500/520 DB official thread

spikedaddy99 said:
This is probably a stupid question relating to prop pitch, but do the props need to match? My port exhaust is 900 degrees religiously. My starboard is 1100 if I am under 2000rpms. Can I just adjust the starboard more?
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My EGT's touch on 1000 during the heat of summer and are within 20 degrees of each other. This weekend they were around 950 with cooler temps and water.

What are your WOT RPM's on each engine?

Are your load percentages close at cruise RPM?
 
quality time said:
My EGT's touch on 1000 during the heat of summer and are within 20 degrees of each other. This weekend they were around 950 with cooler temps and water.

What are your WOT RPM's on each engine?
Click to expand...
I can get 2300+. I was told previously that water temps and air temps have nothing to do with exhaust temps. That came from this forum and Tony Athens (or whoever answered my email)
 
I've heard that also but have seen it with my own eyes numerous times. My EGT's are also affected by the engine room temp as I track that also. Would stand to reason that the engine room runs cooler in the fall then in summer.

If your WOT RPM's and load are consistent between the engines I wouldn't mess with the props to dial in EGT's. Sounds like you have something else going on.
 
I’ve stated this before but ours where fixed with all the correct methods and machined the manifolds and they have been leaking since that was 4 years ago
Just some light soot on the block
I spoke to as many diesel mechs as I could and not one has a fix. One guy says he tells his customers to budget for it every 4 years
So I’m not doing another expensive band aid for them to leak again.
 
We did my Port engine this past spring and it turned out the majority of the leak was from a blown out gasket. We machined .040 off the manifold to true it up then used the latest procedure. So far it's holding after 60 hours so we're going to do the Starboard side this winter.
 
quality time said:
We did my Port engine this past spring and it turned out the majority of the leak was from a blown out gasket. We machined .040 off the manifold to true it up then used the latest procedure. So far it's holding after 60 hours so we're going to do the Starboard side this winter.
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are you keeping fuel burn below 20 gph?
 
Tim Fila said:
Is starboard leaking? If not, why do it?

What was cost on doing the port engine?

Tim
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It has a slight leak but also time to do the aftercooler and heat exchangers so it makes sense to do it now.

I'm using an independent marine mechanic which also happens to be a good friend and slip neighbor. All in with aftercooler service, H/E service, new coolant circulation pump and turbo was around $7,000.
 
quality time said:
My EGT's touch on 1000 during the heat of summer and are within 20 degrees of each other. This weekend they were around 950 with cooler temps and water.


What are your WOT RPM's on each engine?

Are your load percentages close at cruise RPM?
Click to expand...

Curious what your EGT’s are at 1800-1850-1900-1950 RPM’s if you have that info...?
 
quality time said:
Yes, I removed an inch of pitch and most of my cup. At 2000 RPM I'm burning 19GPH with EGT's around 1000F and 64% load.
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I was/am almost there (2000RPM 19.5GPH) but that GPH seems to fluctuate and is not achievable over the last month or so... I assume I have some growth on the bottom. We did a lunch-hang and bottom clean mid-summer so I didn’t think the bottom could be that bad after 2months or so...
 
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rlynch03 said:
Curious what your EGT’s are at 1800-1850-1900-1950 RPM’s if you have that info...?
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I don't have exact numbers but I can tell you that they go up considerably at anything less than 1950. I don't think I've ever seen them above 1150 though nor would I run for a period of time with them that high.
 
Havana Shamrock said:
I don’t have the delaminating problems it’s actually water that splashes from the galley sink to the 2 doors behind the faucet. My for now my wife put a clear film over the bottom 3rd of the doors to keep them dry and it works.
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I am looking at either having a carpenter re-make these two doors and the center section which they said it could be done and match very close. Another option is to remake those doors and center section in glass.
 
quality time said:
It has a slight leak but also time to do the aftercooler and heat exchangers so it makes sense to do it now.

I'm using an independent marine mechanic which also happens to be a good friend and slip neighbor. All in with aftercooler service, H/E service, new coolant circulation pump and turbo was around $7,000.
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A couple of relevant threads...
http://clubsearay.com/index.php?threads/cummins-dry-exhaust-service-bulletin.96644/
http://clubsearay.com/index.php?threads/and-we-think-we-know-the-reasons.96855/
 
For those of you that have the Garelick helm chairs on the 08 and newer 52 and 58s. The handle that you use to move the chair forward and backwards is it a pull release or do you unscrew it. If it’s a pull release mine are stuck but I can unscrew them.
 
Havana Shamrock said:
I’ve stated this before but ours where fixed with all the correct methods and machined the manifolds and they have been leaking since that was 4 years ago
Just some light soot on the block
I spoke to as many diesel mechs as I could and not one has a fix. One guy says he tells his customers to budget for it every 4 years
So I’m not doing another expensive band aid for them to leak again.
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Are you telling me that even rescue tape won't fix the leak? :D
 
Alex from what I’ve heard over 5 seasons with qsm11’s I dont know of anyone that has repaired them and done. I’m convinced there is no permanent fix. Even Cummins kept up with a new procedure so that tells me no one has it fixed yet. Maybe flex seal?:)
 
Havana Shamrock said:
Alex from what I’ve heard over 5 seasons with qsm11’s I dont know of anyone that has repaired them and done. I’m convinced there is no permanent fix. Even Cummins kept up with a new procedure so that tells me no one has it fixed yet. Maybe flex seal?:)
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Yeah, it's a shame that such a great engine has this design flow.

I didn't study this engine in great detail, but my understanding is that the nature of the leak is due to extreme temps and lack of cooling. So, until CUMMINS comes up with a mod to introduce cooling (maybe an additional HE?) or a titanium (or any similar material to withstand 1000 degrees temp) gasket, it obviously makes sense for the leak to keep coming back.

In the meantime, if you wish to prolong the life of the gaskets, all you can do is keep the exhaust temp as low as possible. It sounds like trawling speed will save a lot of money not just on fuel, but also thousands on fixing the leak. :)

On a serious note, was there any matrix posted earlier that shows exhaust temps at different RPMs. What I'm trying to get out of this, is if anyone did a study say cruising at lower end (RPMs) just to stay on plane. For example, say at your regular cruising speed you stay at 1900RPMs and your exhaust temp is over 1000deg. What if you take it down to 1700RPMs, does the exhaust temp drop substantially?
 
It's interesting that heavy equipment and trucks that use the M11 don't have the same issues with the exhaust manifolds. Their manifolds are a different design with the turbocharger interface at the middle of the manifold but yet still dry.... But, also they are not pushing those engines to over 600 horsepower either. As you know Cummins did issue a service bulletin in 2016 to use the long bolts at all locations on the exhaust manifold which helps in the clamping force for the gaskets. The manifolds must be able to slide laterally across the gasket face for thermal growth so it is extremely important that the mating faces be clean, true, and flat. Secondly, the bolting must be installed and tightened correctly which means clean threads and proper torque and torque sequencing. I'm skeptical that the typical service mechanic takes the time and effort to assemble this stuff with such precision...
I think also that anything we can do to pull the EGT's down will help as that will reduce that lateral sliding across the gasket faces. I pulled two inches out of the props and found the happy spot is at between 1750 and 1800 RPM (22 MPH at around 17 GPH) which shows to be 66 percent load. I don't know, however, what the actual EGT's are.. No leaks detected so far...
 
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