15-03-2023, 06:53 PM
(This post was last modified: 15-03-2023, 06:57 PM by Graham Barker.
Edit Reason: I meant wriggled sideways in their guides,
)
Robert, thanks for that information. The last time I had an Austin Seven motor in pieces was almost 6 decades ago. So I need updating.
This motor was reconditioned 40 years ago by the previous owner and never used much since then. It produces light blue exhaust smoke when under load and seems to have an inordinate amount of blowby forcing a lot of oil out of the filler pipe and the tappet cover vents. It uses about a litre of oil per hundred miles.
The gap in the ring grooves alongside the rings is 4 to 6 thou. The bores have negligible wear and I see from receipts that they had been rebored. It's a Ruby high compression engine and all cylinders give 100 psi on cold, throttle open compression test.
Also all the valves can be wiggled sideways in their guides a little. Do people think that fixing the outdated ring setup would be sufficient to reduce the smoke and blowby or should I be focused on renewing the valve guides?
This motor was reconditioned 40 years ago by the previous owner and never used much since then. It produces light blue exhaust smoke when under load and seems to have an inordinate amount of blowby forcing a lot of oil out of the filler pipe and the tappet cover vents. It uses about a litre of oil per hundred miles.
The gap in the ring grooves alongside the rings is 4 to 6 thou. The bores have negligible wear and I see from receipts that they had been rebored. It's a Ruby high compression engine and all cylinders give 100 psi on cold, throttle open compression test.
Also all the valves can be wiggled sideways in their guides a little. Do people think that fixing the outdated ring setup would be sufficient to reduce the smoke and blowby or should I be focused on renewing the valve guides?
(15-03-2023, 01:22 PM)Robert Leigh Wrote: The style of rings suggests that the pistons were fitted a long time ago and re-ringed at some time. The Cords oil control rings are something I have not seen in a long time, and through the period I have used A7s (since 1959) all new pistons (except slipper type) had 2 compression rings and 2 oil control rings the upper one being above the gudgeon pin. The upper compression ring pictured appears to be fitted in a very worn groove, and the purpose of the hole is a mystery to me. It looks as though someone did the cheapest overhaul they could get away with.