Odd question-How free does a turbo have be to work

They should spin freely by hand, if they are crunchy you need to take the exhaust bend off and you will find rust is jamming the turbine blades, you can carefully scrape it away with a small screwdriver, they don’t like standing unused.
 
That wont help.

See the orange crystals under the fan blades exhaust side?

7Xrhzp2.jpg


God knows what kind of corrosion that is but they all get them after a layup and after a lengthy layup I've seen them get rather large indeed. Try scraping them off until the fan spins freely. With a very arbitrary test about 2 or so spins with a flick of the finger. If all is clear and it's still tight the bearings may have tightened up with oil glaze or corrosion then it's a refurb job if the housing is still good. The fan to housing gap acceptable allowance is IIRC ~1mm so if the housing has corroded or fan tips burnt away then you may not be getting the neccessary mid range boost to get you over the torque hump.
 
David, you could also use a feeler gauge (thinish) that fits easily between blades and casing and turn it with the rotor to "shave" rusty bits off the casing. Basically anything will do but take it easy. If the one freed itself, I'd expect the other to do so with a bit of effort
 
vas said:
David, you could also use a feeler gauge (thinish) that fits easily between blades and casing and turn it with the rotor to "shave" rusty bits off the casing. Basically anything will do but take it easy. If the one freed itself, I'd expect the other to do so with a bit of effort
Click to expand...
Feeler gauge good idea.
Looked at the offending turbo again last night and the crunchy stuff seems to be on the inlet side.
It now passes the googler spin test.
Will try it out today and report back
 
There is a suggestion if you lay up for extended periods afloat , put a bag sealed over the air filter to minimise sea air from the ER .

The exhaust side is still exposed thought.
It all depends on the quality of the turbo metals to start with .Those KAD turbos just rot away even with use age .Much like the elbows and risers .You start to see orange spots appear in the external green paint .After market S Steel risers and elbows do exist.But the not turbos they are replaceable .
Its just the phaff and potential holiday spoiler…….the unknown fail date .

Last season with Covid movement restrictions etc my engines MANs were left in the ER not run for 8 months .
The engineer I used @ the end of may reported a “ sticky valve “ .Not sure which side - something lost in translation?
Boat ran Ok he said just run it off a few hot runs .He said it was corrosion because it’s left standing so long.
When you started it and it settled you could hear a characteristic bang , a little bang at tickover .
This went when rpms were up kinda lost with the general increase in sounds .
Anyhow he was right it went after a high speed ( read high heat ) run .

Experienced guy .

Normally in none Covid times i would have regularly attended in the winter and run them up .


One winter ( different issue here ) I scoped out a valve adjustment, just wanted to suss out the access and flip off a valve cover to eyeball the head and relate that to the manuals etc .
The valve cover is just two 14 bolts .How ever to my surprise it was bone dry up there .Was expecting a rather oily mess of metal to the touch but nope all very dry .Just goes to show the oil after a few months just runs down and down thinning it’s coating to virtually dry to the touch .
So maybe the valve stems dry out that way after 8 months ? Dunno ?
And a bit of air, sea air leaching in an open cylinder .

Anyhow all good .
Back to regular starts and all other systems run up this winter .
 
Portofino said:
There is a suggestion if you lay up for extended periods afloat , put a bag sealed over the air filter to minimise sea air from the ER .

The exhaust side is still exposed thought.
It all depends on the quality of the turbo metals to start with .Those KAD turbos just rot away even with use age .Much like the elbows and risers .You start to see orange spots appear in the external green paint .After market S Steel risers and elbows do exist.But the not turbos they are replaceable .
Its just the phaff and potential holiday spoiler…….the unknown fail date .

Last season with Covid movement restrictions etc my engines MANs were left in the ER not run for 8 months .
The engineer I used @ the end of may reported a “ sticky valve “ .Not sure which side - something lost in translation?
Boat ran Ok he said just run it off a few hot runs .He said it was corrosion because it’s left standing so long.
When you started it and it settled you could hear a characteristic bang , a little bang at tickover .
This went when rpms were up kinda lost with the general increase in sounds .
Anyhow he was right it went after a high speed ( read high heat ) run .

Experienced guy .

Normally in none Covid times i would have regularly attended in the winter and run them up .


One winter ( different issue here ) I scoped out a valve adjustment, just wanted to suss out the access and flip off a valve cover to eyeball the head and relate that to the manuals etc .
The valve cover is just two 14 bolts .How ever to my surprise it was bone dry up there .Was expecting a rather oily mess of metal to the touch but nope all very dry .Just goes to show the oil after a few months just runs down and down thinning it’s coating to virtually dry to the touch .
So maybe the valve stems dry out that way after 8 months ? Dunno ?
And a bit of air, sea air leaching in an open cylinder .

Anyhow all good .
Back to regular starts and all other systems run up this winter .
Click to expand...
Porto, you should do what I do and pay for the boat to be run every few months. A sticky valve could be catastrophic.
 
vas said:
that's odd, all turbos I've seen stuck were on the exhaust side! good luck with the trail
Click to expand...
Although I’ve cleared the easy end, my no improvement trial today shows that I need to do the more hard to get to end as you suggested would be the more normal end.
However I’m in a lovely cala and happily in denial.
I hope running with a non turning turbo doesn’t cause any harm
 
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DavidJ said:
Feeler gauge good idea.
Looked at the offending turbo again last night and the crunchy stuff seems to be on the inlet side.
It now passes the googler spin test.
Will try it out today and report back
Click to expand...
Problem is….your turbos/ engines are in too good condition. If they where a bit knackered and the turbo inlet side was coated with oil…wouldn’t have seized. Proper upkeep is a bad thing on this occasion ?
 
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DavidJ said:
Although I’ve cleared the easy end, my no improvement trial today shows that I need to do the more hard to get to end as you suggested would be the more normal end.
However I’m in a lovely cala and happily in denial.
I hope running with a non turning turbo doesn’t cause any harm
Click to expand...

I think your engine fueling is boost controlled so shouldn’t be dumping loads of fuel in which is good.

is the S/C boosting to get the turbo going? If you can spin turbo wheel by hand easily…can’t see why it wouldn’t spin up
 
Mr Googler said:
I think your engine fueling is boost controlled so shouldn’t be dumping loads of fuel in which is good.

is the S/C boosting to get the turbo going? If you can spin turbo wheel by hand easily…can’t see why it wouldn’t spin up
Click to expand...
Agree I thought I had cracked it
Mr Googler said:
I think your engine fueling is boost controlled so shouldn’t be dumping loads of fuel in which is good.

is the S/C boosting to get the turbo going? If you can spin turbo wheel by hand easily…can’t see why it wouldn’t spin up
Click to expand...
It did spin so I was quite confident.
Just hope there are no other issues
The S/C kicks in and out the same on both sides at the right rpm Afer that the trouble start on the suspect side
 
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guess no boost gauge there David?
I'd have thought if it spins without grinding/sticking with engine off, would be happy to spin at 50k rpm under load.
will probably have to remove the whatever you have after the exhaust side (sterndrives so horn?) and check blocking there
boost leaking would I guess affect s/c as well, so unlikely
 
Also take a bit of tissue paper, run the engine so the SC is blowing hard and do a walk around the induction system looking for leaks. Particularly the manifold between turbo to CAC elbow.
 
BruceK said:
That wont help.

See the orange crystals under the fan blades exhaust side?

7Xrhzp2.jpg


God knows what kind of corrosion that is but they all get them after a layup and after a lengthy layup I've seen them get rather large indeed. Try scraping them off until the fan spins freely. With a very arbitrary test about 2 or so spins with a flick of the finger. If all is clear and it's still tight the bearings may have tightened up with oil glaze or corrosion then it's a refurb job if the housing is still good. The fan to housing gap acceptable allowance is IIRC ~1mm so if the housing has corroded or fan tips burnt away then you may not be getting the neccessary mid range boost to get you over the torque hump.
Click to expand...

I had my turbo reconditioned last year and had stainless sleeve welded in - works a charm now
 
This morning I opened up the exhaust side of the turbo and the turbine was jammed solid. (Honest! I had got a spin when clearing the inlet side yesterday.)
My small screwdriver did well and it’s now quite free.
What’s the tip in the trade to removing and replacing the KAD43 exhaust clamp. It took me ages this morning.
I’ve had enough of ******* boats at the moment so will go and have moules and beer and try it out tomorrow.
…..and for all you nice folk who suggested the exhaust scrape out early on, feel free to say “I told you so!”
 
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Now I’m more concerned. If the exhaust side was stuck…and the air side span easily…the turbo wheel shaft could be snapped!

before you do anything…spin one side and make sure it spins the other side.

As for the clamp…loosen off the elbow to outdrive horn rubber hose clamps. Makes lining the elbow with the turbo easier.
 
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