Quote:
Originally Posted by Spacemonkey
So it appears after a compression test one of the cylinders is half what it should be which is what is causing the misfire. Possible a leaky/burnt/bent valve. Looks like I'll be dismantling this engine to try and fix it  |
A sticking hydraulic tappet would cause that too. Or if the oilway to the tappet is blocked the tappet(s) will slowly lose oil and this will cause lack of compression.
A couple of months ago I had a KV6 that wouldn't start, history was that the car had been stood for about 3 months. The owner had tried everything. When I looked at the car and tried to start it it turned over as if all the plugs had been removed. There was no compression at all.
After numerous attempts to start the engine it would give an occasional slight hiccup. It had a full charge in the battery so I thought I'd do something I don't like doing I turned it over on the key continuously for a good 40-50 seconds
The engine spluttered and then roared into life, result
What had happened was that while the car was stood the tappets had lost their oil, turning over the engine sufficiently built up the oil pressure which refilled the tappets enabling the car to start.
Not saying this is the cause but it can be a possibility
Russ