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Water leak into a cylinder

Posted: Thu Nov 05, 2015 11:09 am
by don58van
Hi

I am pretty sure my 948cc has developed a water leak into number one cylinder.

It started running roughly. There is a bit of bubbling in the radiator. I took all the plugs out and spun the starter--some drops of what I am pretty sure is water splashed out of number one. A gauge showed that compression is significantly down on number one.

Is this a rare occurrence for these engines? I often read that others have the head gasket go between cylinders 2 & 3, but I don't see much on water leaks.

I am assuming that in all likelihood I just need to replace the head gasket. Correct?

Don

Re: Water leak into a cylinder

Posted: Thu Nov 05, 2015 11:10 am
by bmcecosse
It can happen - so yes - off with it's head!

Re: Water leak into a cylinder

Posted: Thu Nov 05, 2015 11:58 am
by POMMReg
Does the water need topping up regularly?

Re: Water leak into a cylinder

Posted: Thu Nov 05, 2015 12:34 pm
by BLOWNMM
Don
Make up a fitting to screw into the plug holes ie. silver soldering/welding or what ever you can, even an old compression tester fitting to attach to a compressor. With the radiator cap off pressurise each cylinder to be tested and if there is a gasket leak you will see bubbles through the radiator filler neck.
Cheers Bob

Re: Water leak into a cylinder

Posted: Thu Nov 05, 2015 4:05 pm
by bmcecosse
For all the effort involved - just change the gasket ! Take the chance to grind in the valves - and check the surfaces are absolutely flat and spotlessly clean. Certainly don't run the engine again until you find out what's going on.

Re: Water leak into a cylinder

Posted: Thu Nov 05, 2015 5:37 pm
by dalebrignall
i love it when roy says off with its head just makes me laugh dont know why , good luck with the head gasket change

Re: Water leak into a cylinder

Posted: Thu Nov 05, 2015 6:38 pm
by bmcecosse
Queen of Hearts....... :)

Re: Water leak into a cylinder

Posted: Thu Nov 12, 2015 10:49 am
by don58van
Thanks to those who gave advice.

I have taken the head off and confirmed that water was getting into number one cylinder. The bore feels rough, so I suppose it will need honing at the very least :cry: . There seems to be a bit of a score in number 4 too :evil: .

I need to make a more detailed inspection to work out exactly how the water was getting in.

Don

Re: Water leak into a cylinder

Posted: Thu Nov 12, 2015 2:52 pm
by bmcecosse
Hmm - well if the gasket looks ok - could be crack in the head, or in the block.

Re: Water leak into a cylinder

Posted: Fri Nov 13, 2015 6:57 am
by don58van
I've had a chance to have a close look at the head, deck and gasket.

Here are some pix.

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So the path of the water leak is quite clear. No head or block cracks.

It was a really fancy gasket too -- a 'Monotorque'.

Perhaps the front head bolt, nearby, wasn't torqued down correctly (not by me -- this is the first time I have touched the head).

The puddle in the piston bowl is oil, not water. There was quite a bit of water there when the head came off, but this is after I had cleaned the cylinder and piston top. I tipped some oil in and coated the cylinder wall to stop any more rusting until I decide what to do next.

I note that the exhaust valve seems to be recessed quite a bit -- fortunately the others look much better.

Don

Re: Water leak into a cylinder

Posted: Fri Nov 13, 2015 2:17 pm
by bmcecosse
I've never seen such a sunken exhaust valve.... I suggest unleaded seat insert is the way to save the head.