Volvo 3.0 sx- quick question!

[seventeen2]

Hey all,

I have been trying to sort out a problem with one of my engines and have stumbled upon a couple of possibilities.
Quick run down is, the engines are 2006 volvo 3.0glp-d only 55 hrs each.
Boat sits for long periods idle in a marina (in water all the time).

I have had a fault with seawater in no4 cylinder only.
Found that the pushrod was bent, but valve had not hit the piston, but was seized solid in the head.
Ive got the manifold and riser in for pressure testing, but the engineer is dead slow.
Whilst sourcing the new valve and pushrod etc, i found a guy who customises v8 engines and suchlike here in the uk, really helpfull chap!
He said that the valve could have seized first due to it being exposed to the salty air in the exhaust, and being in the open position.
Rust could have seized the valve and starting has bent the pushrod.
But with the exhaust valve stuck open, would trying to turn the engine over to start (a whole morning!) could this cause water to be drawn into the exhaust chamber??
Any advice appreciated!!

Danny

 

[Don S]

Re: Volvo 3.0 sx- quick question!

If the valve was stuck open, and you cranked the engine over, the valve DID hit the piston. That is what bent the push rod.
When you shut the engine off last, did it diesel (aka run on) after you shut the key off? If so, then that may be the root of your problem.
Run on with the 3.0L engine is common with an idle rpm above 750 rpm. When they diesel like that, they can suck the water from the riser back into the cylinder and valve. Maybe not enough water to be noticed in the cylinder, but enough to lock up the valve.
When the riser was removed, was there any water tracking (rust streaks) in the riser as well as the manifold?

 

[seventeen2]

Re: Volvo 3.0 sx- quick question!

Thanks for the reply Don,

The top of the piston looks as though it has not come into contact with the valve, i.e no marks at all?
The engine was turning over fine with no untoward noises but refused to start.
There is a little surface rust on the exhuast side of the manifold, but no definative tracking.
Both inlet and exhaust valves have corrosion on the back-side, but only on cylinder no4, no other cylinder affected.
The riser looked a little blocked with rust particles, but again doesnt look rotton, although the manifold to riser joint looked a little carbonised, I was getting a lot of white salt/sulpher build up on the exterior of the joint.
The engine has never dieseled to my knowledge, a;though I have had trouble getting the rpm down to 650 in forward gear as i need to set the idle mixture screws, adjusting the tickover screw just makes it run really rough.

Thanks again for the advice

Danny

 

[Don S]

Re: Volvo 3.0 sx- quick question!

I was getting a lot of white salt/sulpher build up on the exterior of the joint.

If the manifold and riser test ok for leaks, just the gasket surface of both to make sure they are flat, then put it back together and see how it works. It may just be the gasket failing.

I have had trouble getting the rpm down to 650 in forward gear as i need to set the idle mixture screws, adjusting the tickover screw just makes it run really rough.

You need to adjust the idle mixture screws to get best idle before you try to adjust the idle speed adjustment screw (aka tickover screw ??????). The you should be able to adjust the speed and continue the smooth running.

 

[seventeen2]

Re: Volvo 3.0 sx- quick question!

Thanks Don,

Ill try and hurry the engineer guy up, it was only 3 weeks ago that I dropped them off!
I hoping its not them as they look pretty expensive and I have always drained them in the winter and flushed them through! (they are brand new in 2006).
So am i right in thinking that a seized valve would not draw water back into the cylinder?
How often should the manifold to riser joint be renewed?
Sorry meant idle adjustment screw!

Kind Regards
Danny

 

[Don S]

Re: Volvo 3.0 sx- quick question!

So am i right in thinking that a seized valve would not draw water back into the cylinder?

It could, it won't suck water up from outside the boat, but it could suck the water back in from where it exits the riser.

 

[seventeen2]

Re: Volvo 3.0 sx- quick question!

So, in theory, an engine that wont start for whatever reason could suck in water if repeatedly turned over?
Im only persuing this angle as the boat was left for about a week after refusing to start before i removed the cylinder head.
The exhaust valve is well seized in the guide, and both valves in that cylinder look affected by saltwater, although the inlet removed ok.
I know why the boat wouldnt origionally start, but if the engineer cannot find fault with the manifold im stumped as to where to start looking for the other cause.
I spent a whole morning trying to fire up the starboard engine, and am concerned that this may be the cause?
Do you think that the salty air in the exhaust outlet could potentionally seize the valve?

Thanks again
Danny