Thornycroft T80

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Aja

Aja

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Had motor on for about 20 minutes. Slight whining sound. Thought it was stern gland so tightened that. No loss of power. Oil pressure/temp all ok. Picked up mooring with engine at tickover and Sheena went into reverse. Engine stalled. Tried to start again. Turn key, starter engages but doesn't turn engine over. Nothing. Tried a couple of times. Wait 20 mins and try again. Engine starts first time and revs up to 3000rpm. Let it run a couple of minutes all ok.

Next morning - with some trepidation - start engine. Perfect. Let it run at fast tick-over for 5 mins - engine dies. Try to start again - seems that engine is seized. Same as previous day. Cool down - starts but this time with a clattering sound at gearbox end. Tried bleeding engine incase of fuel starvation - plenty fuel. Filters are clean.

When cold - engine stars on the button. When running for a couple of minutes engine dies.... and a horribly expensive noise.......

Anyone any suggestions as to what the problem/cause is?

TIA
Donald
 
Any excess smoke from exhaust when running ? It might be a failed injector, I had a CAV injector split across its face leading to serious overfuelling in one cylinder and a bit of a death rattle.
 
I had similar symptoms a few years ago on an old Perkins 4.107. It turned out to be a b******d back main bearing - I hope it isn't that for you as I have the same engine in my M376, which I suspect is a similar age to yours.
Do you know how many hours yours has run?

Good luck
 
No smoke. No nothing to indicate anything wrong. That's the problem. Apart from the noise - which isn't excessive - nothing to indicate a problem!

Donald
 
The engine - although 16 years old has only done 1600hrs. If as I suspect it is a bearing - either big end or top - it hasn't seized the engine which is puzzling.

Donald
 
I have just spoken to Thornycroft. Straight through to their Service Manager.

Their diagnosis - over the phone - was one of either piston expansion or a bent con-rod.

I'll start a new thread as to what I should be looking out for when towing a 34' Moody behind a Princess 38 for 30 miles!

Thanks for your input.

Donald
 
That's worrying - it is the same age and similar hours.
Was there any signs of oil consumption or smoke? On our Perkins there was excessive oil consumption (which we found afterwards under the engine and in the bell housing). It was getting on for 20 yrs old at the time, but had been abused for most of it.
Good luck!
 
Hardly any smoke. I think I have put a pint of oil max in the engine in about 150 hours running this season.

This engine has not been abused in the past. I have the previous owners very detailed notes of running times and maintenance. He went as far as to put inhibiting oil in the engine every winter.

I'm actually quite concerned that if I decide to go for another Mitsubishi based engine (which are very attractively priced) that a similar situation may occur.

This engine has done very few hours - I would suspect much less than 2000, and to have a problem like this without any indication is worrying. I'm lucky that we are only 30 miles from where we lay up for the winter. We were in Stornoway earlier this year. Now that would have been a problem.

Donald

N
 
We did it in the last boat from Tobermory, blagging our way through the canal. No problem.

Whether we would have sailed back from Stornoway in the time we had left on holiday is another thing.

Aja is still at Kames. Friends are giving us a tow with their Princess 38 this weekend to Dumbarton. So if you see a Moody 346 hitting 24 knots up-river on Sunday.....give us a wave.

Whatever happens with the engine it will be expensive. No doubt about that!

I'll pass the hat round....

Donald
 
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