dry sump set up but I honestly don't think the engine particularly needs it.

 

Edit: I found these images of the 2.5 litre (left) and the 2.0 litre (Right) sumps, as you can see the 2.0 litre sump is quite well baffled. The second image is taken directly from the workshop manual and again shows that the sump is indeed baffled (or at the least slightly confused ;))

 

 

Sumps.jpg

 

 

2006_2008_engine_overhaul-18.jpg


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#36
Antioxide

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Hi Chaps,

Appreciate all the time and effort from you guys. I could bore for Britain on petrol BMW's but as you've discovered, I'm on a big learning curve with the NC. Yes, I've had it for almost a decade but until now, done nothing other than add a few enjoyable Summer miles - and service it! I have no plans to track day it, just add a grin factor to the performance and handling... as with my E39. It's nice when a grey haired old fartie in a 5 series 'mobile drawing room' or a 'hairdressers' sports car can put some manners on a juvenile in a hand painted GTi. I jest! My track day efforts are restricted to my second-childhood project! A return to the old fashioned Class 4 karting I did as a teenager, with a 1964 Villiers engined Super Shrike (I'd been searching for a Buckler chassis for years but his was as close as I could get). I think that this is where I get my handling fetish!

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#37
boxerdog1

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We could do a double act , I'd bore Britain on Diesel BMW's  :)   Seeing your first post of the bumperless NC reminded me of the dinitrol exercise I undertook on my recently departed Honda S2000 . It was 20 years old with only 44000 miles when rear bumper was removed and all the exposed panel needed was a wipe over with an ACF50 soaked rag .  Most of the bottom end of the Honda was also in great condition as it had been cosseted all its life although I still gave it a full going over with Dinitrol products . Was going to be a keeper until a 10 year old R171 350 SLK with less than 15000 miles attracted my intention !

 

y0n3rX8l.jpg


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#38
Antioxide

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Hi Boxer,

 

I'll just add this two my BMW resume and then get off the soap box! The current E30 and E39 beemers represent numbers 5 and 14 in my varied lifetime collection! In the background of the attached you'll see a blue 1995 320i (6 pot) Touring (it covered almost 220k miles and died from A pillar rot) and in the foreground, my (then) pride and joy, a near concours fully loaded manual E46 330i Touring in drug dealer gold. It got T-boned to destruction when a myopic moron in a Focus turned right across the central markings of a dual carriageway and lit up all my airbags. All my beeemer experience taught me to cherish REALOEM for parts identification. Why don't all the makers have such a database? Changed to a Merc eh? I've only ever had one, a W201, half leather silver 190E 2.3-16 Cosworth with the quirky but bullet proof Getrag gearbox! Auctioned it about 4 years ago for a decent profit. Despite the complimetary words issued by the muppet on Wheeler Dealers, the steering was rubbish... a form of tractor style recirculating ball. It broke 3 exhaust manifolds whilst I had it. It also had a strange throttle, it was designed to be 'dead' for the first 6-7mm of travel. It took a lot of getting used to. Ayrton Senna may have cut his racing teeth in one but for performance road driving of the time I much referred my 1.9 205 GTi!

Regards, Antioxide 

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