Ruby saloon engine problem..

[Robert Leigh]

Hi folks, can anyone assist please.
I have recently completed a full restoration of my early Ruby saloon and however having just completed my first one hundred miles I had an issue with a head gasket failure.
My restoration has been in two parts, the first of which was 30 years ago which included the engine rebuild and the second over the last 3 years to finish the body etc.
The head gasket failure is most likely due to my own incompetence, I cannot remember what torque I had originally tightened the head down to all those years ago but I know when I removed the head yesterday the nuts came away embarrassingly easily with very little effort using only a short spanner!
So with new gasket and a modern torque wrench I set about replacing the old gasket.
However having removed the head I was surprised with what I found especially as the engine rebuild was complete with re-sleeve back to original size new pistons, rods, bearing etc.
The attached picture shows areas of the pistons that are coated with a black sticky goo which could be removed with a bit of effort and some paraffin. I have never come across anything like this before, interestingly, I contacted a local garage man who deals with older cars and he told me he had another Ruby in with exactly the same problem. He put it down to modern fuel but I am not convinced.
If anyone can shed any light I would be most grateful
Best regards to one and all Denis Sweeney

I have seen similar, but I don't know how much modern petrol has to do with it. I say don't worry; just get the joint surfaces decently clean with no carbon ridge around where the gasket fits, grease both sides of the gasket, and fit it. If it's reluctant to go down the studs use the head to push it down, then fit the nuts, tightening gradually in the standard order. I use 25 ft lbs, but I think some people use a lower figure. After each shortish run which gets the engine properly hot, retighten. After four or five tightenings you will find the nuts don't go any further, but if you don't go through the repeats you are likely to have the same trouble again. This has been the case since asbestos was banned; the new material behaves differently.
Good luck!
Robert Leigh