SOME LIKE IT HOT
Our cover car in all its glory: Darren Tompkins’ wonderful ‘Mongrel’ outlaw. Although it may have started out as a simple no-frills hot-rod, Darren Tompkinsʼ ʻMongrelʼ project quickly morphed into something far more complex. After countless hours of research, the end result is a perfect example of a ʻsports purposeʼ Porsche 911. Words & Photos: Darren Tompkins.
Heavily into the restoration of an F-Series 911, the last thing I needed, or could afford, was another project. Like many before me Iʼd been badly bitten by the early 911 bug and set out to build a ʻsports purposeʼ 911 ST-style hot-rod. I stumbled upon a very nice 1973 2.4E, but the one fly in the ointment was that my nice car was, well, a little too nice! I switched course and set out to restore the car to as close to factory perfect as I could.
Two years into the costly full-on rebuild (which was featured in issue #21 of Classic Porsche), a friend mentioned he knew of an early Porsche requiring restoration that had been stored in a garage since 1989! I was slow to respond, badly feeling the financial pain of my current project, but eventually made arrangements to view the car back in April 2012. Basic homework confirmed the car as a RHD 1972 911T Sportomatic, first registered in the UK in December 1971 and finished in Light Ivory.
At first glance it certainly appeared rough, having lost its original engine and gearbox, the seats had been changed to 924 ʻtombstonesʼ and it had gained the obligatory ducktail and glassfibre spoiler for an RS look. The car had been vandalised just prior to being taken off the road in the late 1980s, with the half-hearted repair never completed. But the car also had plenty going for it: it had new sills, wings and rear quarters that looked in good shape, but best of all it was being disposed of by a ʻmotivatedʼ seller.
A deal was done and, filled with excitement, I called Nick Fulljames at Redtek to ask what could be done with what I thought was a Japanese-spec SC engine and sent him a couple of photos. An even more excited Nick called back telling me I had a highly-desirable complete 2.2S engine with the potential to be transformed into a 2.5 short-stroke screamer!
While I started with the intention of building a budget hot rod, what followed was a three-year journey that became ever more obsessive, detailed and uncompromising in the quest to build my ultimate ʻsports purposeʼ early 911.
One of the most refreshing things with this project was the ability to do exactly as I pleased; nothing could be ʻwrongʼ. My inspiration was to come from all of the great racing 911s Porsche had ever built, along with many hot-rods Iʼd been studying. I set myself the fictional criteria of the car being built in 1978, allowing me to use any parts that had been introduced up to that point, including the Turbo brakes I wanted!
Deciding on the basic spec was easy as Iʼd been planning this in my head for a long time: it had to be lightweight, narrowbodied, with a hot engine coupled to a performance gearbox with limited-slip differential. A stripped-out interior with half cage and racing harnesses, and as many period racing features as I could muster. Oh, and not only did I want my car to look like a period racer but I wanted it to drive like one, too.
For me, Porscheʼs own period race manual ʻInformation Regarding PORSCHE Vehicles Used for Sports Purposesʼ became my Bible, with the suspension set-up lifted from the manual and the guidelines closely followed. The other thing the car had to be was orange – 1970s in your face orange!
Barry Carter was charged with the task of making the car solid and straight again. Heʼs a metalwork genius who never really promotes himself but is revered in early Porsche circles, having rebuilt dozens of early bodyshells, including my previous project. The plan was to restore the body using all steel panels, followed by switching to glassfibre panels and race car strengthening as needed. Barry suggested carrying out the modifications with a little more care and finesse than most race builders and building in a little more detail. That worked for me.
Specification for the build was for a narrow-bodied car which retained steel rear quarters and front wings, with a glassfibre front hood, engine lid and bumpers. We were to add strengthening to all suspension points, torque tube and engine mounts, along with a unique design for the jacking points. Inner door skins were to be cut out, opened and lightened with a nod towards those in the 911R, and we added twin harness brackets welded into the rear parcel shelf. The floorpan was modified to allow gearbox removal without the need for an engine drop, and final touches were the fitting of a factory-correct 40mm half roll- cage, along with an RSR-style front strut brace.
The car was taken to Barry after blasting in March 2013 with an expected four month build time. Now you never really know the true extent of a ʼshellʼs condition until you have it media blasted. This one turned out to be a horror! At this point, if I knew just what I was getting into I could never have justified the cost, and probably would never have started…
The new front wings and rear quarters had disguised what lay beneath, as the car was pretty much rotten to the core – and it transpired that the whole front nose was pushed a full 19mm to the right! Barry also commented that the car was probably on its third set of sills and heʼd never previously seen these air-chiselled off! One of the the crowning glories had to be the holes cut into the front bulkhead so that speakers could be fitted under the hood.
The ʼshell was first pulled straight and then received new front inner wings, doors were fabricated and re-engineered, the inner rear wings were lovingly recreated, a complete new roof section was added, deleting the previous sunroof, along with new sills, sections of floors and countless other repairs and modifications. The newly-fitted rear quarters were carefully unpicked at the seams and perfectly refitted onto the final solid ʼshell.
It was a full 11 months before I collected the car following more than 600 hoursʼ work on the bodyshell. It was well worth the wait, for the car returned as straight and true as the day it left the factory, although this time ʻraceʼ strengthened with a number of discreet modifications. While the ʼshell was being prepared, the engine was delivered to Nick Fulljames at Redtek, who suggested building a twin-plugged 2.5, boring out the butterflies and stacks to suit.
One way to achieve the engine size, and by far the easier option, was to fit 90mm pistons and 2.7 barrels, however the true short-stroke engines were built using 89mm barrels and pistons and this is the way I wanted to go, although these are came from FVD in Germany who stated that they were one of the last two sets available from Mahle. With such a small market and no plans to produce any more, they were a pretty lucky find.
Around this time a discussion was started on the DDK-online forum about the ingredients of an authentic ST engine. I asked Nick how mine would differ: ʻJust the induction system, reallyʼ, came the reply! This led to a whole new chapter of learning for me and I was soon to appreciate the ingredients of what made a real race-spec engine. My slippery slope was about to become a vertical drop!
A key ingredient for my engine build was now to fit the correct high butterfly injection. My search led to Ben Coles, who showed us his range of high-butterflies, racing oil filter housings, Magneti Marelli twin-spark distributors, and much more. All had been produced copying genuine original items, using the same processes and materials, and in minute detail.
My engine wouldnʼt be what it is without him; at one point I realised the distributor Iʼd purchased only fitted later engine cases. ʻNot a problem – Iʼll make you oneʼ. And thatʼs what he did, from scratch and exactly as per the original! The one item that was missing was a racing MFI pump, and I planned to modify the pump that came with my 2.2 S engine.
However, I started to explore the possibility of finding the correct 2.5 ST pump I needed. From my research on the Early 911S Registry forum in the USA, Gus Pfister at Pacific Fuel Injection, an old school MFI specialist, came highly recommended.
This is when luck and timing all play a part. After a conversation with Gus, it transpired he could supply it in just eight weeks – that subsequently turned into five weeks when I discovered a relative was visiting San Fransisco, so Gus pulled out all the stops to ensure my pump was ready in time!
With Redtekʼs engineering, machining and build skills, along with parts from Ben and Gus, I now have my ideal 2.5 ST-style engine, the spec of which is as follows: 911/02 2.2 S shortstroked, twin-plugged, bored, fully balanced, blueprinted and taken to 2.5-litres with new 89mm Mahle barrels and pistons, the barrels having been modified and gas flowed. It also has GE60 cams, Pauter lightweight forged steel con-rods, Patrick Motorsport lightweight flywheel and Sachs racing clutch.
High-butterfly induction fed by the Gus Pfister 2.5 RSR-spec pump is used in conjunction with early Magneti Marelli twinspark distributor, while a racing oil filter housing with disc filter and twin front-mounted oil coolers keep things lubricated, a 226mm small-diameter fanhousing and ʻclearʼ lightweight shrouding keeping things cool.
Custom race headers can be used with straight-through megaphones, but a twin-outlet sport muffler is usually fitted for ʻquietʼ days.
With up to 250bhp now available, the 915 gearbox required a meatier build. Mike Bainbridge was chosen to take this on, specifying a stronger side-plate with 930 bearing and bearing retainer, while the main-shaft was upgraded to an SC type with aluminium selectors. Mike suggested a plate-type limited differential from Matt Monson at Guard Transmission and, with Matt and Mikeʼs input, Guard Transmission custom gear ratios were fitted to make the most of the characteristics of the short-stroke engine. To cool things down, a Ben Coles RStype oil pump and spray bar kit was also fitted.
We set about painting the car in our own small bodyshop, this work being carried out by Richard Deegan, our bodyshop manager. Rich is a perfectionist who cares deeply about the quality of his work – probably too deeply, as these projects give him sleepless nights!
No underseal has been added to ʻbuild inʼ lightness, and the bulk of the ʼshell and complete interior have been painted satin black, as have the engine bay and door shuts, as per factory race cars. The body was then painted in 018 Tangerine (or Blood Orange), with slots cut into both sides of the front bumper to increase airflow to the oil coolers. The front and rear bumpers are excellent quality EB Motorsport items that have been modified to fit.
The gauges were refurbished by North Hollywood Speedometer, copied from an old photo of a racing RSR, complete with 180mph speedo and 10,000rpm rev counter. The oil level gauge has also been flipped, with the fuel sender gauge omitted and replaced with a warning light. The clock has also been deleted.
For headlights, I sourced a set of Cibie Biodes, a preferred choice for early rally cars. These resembled little more than a collection of tired, worn parts which were sent to Genius of the Lamp in Birminghamʼs jewellery district, coming back looking as good as new.
When it came to seats, I learned that Vintage Seats produce the most accurate reproductions available. I chose their ST driverʼs seat, with an R-type passenger, both finished with German black vinyl bolsters and basket-weave insert, all mounted on lightweight Recaro sliders.
For wheels, I had the idea of replicating a wide-body ST look by fitting 7R-type Minilites to the rear, but hit a stumbling block when I discovered they werenʼt available in the required 7R offset. After talking to Harvey Weidman he suggested that ʻdeepsix ʼ front and 7R rear Fuchs in a racing finish would give me the look I was after. The quality of the finish is superb and they look fantastic fitted with Avon CR6ZZ 185/70s on the fronts and 215/60s on the rears.
Marek Lappock is a keen early Porsche enthusiast who helps many specialist suppliers, including Porsche themselves, by manufacturing obsolete and hard to find parts. When I learnt he was displaying the first prototypes of a 100-litre fuel tank, another rare race part, at Techno Classica in Essen I decided I had to get there first before these tanks were snapped up! This involved a round day trip of nearly 1000 miles, where I secured my tank and was also able to collect a number of other parts I needed.
Through this journey, I have developed a passion for early steering wheels, with my favourite being a flat black Momo from the late ʼ60s or early ʼ70s. Itʼs the first thing I notice when looking in an early Porsche and for me enhances any hot-rod build. Thereʼs something about a well-used early wheel that I find intoxicating with its worn leather holding on to secrets of a life well spent.
When it was time to start the assembly, Nick Fulljames introduced me to Gary Cook. At the time he was working freelance for a number of early Porsche specialists, having spent 17 years working at Autofarm, and I was told he was very knowledgeable when it came to early Porsches. That has proved to be an understatement, for this guy knows everything!
Parts were sent to Gary for cleaning, re-plating and powdercoating. The wiring loom was taken apart and carefully restored, front A-arms strengthened and all the other parts needed for the build finally acquired.
Gary has now opened his own workshop – GD Automotive near Buckingham – and I soon learnt to have full faith in his ability, knowledge and attention to detail. Being a modified car thereʼs a whole host of items that have needed to be fabricated or adapted. For example, the 930 calipers were shaved to fit behind the Fuchs wheels, and re-engineered to fit the early 1973 aluminium rear trailing arms.
Special brackets were also made to mount the twin ATE brake fluid bottles and an adjustable brake bias set-up was added, with a modified pedal box. With every detail Gary has kept to the pre-1978 ethos and ensured all is period-correct. When it came to the interior we received the help of Dave OʼConnor. Dave is building his own ST and is a stickler for detail.
He reproduces authentic Repa harnesses using the correct webbing and labels, and all original restored hardware. Gary has carefully cut and glued Daveʼs own correct needle-felt lightweight carpet into the car with unbound edges as per earlier STs which, along with the ribbed matting and a black headliner, provides a stark race look. Finishing touches included a period Butlers map reading light, a Halda Twinmaster and a Heuer Master-Time set, all essential equipment for rally cars of the period.
Finally complete, the car was sent to Center Gravity for geometry set-up and and corner balancing, where it spent a whole day with Chris Franklin, who knows just how to tune the suspension perfectly for fast road use.
Was all the heartache, mental anguish and financial pounding worth it? Well, as soon as the car was complete, I spent a frantic few days piling on some miles to get a running-in service out of the way in time for a planned tour of Wales. It turned into a two-day, 700-mile trip with several other early Porsches, including two genuine 2.7 RSs, a 993 RS and a very quick 930 Martini tribute hot-rod. Road trips donʼt come any better than that!
Since completion late last year Iʼve enjoyed the car on track at Oulton Park, along with other trips and another Welsh tour, hanging with friends and clocking up nearly 4000 miles in the process. The drives, community and friendships are what itʼs all about. Itʼs certainly been worth all the effort to get here.
The restoration process is a love/hate experience for me. I find it too intense and the guilt I feel from it taking over my life is difficult to live with. But no-one got harmed in the process – there are many worse vices. Iʼm finally cured of my restoration addiction and have promised my wife thereʼll be no more projects… Well, not quite yet!
Slots cut into the front bumper are a Darren ʻsignature touchʼ, allowing air through to the front-mounted oil coolers. Panel fit is exemplary throughout…
Halda Twinmaster and Heuer Master-Time help add to the period race/rally look that Darren was keen to replicate. ʻFrostedʼ finish on the Fuchs wheels was courtesy of Harvey Weidman in the USA. Tyres are Avon CR6ZZs.
Interior features seats from Vintage Seats, with one of their ST-style perches for the driver, an R-style one for the passenger. Period Momo steering wheel adds a touch of patina to the interior.
World-famous Pendine Sands in Wales was the photo location – 5.00am and the lighting is perfect to bring out the best in this spinetingling symphony of detail.
Early morning sunlight shows the lines of Darrenʼs narrowbodied hot-rod to perfection. Car is impressively detailed throughout – check that slotted rear apron.
“WITH UP TO 250BHP NOW AVAILABLE…”
“THE LAST THING I NEEDED WAS ANOTHER PROJECT”
A trip to an Oulton Park trackday gave Darren the opportunity to wind those high butterflies wide open…
Opposite page: photo montage only hints at the amount of effort that went into this build, but check the state of the original car, and how much work was required to put it right! Strengthened ʼshell is full of neat touches by Barry Carter. Nick Fulljames built the engine, Mike Bainbridge the ʼbox.
Things donʼt come much better detailed than this. Note cross-over pipes running between twin frontmounted oil coolers. Engine is a short-stroke 2.5-litre ʻscreamerʼ running highbutterfly injection, and pumps out 250bhp.