Water in cylinder...head gasket or porous block

[A7novice]

I am getting water in cylinder 1. I have removed head, cannot see any obvious damage to gasket.
I need to establish if water is entering via gasket, or via a porous cylinder block. 
No obvious signs of damage/rot on surface of bore. I have refilled block up with water to very top surface of block in the (nieve) belief that I might see any water entering g bore after several hours and/or water level will drop below top face of block.  Is there 'more scientific' way of determining if block is porous? Advice please.

[Chris KC]

I should have thought if the block is compromised you would be able to see something - a dark spot perhaps, or a crack - in the bore. I don't think leaving it standing is the best test, as under working conditions there's a lot more stress, pressure and vacuum at play.

I should have though a leaky head gasket (or warped head) is more likely.
Can you see any witness marks on the head? (e.g. often you see a sooty patch between no.2 & 3 cylinders where gases have been blowing by)
Have you tried the head for flatness on a surface plate or with a steel rule? (n.b. often they are slightly domed convex in the middle).

Sorry, more basic questions - what sort of head? and was it tightened down with a torque wrench, following the correct tightening sequence? Was the gasket dry or greased?

[Henry Harris]

Water can also enter the cylinders via a seeping manifold stud, a badly fitting manifold gasket and an inlet or exhaust port.

[John Mason]

A good way to check for flatness on the head and block is to put a straight edge along each in turn and see if you can get a thin feeler gauge under it anywhere along it’s length and width.

John Mason

[Andy Bennett]

And more questions.
How much water was in the bore and did you do a compression test before removing head (and any time ago for comparison) and did the water appear after you had done any work or was it just that you had a misfire to alert you?

[A7novice]

It's a HC head on 3 bearing bottom end.
Just been on a run, performed perfectly.....then towards end of run, started to produce clouds of steam out of exhaust.
Before removing head, did compression test....85, 85, 80, 85.

[Chris Garner]

Is the block sleeved?

[A7novice]

Yes it is sleeved

[Stuart Giles]

The thinner HC head gasket isn't as tolerant of warpage and waterway corrosion as the early type. Your problem could just be a leak from one of the water passages into the combustion chamber, rather than a 'proper' head gasket blow. checking the flatness (or not) of the cylinder head is simple if you have the head off already. A straight edge can produce misleading results unless it is the 'Camelback' type. A surface plate is the best thing really, but a piece of thick plate glass will do if you don't have access to surface plate. If the block and head are both flat, it's really down to pressure testing the block. you can do this at home if you have access to a compressor with a pressure regulator. The head/block is filled the brim with water and then the air pressure is raised to about 50 PSI. These photos are of a 1920s Chevrolet cylinder head I did a while ago, but I have done the same with A7 blocks. There's nothing more frustrating than  doing a load of work/spending a load of money on a block or head, and discovering that it's only good for a door stop when you come to run the motor up.