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Boat Engines etc - Maintenance and Repair

Excessive moisture

by mlines » 21 Apr 2017, 20:00

It's not the compression tester itself not sealing properly on that specific bore?

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by shibbs » 21 Apr 2017, 20:42

mlines wrote:It's not the compression tester itself not sealing properly on that specific bore?

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I did wonder this, i removed it and tried it again and still nothing. Then tested the remaining 3 with correct results.. :?:

I have just immersed the valves in paraffin also to see if any passes indicating a knackered valve / seat but nothing, not one passed a single drop.
Confused is an understatement.

Surely to have no compression whatsoever something drastic must be wrong.

Gauge not working correctly would make sense seeing as there is
a: no hole in the piston
b: The rings seem to be sealing ok
c: The valves and seats are sealing
d: Head 'seems' to be in good condition and the head appeared to be without damage.

Anyone got any further ideas / things worth checking? :geek:
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by Ianfs » 22 Apr 2017, 11:32

It may be a bad tester but you checked it on the other cylinders and its ok. Good call though.

I think fitting the V8 inlet manifolds are the same as the V6's, consequently some of the sealing is done by an RTV Gasket Sealant. The thing is, the head gasket may look OK but even a small nick or break will leak.

Bent valve stem? Valve remains open, but when you took the head off it closed. Just clutching at straws. :? What about releasing the valves and checking their movement and maybe re grinding while you have the chance, adding new stem seals too?
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by Ianfs » 24 Apr 2017, 08:49

This is a much older version but the principal is the same.

2012-07-08_223006_260.jpg
2012-07-08_223006_260.jpg (110.16 KiB) Viewed 9242 times
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by shibbs » 24 Apr 2017, 18:49

So with that cooling diagram in mind, i'm really confused as to what will be going through the center port in this picture.. It has definitely had water coming in through it though which is what has caused all the moisture in the middle of the engine / rockers.
I'm beginning to think that water has passed inwards from the exhaust manifold over the valves and into the inlet manifold. The Manifold and elbow (riser) are in good condition but the gaskets were definitely past sell by date and i know water had passed externally. (only now after a considerable amount of reading)

Whats everyone's thoughts?

Image
After considerable time and effort, all this horrible muck and rust is now removed!!

Image

Image

Head, manifolds and inlet manifold are in with an engineer to have surfaces skimmed and pressure tested so we'll see what comes back.
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