Part of the Family - The 1970s

So that was it, in October 1976 I was the proud owner of a very special motorcar, although it was February 1978 before I registered this change of ownership with the DVLC on the logbook. The reason for this was that I was only 22 years of age and though I had 5years NCD, was worried that the insurance premium would be prohibitive.

Edensor - 1977

As had been the case with Dad, my ownership of the car got off to a shaky start. This I confess was all my own doing.

Early in 1977 I decided to go and visit my old friend Alan Coultas in Hull, to see what he was working on with his Velocette and to find out what he had planned for the coming season. I spent the day with him and we talked about all the usual racing stuff, then he then suggested that I race his bike for the season. I looked at what was there, what needed doing and came to the conclusion that I could make something of it.

Alan Coultas- 1975

 The deal was that Alan was to prepare the engines and I would look after all the cycle parts and running gear. So I set off home back to Sheffield with a complete bike minus the engine in the back of the van. All the way home I was thinking about what I would say to Dad and how I could explain another bike appearing. I decided that I would be ‘testing’ and ‘developing’ the bike for Alan, surely that would be acceptable?

But he was having none of it. Dad was furious with me and took the car back immediately. This was easy for him to do, as it was still in his name for insurance reasons. I had to return the keys and it seemed to me as if to prove a point, he would get the car out, clean and polish it like never before.

It was not long however until he relented and passed me the keys for a second time.

Burbage moor - 1977

I used the car at every opportunity; it was such fun and so predictable to drive at speed. The more I used it, the more I began to notice all its little quirks and idiosyncrasies and I also started to notice when things were not quite right. One thing that annoyed me was that even after setting the carburettors up properly, it still had a slightly weak and irregular tick-over. It was always the same two cylinders that were unreliable in firing and after checking all the usual ignition components for fault, decided I must get to the bottom of this. I borrowed a cylinder compression gauge and tested the cranking pressure of each cylinder in turn. Sure enough I found that two of the cylinders were well down on the other four readings. These were not adjacent cylinders, so I was fairly confident it was not a head gasket problem. At this stage I removed the cam covers and it was immediately obvious that there was no exhaust valve clearance on both the troublesome cylinders. I made the decision that the head would have to come off to investigate further. As soon as the head was removed it was clear where the problem lay. The lack of exhaust valve tappet clearance had resulted in two of the valves being held off their seats whilst the cam was on base circle and the engine on compression/firing stroke. This caused the offending valves to be badly burnt which resulted in the recorded loss of compression. The clearances were also minimal on the remaining undamaged valves and as I was worried about any possible overheating effects, decided to replace all six to be sure.

Robin Hamilton invoice

I also decided to replace both inlet and exhaust valve springs whilst overhauling the head and purchased all the necessary parts from Robin Hamilton of Burton-on-Trent. They were an approved Aston Martin service dealer and ran the Nimrod race car with help from the factory. Quite how I managed to persaude them that the University of Sheffield had a DB6 and should be eligible for a trade discount I do not know. 

Burnt DB6 exhaust valve

At the same time I recut all the exhaust valve seats and also re-ground the inlet valve seats as they proved to be extremely hard and the seat-cutter would not touch them. I made a mandrel and grinding stone piloted by the valve guide bore for this purpose. At this time Aston Martin exhaust valves were forged from KE steel – Kayser Ellison heat resisting valve steel.  Sheffield steel….the best in the world.

Sheffield Steel

The steel was that good, after inspecting and machining, I used the four undamaged exhaust valves in various Velocette Thruxton racing engines and they never gave a bit of trouble. Far better in fact than the original item, whose head fell off if a limit of 6,200rpm was exceeded.

Coultas Velocette head

New inner and outer springs were fitted to all the valves and an initial measurement of the valve clearances was made. As in a racing engine there are no adjustment shims on a DB engine, the valves being ground exactly to length to give the required clearance. Both inlet and exhaust valve clearances were set to their specified upper limit. Being a direct acting DOHC engine, the clearances close with wear to the seats. I then set about re-fitting the refurbished cylinder head to the engine and assembling all the ancillary components.

I also had to re-time the engine from scratch using dial gauges on both camshafts and piston, as the secondary timing chain had slipped out of mesh. Eventually it was all done, the engine re-built and the car ready to go. However try as I may, the car would not start. The battery would not turn it over properly even when fully charged, but I was convinced that it was just due to the increased compression. So having the courage of my convictions I decided to bite the bullet and bump-start it down the drive. Sadly there was no chance, as in reverse the ratio was far too low and it locked the wheels. Now I was out onto the street, which luckily was a quite steep downhill run and I gave it another go in second gear. The same result again unfortunately, so I tried it in third. The problem was that I was getting very near to the junction at the bottom of the road and could only have one more attempt. It was a bit like the ‘Flight of the Phoenix’, where the pilot has to clear the engine with his last but one starting cartridge. I had to build up enough speed to be sure, as third in the DB is good for 106 MPH. Luckily it fired as I reached the main road and I turned left into the parking bays in front of the supermarket, being oh so careful to keep the engine running. This caused an unwelcome amount of interest, as the bonnet was still removed and the engine and carburettors minus the air-box were there for all to see and hear. In the end I had to move off as so many people were gathering round the car to have a look that I was worried the police would think I’d nicked it. This and of course the small fact that it was not taxed at the time.

Two things perplexed me however.

The first was how did the car run so well with such a loss of compression in two cylinders due to the burnt-out valves? Secondly how did Aston Martin Lagonda not pick up on this when carrying out the improvement work for Dad? After all the head was only removed in late December 1971 following the outcome of the Road Test Report. A 5,000 mile service was carried out on his behalf in December 1972 and the 10,000 mile service done in April 1975. Since 1971 the car had barely covered 5000 miles and it is hard to believe that the exhaust valve clearances had reduced to nothing in this short a time. It is fair to say that in the forty years since I did this overhaul, the clearances have altered less than .002”.

 

If Dad was worried about parts being stripped from the car and left all over the garage floor, Mum was concerned over the attention I was getting. So much so that she took me to one side in the kitchen and went on to explain that the ‘right sort of girls’ are not attracted by flashy motorcars and that I should keep my distance from those that were. Poor Mum, I guess all she got for this advice was a gruff laugh. I have always believed sports-cars are for young people and if you are going to have a car like this, then have when you are young and can enjoy it to the full. I never wanted to be that old man in the red Jaguar.

Cheddar Gorge/Yorkshire Tea - 1979

I continued to improve the car and little things that I felt were not quite right were either replaced or repaired. An example of this was the door opening quarter-light stop, which Dad had replaced on at least one occasion. The choice of chromium-plated brass for this part was not good, as the stop would break at the first sign of resistance. This made it very easy to break into the car by forcing the quarter-light, turning the opening vent operating handle and putting one’s hand through to open the door handle. The original stop would fracture through the reduced section at the point where it is attached with counter-sunk screws to the door frame. I made a new stop from stainless steel and with its increased strength, never had any such problems in the future.

I also removed and completely rebuilt the Selectaride rear damper units. They had been somewhat lazy in their operation and I was never convinced that they were properly synchronised. Once again they continue to work perfectly after all these years.