Volvo D2-75 Turbo

[Seahorse7101]

I have a Volvo D2-75 turbo new in May 2013. Within 5 months the jubilee clip holding the charged air pipe was found to be lose by Volvo engineer. On next service it was found to be lose again and re-tightened. In October 14 I noticed it was lose again - this time Volvo said the pipe needed replacing because it had become contaminated with oil so would not grip. At this point Volvo were going to cover it under warranty. To replace the pipe the turbo has to be removed. On removing the turbo they found that the waste gate had seized due to light loading of engine, so would not cover the work under warranty. Turbo was sent away by Volvo for complete refurbishment at a cost of £500. Total repair bill £1850.00.
I subsequently found out from another dealer that the wastegate does not open until 2800 rpm my engine revs to 2700 which is within the recommended max revs in Volvo handbook. I took Volvo Penta UK to small claims court and they paid me back in full without admitting fault.The work was completed in January of this year. Within a month I could see the jubilee clip was being forced back, it was not lose. It appeared as if the pipe was expanding so pulling the clip back. Volvo dealer coming down next week to look, they are suggesting abrading the pipe so that clip gets a better grip. I am not sure this is the problem because I know of several D2-75 owners who have not experienced any of these problems and I am on my 2nd pipe.
The charged air pipe is about 8cm long, takes air from the filter through the charger to pressurise the air and then connects to the inlet manifold. The only other thing that connects to it is the crankcase breather hose. My feeling is that there is too much pressure in that part of the system. I have tried seeing it the wastegate opens at max rpm but cannot see the rod from the actuator moving.
Does anyone know what the problem maybe?

Thanks

 

[Tranona]

Suggest you replace the clip with a more substantial one such as those used to clamp exhaust hose.

 

[Aja]

Try something like these first?

http://www.hoseshop.net/clamps-clips/stainles-steel-hose-clamps/stainless-steel-heavy-duty-hoseclamp-20?language=en&currency=GBP&gclid=CPyOssfe0sUCFUoJwwodzQQA6w

Regards

Donald

 

[Strolls]

I know of several D2-75 owners who have not experienced any of these problems and I am on my 2nd pipe.
… My feeling is that there is too much pressure in that part of the system.

I'm not a marine diesel engineer, but I think you're sane.

My spidey-senses say that the hose and clip are just symptoms of the problem, and the cause is the pressure forcing it off.

If other D2-75's do not exhibit this problem then your engine is producing more pressure than they are (or, as I think you observe, not releasing it).

 

[VicS]

Ive never known worm drive clips work loose! but if they are genuinely working loose / coming undone I would replace them preferably with better ones or those in AJa's link.

 

[Skylark]

It does suggest some form of panting, pressure pulsation, is causing the hose/clip to loosen. The hose should have sufficient stiffness to resist the pressure from the turbo discharge. Oil contamination around the joint before it was tightening could also be a potential cause of loosening.

Is the hose the correct spec? Was everything clean and dry when assembled? It should not be necessary to use "beefier" hose clips.

What is the engine max rpm? How do you use the engine...a lot of time at full speed/load or just mid speeds and part load?

How is the wastegate modulated? Is it simple boost pressure (a tapping direct from the compressor housing volute) direct to the actuator or does the pipework go into a PWM valve or some other electrickery?

Why did they think that the wastegate had stuck closed? This would cause an overboost and, possibly, be responsible for the loosening. How many hours has the engine done? Wastegate sticking can be caused at both ends of the operating envelope. Running very hot for long periods is one. Running light load and generating a lot of soot (poor quality fuel?) could quite literally clog the gap between rod and bush.

The wastegate valve is moved by an actuator, a very simple spring over a diaphragm arrangement. The spring stiffness will depend upon whether it takes boost pressure directly or pressure from a PWM valve. There's more control from the latter arrangement but the former is low cost.

I don't know the useful rev range of the D2 engine but as you say, the wastegate valve will probably be closed at lower and mid speeds. It serves to bypass excess exhaust gas from around the turbine to control speed, hence boost. Once the valve opens, boost pressure will be largely constant, depending upon actuator spring rate or PWM.

It would be nice to get hold of the boost curve? Then it would be fairly easy to check the air delivery against spec.

I spent 19 year as an engineering manager for a very large turbo manufacturer. Please keep posting and let us know how you're progressing.

 

[<152587>]

Suggest you get Volvo engineer to fit a boost gauge to the engine and take it for a high speed high load run. You can expect around 1 bar of boost possibly. I am somewhat in awe of the waste gate operation being linked to engine revolutions, it is usually a method of dumping excessive boost pressure for instance when throttles are pulled back but torbo is still spooled up.

 

[Seahorse7101]

Thank you for all your replies. The engine had only done 100 hours when jubilee clip problem was first noted. When the turbo was overhauled it had a new actuator fitted. The problem then occurred within 20 hours of use. I use mixed revs, occasionally max revs to burn of carbon deposits. This was recommended by Volvo Penta UK. It is very difficult to see if rod from actuator to waste gate is moving at any level of revs, even Volvo dealer doesn't know. I know actuator is pressure driven but you would expect it to move at an approximate level of revs. I do believe that excess pressure is causing the issue, could the crankcase breather have anything to do with it? Picture of overhauled turbo before fitting in January 2015. One point, it is impossible to move the metal rod that joins the actuator to the waste gate with the engine off even using pliers and as much effort as possible? The Volvo dealer seems to think that is normal but I don't think it seems right. I am still waiting for Vovo dealer to visit boat. I agree pressure tests need to be taken then you are dealing with facts.

 

[Skylark]

I am somewhat in awe of the waste gate operation being linked to engine revolutions, it is usually a method of dumping excessive boost pressure for instance when throttles are pulled back but torbo is still spooled up.

Not correct, I'm afraid. Diesel engines don't have throttles. The induction system is open. More speed and power, right foot in a car, morse control on the boat, adjusts the fuel injection system.

Petrol cars have throttles. When it's closed and the turbo is still developing a lot of boost (air) the compressor stage will surge, that it operating in a region of high pressure with low flow. This is an unstable condition and bizarre noises are often generated. It will eventually leak away through the induction system or there may be a compressor recirculation valve fitted if it's a hi-tech engine. Turbo rally cars changing gear under high acceleration is the classic example.

A wastegate, also know as a turbine bypass, is a fairly crude device to control the speed of the turbine stage, enabling pretty much delivery of constant boost over a wide engine operating speed.

When the turbo was overhauled it had a new actuator fitted.

It is very difficult to see if rod from actuator to waste gate is moving at any level of revs, even Volvo dealer doesn't know. I know actuator is pressure driven but you would expect it to move at an approximate level of revs.

I do believe that excess pressure is causing the issue, could the crankcase breather have anything to do with it?
Picture of overhauled turbo before fitting in January 2015. One point, it is impossible to move the metal rod that joins the actuator to the waste gate with the engine off even using pliers and as much effort as possible?

The Volvo dealer seems to think that is normal but I don't think it seems right. I am still waiting for Vovo dealer to visit boat. I agree pressure tests need to be taken then you are dealing with facts.

Very unusual, in my experience, to have an early life issue with the actuator but it may explain overboost if it was not moving with boost pressure applied.

Revving an engine is not putting it under load. The wastegate will only start to open once the predetermined boost pressure is being generated. You'll need to put the engine under load for that (think HS&E police, please).

Where is the crankcase breather being recirculated? I'd be surprised if this was the culprit.

If you can't move the actuator rod, that suggests a high rate spring which in turn suggests that it takes boost direct from the compressor, not via a PWM valve. Eat three Wheetabix and try again! It should move. If for example it gives 1 bar(g) of boost pressure, the diaphragm is, from memory, about 2 inch square. That's 28 lbf to move it.

The Volvo dealer should have access to the turbo boost characteristic. You'll need to measure actual boost and compare to nominal to see what's happening.

 

[Anders_P42]

Here's some data from volvo spec I found. It's not running much boost, but upgrading hose clamp still good idea.

Turbo pressure.

kPa psi rpm
30 4,4 1200
41 5,9 1400
51 7,4 1600
58 8,4 1800
60 8,7 2000
60 8,7 2200
60 8,7 2400
60 8,7 2600
60 8,7 2800
61 8,8 3000

Anders

 

[Skylark]

Here's some data from volvo spec I found. It's not running much boost, but upgrading hose clamp still good idea.

Turbo pressure.

kPa psi rpm
30 4,4 1200
41 5,9 1400
51 7,4 1600
58 8,4 1800
60 8,7 2000
60 8,7 2200
60 8,7 2400
60 8,7 2600
60 8,7 2800
61 8,8 3000

Anders

Upgrading the hose clamp is addressing a symptom, not the cause.

The pressure curve info should be very helpful (assuming it's for the right engine spec?). The turbo pressure ratio (out/in in absolute) is 1.6:1 which as you say is not high but seems perfectly reasonable.

 

[Seahorse7101]

Met Volvo Penta engineer on boat today. He fitted larger jubilee clips, but I do not think this is the way forward. No other D2-75 I have seen has had to go down this route and it maybe masking other problems. The Volvo dealer is contacting Volvo Penta UK to find out what they suggest. Thank you all for your responses and I will update as and when I get an information.
I will post photos I took today.

 

[Skylark]

I would ask the VP engineer to give you copies of all correspondence with VP UK.
You seem to be dealing with the engine maker. How about pushing the boat manufacturer for help in getting resolution.
As we discussed earlier, I also bought a new boat in August 2013 and would not be happy at all if I had oily bilges. I agree with your comment that larger jubilee clips is solving an effect, not a cause.
Regarding the £500 turbo repair, did you get an itemised receipt.....what work was done to it? Did they recalibrate the wastegate setting? This is simply applying a specified air pressure to the actuator and adjusting the movement of the valve to ensure the correct preload. This affects the boost delivery characteristic.
I'll call you again tomorrow morning.
Good luck with it

 

[Vitaluna]

Just had to rebuild my wastegate on my d2-75 turbo caused by a volvo penta casting fault on the exhaust water injection elbow. The bottom fixing point of the casting obstructs the waste gate from opening and requires grinding away if you want the waste gate to ever open. My engine has done less than 300hrs!! It's worth checking all you d2-75 owners, just put your hand under the turbo from the port side and tug the wastegate actuator bar it should move towards you approx 15mm.

 

[Ring of fire]

Do you have any photos? We have a d2 75 that spurts oil beneath turbo but wastegate seems impossible to move by hand. It also stops at the exhaust casing.

 

[Kuno]

Met Volvo Penta engineer on boat today. He fitted larger jubilee clips, but I do not think this is the way forward. No other D2-75 I have seen has had to go down this route and it maybe masking other problems. The Volvo dealer is contacting Volvo Penta UK to find out what they suggest. Thank you all for your responses and I will update as and when I get an information.
I will post photos I took today.
View attachment 51873View attachment 51874View attachment 51875View attachment 51876
We have the same problem with our 2016 D2-75F. did you evver resolve the problem? did the stonger hose clamp hold or blow the hose?

 

[Kuno]

Just had to rebuild my wastegate on my d2-75 turbo caused by a volvo penta casting fault on the exhaust water injection elbow. The bottom fixing point of the casting obstructs the waste gate from opening and requires grinding away if you want the waste gate to ever open. My engine has done less than 300hrs!! It's worth checking all you d2-75 owners, just put your hand under the turbo from the port side and tug the wastegate actuator bar it should move towards you approx 15mm.


We seem to have the same problem with our 2016 D2-75F. is it a big job to take the elbow off? did you do it yourself? thanks.

 

[If only I had more speed]

Having realised that several others are experiencing difficulties with "the jubilee clip walking back along the hose" and "wastegate not operating/seized" I took the initiative to monitor the boost pressure on my engine as my wastegate has been seized virtually since the day I took delivery and I too had noted the clip moving back on the turbo outlet hose. My boat is a displacement type and I imagined that as it had been propped for 3000 rpm flat out I would be within the normal operating parameters of the engine and that the wastegate wouldn't need to open if I was mechanically sympathetic when reducing power. It would appear that the wastegate is designed to operate at part loads and is normally well open at full load.
The previously posts have included a schedule of pressures against RPM, showing 8.8psi at 3000 revs. I connected a calibrated pressure gauge to the pipe used to operate the wastegate and fully secured the hose clips on the turbo outlet hose. Imagine my surprise to find that the boost pressure was around 17psi !!!! I then released the turbo outlet hose clip and recorded around 11psi at 3000 revs.
As I believe the engine has the same internals as it's naturally aspirated baby brother the D2-55 I am now concerned about doing damage at even the 11psi recorded with the clip loose and hose releasing the additional pressure.
It would be really nice if anyone whose wastegate has not yet seized could also record pressures against revs to give us an idea of the actual real world pressures to compare with the Volvo parameters. From that point we can all assess our risks in continuing to run with a seized wastegate.

 

[If only I had more speed]

Turbo assembly removed today. Saw problem noted by Vitaluna in that the exhaust outlet casing adjacent to the support bracket lug would foul the wastegate linkage if it were free to move. If you want pictures please PM me.
After removing the exhaust outlet casing I found a considerable amount of carbon and corrosion deposits around the wastegate valve and the spindle seized. Said deposits were cleaned off and the assembly was then placed in boiling water on its gas outlet flange just deep enough to submerge the wastegate valve and spindle for a few hours. At this stage I found that by levering the valve and simultaneously levering the actuator lever I could just about move the valve. Removing the circlip and disconnecting the actuator meant I could deal with just the seized spindle. After several cycles of levering and soaking resulted in a spindle free enough to move under the influence of gravity and was then reconnected and reattached to the ground down exhaust outlet casing. Putting an unmeasured air pressure on the actuator everything moves as desired.

 

[Dave100456]

Pleased you got it sorted. I have the same job to do at sometime soon. Did you reuse the gasket or use a new one?
thanks