Running Report 1 - November 2002

1990 C4 Coupe with a 3.8L Conversion

Calling this (my first) report a "running report" is a bit of a misnomer as apart from a fabulous first week back in March when I bought the car, it has spent the last seven months "resting" whilst a painstakingly slow engine rebuild has been undertaken.

I had been looking for a 911 for some time and had narrowed my choice down to a 964RS (the car will be used as both a daily drive and a club car). Unfortunately there are not to many RS's in Australia and 993RS's are too expensive and also call me weird but I prefer the looks of the 964 over the 993 - long live upright headlamps! It is also interesting to note that the 964 motor is a better base for tuning than a 993 as it has solid valve lifters and a stronger crankshaft.

So when I came across a 1990 C4 coupe with a 3.8L conversion and RS spec suspension at a reasonable-ish price I took it for a test-drive. The car had a full history and has had no expense spared over its life. I can't help thinking that after the bashing my wallet has taken over the past six months that this need for dollars is part of the cars personality and seems set to continue. The gearbox had been rebuilt with steel syncros and the engine was especially interesting having been converted to a 993 hot-wire induction system and managed by a motec computer instead of the standard motronic. Motec are an Australian based company who build some of the best racing engine management systems in the world. Performance was very impressive (dyno reports for the car show around 350-370bhp) and coupled with go-kart like handling. Too late for me - I was hooked. Not even a full pre-purchase inspection which revealed the need for a top-end rebuild and a new clutch at a bare minimum could deter me. After using the inspection report in the negotiation the car was mine. In a bizarre way I was actually happy to get something that required some work as I could make it my own. I actually got a bit more work than I bargained for.
 

Engine Rebuild

Before and After

The first week’s use revealed some of the shortcomings of the set-up. A clear open road and loads of revs - perfect, any traffic meant stalling and cutting out and the car had a rather serious drinking problem. The motec was obviously pouring fuel in which worked fine at 5000 rpm upwards but made for an interesting drive below that.

I bit the bullet and took the car to Phill Hearn at Auto-Coupe in Eltham,Victoria. Phill is one of the most respected independent Porsche experts in Victoria and because of this has a very full workshop! He specializes in full engine re-builds and is extremely thorough.

As the engine was dismantled a litany of expensive news commenced. Most serious was #6 cylinder barrel which had the beginnings of a crack at the head mating surface (see photo). My decision to get the engine work done sooner rather than later was vindicated - if this cylinder had let go it would have been very messy indeed. All the other internals were showing signs of the power the car had been producing in its previous life. The poor motec set-up (no knock sensors connected) showed in signs of running very rich and some detonation having occurred.

Seeing the engine spread out over a bench I realised that there was actually no going back, I could also not countenance doing anything less than the best job I could afford, it was "in for a penny, in for a pound", many pounds actually!

Phill uses some very good engineers to do his machining work - unfortunately they work at their own pace. Many frustrating weeks passed by as the case and internals were sent out to be fettled. The case was "windaged" for less internal air-resistance and shuffle-pinned (the Porsche equivalent of 4-bolt mains) for more strength (see photos). Luckily we managed to source a single matching barrel and piston to replace the cracked one - a new set of six would not have been financially feasible.

And a Varioram Inlet

A side-effect of all of the waiting time was that I started asking dangerous questions like - would a varioram inlet manifold fit? The answer was yes; it would work very well if I could get one. I discovered that secondhand variorams are as rare as rocking-horse excrement. Who in the world would actually be taking them off cars? An email to RUF in pfaffenhausen gave me the answer and 900 Euros later a pristine used varioram was on it's way down under. It would have been possible (with a lot of hours) to set up the motec to drive the varioram but after consideration it was agreed that a 993RS motronic would be the optimal solution as this was designed for 3.8litres with a light flywheel and a varioram. I actually managed to find a secondhand one in the US but the price was not much cheaper than a new (and warranted) one from Porsche in Australia. I also had to get a new engine harness set to connect the new motronic up. Whilst all of my sourcing was going on the bottom end went together (the machining/balancing done by the man who builds custom 16000rpm VW cranks for SCAT in the USA) and included Raceware connecting rod bolts and lightweight cosworth gudgeon pins.

After much measuring and machining the heads were all trued to exactly 11.3:1 compression ratio and fitted with new valves. It was beginning to look like an engine again.

Two weeks ago the engine was back in the car and the last couple of weeks have been used chasing down parts like 993 high-flow injectors, the 993 twin coils pack and associated triggers and connecting everything up with an impressive attention to detail.

The car was sent off to another Porsche specialist to have some custom exhaust work done. The existing catalyst was removed (don't worry not permanently!) and replaced with a loop of pipe from the left hand bank, which is exactly the same volume as the crossover pipe form the right hand bank. The gives an equal length exhaust and should improve low and mid-range torque. The primary muffler was removed and replaced with a catalyst from a 1991 turbo (low back pressure and it fits nicely) and finally the existing secondary muffler was retained. I can't tell you what it sounds like yet but have heard a similar system and I am optimistic. I have also had fitted some 17 inch 993 cup2 wheels with Falken Type R tyres (road legal racing rubber) and have the first run on the track before the end of the month.

I had hoped to be able to give you an actual running report but unfortunately the car still awaits it first start-up and run - scheduled for next week although I have been disappointed before.............. Wish me luck.

Running Report 2 - May 2003

You will note by the change in mileage that the car is running at long last. I have been making up for lost time and during the last five months I have gone through the following:-

Hardly low maintenance but I am enjoying the car immensely and if you don’t add it all up you can keep yourself in a comfortable state of ignorance about how much it is costing.

The story so far………….

I can’t explain the excitement I felt when (a week after I posted my first “running” report I got a call from Phil Hearn (Porsche engine builder par excellence) to let me listen to the sound of my car running. It took a few more days to ready the car for the road. All of the brakes calipers were serviced with new seals and the front differential oil seals were replaced. One minor problem that arose was that the new varioram inlet manifold would not fit under the 964 rear spoiler; some judicious trimming of the supporting plastic framework provided just enough space.

 Driving

The car drives superbly. The power delivery of the engine is seamless and the flat torque curve means that it is a delight to drive on the road as it is always responsive in just about any gear. Overall the car feels much newer than its 14 years. I use the car daily (excepting its regular visits to the workshop) – I have driven stock 964s and I can testify that the investment in the engine makes a noticeable difference to performance.

964 bogey men – Idle problems and oil leaks

Having replaced all the 964 engine management and induction systems with 993 items I was fairly confident that I would not suffer from any of the traditional 964 idle problems and this was certainly the case until I made the mistake of gassing up and connecting the aircon after a month or so’s running (it was the middle of a rather warm Australian summer). The aircon seems to confuse the 993RS motronic and the car intermittently displays classic Porsche idle hunting problems. Just recently it has settled back down to a rock solid specification 960rpm so I am at a bit of a loss as to what to do. At the moment I have chosen to ignore it and hope it will go away. What I couldn’t ignore was the blue smoke screen that the car started to trail behind it (think James Bond’s Aston in Goldfinger) – a quick investigation revealed an oil pipe leak dripping onto the secondary exhaust silencer. This was quickly followed by discovering spots of oil under the front oil cooler. It was almost as if overnight every oil line on the car had decided to start weeping. All oil lines and the cooler itself have now been replaced with new items.
 

Track

The times when I feel the car really comes alive (and the only time I can enjoy anything approaching the cars performance) are when it gets some track time. I have managed to take part in a number of private track session and club sprints at a variety of circuits and I am still finding ways of getting the car to go quicker.  The two areas I have had issues with are the AWD drive system and the brakes. I would not be without AWD on the road and I really like the balance it gives the car. On the track however it does require some modifications to driving technique and style in order to get the best from it. As always though the smoother I manage to drive the better the times and the better the car feels. Whoever set the suspension up did a very good job as for the most part the car is very neutral.

I generally manage to get the PDAS warning light & chime on at least once every track session but this seems to have stopped and the jury is still out on both the reason it happenned and the reason it has gone away.

I can recommend lots of negative camber on the front for the track – now it is loosened up I can get close to 3 degrees – it makes a difference.

My most interesting track experience was six laps of a very bumpy 1.8km 25 degree banked oval. After a drivers briefing designed to put the fear of God into all participants I went out intending to take it very easy indeed. Notwithstanding that I managed to lap at an average speed of just over 100mph. As usual the car felt like it could have gone quicker but I was just happy to get off what felt like a concrete walled roller coaster in one piece

Brakes

Confession – on the track at least I am a late braker – I know that this does not necessarily translate into faster lap time but I enjoy it and basically when I am really trying I can’t help myself. I have stock brakes (with extra front cooling ducts) running Ferodo semi-race pads. 964 brakes are the best road-car brakes I have ever experienced; unfortunately on the track my heavy right foot has resulted in two cases of warped front discs. Both skimmed out but I have invested in another set of discs so I can do quick changeovers if required. I seem to have developed a solution which involves never letting the car stand still for very long on hot brakes; I cool the brakes down zealously by both a couple of cool down laps and a drive around and then finally roll the car backwards and forwards a few feet so that the pads are never next to the same area of disc for very long. It is a bit of a rigmarole but I haven’t warped the discs since February so I am sticking with it.

CV – Joints

I discovered the outer left hand cv joint boot had split recently and stripped the driveshaft down, cleaned and replaced the boot. Last weekend the right outer joint started making the tell tale road speed dependent knocking, at first just around left hand corners but quickly developing into an immediate attention required state. Two new driveshafts sourced and fitted this week.

Miscellaneous

My dear family (having noticed my growing obsession with my car) clubbed together for my birthday and bought me a set of teardrop “cup” mirrors. Painted and fitted these look great (see photo) and I think really set the car off – I can also vouch for the fact that they weigh much less than the flag mirrors that I removed so I can add these to my the car’s ongoing dieting program.Future Plans

I do not want to turn the car into a full club-spec track tool. It is my daily transport (check out the child seat in the back in some of the photos). Because of its non-standard nature I am forced to compete in modified classes against lighter cars with similar power. My goal therefore is to try and lighten the car – I have calculated that taking out the stock electric seats and replacing them with RS recaros would be worth in the order of 40-50kg. All I need is a pair of 2nd hand recaros, all suggestions on where to find some gratefully received. Next I would like to do a little more work on the suspension. I must admit however that I am extremely happy with the car as is and my wallet would certainly appreciate a rest for a while

Running Report 3 - May 2004

My pre-running report review of the car’s history file has revealed a considerable amount of activity (and expense) over the last 10 months. However I have covered ~ 16,500 kms and the car has also been busy in its other life on the track so it is earning its keep and it deserves 11/10 for entertainment value.
 

Seats

I mentioned in the last running report that I was searching for some racing seats and amazingly enough I did find a pair of original second hand RS recaros for sale in the UK. The catch was that the (non-negotiable) asking price was more than a new pair through FVD in Germany and way above my budget.
Luckily I came across a small local (and reasonable) bespoke seat maker who made me some well engineered and very light seats (see photo). A stainless steel harness bar and some 4-point Willans harnesses supplemented the seats.
As the seats were “fitted” to me they are comfortable enough for daily driving and with the harness make an incredible difference on the track. My recommendation is that if you are going to track your car more than once get a seat/harness - you do not have to allocate valuable mental capacity to positioning your body as part of corner entry set-up!

Track Work

Phillip Island in Victoria is generally accepted to be the home of the finest circuit in Australia and is still the venue for a round of the MotoGP bike world championship.
It is a very challenging and fast circuit and my personal favourite although as I learnt recently it does need to be treated with a lot of respect.  A fast (180km/h +) off-track excursion at the Island in October last year taught me a couple of valuable lessons - firstly do not follow a BMW M3 closely if said M3 is not following the correct line and secondly you can get massive snap over-steer in a C4 if you lift off and try to turn in more in a fast sweeper to avoid running up the back of the M3.
All my fault and I was very lucky indeed as I rocketed backwards off the track and ran parallel to a tyre wall for 75metres without contact.
 

Big clean-up.

The above incident resulted in the removal of one of the side skirts, the collection of a large amount of debris (grass, gravel and earth) by the underside of the car and the loss of one or two of the aerodynamic aids mounted on the front suspension. The lock-up of the wheels had flat-spotted all four tyres (not terminally) and the associated torque “shock” through the drive train had resulted in the cracking of a number of the plastic mounts between the engine and the inlet manifold.

Kane Hearn at Autocoupe fixed everything up and did an absolutely superb job of bringing the underside of the car to concours standard (see photo of gleaming gearbox). It was almost a shame to drive away and dirty it. The clean up also identified an unrelated leaking PDAS slave cylinder which was replaced.

Fuel Tank Collapse

As I was filling up with fuel one day in December I heard odd crunching noises coming from the trunk. Opening the bonnet revealed a fuel tank which had almost totally collapsed in on itself. I unscrewed the filler cap and a rush of air reversed the collapse leaving me wondering if I had imagined it all.
The tank continued this cycle all day and the car was swiftly delivered to Autocoupe for their diagnostic wizardry. I must admit I was a little perturbed when Autocoupe chief Phil Hearn looked at the half collapsed tank and said “I’ve never seen one of those doing that before” but I needn’t have worried as he and Kane quickly worked out what the problem was – a defunct fuel ventilation system valve. A relatively inexpensive 993 numbered part (see photo) was sourced as a replacement. The plastic tank is obviously very robust and is none the worse for its ordeal.
 

New Starter motor

The starter motor had been playing up for some time; the symptoms were a spin followed by a click as the bendix gear refused to move the shaft. After discovering the price of a new motor (~1300AUD) I opted to try a rebuild for about a fifth of that. For a month this seemed to have worked but then it got much worse than before. I endured two weeks of parking at the top of hills (in order to get a start by rolling down) and a couple of embarrassing push starts (Passers by seem to feel that the assistance required is a smart-arse remark when the car involved is a Porsche.) I finally bit the bullet and blew half of my 2004 tyre budget on a new starter motor. It has been money well spent.

Front tyres

Talking of tyres my Dunlop D01J track tyres have been wearing very well considering they get a monthly outing. However the wear pattern on the front (see the photo and look at the high wear on the outside edge) revealed the need for more negative camber.

It also meant they were getting close to the legal limit and also that they were not much good in the wet.
Unfortunately The DO1Js have been superseded by D02Js so I bought a pair of these for the front only (refer to the budget constraints above). They are the same compound as the D01Js but have an asymmetric tread pattern as opposed to a directional. The only difference in driving is that they feel better and the car appreciates the extra grip at the front. Lap times are quicker as a result. I will replace the rears when necessary.

Future work - New Suspension

Plans for the future started with the purchase of some secondhand Camber Plates (see photo) for the front suspension. These will allow me to dial in as much negative camber as required for the track and hopefully as a result go faster. It seems silly to fit these without fitting new shocks and springs and lowering the car a little more (I sometimes worry about the way my mind works). More details hopefully in the next report.