410 Sundancer/Express Cruiser and 400 Sundancer/Express Cruiser **Official Thread**

[TitanTn]

Looks great Riptide. I look forward to seeing the finished product. I'm working on a swim platform fiberglass project and too am waiting for a little warmer weather to finish it up. This is my first time on a project this big and I'm not quite brave enough to be posting it yet!

 

[Cocktail Time]

Question on Impellers for 3116's- do you guys prefer the Sherwood 17000K ones or is ok to use the StayCoolPumps version? I'm attempting my own this time. My mechanic/friend warned me to stay away from the StayCoolPumps impellers but they are both the same price and the SCP kit comes with a puller, key ways, and end caps as well as gaskets. Thoughts? Tips? https://www.amazon.com/gp/product/B0859NYHK3/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

[Strecker25]

PSA, clean your turbos! This would be a royal pain and downright dangerous in the risk of damaging the compressor fins if the aftercooler wasn’t removed. Since I had my aftercooler off I figured noe was the time to pull the housing and give it a go. Glad I did, they were dirty. I’m fairly certain the boat was run with multi-vis oil early on which probably contributed to the buildup.

The service manual recommends a hydrosolv product for the back plate and compressor wheel. Most of the citrus degreasers at HD or Lowe’s have it (pretty sure simple green does as well) so I’ll be extremely careful when cleaning those. The housing cleaning up nicely so far

 

[Strecker25]

@SeaNile start the 3126 thread, then I can stop spamming everyone here with my diesel stuff

 

[Stee6043]

@SeaNile start the 3126 thread, then I can stop spamming everyone here with my diesel stuff

No doubt. Us disadvantaged, underrepresented gas owners would appreciate if you'd take your elite discussions to another thread. I imagine your new diesel thread to be stocked with expensive cigars, well aged bourbons and an attractive server. Us Merc long block guys will crack open a Keystone Light or mix a Kirkland and Coke contemplate and our next move.

 

[Stee6043]

No doubt. Us disadvantaged, underrepresented gas owners would appreciate if you'd take your elite discussions to another thread. I imagine your new diesel thread to be stocked with expensive cigars, well aged bourbons and an attractive server. Us Merc long block guys will crack open a Keystone Light or mix a Kirkland and Coke contemplate our next move.

I do hope you guys don't stop posting, in all seriousness. You guys have some pretty neat kit under those engine room covers...some of it makes me appreciate the simplicity of my rig at times...

 

[Strecker25]

I do hope you guys don't stop posting, in all seriousness. You guys have some pretty neat kit under those engine room covers...some of it makes me appreciate the simplicity of my rig at times...

haha! But of course we smoke fine cigars while closed in the engine room, diesel can’t explode, right?

I bet you gas guys didn’t know they offered a 3 stateroom version of the 410, but all diesel options have a berth in the bilge between the engines where us elitists sleep. My wife closes me in down there so I can admire my colossally expensive hunks of steel before I doze off.

Ill keep posting here, especially the model specific stuff that applies to all of our boats.

 

[knotonduty]

Hello group, purchasing a 1999 40 DA, 3110 CATS 350 HP. Just wondering if anyone has messed with props, and what the optimal prop was to reach the 2850 rpm. Look forward to some good discussion.

 

[Strecker25]

Hello group, purchasing a 1999 40 DA, 3110 CATS 350 HP. Just wondering if anyone has messed with props, and what the optimal prop was to reach the 2850 rpm. Look forward to some good discussion.

I think many of us have taken some pitch out to get to 2850 or so. I have a 2002 410 and we needed to drop to 21.5 versus the 23 original

Don’t make any changes until you have a chance to run the boat wide open and fully loaded how you will use it. you want to make sure the tachs are accurate and give that data to your prop man

replace the tachs with aetnas too, worth every penny

 

[knotonduty]

I think many of us have taken some pitch out to get to 2850 or so. I have a 2002 410 and we needed to drop to 21.5 versus the 23 original

Don’t make any changes until you have a chance to run the boat wide open and fully loaded how you will use it. you want to make sure the tachs are accurate and give that data to your prop man

replace the tachs with aetnas too, worth every penny

I appreciate it. I have read about the Tachs and def will be replacing those for sure. We are gonna shoot the crank pulley to get true RPM. I’ll prob live mostly in the cruising range of 22-2400 rpm.

 

[Strecker25]

I appreciate it. I have read about the Tachs and def will be replacing those for sure. We are gonna shoot the crank pulley to get true RPM. I’ll prob live mostly in the cruising range of 22-2400 rpm.

your engines and fuel budget will be quite happy between 2100-2200 once you are propped to 2800

Did you survey it yet? Make sure your surveyor runs it up to wide-open

 

[knotonduty]

your engines and fuel budget will be quite happy between 2100-2200 once you are propped to 2800

Did you survey it yet? Make sure your surveyor runs it up to wide-open

yes we did. Port went to 2700 and Stbd 2500. Having them deduct money to get props done. Surveyor said def needs prop tuning. Owner never ran over 2200. Can eat off the engines and bilge. I had read where a lot of people had them re pitched. But figure y’all would def know.

 

[SeaNile]

yes we did. Port went to 2700 and Stbd 2500. Having them deduct money to get props done. Surveyor said def needs prop tuning. Owner never ran over 2200. Can eat off the engines and bilge. I had read where a lot of people had them re pitched. But figure y’all would def know.

That must have been one cold sea trial!!

 

[dtfeld]

@knotonduty... 2500 RPM is really, really low for WOT on a CAT 3100 series engine. Optimal is 2800 +25 to 50 RPM with everything clean, fresh, and loaded for the way you run the boat. Normal for these boats with factory props would be 2700, maybe even high 2600's, but 2500? Your 30% over propped, and that is not going to be fixed tweaking the props. The big split between them is also concerning. Were the props clean and undamaged?

The first question I would have is how was the RPM measured. If it was the stock Sea Ray tachometer, I would not believe that number. Did someone strobe the flywheel while running WOT? Did they record boost pressure and EGT as well?

Could be a lot of benign things, but could be major issue as well.

You need to get to the bottom of why one engine only turns 2500 RPM.

Some reading. All of this is written for Cummins engins in particular, but this applies to all mechanically governed turbo diesels.


-- >https://www.sbmar.com/featured-article/propellers-move-boats-engines-just-turn-them/

--> https://www.sbmar.com/articles/engine-life-vs-engine-loading/

--> https://www.sbmar.com/articles/boost-egt-and-horsepower/

 

[Strecker25]

yes we did. Port went to 2700 and Stbd 2500. Having them deduct money to get props done. Surveyor said def needs prop tuning. Owner never ran over 2200. Can eat off the engines and bilge. I had read where a lot of people had them re pitched. But figure y’all would def know.

Was CAT present for that portion? Did they check boost and blow by, any smoke?

dirty bottoms or fouled running gear can drastically reduce wot as well

 

[knotonduty]

That must have been one cold sea trial!!

Was a little chilly mid 30s. Had full enclosure up so wasn’t bad at all.

 

[knotonduty]

Was CAT present for that portion? Did they check boost and blow by, any smoke?

dirty bottoms or fouled running gear can drastically reduce wot as well

no I didn’t have a CAT rep. But there was no smoke or blow by. Engines came up to RPM nice and strong. EGTs were good. I have to install boost gauges but no sign of turbo issues. I know my way around an engine room just used to dealing with 9k horsepower diesels on navy ships. . Surveyor said he is certain it’s prop tuning that is needed. I am coming out of the go fast world so just was asking for a good baseline. Once I get the boat down here I can do some more research and testing.

 

[knotonduty]

@knotonduty... 2500 RPM is really, really low for WOT on a CAT 3100 series engine. Optimal is 2800 +25 to 50 RPM with everything clean, fresh, and loaded for the way you run the boat. Normal for these boats with factory props would be 2700, maybe even high 2600's, but 2500? Your 30% over propped, and that is not going to be fixed tweaking the props. The big split between them is also concerning. Were the props clean and undamaged?

The first question I would have is how was the RPM measured. If it was the stock Sea Ray tachometer, I would not believe that number. Did someone strobe the flywheel while running WOT? Did they record boost pressure and EGT as well?

Could be a lot of benign things, but could be major issue as well.

You need to get to the bottom of why one engine only turns 2500 RPM.

Some reading. All of this is written for Cummins engins in particular, but this applies to all mechanically governed turbo diesels.


-- >https://www.sbmar.com/featured-article/propellers-move-boats-engines-just-turn-them/

--> https://www.sbmar.com/articles/engine-life-vs-engine-loading/

--> https://www.sbmar.com/articles/boost-egt-and-horsepower/

Was noticed at tachs then shot the output shaft of the transmission. Was 2500-2600. I am gonna shoot the crank when I get the boat down to Va Beach. Pervious owner maintained the boat in pristine condition. Thank you for the links will make good reading today as I fly down to Florida to inspect a few Navy ships. I’ll keep everyone updated on what I find. Thanks for the responses.

 

[Strecker25]

no I didn’t have a CAT rep. But there was no smoke or blow by. Engines came up to RPM nice and strong. EGTs were good. I have to install boost gauges but no sign of turbo issues. I know my way around an engine room just used to dealing with 9k horsepower diesels on navy ships. . Surveyor said he is certain it’s prop tuning that is needed. I am coming out of the go fast world so just was asking for a good baseline. Once I get the boat down here I can do some more research and testing.

Sounds like you’ll get it sorted. If you shot the output/coupler of the trans you accounted for the 1.6:1 gearing right?

our boat has/had a 100rpm delta between the two sides at wot as well. I had the props tuned this winter but I also had a bent strut putting a significant amount of bind in the driveline. Hoping the props and strut work fix ours up

 

[knotonduty]

Sounds like you’ll get it sorted. If you shot the output/coupler of the trans you accounted for the 1.6:1 gearing right?

our boat has/had a 100rpm delta between the two sides at wot as well. I had the props tuned this winter but I also had a bent strut putting a significant amount of bind in the driveline. Hoping the props and strut work fix ours up

yes we accounted for the drive ratio. I was going to purchase a new/used set of props and keep these onboard as spares. The owner ran with tabs completely down at all times so I am sure that didn’t help either. Not like I am going to be trying to set the water on fire either lol.

Bent strut interesting. I’ll keep an eye on on that for sure.

Def exciting for the change of pace and doing some serious entertaining and overnighters.