Reconditioned a legal term?

You have made the right call. Take it home - take the head off. Check the gasket, valves etc ( all cheap stuff ) Ok - mounts will cost you - as will an aftermarket alt and starter. - but not 6 grand.
Also - you will learn so much - and every hr you spend on it hear the chink of £50 going into your pocket on saved labour. I'll be willing to bet two exhaust valves are stuffed - which is an easy fix. They burn out for a pastime.
You can check conrod length easy once the head is off - as tdc piston crown to crankcase face has a spec dimension ( usually about 0.6 - 0.9 mm above face - ie tdc mid gasket thickness )
If that is ok I would leave the rings and bores alone. Just give it a good head job while its off, seals springs etc.
Get the proper Workshop Manual ( Yanmar ) might be online free if you look hard.

Have fun - boats are supossed to be pleasure !
 
Malabarista said:
The OP has, as always been blown away by the kind help and expert knowledge received on this forum. Thanks guys ( and girls if applicable)
I shall forget any notions of moaning to the PO or bitching to the broker. My plan is to pay French Marine and thank them very much for their work. Take the engine home put it on the kitchen table ( maybe) and teach myself a bit of spannering. Then i will probably be back on here asking for help in how to tell which way up things are supposed to go :)
Click to expand...

Dave good choice , I personally never through you get any way with the PO ,
As I said in other posting , that the head off and have a good look , it isn't going to cost you more then a small part of your right arm ,if you can't do it your self get a good engeering shop to remover the valve check seating and re ground de coke .
Like many others I also think your problem of loss compressing is most likely the valves
There some good guys here with good advise if and when you need it .
 
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if you are unfamiliar with engines, then let the mobile phone be your friend- take pics as you strip down so you know where it all goes, and label everything. It will be easier than you think. Dont go mad and strip it right down either!
 
PaulRainbow said:
So, when no 1 comes to the top and locks, bending the rod (just enough to drop the piston height a few thou), how do you get no 2 to lock and bend the rod ?
Click to expand...

Again nail on head. A mate had a Mitsubishi Pajero. It used to have a slight misfire and little puffs of smoke on tickover. Turns out it had been seriously hydrolocked and one rod had bent slightly. Enough to lose a bit of compression ratio so not firing properly on tickover. He reckons he found out that they actually designed bendability in to the rods for occassions such as this! In this case, as Ive said before, CYA in the report, blowing smoke up the OP ass as they say in the business! Bull baffles brains! As you say, if there had been a hydrolock, enough to bend a rod, then it wouldnt have got to the second rod! My money is on pitted valves as well. Simple job. Ive said this to others, my mobile is available if anyone wants advice.
Stu
 
That's a very generous offer,
Stuff. Hope you're not overwhelmed.
skipper_stu said:
Again nail on head. A mate had a Mitsubishi Pajero. It used to have a slight misfire and little puffs of smoke on tickover. Turns out it had been seriously hydrolocked and one rod had bent slightly. Enough to lose a bit of compression ratio so not firing properly on tickover. He reckons he found out that they actually designed bendability in to the rods for occassions such as this! In this case, as Ive said before, CYA in the report, blowing smoke up the OP ass as they say in the business! Bull baffles brains! As you say, if there had been a hydrolock, enough to bend a rod, then it wouldnt have got to the second rod! My money is on pitted valves as well. Simple job. Ive said this to others, my mobile is available if anyone wants advice.
Stu
Click to expand...
 
If the engine parts were not cleaned enough then there would be corrosion of the alloy parts (sometimes referred to as rust to keep it simple), usually showing as a white powder.
If the pistons were not removed for cleaning there will be a good chance of corrosion on the sides. Especially around the grooves for the rings. This could show as a white powder.
If this is the case a good soaking with Plus Gas just might free up the rings.
You should be able to tell with the cylinder head removed.

Again lots of photos are the best way to remember how to put the thing back together.
 
PaulRainbow said:
So, when no 1 comes to the top and locks, bending the rod (just enough to drop the piston height a few thou), how do you get no 2 to lock and bend the rod ?
Click to expand...

I'll easily deal with that point in due course. As I said, it's not rocket science. ;)

But I was actually addressing Superheat6k so first we need to hear from him to find out exactly what he was querying.

Richard
 
skipper_stu said:
Again nail on head. A mate had a Mitsubishi Pajero. It used to have a slight misfire and little puffs of smoke on tickover. Turns out it had been seriously hydrolocked and one rod had bent slightly. Enough to lose a bit of compression ratio so not firing properly on tickover. He reckons he found out that they actually designed bendability in to the rods for occassions such as this! In this case, as Ive said before, CYA in the report, blowing smoke up the OP ass as they say in the business! Bull baffles brains! As you say, if there had been a hydrolock, enough to bend a rod, then it wouldnt have got to the second rod! My money is on pitted valves as well. Simple job. Ive said this to others, my mobile is available if anyone wants advice.
Stu
Click to expand...

If the rods are bent, they are only very, very slightly bent. The compression pressure is down by what, from 20:1 to 15:1? Roughly
Say the stroke is about 100mm. To have 20:1 that's a head volume equivalent to 5mm height. 15:1 would be about 6.6mm height.
When the rod is nearly straight up the bore, with the piston just a couple of mm below TDC, the crank and flywheel have immense mechanical advantage with which to bend the rod.
So it is quite likely the crank will keep turning and be able to bend a second rod.

However, it seems unlikely that both cylinders will have the exact same amount of water in, to bend the rods the same amount?

Another possibility occurs to me, there could be a very slight gasket leak between the two pots.
 
lw395 said:
If the rods are bent, they are only very, very slightly bent. The compression pressure is down by what, from 20:1 to 15:1? Roughly
Say the stroke is about 100mm. To have 20:1 that's a head volume equivalent to 5mm height. 15:1 would be about 6.6mm height.
When the rod is nearly straight up the bore, with the piston just a couple of mm below TDC, the crank and flywheel have immense mechanical advantage with which to bend the rod.
So it is quite likely the crank will keep turning and be able to bend a second rod.

However, it seems unlikely that both cylinders will have the exact same amount of water in, to bend the rods the same amount?

Another possibility occurs to me, there could be a very slight gasket leak between the two pots.
Click to expand...

How will the crank keep turning, the engine has hydraulically locked the first cylinder ?
 
I see some suggestions for taking the head off, servicing it and refitting. This a an extremely bad idea here. We have no idea of the extent of original flooding, how well the water was removed (if any got in), if the engine hydraulically locked etc etc.

IMO, the sump has to come off and all of the pistons must be removed. At which point it would be daft not to take the main caps off for an inspection of the crank and bearings. What is found here would determine the way forward with regards to the bottom end, but i can't imagine i would be putting it back together without a light hone and new rings.
 
PaulRainbow said:
How will the crank keep turning, the engine has hydraulically locked the first cylinder ?
Click to expand...

Theoretically possible if only a splash of of water has entered the air intake. If the rods were to bend slightly but not enough to lock the pistons, they could allow piston 1 to go through TDC with the weight of the flywheel carrying it forward, and only stop on the second piston as it too locks and bends. It might possibly even keep running with a heavy flywheel carrying it through once the pistons have dropped and blown most of the water out on the next stroke. The problem would only show up subsequently with poor starting, smoking etc from the reduced compression. As they say, stranger things have happened at sea! All theoretical, and I have never actually sen it. But I have had an engine with a broken crankshaft get me home, firing on all cylinders still! And yes it was making horrific noises! I have heard of others doing the same, notably with Ford diesels.
 
OK, it appears that several engineers out there understand how more than one con-rod can be affected by hydrolocking. ;)

I would also add one other point ..... if you are going to interpret absolutely literally an "s" on the end of the words "piston" and "con-rod", it suggests that you have never read an engineers report before, and particularly not one that has been specificially requested to be written in plain English. :encouragement:

Richard
 
oldharry said:
Theoretically possible if only a splash of of water has entered the air intake. If the rods were to bend slightly but not enough to lock the pistons, they could allow piston 1 to go through TDC with the weight of the flywheel carrying it forward, and only stop on the second piston as it too locks and bends.
Click to expand...

How the hell is the rod going to bend if the piston doesn't lock ?

How will the weight of the flywheel carry it to the next cylinder ?

The engine isn't running, it's being turned over by the starter.
 
RichardS said:
OK, it appears that several engineers out there understand how more than one con-rod can be affected by hydrolocking. ;)

I would also add one other point ..... if you are going to interpret absolutely literally an "s" on the end of the words "piston" and "con-rod", it suggests that you have never read an engineers report before, and particularly not one that has been specificially requested to be written in plain English. :encouragement:

Richard
Click to expand...

How patronising.

Cylinders 1&2. Four possible causes of low readings
a) The piston heights could be incorrect. This could be if water got into the cylinders and wasn't removed fully from the engine before trying to start it. You will try to compress water, which won't happen and the weak point is the connecting rods which bend and then make it short reducing the piston height and compression pressure.
Click to expand...

Note that it refers to cylinders 1 and 2, that's two cylinders. Each cylinder has a piston and con-rod, so that's two of each of those, both ending with an s


Also note
removed fully from the engine before trying to start it
Click to expand...

So you're going to turn it over on the starter,hydraulically locking one cylinder to a sufficient degree to bend the con-rod, yet continue cranking the engine to allow another cylinder to lock and bend the rod ?

Meanwhile, back on planet Earth....................
 
There are plenty of people who will tell you about engines that have been running with slightly bent rods.
Another possibility has occurred to me.
Maybe the motor was rebuilt with mis-matched rods or pistons?

The usual suspects of rings or valves still seem the most likely.
 
lw395 said:
By bending the rod, obviously!
Click to expand...

It was imho cya speak also it helps to lead the OP down the frightened path of new engine, the bent rods are a blind alley. My money is still on the valves. In 60 years of repairing engines Ive never actually seen an example, just heard of the one off my trusted friend.
Stu
 
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