Any High hour DI engine owners?

[addkerr]

So DI engines gave been out a bit now. Are there any high hour owners out there that can chime in how the engines are holding up?

 

As an engine design DI engines have a few pitfalls vs MPI when it comes to longevity, i.e valve carbon/ deposit build up. High pressure fuel pump/ injectors.

 

Would be interested to see if the marine engines are holding up well vs the MPI that we have had for a while now.

[2Valve]

I'm a regular Techron user in my carb motorcycles and fuel injected vehicles (and Inboard), but with DI, the fuel charge doesn't hit the back side of the valves, so its interesting to see how carbon buildup can be a potential issue.

[BraceMaker]

I've had the head out of an Audi twice in 110. Carburization of valves leads to sticking. Granted turbos probably worse for oily residues.

[addkerr]

@2Valve Im not by any means clued up on this, but my understanding is that in GDI engines you can get blowback and also circulation from the crankcase. These deposits stick to the back of the valves but unlike MPI engines where fuel washes them off, they stick and stay. Reducing efficiency and power. This is completely stolen off the internet and not my own deduction. There are few good videos on youtube explaining the issues of GDI such as the previous mention build up on valves, as well as possible fuel ingress into the oil through the piston rings.

 

Only reason Im asking is that Im in the market for a new boat but only have experience with MPI engines and the longevity of them is really good. I have no experience with GDI so I'm just putting feelers out there.

 

[Andre]

A friend club's boat ,19 Ski Nautique with 50 hrs, is having issues of gas getting into oil.

5.3 DI.

[addkerr]

@Andre I belive gas in the oil is a common issue with GDI engines. I believe its to do with the high pressure and injectors staying open. From what I have read the problem is with all manufacturers of GDI engines just some are worse than others. I was hoping the marine engine managacturers would have this problem down to minimal rather than some Auto engines that have a big problem.

 

No problem when an engine is in warrenty but when your planning on keeping the boat past the warrenty it makes me nervous.

[skihacker]

I won't remember the exact explanation but @addkerr is correct, it's due to a slightly newer strategy for the valve timing, it allows a lot more crank case vapors back up into the intake. I see lots of problems with coked up throttle bodies and intake valves. It seems to be especially bad on cars that do lots of short trips.

[Andre]

@addkerr

Maybe that's where the base 6.0 engine in the Prostar could make sales happen.

You're buying new?

[BraceMaker]

Fuel in crank case on DI engines can only come from the injectors dribbling when the engine isn't running. Why they would dribble and how to solve it is a good question and I suspect largely comes down to the injectors themselves.

 

@addkerr - that's exactly the case, engines rebreath the crankcase vapor by sucking it in using intake vacuum pressure and then reburn it to reduce emissions. Cars have been doing this for many years simply running the crank case breather into the air filter housing and sucking it back through the carb and burning it. PCV's control that flow as well. In cars systems such as cyclonic oil separators try to reduce the amount of oil that is in that air to be burnt but the residue will be there.

 

As this residue is drawn over the hot stem of the intake valve it has a tendency to form a carbon coating which builds up over time.

 

This problem is made worse the more oil residue is being burnt. That all said this was a huge issue for Audi specifically, but is generically a fault of DI formats. I'm not sure I would specifically worry about this, what kills it for Audi specifically is that they have oil consumption issues. On turbo they have a tendency to blow oil out the PCV into the intake tract, that oil needs to be reburnt and absolutely coats the valves.

 

[Jody_Seal]

What is considered high hours in today's ski boat world?

 

[addkerr]

@Jody_Seal well iv got a response on 5200hrs haha but im not at all suggesting that. Id be interested to hear from boats near the 750/1000 mark basically out of warranty motors.

[UWSkier]

What temps are these GDI engines running in marine applications? They run hot in the trucks. Wonder if that has any bearing on the carbon accumulation.

[jhughes]

Mine runs in the 160's at speed, 150's otherwise. FWIW I don't care about the carbon. The performance of these motors is well worth it.

[skihacker]

I would suspect you won't see the carbon issues with ski boats, the higher rpm's will tend to keep them clean.

[MichaelGoodman]

@addkerr Is that 5200 hrs on the original engine?

[addkerr]

@MichaelGoodman original block, had second hand heads put on about 1200 hrs ago. Took a head off last year and the cylinders are looking spotless. I’m not saying compression is fantastic but she’s doing what she needs to do happily.

[addkerr]

@Andre yep buying new, I would love that motor, iv asked the question about closed cooling availability but haven’t heard back from them. Hopefully they do, otherwise the only MPI is going to be the zr4.

 

That is unless the GDI engines are looking good for reliability and longevity, which I have seen nothing arguing for yet.

[Andre]

@addkerr You're in salt/brackish water ?

[addkerr]

@Andre limescale build up.

[UWSkier]

there have to be some ski school boats somewhere with high hours on these GDI engines. They've been around awhile now.

 

Guess your closest analog(ue) is to go over to the GM truck forums and look for guys who have 300k on the ticker of their 2014+ trucks. Granted it's a far different use case and AFM might skew the results, but I haven't read of a rash of these coming in with gunked up valves.

[jjackkrash]

Is gunked up vales a catastrophic problem, or a take-it-in-and-get-the-valves-cleaned problem? I have 170 hours on my H5 and love the engine. It will take me 10-15 more years to hit the 1000 hour mark.

[Not_The_Pug]

I don't know the exact hours, but our neighbor has one of Rini's old ski school boats and I think it is around 2000 hours on a 6.2 DI motor. Runs good for them.

[UWSkier]

CRC makes a GDI valve cleaning spray that you simply shoot into the intake and let work for a while. Again, not sure if the marine use case operates at a high enough temp for it to have the same effect, but would be easy as heck to do on a DD. You can do the same thing with Sea-foam as long as you have a way of limiting the rate at which it's getting sucked in and you don't get any on the MAF sensor. Used to Sea-foam the engine on my Nissan Titan once a year. Would smoke like a mother as it burned out all the crud on restart.

[jhughes]

We have a DI 4cyl turbo BMW, 70K Mi. Lotsa lotsa hours I’d imagine. Runs great. Shocker.

[EricKelley]

Hard to tell how widespread the problem is but one of my GM tech patients said that he has seen more than coincidental failures of the DI engines because of the carbon buildup on the valves. He said that the carbon builds up, then eventually gets so thick a chunk falls off into the combustion chamber and causes failure of that cylinder. He said you can't even get the last bit of carbon off with a wire wheel on a bench top grinder. I am trying not to think about it with our Denali. He said he didn't think any of the treatments/injector service things would help.

I know that ford is now running part of the fuel charge from the throttle body to help with this issue in their ecoboosts. I am going to stick with my 6 liter because of this. I have not heard of a marine failure with the DI engines and hope I don't.