Cylinders out and knocking

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Davthomp
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Cylinders out and knocking

Post by Davthomp »

My Minor 1000 recently started to make a knocking noise on acceleration and is now running on only two cylinders. I have owned the car since 1978 and was convinced this was an internal failure.
I swapped the spark plugs around to eliminate these as the problem. I removed the rocker cover, turned her over with the starting handle and all valves appeared the be operating as normal. I then removed the cylinder head and the valves looked fine and have since pulled the engine out and inspected the crank shaft. Everything looks intact.
Unfortunately I didn’t notice whether or not the oil light was on when this problem presented itself.
I recently adjusted the valve clearances per the book in preparation for a trip to France and now wondering if I have got this wrong somehow but she drove smoothly on a 2 hour drive just prior to the problem appearing.
Does anyone have any ideas of what the problem might be?
Tinasminor
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Re: Cylinders out and knocking

Post by Tinasminor »

Was the headgasket ok then?
ManyMinors
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Re: Cylinders out and knocking

Post by ManyMinors »

The "knocking" combined with only firing on two cylinders sounds exactly like the symptoms of a head gasket blown between two cylinders to me :wink:
simmitc
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Re: Cylinders out and knocking

Post by simmitc »

Agreed. As you have already got the head off, look at the gasket that you removed and check both block and head with a straight edge. There's another thread running on exactly this type of fault, and I've got one Minor off the road with the same problem.
myoldjalopy
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Re: Cylinders out and knocking

Post by myoldjalopy »

If the head was removed, I would have thought that a blown gasket would be immediately obvious...............its hard to miss :-?
kennatt
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Re: Cylinders out and knocking

Post by kennatt »

its a shame you didnt post pror to head off and crank examination,since I.m sure you would have been advised to have a compression test,obviously not possible now untill all is back together. Its the classic symptoms of head gasket failure,and a test would have removed any doubt.
Davthomp
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Re: Cylinders out and knocking

Post by Davthomp »

All. Thanks for all your input, which of course was spot on and has left me feeling very foolish for not having checked the head gasket as soon as I had lifted it. The knocking noise had me thinking bearings or valve stem before I realised that two cylinders were out. I least everything else I’ve checked is it good condition although I did find a crack in the exhaust manifold which I will now replace. Thanks again.
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