Flooded to the point of hydraulic lock?
Discussion
As posted here I recently had a spot of bother with my engine flapping about. I've fitted a new engine mount, and was looking forward to the test drive.
Except it wouldn't start. Not only would it not start, but after a few attempts its seemed to seize altogether. After a bit of head scratching with the bonnet up, I tried cranking her again. I could hear a squelching sound as the starter clonked, then ever so slowly she turned over once, then locked again. I whipped out a plug, one of the easy ones (!), and while the (very wet) plug was out, cranked her again. A plume of liquid shot out of the plug hole, and she cranked over fine.
Didn't start though. All the plugs are sopping wet, so I've taken the lot out. I may get a new set tomorrow (any recommendations other than the B7ECS that were in?), or clean them on the cooker after the wife has gone to work
.
Flooding is one thing, but getting so much fuel in the cylinder that it hits hydraulic lock seems pretty weird. And was I just very lucky that the first plug I pulled was the cylinder that was full?
Of has something really seriously nasty gone wrong in there? I did drive the car for about 3 minutes after the pulley ate through the swirl tank inlet, and it was loosing coolant at a rate of knots. The engine bay was swimming in antifreeze, but it ran until I got home OK. The engine didn't get overly hot; I was ignoring the water temp as it wasn't likely to be reliable with the cooling system venting through a 10p sized hole, but the oil temp gauge didn't go over 90.
Basics: when turning over I get a fat yellow/white spark at the plugs. There is a fuel mist coming out of the plug holes. With the plugs in it kicks occasionally but doesn't catch. The plugs come out VERY wet and black.
Any of this ring any bells with anyone?
>> Edited by victormeldrew on Monday 14th November 07:50
Except it wouldn't start. Not only would it not start, but after a few attempts its seemed to seize altogether. After a bit of head scratching with the bonnet up, I tried cranking her again. I could hear a squelching sound as the starter clonked, then ever so slowly she turned over once, then locked again. I whipped out a plug, one of the easy ones (!), and while the (very wet) plug was out, cranked her again. A plume of liquid shot out of the plug hole, and she cranked over fine.
Didn't start though. All the plugs are sopping wet, so I've taken the lot out. I may get a new set tomorrow (any recommendations other than the B7ECS that were in?), or clean them on the cooker after the wife has gone to work
. Flooding is one thing, but getting so much fuel in the cylinder that it hits hydraulic lock seems pretty weird. And was I just very lucky that the first plug I pulled was the cylinder that was full?
Of has something really seriously nasty gone wrong in there? I did drive the car for about 3 minutes after the pulley ate through the swirl tank inlet, and it was loosing coolant at a rate of knots. The engine bay was swimming in antifreeze, but it ran until I got home OK. The engine didn't get overly hot; I was ignoring the water temp as it wasn't likely to be reliable with the cooling system venting through a 10p sized hole, but the oil temp gauge didn't go over 90.
Basics: when turning over I get a fat yellow/white spark at the plugs. There is a fuel mist coming out of the plug holes. With the plugs in it kicks occasionally but doesn't catch. The plugs come out VERY wet and black.
Any of this ring any bells with anyone?
>> Edited by victormeldrew on Monday 14th November 07:50
Are you absolutely sure that it's neat fuel that's filling the cylinders? It would take a LOT to do that since each turn of the engine should push it out of the exhaust - does the exhaust smell of fuel?
If you have a coolant leak in a head gasket, that would fill the cylinder with water - the plug would still burn very wet and black (least it did the last time I had a head gasket let go) - if there's fuel mixed in it might still smell of petrol but be mainly water. Again, though, it should be pushed out the exhaust...
You don't have a jammed or broken valve? Or a bent follower? (sorry I'm not familiar with the griff engine, I might be slavering... I'm only thinking out the principles of how water or fuel could be getting trapped above the piston...)
If you have a coolant leak in a head gasket, that would fill the cylinder with water - the plug would still burn very wet and black (least it did the last time I had a head gasket let go) - if there's fuel mixed in it might still smell of petrol but be mainly water. Again, though, it should be pushed out the exhaust...
You don't have a jammed or broken valve? Or a bent follower? (sorry I'm not familiar with the griff engine, I might be slavering... I'm only thinking out the principles of how water or fuel could be getting trapped above the piston...)
it's perfectly possible for the engine to hydraulic on it's own fuel .. it doesn't take much to fill the chamber to the point where the compression pressure goes throgh the roof.
continuous cranking on cold start fuelling wuld do it, also some kind of earth return problem on an injector wire or a stuck injector woud all do it too.
over the years I've seen quite a few engines do this .
continuous cranking on cold start fuelling wuld do it, also some kind of earth return problem on an injector wire or a stuck injector woud all do it too.
over the years I've seen quite a few engines do this .
trackcar said:
it's perfectly possible for the engine to hydraulic on it's own fuel .. it doesn't take much to fill the chamber to the point where the compression pressure goes throgh the roof.
Sorry, me thick. If the exhaust valve opens on every other stroke, surely that releases the pressure and gobs the excess fuel down the exhaust ready for the next intake? What am I missing here?
what you're missing is that the valves are at the top of the combustion chamber and fuel is heavy so sits in the piston at the bottom of the combustion chamber. If an injector is stuck open and the piston is some way down it's stroke, then on the next compression stroke you're trying to compress a lot of liquid fuel into a small space .. it doesn't work.
tvrgit said:
it's perfectly possible for the engine to hydraulic on it's own fuel .. it doesn't take much to fill the chamber to the point where the compression pressure goes throgh the roof.
Sorry, me thick. If the exhaust valve opens on every other stroke, surely that releases the pressure and gobs the excess fuel down the exhaust ready for the next intake? What am I missing here?
depends if it's on the compression stroke or not
if the injector is stuck, fuel is contantly pumped at fuel rail pressure.
all the time the ignitions on.
its sits on the inlet valve filling the inlet manifold tube.
the valve opens on cranking and all that fuel drops in.
VERY bad for the rings, con-rods etc as fuel don't compress!!!! (35cc'ish i believe)
if the engine did'nt fire should be ok.
could be the injector victor.
BTW hows the Crimson Avenger?
>> Edited by Guillotine on Tuesday 15th November 16:11
all the time the ignitions on.
its sits on the inlet valve filling the inlet manifold tube.
the valve opens on cranking and all that fuel drops in.
VERY bad for the rings, con-rods etc as fuel don't compress!!!! (35cc'ish i believe)
if the engine did'nt fire should be ok.
could be the injector victor.
BTW hows the Crimson Avenger?
>> Edited by Guillotine on Tuesday 15th November 16:11
Started new thread Just a postscript to wrap this one up: when the engine was stripped down there were numerous faults, pretty much all down to the air filter having become disconnected. Its highly likely that some foreign matter has been ingested and impacted a valve, one lobe was worn off the cam, a liner had dropped, and a piston skirt has collapsed leaving bits of skirt rattling about the bottom end. And yes, the head gasket had blown. The suspected hydraulic lock may well have been simply a piece of skirt getting lodged somewhere.
I'm not saying it wasn't hydraulic lock, but it could easily have been something else.
I'm not saying it wasn't hydraulic lock, but it could easily have been something else.
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