Oil and water

Well, the k-seal seems to have stopped the radiator leak. Although Max is very concerned that it will have blocked the heater matrix (which is a dog to remove if that is required). We'll see, but clearly there are no easy wins here.

Oil consumption, with the 25/70 oil, has certainly slowed to around a more reasonable (less unreasonable) 500 miles per litre. I let the oil level reduce to just above the minimum on the dipstick and added 250ml.

But I do have a concern that, based on the mechanical oil gauge, it does take a few seconds to get up to working pressure form a cold start. It could just be the gauge is slow to respond, but equally it could be a pick-up problem due to the high viscosity of the oil.

If the latter, it would be bad. Again, no easy wins.

Checking the plugs, 1 and 4 are still dirty but not as bad as before the carbs were re-choked. 2 and 3 are an acceptable brown colour. The exhaust tail pipe is not as dark but the particles of soot feel a bit oily.

When I start from cold, the engine is quieter and smoother until the oil is up to temperature. For example we set off from some friends, a couple of miles of minor roads, then dual carriageway at 3000-3500rpm. To start with, less noise in the "problem" range of 2750/2800 up to 3500rpm, and no significant noise on the overrun. Once the oil was up to temperature (a few miles after the water temperature stabilises, based on the oil pressure stabilising) the engine is definitely noisier in the rev range mentioned and there is significant noise on the overrun.

I'm pretty sure that the noise and vibration are engine rpm dependent, and not road speed. I have previously had a new, balanced, propshaft fitted.

Had another chat with Grahame. Despite his high workload, he's kindly offered to take the car out for a test drive to see if he can pinpoint the issues. His current theory is that oil is passing the piston rings - from the colour of the plugs he could well be spot-on, with 1 and 4 being the primary suspects.

Could the overrun noise be crankshaft float? I've learnt not to trust anything done by the previous owner, and he changed the crankshaft and rods (and possibly the pistons) when he put in the longer block.