V2203, faint knock from cylinder no 4

[Fourksb]

Hello all,

I am looking for ideas about what might be causing a faint knock from no 4 cylinder on my V2203.

The engine is in a boat and has only 30 hours use. My feeling is the faint knock has been there since new.

I had a diesel specialist come out today and look over the engine. He was just as puzzled but observed that the engine itself was running very smoothly and showing no other signs of problems.

In the end we thought maybe a faulty injector so I swapped the injectors between one and four to see if the noise followed the injector. It did not, it stayed on four.

Can anyone suggest a course of action from here?

Matt

 

[North Idaho Wolfman]

You need to check the output of the injection pump too.
Have you checked the valve lash?
Crack the injector line while running, does the knock go away?

 

[Fourksb]

You need to check the output of the injection pump too.
Have you checked the valve lash?
Crack the injector line while running, does the knock go away?

By valve lash, I think you mean gap? They are good.
Cracking the injector lines was how we tracked it to no 4.

What is involved in checking the output of the injection pump?

 

[North Idaho Wolfman]

If you can get the noise to go away when you crack the injector, it's more likely a wrist pin issue or a bearing issue.

To simple test the injection pump output, remove the injector lines from the pump and the injector.
Remove the injectors.
install a line off to the side of the engine and attach the injector to it loosely set the throttle to high, crank in short bursts till you get fuel to injector then snug up line to injector connection.
Use a piece of cardboard to see the spray pattern.
If the pattern is weak, you'll need to have the injection pump rebuilt.

 

[Fourksb]

Ok, I’ll try that flow test.

On a side thought, the mechanic cautioned me to avoid turning the nuts below the fuel connections to the pump body as they will affect the timing. We agreed that marking them with a permanent marker before I started would be wise.

he said they affect the timing. If this is the case does it mean the timing can be adjusted on a per cylinder basis? And if so, could it be that number four is slightly too advanced? It certainly sounds a lot like an over advanced kind of knock.

 

[North Idaho Wolfman]

The delivery valve on some models can have the fuel delivery curve altered, but it's not something you can change without the proper equipment.
It's really not timing per say, it's more of a delivery amount.
The timing is all done with shims under the pump.

If there is any doubts about the condition of the injection pump find a good fuel injection shop to do a test and rebuild on it.
Also have the injectors tested at the same time.

 

[Fourksb]

If you can get the noise to go away when you crack the injector, it's more likely a wrist pin issue or a bearing issue.

To simple test the injection pump output, remove the injector lines from the pump and the injector.
Remove the injectors.
install a line off to the side of the engine and attach the injector to it loosely set the throttle to high, crank in short bursts till you get fuel to injector then snug up line to injector connection.
Use a piece of cardboard to see the spray pattern.
If the pattern is weak, you'll need to have the injection pump rebuilt.

The delivery valve on some models can have the fuel delivery curve altered, but it's not something you can change without the proper equipment.
It's really not timing per say, it's more of a delivery amount.
The timing is all done with shims under the pump.

If there is any doubts about the condition of the injection pump find a good fuel injection shop to do a test and rebuild on it.
Also have the injectors tested at the same time.

Thank you for the explanation.

With only 30 hours on the engine I’d like to think the pump and injectors were ok, but at the rate things are going I suspect I’m going to have to pull them and have them checked.

I have a problem in that I have a weather window and I have to get going. Where I am sailing to it will be more convenient to get the injectors etc checked out too. In theory I won’t need the engine much anyway, and the mechanic who inspected it was not worried about it being damaged by light use.

Bugger. Difficult decision.

With those adjustable fuel delivery nuts marked, is there any harm in trying the one on cylinder four to see if it makes a difference? Like maybe back off the fuel flow a bit and see if the knock goes away? If so, which direction would I rotate it? I assume unscrewing it would reduce the delivery amount.

grasping at straws here, but happy to try anything that does not cause bigger problems.

 

[North Idaho Wolfman]

To give you better answers, I need more information.

There is 2 different fuel systems used on the V2203 series of engines.
One is for the IDI (indirect injection) engine and one is for the DI (direct injection) engine.

Can you give me the exact model number that is stamped on the block facing up right next to the injection pump.
I have manuals for both the IDI and DI engines and should be able to give you some better direction.

 

[Fourksb]

To give you better answers, I need more information.

There is 2 different fuel systems used on the V2203 series of engines.
One is for the IDI (indirect injection) engine and one is for the DI (direct injection) engine.

Can you give me the exact model number that is stamped on the block facing up right next to the injection pump.
I have manuals for both the IDI and DI engines and should be able to give you some better direction.

Thank you, I am grateful for your input. I'm away from the engine now but should be back in an hour. I will find that info and send it through.

 

[Fourksb]

One of the problems with marine engine conversions is that they tend to drown the engine in paint. In this case a metallic blue. And they’ve flooded those numbers.

so, I think it reads either:

V2203-7nz1896

or

V2203-Znz1896.

Do either of those check out for you?

 

[North Idaho Wolfman]

Ugg, those numbers didn't help me to help you.

Can you take a picture of the injection pump and the injectors?

 

[Fourksb]

Ugg, those numbers didn't help me to help you.

Can you take a picture of the injection pump and the injectors?

Do these help?

 

[North Idaho Wolfman]

Perfect, yes that should give me the answers I need, let me do some digging in the manuals and get you some info shortly.

 

[Henro]

Just a curiosity question. When you say the engine only has 30 hours on it since new, do you mean since it was newly rebuilt? The reason I ask is because it looks like everything was spray-painted after assembly or even installation. Even hose clamps are painted in the same pretty metallic blue color… As are all the hoses that I saw or noticed…

Of course this question is of no help to you and I understand that…… and I do remember what curiosity did to the cat!

 

[Fourksb]

Just a curiosity question. When you say the engine only has 30 hours on it since new, do you mean since it was newly rebuilt? The reason I ask is because it looks like everything was spray-painted after assembly or even installation. Even hose clamps are painted in the same pretty metallic blue color… As are all the hoses that I saw or noticed…

Of course this question is of no help to you and I understand that…… and I do remember what curiosity did to the cat!

The engine is brand new. Just a typical marine conversion, they drown everything in paint.

 

[Fourksb]

Perfect, yes that should give me the answers I need, let me do some digging in the manuals and get you some info shortly.

Not a nag, and I appreciate the help so far, but if the manuals are proving elusive I am happy to go ahead and turn the nut to see what happens.

Of course I would rather know what to expect first but I am on the clock. A weather window a few days from now that I have to grab.

Please let me know if you think you will be able to find the info, otherwise I will cross my fingers hard and turn that nut.

 

[North Idaho Wolfman]

I've dug into this as deep as I can, I'm not finding any serviceable specs to help guide you.
I would love to tell you that that is your issue, but I honestly doubt it.
But if it works and proves me wrong, great.