Yanmar 1GM catastrophes

[michael jones]

Has anybody any ideas or similar experiences?

The Yanmar 1GM10 in my boat (a Trapper T28) has functioned flawlessly since
it was fitted about 6 years ago. It has run for about 400 hours in all.
Regularly serviced by a good Yard. Just around Christmas, I asked the Yard
to do a routine service. The only problem at that point was a fan belt
slipping at high revs.

The Yard (usually very professional, technically able and who had serviced
the engine since new) did the service and that was that. However, they found
it hard to start. They had a hunt around and found that a small component
which located the governor was kaput. This was replaced, but the engine
still wouldn't start. Another examination, replacing a piston ring etc., and
it still wouldn't start.

Eventually, they discovered that the con rod was distorted. Not clear why.
Replaced that, and the engine still wouldn't start. Then they dissembled the
engine to its constituent molecules to discover that the camshaft was bent
out of true!

At the time of writing, I don't know if this has solved the problem.

How did all of this happen? What was the originating problem? What caused
what?

The cost is appalling (yard are covering labour, I am covering parts. It is
not clear what happened or who is culpable (if anybody).

Ideas?

Mike Jones

[chrisknibbs]

michael jones <mi...@piassociates.org.uk> wrote in message
news:973um2$9hl$1...@news5.svr.pol.co.uk...

> Has anybody any ideas or similar experiences?

re covering labour, I am covering parts. It is
> not clear what happened or who is culpable (if anybody).

The Yard (usually very professional, technically able and who had serviced
the engine since new) did the service and that was that. However, they found
it hard to start

Did the 'find it hard to start' ...

a) when they recieved it from you?

b) After the service?

This would be my first question....

[chrisknibbs]

michael jones <mi...@piassociates.org.uk> wrote in message
news:973um2$9hl$1...@news5.svr.pol.co.uk...

> Has anybody any ideas or similar experiences?
>

Thinking further...

Well damaged conrod and camshaft go together - either one could cause the
other.
Slipping fan belt .. U'm .. charging / cooling probs - doesn't sound a
very likely culprit - yes could upset cooling but I assume you would have
noticed overheating symptoms - did you??

>
> found that a small component which located the governor was kaput.

ummm suspicious - what exactly is this component - where exactly did it end
up - they didn't drop it anywhere did they?? - I'd certainly enquire as to
where it is now!!!!!

replacing a piston ring etc., ....
So they took the head off.. ...followed (resulting in) a distorted conrod
and camshaft --- I would be VERY VERY keen for them to explain the initial
cause or else I would suspect that they'd messed up - My feeling is that the
onus is most definately on them to ascertain the cause of the damage -I
think I'd probably be looking for an external arbiter at this stage because
to me it sounds like they've made a mistake in this case (it happens even in
good companies - they employ trainess I'm sure like all good companies).
Thinking further - camshaft out of true???? Now how can that happen?? one
conrod damaged - seized cylinder? Incorrectly set up?? Something dropped in
to seize it up?? I certainly would be unhappy and want an explanation --
>
>

[Stephen A. Firth]

In article <973um2$9hl$1...@news5.svr.pol.co.uk>, mi...@piassociates.org.uk
says...

> Eventually, they discovered that the con rod was distorted. Not clear why.
> Replaced that, and the engine still wouldn't start. Then they dissembled the
> engine to its constituent molecules to discover that the camshaft was bent
> out of true!
>
> At the time of writing, I don't know if this has solved the problem.
>
> How did all of this happen? What was the originating problem? What caused
> what?

At a guess, water in the cylinder, probably caused by water getting back
up the exhaust.

--
Depressing teenagers is like shooting fish in a barrel

[guy fawkes]

conrod damage without a blasted piston usually means it has
"hydrauliced" (oil or water getting where air and fuel is supposed to)
could be water siphoned up wet exhaust but slipping fanbelt would mean
most likely suspect blown head gasket.

if it was blown head gasket then you have no recource but to pay up.

[to...@thoward.plus.com]

Hydraulicling an engine doesn't bend the camshaft.

This sounds highly suspicious.

Tony

[michael jones]

Thanks to everyone for the thoughts - gives me the questions to ask, and
therefore of great value.

Mike Jones.

[Rich M]

It might if the pressure against the valve opening was much greater than
spec, causing the valve to push back against camshaft.

Rich M

to...@thoward.plus.com wrote in <3a9621a1...@news.f9.net.uk>:

[guy fawkes]

On Fri, 23 Feb 2001 18:11:19 GMT, n...@thanks.com (Rich M) wrote:

>It might if the pressure against the valve opening was much greater than
>spec, causing the valve to push back against camshaft.

particularly if the motor has hydraulic lifters.

[Mike James]

Sounds like water in the cylinder, because the engine was hard to start
because of e.g. a dodgy injector or a flat battery. Slipping fanbelt ?
Not charging battery fully ?

My guess on the culprit.

Water filled up the exhaust and got back in the cylinder while turning
the engine over with the decompressor open, and then the decompressor
was released. (or water just ran back through the exhaust valve while it
was open)

The inertia of the flywheel then was used to do the damage mentioned.
There is a space 0.7mm high above the piston when it is at top dead
centre (with some extra volume for valves and precombustion chamber) It
takes very little water to fill it. Attemtping to heat the water by
compressing it will not work....

As it says in the manual, after 2 attempts to start the engine, close
the water inlet seacock and then _open it_ when the engine starts.

My engine has just reached the 'hard to start' phase of this process.
I just had the spare injector serviced and I refitted it this evening.

I also checked for signs of bent con-rods and worn bearings measured
simply by crushing fuse wire between piston and cylinder head.
The wire is poked down the hole where the injector and precombustion
chamber are fitted. It gets impressively flattened and should be
0.7mm thick afterwards. I measured 0.9mm but it I used a vernier
caliper rather than a micrometer. This is as in the service manual..

Starting seems better, but I will have to wait for a proper frosty
morning before I can be sure. The engine used to fire up after
just a quick blip on the starter.

I am also going to replace the batteries and the isolator switch with
one that works when it clicks to 'off'. Currently the one I have doesnt
always turn off when turned to 'off' leaving me with a flat battery.

You are lucky someone is helping with the cost.... otherwise..I think I
was quoted £1500 for a re-condition of the engine a few years back.

My experience with 'professional' service was £250 spent to have a head
gasket so badly deformed by random tightening of cylinder head bolts
that it leaked hot sea water round the back of the engine for a year
before I decided to take a look inside the cylinder myself.
Fortunately the damage was just horrible cosmetically outside the
engine.

I have bought a service manual and just buy the gold-plated spares
(e.g. copper washer for about £3.00)

Mike.

[Alisdair Gurney]

"Mike James" <mi...@hamble.demon.co.uk> wrote in message
news:3A95A39B...@hamble.demon.co.uk...

>
>
> The inertia of the flywheel then was used to do the damage mentioned.

Inertia in a flywheel?
I doub't you could get enough energy into a 1GM10 flywheel
to bend the shaft just by trying to start it.

>
> As it says in the manual, after 2 attempts to start the engine, close
> the water inlet seacock and then _open it_ when the engine starts.

It doesn't say that in my manual, is that something that's been added
in the last few years?

[Paul]

No end of engines have been damaged by water backing up in the exhaust. If
you have ever watched how much water the pumps deliver you will know why
this is advised. Always stop or gag the inlet when your engine is reluctant
to start!!
however i guess just as many are damaged by people forgetting to open the
water inlet.
"Alisdair Gurney" <ne...@agurney.com> wrote in message
news:983270369.11326.0...@news.demon.co.uk...

[Mike James]

Alisdair Gurney wrote:
>
> "Mike James" <mi...@hamble.demon.co.uk> wrote in message
> news:3A95A39B...@hamble.demon.co.uk...
> >
> >
> > The inertia of the flywheel then was used to do the damage mentioned.
>
> Inertia in a flywheel?
> I doub't you could get enough energy into a 1GM10 flywheel
> to bend the shaft just by trying to start it.
>

It weighs 12.6 KG and the starter motor spins it at several hundred rpm
if you have the decompressor open.

Dependent on how suddenly you manage to stop it forces can be huge.

(especially when it is being pushed by a starter motor with a heavy
armature spinning ~12x quicker

I am still surprised so much of the engine was damaged.

> >
> > As it says in the manual, after 2 attempts to start the engine, close
> > the water inlet seacock and then _open it_ when the engine starts.
>
> It doesn't say that in my manual, is that something that's been added
> in the last few years?

Sorry, it doesnt say that at all, in fact it says 'if the engine doesnt
start wait 30 seconds'

The advice there is from another source. Its still true that you will
fill the exhaust with water in many installations if the engine fails to
fire.

[Hosheen]

michael jones wrote:

> Has anybody any ideas or similar experiences?
>

> <snipped for brevity>

> The cost is appalling (yard are covering labour, I am covering parts. It is
> not clear what happened or who is culpable (if anybody).
>
> Ideas?
>
> Mike Jones

I haven't the faintest, but I have the same engine in my Watkins 25 so I will be
very interested in further developments. One tip I received that sounded
rather strange to me, but seemed to work was to add some automatic transmission
fluid (ATF) to the fuel. It was said to "clean the injectors". I thought well,
it can't hurt and tried it. I have to say, my Yanmar has never run better and
has about 450 hours on it.

It had smoked a bit before but now is running much more cleanly. I also read
that the head maintenance guy at Yanmar insists that they all need to be run
vigorously about once or twice a month, at minimum.

I am also interested in learning if anyone has any experience in changing the
sacrificial zinc on the engine. I have the factory manual and it recommends
checking it at 500 hours and replacing it if it is more than half eroded. Mine
seems to be very difficult to reach and so it hasn't been done so far as I
know. Has anyone had and experience with this?

Fair winds and following tides,

JES

[Alisdair Gurney]

> I am also interested in learning if anyone has any experience in changing
the
> sacrificial zinc on the engine. I have the factory manual and it
recommends
> checking it at 500 hours and replacing it if it is more than half eroded.
Mine
> seems to be very difficult to reach and so it hasn't been done so far as I
> know. Has anyone had and experience with this?

£5 +VAT for an anode and gasket last time I bought one, and just a couple of
minutes to fit it. It's not difficult to get at - it's attached to a plate
in the block next to the
alternator. Undo the two small bolts and remove the diamond shaped plate.
The anode is attached by the nut in the middle, so leave that alone until
the plate's been
removed.

There's not much zinc on the anode to begin with, so If it hasn't been
replaced for a few
years then there won't be anything but mush.

Alisdair

[Giles Morris]

"Alisdair Gurney" <ne...@agurney.com> wrote in message

news:983996548.10380.0...@news.demon.co.uk...

> It's not difficult to get at - it's attached to a plate
> in the block next to the
> alternator

That's what I thought until a friend asked "did you change both of them?".

Both?

If it's like the 2GM, there are two, but they're both easy to get at. If the
enquirer is interested I'll make a note to check where the other one is when
I next go to the boat (perhaps tomorrow).

Giles Morris

[Andrew Turner]

Hi Hosheen,

The zinc on a 1GM10 is easy to get at if the alternator is removed.

Regards,

[Alisdair Gurney]

"Giles Morris" <Giles....@uasdot.net> wrote in message
news:9865mv$3it$1...@mail.pl.unisys.com...

I believe there's a second zinc on the aft/gearbox end of the 2GM20 block,
but only one zinc for the 1GM10. I'm happy to be proved wrong, though.

Alisdair.

[david....@lineone.net]

It looks to me as if someones messing with it has made it far worse than it ever was. Of course a marine engine's number one problem is rust. After all how is it that a diesel engined car can be left stood for several years yet start up straight away as soon as a fresh battery is fitted? The answer of course is that the car doesn't have a gallon of sea-water lurking in its silencer. On a boat the water in the exhaust evaporates, goes up the exhaust pipe and condenses in the cylinders. Its almost enough to make one go air-cooled. If the valve timing has been upset one can have valves hitting pistons. I had this with a Land Rover Discovery that I bought from a pair of Hooray-Henries. Sure the car had the snorkel, the bull bars and the "One Life Live It!" slogan but when I removed the cylinder head it was discovered that the pistons all had little aluminium volcanoes on them where the valves and pistons had been having an argument. Now at this point I would like to mention that a prolific cause of bad running with a diesel engine is a weak lift pump. Unless the injection pump is being fed at a decent pressure all kinds of trouble will occur. On miniature diesel engines it is essential that the injector is in tip top condition. Take the Petter Mini 6, 1800 psi injection pressure gives very poor running, choking diesel fumes and grey smoke. The problem is that at 1800 psi the fuel droplets are too big to burn in the time that is available. The injector will need either a new spring or some shims. Once the injection pressure is raised to more than 2200 psi the engine will run beautifully. Its all about atomising the fuel into droplets that are small enough to burn quickly. One snag with 1GM10 is that any water leaks from the head are apt to end up in the aft-tappet-tunnel. If the engine is then neglected for years because its owner is ill or deceased the tappet and the block can rust solidly together. If the engine is forced to turn the camshaft will either twist or bend (it will probably do both) IMHO leaky boats need shore-power and a mains operated bilge pump. As to head gasket failure, this can occur when the engine gets choked-up with carbonates. A vicious circle gets set up of more overheating causing more carbonates. Unfortunately cleaning out the water jackets is more difficult than it is on a British Seagull. Basically these engines are very simple but they do need TLC. Good luck!

[Vir Campestris]

On 29/07/2014 04:17, david....@lineone.net wrote:
> It looks to me as if someones messing with it has made it far worse than it ever was.

Whatever messing about they did won't matter any more. It was posted in
2001 - this could be a record!

Andy

[Ignatios Souvatzis]

Must have been on a long circumnavigation...

-is

[Ian Malcolm]

Martin <m...@address.invalid> wrote in
news:7pgmt953q655qtqpg...@4ax.com:

> Maybe the bottle has just arrived from the crew shipwrecked on a
> desert island all these years.

Its on-topic content which is rare enough here nowdays.

Other 1GM10 weaknesses:
* Water Pump - if you often operate in estuaries or othere areas where
there is silt in the water, they just dont last. The silt acts as an
abrasive and the seal wears a groove in the shaft then it leaks. The
shaft is very expensive. You can rebuild it with fibre washers as packing
under the water seal to shift the point the seal lip meets the shaft to
buy another season or two but sooner or later complete pump replacement
is required.

* Oil line across front of engine under water pump - Who thought putting
a mild steel oil line where the pump would drip on it was a good idea?
Its worth getting a replacement made up in copper as this line has a
tendency to rust out and dump all your oil in the bilge

* Exhaust water injection elbow - this suffers from impingement corrosion
where the water hits the inner elbow. Once it pinholes, water tends to
get sucked back into the exhaust port on shutdown causing corrosion that
often causes porosity through into the lifter gallery which ends up with
the exhaust pressurising the sump and massive oil consumption or even the
dipstick blowing out and total oil loss.

* The OEM mounts debond easily if they have been contaminated with oil or
diesel or if they stay damp too long and get rusty. They do noty
positively retain the engine. Best replaced with aftermarket ones
incorperating a drip shield e.g. from R&D couplings, but either adapter
plates must be made or the engine beds must be modified.

Enjoy!

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
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