After Phil had persuaded me that we really had to dismantle the engine to assess its condition I took the cylinder head away to work on it in the small workshop at the place where I was employed. This took up most of my lunchtimes for the next couple of weeks.
Phil in the meantime had stripped the engine. The crank and bores measured up OK but once the pistons were out it was pretty obvious what had been wrong. The rings had worn their grooves and one end of the compression ring on one cylinder had practically worked its way through to the top of the piston. With certainly little compression on that cylinder it must have run very badly and was quite possibly using a lot of oil as well.
The bores themselves were in remarkably good order and just needed honing. I bought a new set of standard size pistons and once the block had been cleaned up and fitted with a new set of bearing shells and core plugs all was ready for the cylinder head.
Once I had started work on this and had cleaned off all the carbon deposits I could see why there was no compression on two cylinders. With the cams removed and a light held in each port on two of the inlet valves I could see the light (literally). With the cams out, obviously all the valves should be closed but they weren't. At first I thought that the two valves in question were just sticking but it didn't take long to realise that they were bent. I think what must have happened is that after standing for so long these valves had stuck and that when we had tried to get the engine to run two pistons must have touched the valve heads and bent them slightly. This was one of the causes of the lack of compression.
|When I tried to grind in the exhaust valves it was clear that I was not going to get rid of the pitting on the heads. This pitting seemed to be due not to burning but to rust - again I suspect a result of prolonged standing unused. So I replaced all six with new ones as well as the two bent inlet valves. After grinding in I went through the laborious process of shimming the valve clearances. This is done by measuring the existing clearance and then, knowing the thickness of the current shim, doing a simple sum to give the thickness of the shim needed to give the required clearance.|
It sounds simple. Why does it take so long and why after careful measurement don't you get it right first time. After several goes I got all the clearance gaps right but I needed a few shims that are thinner than the thinnest available (0.085"). I had to have some spare shims ground down to the right size by a local engineering workshop.
Meanwhile, the carburettors and inlet manifold had been in Dave Morris's care. He does a wonderful job on refurbishing these to a very high standard and they came back from him looking immaculate.
By this time Phil had also repaired and rebuilt the engine ancillaries so all was ready to be reassembled.
Are you out there Tom?
One thing leads to another.......
Jaguar E Type Restoration