help?? anyone???
Discussion
hello i have a 998cc mini wich ive reacently purchased. . . now the person i baught it off says he had it stood in his garage for years and that he couldent get it started. i towed it home, cleaned the spark plugs, put a bettery on it and it started. it sounds like its misfiring tho and i came out again after leaving it for a few days and it was flooded again. it looks like theres oil on the sparkplug in one of the cylinders. what does this mean?
Daz, it could mean any one of several things.
It could just be a duff plug, or one where the plug gap is incorrect. It could be an ignition lead breaking down or a fault in the distributor cap.
Any of those things could cause one plug to not fire and thus to oil up as a result.
Alternatively it could be a burnt valve, although one might expect it still to fire and not oil up, but not necessarily so.
So, remove the plug on the offending cylinder, clean it, set the gap to 0.025", refit the plug cap, lay it against the block and check for a spark.
Beg, borrow or steal a compression tester and measure the compressions in each cylinder to rule out or identify any valve/compression issues. You should be seeing a compression at cranking revs of around 125psi to 140 psi minimum for each cylinder. Before doing this test, spray a little light oil down the bores to ensure piston ring sealing.
In a worst-case scenario, it could be a cracked piston or a broken ring. To check the bore efficiency run the engine warm at tickover with the oil filler cap removed. If it 'puffs' smoke out of the filler cap, then it's either worn rings, broken rings of a damaged piston.
Do this methodically and eliminate the electrical/ignition system first (the most likely faults), then move on to check compressions, etc.
Personally, on a car that's been standing, I would fit a new set of spark plugs and ignition leads anyway, then go from there.
Let us know how you get on.
It could just be a duff plug, or one where the plug gap is incorrect. It could be an ignition lead breaking down or a fault in the distributor cap.
Any of those things could cause one plug to not fire and thus to oil up as a result.
Alternatively it could be a burnt valve, although one might expect it still to fire and not oil up, but not necessarily so.
So, remove the plug on the offending cylinder, clean it, set the gap to 0.025", refit the plug cap, lay it against the block and check for a spark.
Beg, borrow or steal a compression tester and measure the compressions in each cylinder to rule out or identify any valve/compression issues. You should be seeing a compression at cranking revs of around 125psi to 140 psi minimum for each cylinder. Before doing this test, spray a little light oil down the bores to ensure piston ring sealing.
In a worst-case scenario, it could be a cracked piston or a broken ring. To check the bore efficiency run the engine warm at tickover with the oil filler cap removed. If it 'puffs' smoke out of the filler cap, then it's either worn rings, broken rings of a damaged piston.
Do this methodically and eliminate the electrical/ignition system first (the most likely faults), then move on to check compressions, etc.
Personally, on a car that's been standing, I would fit a new set of spark plugs and ignition leads anyway, then go from there.
Let us know how you get on.
Gassing Station | Classic Minis | Top of Page | What's New | My Stuff