Wednesday, 16 November 2011

Porsche 906 - Carrera 6

One of our customers was a man called John Sergeant who was a dentist by profession and lived in a small village called Eye, just south of Diss just off the Ipswich to Norwich road.
Previously we had the Porsche 906 at the farm for a lot of work, including an engine and transmission rebuild. One day Chris asked me if I would go over to John’s home and do a small service and tune up on his Porsche 906.  So I drove over the next day in one of our customers Porsche 911 with a set of tools and parts, which would allow me to do any basic service or tuning job required.
I arrived in Diss and met John and his wife, and their dental receptionist/nurse. I am not sure how old John and his wife was, but they were not far of retirement age and certainly well into their sixties. He was still the local practising dentist and was obviously doing fine for himself and I must say Eye was a very lovely picturesque village to live and work in.
John also had a really quick and specially tuned Mini Cooper S, which Downton in the West Country had built and he spent a long time talking to me about his cars up in his study.
I eventually set to work on the Carrera 6, which was completely street legal, as John and his wife drove the car once or twice a week on average around their local area. I started the car up and took it for a run through the village and winding up road the local roads to see how it was running. The engine was not running smooth at all, so I thought I would take it back and just go through the basic service and replace the spark plugs, points, and condenser and then check the ignition timing.
Upon my return I put the car up on some axel stands using John’s small trolley jack and drained the engine oil, also checking the sump plugs for any metal particles which were totally clean. I also checked the valve clearances which were fine as to have found any of these requiring adjustment would have proved difficult as they could only be adjusted by replaces the shim caps which were supplied from Porsche in various thicknesses and a big job to undertake with the engine still installed. I replaced the valve covers with new gaskets and changed the oil filter and replaced the engine oil.
We were using platinum tipped NGK spark plugs a lot in those days, and the properties of these spark plugs were much better than Bosch and certainly a lot cheaper. I fitted a new set of plugs, checked the resistance of the HT leads, plug caps, rotor and distributor and then started the engine. I warmed it up to check the oil level and then once the engine was hot enough, check the ignition timing which was done at 6,000rpm, using a stroboscopic timing light. After topping up the oil level, I took it for another run and it was running noticeably better.
The Porsche 906 engine looks basically like an early sporty 911 unit to look at casually. It is a flat 6 air cooled with two, triple chokes Weber carburettors mounted on each bank of cylinders with no air cleaner, just flame traps. The carburettors are set-up with idle, main jets and venturi’s, which are fixed, but size can be varied if required. There are adjustable ball joint throttle linkages to set up each set of carburettors and to balance between the two banks. There are also idle airscrew adjustments to synchronise and balance the air to be even over the six intakes.
At Maltin’s we nearly always tuned the cars on the public roads in those days. There is no substitute for driving the car on the roads as the customer would. It also kept the engine oil, carburettors and air at the correct temperatures. If you do this in a workshop, you can still get reasonable good results but you face the heat building up in the engine and you are putting warm air in the air intakes, which can throw you off slightly.
So every few minutes of driving on the open road around Diss I would stop the Carrera 6 and check it’s idle and air intake synchronisation until I was satisfied with it.
I returned the car to John’s house declaring it was finished. I then went up the road with John driving and he drove the car much quicker than I did. He told me it was running perfectly and thanked me for my efforts. His wife then drove the Porsche 906 herself and came back about fifteen minutes later. John had by this time taken me off to his study and gave me a cash bonus, as I told him Chris would mail his account to him.
Shortly after we sat down in the garden and had afternoon tea. There was a knock on the door and John came back with the local policeman in tow who they obviously knew extremely well. He sat down and joined us and I was introduced as the expert Porsche mechanic. The policeman stated he had seen me driving sensible but could John and his wife please keep it under 60mph until they are clear of the 30mph speed limit inside the village! He looked at me and winked and to this day I am not sure if he had got totally fed up with telling them to drive slower or it was just a joke between them all.
Martin Hone of the “Opposite Lock Club” subsequently purchased this car and some photographs are included during his ownership. 

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