Volvo tamd60 pressure drop puzzle

[Craigaddison]

Hello, thought I would cast this out to the masses for idea's / suggestions

Here is my issue

I have recently bought a boat with a pair of Volvo tamd60 b's in place. Done 1500 hours and recently serviced

Both engines run well up to 1700 rpm and will happily sit there all day, rather smokey to start with but only what would be expected from old diesel engines

If you get to 1800 rpm to take her onto the plane, which seems to be the exact point the turbo's come in, it runs fine an pulls well but as soon as you do, the port engine oil pressure drops completely. Drop the revs off and you get a bit of pressure return but not much, stop the engine and restart it right away, pressure is fine again

Oil coolers have been removed, cleaned and replaced, mechanical gauges have been used to rule out problematic gauges, pressure releaf valvehas been changed but all to no avail ... The engines rev up while not under lad with the oil pressure fine

Any suggestions ? ... Any help greatly appreciated as this is very annoying !

 

[paultallett]

Bump......

 

[superheat6k]

losing oil pressure

At risk of asking the obvious, have you checked your oil level.

Is the crank vent filter clean (my TAMD60C's have these) ?

What Oil filters are you using, and how many hours have they done ?

Does the same happen out of gear, as the turbo will be far less effective with no load on the engine ?

If all OK out of gear I would be looking at the turbo seals. The connection with the turbo coming in seems fairly convincing. If air pressure from the Turbo were forced back along the lubrication feed pipes when it reached the pump it would simply stop pumping. Not sure if this is a valid train of thought, but would be interested to know what you discover.

 

[tinkicker0]

Hello, thought I would cast this out to the masses for idea's / suggestions

Here is my issue

I have recently bought a boat with a pair of Volvo tamd60 b's in place. Done 1500 hours and recently serviced

Both engines run well up to 1700 rpm and will happily sit there all day, rather smokey to start with but only what would be expected from old diesel engines

If you get to 1800 rpm to take her onto the plane, which seems to be the exact point the turbo's come in, it runs fine an pulls well but as soon as you do, the port engine oil pressure drops completely. Drop the revs off and you get a bit of pressure return but not much, stop the engine and restart it right away, pressure is fine again

Oil coolers have been removed, cleaned and replaced, mechanical gauges have been used to rule out problematic gauges, pressure releaf valvehas been changed but all to no avail ... The engines rev up while not under lad with the oil pressure fine

Any suggestions ? ... Any help greatly appreciated as this is very annoying !

I'd be taking the sump off and taking a gander at your oil strainer.

DO NOT RUN IT! You need to look at your crank and turbo bearings. They may be damaged now. Also, if the oil pump is anything like a Volvo D7C / TD71, there are also 2 bypass valves in the pump itself as well as the reducing valve at the bottom of the block.. Can't be more specific cos I know nuthin about the D6 in particular and the marine variants in general.

 

[volvopaul]

Tinkiker is on the right lines.

The oil pressure drop at higher rpm could and im 90% sure you have a piston cooling jet problem.

The system works by not cooling the lower piston at low rpm, but as soon as the revs increase and the pressure builds it opens the piston cooling jet valve to allow oil to the jet gallery.

The oil feed to the turbo is constant, if it wasnt the turbo would seize up straight away when the engine has started.also air pressure wuld not force back down the turbo oil feed as its pressure is far less on full boost than the oil pump produces.

You can test pressures on the 61a on the oil valve block, I can take a look in my manual and get back to you if its possible to test the 60c at various points.

Not sure id be wanting to run the engines now under load at the point where the OP drops, so id start looking before cruising.

What boat are they in out in out of interest?.

 

[volvopaul]

Ignore my info about piston ccoling the 60b doesnt have it, just looking in the book there is only one relief valve as you have changed it its not that unless there is a flaw somewhere, where it seats.

If you have a shallow sump, it has another scavenge pump in the sump which diverts oil to another point in the sump to e sucked.

If this only looses pressure when to rev the engine and the inclination of the boats stern down maybe the problem lies there, id check your engine numbers to see if you have the second scavenge system fitted to your engine.

 

[tinkicker0]

Ignore my info about piston ccoling the 60b doesnt have it, just looking in the book there is only one relief valve as you have changed it its not that unless there is a flaw somewhere, where it seats.

If you have a shallow sump, it has another scavenge pump in the sump which diverts oil to another point in the sump to e sucked.

If this only looses pressure when to rev the engine and the inclination of the boats stern down maybe the problem lies there, id check your engine numbers to see if you have the second scavenge system fitted to your engine.

I'm thinking pump cavitation again in this case. Is the strainer on this motor a perforated tube or a canister type? How close does it fit to the bottom of the sump if a canister and are these motors particularly sludge prone? Won't take much resistance to draw air in past that pick up tube O ring.

 

[volvopaul]

I'm thinking pump cavitation again in this case. Is the strainer on this motor a perforated tube or a canister type? How close does it fit to the bottom of the sump if a canister and are these motors particularly sludge prone?

Any motor is sludge prone if not serviced enough.

The strainer is a round flat mesh about 5 inch diameter, id guess at 20mm from the sump floor.

Did op say its ok in neutral when revved as it would do the same as oil flow/suction is not load rated like boost and power/ dropping off.

60 b and c is avery simple lube system with only 1 main RV in the system ad no turbo oil feed valve to stabilise pressure and flow to the turbo, unless there is arestriction somewhere in the gallery or just plain blockage which might be the case as you can change the RV easy.

Lets see what boat its in first.

 

[tinkicker0]

Any motor is sludge prone if not serviced enough.

The strainer is a round flat mesh about 5 inch diameter, id guess at 20mm from the sump floor.

Did op say its ok in neutral when revved as it would do the same as oil flow/suction is not load rated like boost and power/ dropping off.

60 b and c is avery simple lube system with only 1 main RV in the system ad no turbo oil feed valve to stabilise pressure and flow to the turbo, unless there is arestriction somewhere in the gallery or just plain blockage which might be the case as you can change the RV easy.

Lets see what boat its in first.

20mm is a lot sludge. OP quoted 1700 rpm everything fine. 1800 rpm and everything goes awry which sounds like a delivery problem due to a restriction, cavitation and air in the system.

I think engine load and turbo boost is a red herring.

However you are right, it needs boots on the ground and a good look see rather than idle speculation.

Another thought - back to basics. The OP HAS checked that the sump is not overfilled of course?

 

[moonraker 36]

wrong grade oil.. thinning out??

 

[Latestarter1]

wrong grade oil.. thinning out??

When oil goes into 'shear' damage in permanent, when lube cools it never recovers original viscosity.

This is likely a mechanical issue. Overfilling certainly causes lube pressure failure but once again recovers after shut down. Thanks to VolvoPaul I am learning about the Volvo 60 Series and am intrigued.........

 

[superheat6k]

Did you ever resolve your problem ?

 

[addi]

For some reason it has only just notified me of replys to my thread !!! Very sorry for not replying sooner.

Things have progressed nice. I have now found it does it in the Marina as well as under load. If it's cold, it will do it earlier. When it does it you can hear a sucking noise .. Then the pressure goes. Oil level is fine and I've checked and changed the filters

 

[longjohnsilver]

Lots of good advice given, time taken in posting and not a squeak from the OP. Not even a thankyou. 2 posts exactly the same and he disappears.

If you're reading this Craigaddison (which I very much doubt) then at least come back and acknowledge the help given. Otherwise it looks like you've wasted peoples time.

Good I take it all back, looks like yr new post was held up by the mods.

 

[superheat6k]

I remain interested because my engines are similar. It is always interesting to see how the theories balance with the actual problem.

 

[volvopaul]

Lots of good advice given, time taken in posting and not a squeak from the OP. Not even a thankyou. 2 posts exactly the same and he disappears.

If you're reading this Craigaddison (which I very much doubt) then at least come back and acknowledge the help given. Otherwise it looks like you've wasted peoples time.

Plus 1. I'd have thought a beer would have been a nice gesture too.

 

[asteven221]

Plus 1. The advice from contributers (especially from the pro's) in this forum is briliant and should be appreciated by all. I am sure it is by regular visitors. Maybe the OP has never been hear before.

 

[paultallett]

I think the OP has replied...... but under a new name!!

User name addi........

 

[addi]

yes i did reply .. i lost my original signed up email address so had to re reg.

I do appreciate the ideas .. as i didn't have access to my old email account, i didn't know my post had received any reply's so never logged back to check .. only casually searching, did i see i had received reply's so sorry if i have offended anyone and i do very much appreciate any help given ! !

A beer ... there's a bloody truck load if i can find out what this issue is !

 

[volvopaul]

Right, this is a longshot but it could be an electrical issue related to the alternator voltage in the loom.

I'd be fitting a mechanical gauge and taking some more readings.