EXPRESS DELIVERY
Forget everything you thought you knew about Porsche’s ‘chocolate’ M96 engine. This 300,000mile 996 Carrera 4 and its race-engineer owner are rapidly recalibrating decades of horror stories and thousands of forum posts...
A 300,000-mile 996 that earns its keep delivering historic race car parts across Europe
Forgive the pun, but everyone surely knows the score when it comes to Porsche’s M96 engines. Imploding intermediate shaft bearings leading to catastrophic knock-on damage. Open-deck bores with a penchant for going oval and spitting out ‘D’-shaped chunks of cylinder liner. Leaky RMS seals. Cracked heads. Snapped chains. Oh, and the minor matter of scored bores.
While the list goes on and on, the implications are always the same. The M96 engine debuted with the 986 Boxster in 1996, found its way into the Type-996 911 the following year and was tweaked to create the M97 upgrade that eventually powered the 987 and 997 facelift cars right up to 2009. And it is irredeemably, unforgivably chocolate. Indeed, in many ways it actually got worse over time. The first of two IMS updates was, if anything, more failure prone than the original bearing design, and bore scoring reached epidemic proportions with the later, larger M97 engines.
At least, all of the above is the usual refrain and the received wisdom that’s developed over the last 20 years. But is it entirely accurate? Recently, a more nuanced narrative has begun to emerge regarding Porsche’s first attempt at a fully water-cooled flat-six for the road. Maybe, just maybe, the M96 isn’t so bad after all. The mega-mile 996 Carrera 4 you see on these pages is surely the poster car for that alternative version of reality. Not only does its physical bearing ooze with weapons-grade purpose. It just so happens to have well over 300,000 miles on the clock, the vast majority of which were accrued courtesy of the original 3.4-litre M96 engine, including the original IMS bearing and indeed the original gearbox. How do you like them apples, air-cooled aficionados?
That huge mileage, however, is just part of this very particular Porsche’s truly unique story. Conceived primarily to sustain high speeds over very long distances and packed with bespoke features and technology, there is surely no other 996 quite like it. Created by a race engineer based in the UK, the character of his company's work is extremely specialised and for that reason he and many of his clients prefer to keep a low profile and remain anonymous. But if we tell you that his workshop is not only full of V10-era Formula One cars being prepped for competition by ex-f1 engineers, but also capable of doing everything from engineering gearbox internals to prototyping and 3D printing alloy components and developing engine management systems for major OEMS, you’ll get a rough idea of the character of the operation. These boys are fairly serious.
In which context, it’s pleasing to report our man is not only self-effacing but also carries himself with an extremely easy humour. Let’s just say when you definitely know what you’re doing, you often don’t feel inclined to prove it. So why did he choose the 996 and what exactly is its remit? Long story short, the car is a glorified delivery van, albeit a fairly quick one.
“We operate all over the world, but most often in Europe,” he explains. If something breaks on one of the race cars his outfit is supporting, it’s the 996’s job to deliver a
replacement, pronto. “We do have a plane and I can fly, but we’re often limited by regulations with components like lithium batteries.” In short, for things that can’t be put on the plane, when there isn’t an airfield within a few hundred kilometres of the circuit in question or if it’s really urgent, it’s time to roll out the 996.
“It gives us the option to get to places quite quickly. It’s used as a chase car and a fire tender occasionally. But for the most part, it’s a road car and it’s set up as a road car, only with the fuel capacity to do 600 kilometres in one go.” Achieving that requires a trick fuelling system, just one of many modifications that enable the global-trotting remit. But hold that thought. First, what is it about the 996 that makes for the ideal starting point for this type of project? For starters, packaging. “It’s little. It’ll go down narrow sideroads in Italy,” our man explains, “but it will do that without being massively compromised in terms of comfort. It’s a nice place to sit and do 120mph.” The Carrera 4 spec means it’ll do that in all weathers, too.
Contrary to the 996’s reputation in some quarters as a cost-cutting exercise gone too far, the car’s engineering is also a factor. “A lot of the ways the 996 is put together is very ‘race car’. Things like the engine installation, the way the suspension is built – it gives you a lot of options. You can easily add strength where you need it. The Carrera 4 shell is shared with the race cars and is very stiff, too. This car is 20-years and 500,000km old, but if you lift it on one corner, you’ll lift three wheels. That’s a relatively rare thing, especially with something as well used as this.”
An example of adding strength involves the front brakes and uprights. The front calipers started as Cayenne items and have been machined and converted from lug to radial mount. That the ABS has also been recalibrated to suit the new brake setup is an indication of both the thoroughness of the specification and the technical capability brought to bear. But the really clever bit is the uprights. They’re laminated in carbon-fibre. “The factory uprights are hollow-cast aluminum. They’re super-light, but not the strongest things. Wrapping them in carbonfibre significantly increases their stiffness and stops them from cracking.” Nice.
Back to that increased fuel capacity. Pop the C4’s standard 996 bonnet and you’re presented with a veritable Aladdin’s cave of trinkets, tweaks and gadgets, all designed to help maintain high-speed, on-road uptime. Most obvious is the 33-litre fuel cell with an easy-access fuel filter situated directly on top. Combined with the standard 996 tank, total fuel capacity is 101 litres. That’s handy, because this 996 hasn’t only been just about
everywhere in Europe. It’s been just about everywhere else, too, from the Arctic circle right at the very top of Norway to crossing the Sahara desert.
Operating so far afield, fuel quality cannot always be relied upon and the massive replaceable filter atop the auxiliary tank can make all the difference. What’s more, the primary tank has redundant lift pumps and a collector, while the secondary tank has a low pressure transfer pump to feed the main tank once it drops below 50 per cent capacity. That approach maintains better control over weight distribution as fuel is burned. It’s also possible to return fuel to the secondary tank in order to fuel another vehicle. Yup, pretty much every eventuality has been considered.
Next up is full data telemetry. A wide range of data is collected and the car can automatically fire off emails if a fault has been detected. The list of kit is extensive, but highlights include an AIM Evo 5 data logger, an AIM GPS08 GPS/GLONAS receiver for positioning, 2D laser ride height sensors front and rear and a tyre pressure monitor with incabin display. Another very funky feature involves the self-sealing tyres. They’re filled with ballistic-grade self-sealing gel, the same stuff that armoured cars run and capable of coping with up to 9mm rounds. “The idea is that it reacts very quickly with heat and air,” our intrepid engineer explains. “So long as the tyres are warm, it forms a plug and seal when coming into contact with open air. We’ve arrived back from Monaco with seven nails in one tyre and not even set the tyre pressure monitoring system off, it loses that little pressure.”
Elsewhere, this 996 has a custom lightweight Facom tool kit and spares package, 48-hour emergency food and water rations, the ability to wade in half a metre of water, extensive underbody protection and a 3.375 litre AFF fire suppression system designed to defeat fuel and engine fires long enough to safely exit the car. Still not quite enough? How about solid titanium brake and steering lines, dash-mounted shift lights that also display the throttle mode and an onboard 240V inverter. If all that gives the likely impression of an overweight lump, the reality is remarkable. Despite all the trick bits and added hardware, this unstoppable 996 tips the scales at a little over 1350kg. It’s scarcely more than 10kg heavier than a Type-996 911 GT3. And remember, this is an all-wheel drive Carrera 4 with a propshaft, forward diff and an extra pair of drive shafts.
Needless to say, plenty of work has gone into packaging and weight reduction. Aside from aircon delete, the sound deadening has been reduced, numerous titanium fasteners are used with excess thread removed, multiple suspension components have been upgraded from cast solids to machined hollow items, the exhaust system is much lighter than standard and the lithium battery alone saves around 15kg over the standard leadacid lump.
At this point, of course, we’ve barely touched on the kind of kit you’d normally expect to find in a modified 911. You know, stuff like upgraded suspension and a fettled motor. Don’t panic, that’s all present and accounted for in forensic detail. The dampers are Ohlins R&T with custom valving and spring rates to suit the car’s unique specification, plus redesigned lower and upper mounts. The top mounts, meanwhile, are all spherical and specific to the car. Likewise, several other elements of the suspension are fitted with spherical bearings and both the track rods and steering rack mounts have been strengthened.
Then there’s that mega-mile M96 engine. Recently rebuilt, it managed over 300,000 miles before being opened. Most remarkable is the relatively low level of maintenance required over that mileage. “It had some new variable valve actuators. We do the water pump every year, because they’re a common failure point. We also refresh the exhaust manifolds every year. That is pretty much it.” Indeed, the gearbox is still the original, thanks in no small part to regular oil changes.
“A lot of the problems on these cars are well overblown,” he explains. “We run regular oil analysis at every oil change and the only reason we pulled the engine apart was because the copper count went up significantly. We thought we were getting to the end of the bearing life. But, actually, a piece of material had broken away from the timing chain guide and embedded itself in number one bearing, causing it to wear. At that point the bores were still within Porsche spec – at the top end of wear, admittedly, but still just within spec.”
Remarkably, the crank was mostly fine and has been reused with only a slight polish required. The rest of the engine was rebuilt by well-known specialist Autofarm, often using standard spec items like valve springs. After all, “if you’ve got something that’s run half a million kilometres and your target is durability, you’re pretty sure that’s got the durability in it.” The exception involves new pistons and liners that achieve a larger 3.7litre capacity and around 360hp.
The aim was a “nice, torquey road car engine that doesn’t need spinning to 8500rpm to perform. It’s GT3 power without having to work so hard for it.” It’s not a huge surprise to report that the motor delivers precisely what it says on the tin. A quick run out on the public highway reveals an awfully torquey motor. We’re told it pulls cleanly in 6th gear from 70mph all the way to 180mph and don’t doubt it. As for the rest of the car, thanks to those Ohlins dampers and all the other suspension upgrades, it boasts a sweet and fluid chassis. It’s not hard to imagine doing some serious autobahn miles in this car. Not hard at all.
Of course, doing a car like this full justice on paper is almost impossible. The project file alone would fill these pages. But then brevity rather suits the no-nonsense character of this car and its owner. As he rather understatedly puts it, “it’s not pretty, this car, but it’s got a story.” What a story that is and surely one that comprehensively implodes several decades’ worth of preconceptions. An early 996 as the weapon of choice for notching up truly intergalactic mileage? You heard it here first. PW
At that point the bores were still within Porsche spec