Cummins 6CTA 450,8.3,8m

[Bill kosky]

Morning, need some assistance. 2002, 1000 hours, 5 bladed prop, diameter and pitch unknown. Inter cooler serviced and gear cooler serviced in 2012, at 750 hours, report said seriously corroded, flushing and replacement of antifreeze done 2 years ago. WOT rpm unknown or at least that is what I am being told. Hot end of turbo and pipe and small part of inter cooler discolored light brown from heat, impeller ,oil , filters ,serviced regularly since 2012. Fuel burn I am told at 2475 rpm, 24.1 gallons, fuel burn at 2160 is 16.7 gallons per hour. I am sorry that I do not have pictures of turbo , but when I looked at engine it was apparent, and drew my attention..

5 bladed prop pushing 19000 lbs, beam 13.6, water line 36 ft, semi displacement down east hull.

Seriously considering boat , but real apprehensive on motor, confirm or dispel my fears please .

bill

Topic

[George Samaha]

Metalube seems have increased aluminum pitting

Hi again, to follow-up on my previous post, we had the aftercooler pressure tested at 30psi, and no leak. So there was no saltwater leak. PHEWW.

The core was soldered, we had repaired some broken pipes and put it back the seaboard way with plenty of Metalube only a couple months ago. Now reopening it because I want to replace the old repaired core with a new one just received from sbmar, but was surprised that it was difficult to separate from the casing. Took a lot of WD40 and about 30-50 strong knocks back and forth (some of them ground shaking) on a thick piece of wood to separate. The water side was still very good but the air side had a lot of new aluminum pitting, on the top and more on the bottom side, actually where Metalube was, ALL Metalube in the air side transformed from green grease to a gray paste with what seems to be aluminum sandings. In 2 months, we created more pitting in the aluminum casing than the whole 19 years before. What is happening?

[George Samaha]

white powder in the air side of the aftercooler

Hi, what is this white powder in the aftercooler’s air side? this is the turbo side. The engine side also has more of it. It is very slightly salty, or maybe I am in denial!!. We will pressure test tomorrow but a mouth pressure test gave no leak.

No unusual smoke or water vapor from the exhaust last time we ran.

Say some salt water went in the engine’s air intake, is there anything to do to stop its effect?

[Rob Schepis]

That chart is part of the article for the 480CE which is an introductory electronic engine with an ECM and can display instantaneous fuel burn. Unless this thread has been hijacked along the way, the subject engine is the mechanical 450 with no such data available unless a FloScan has been installed and verified to be calibrated dead accurate. For the 450 mechanical verify the tachs are accurate and prop for WOT rpm of 2,700-2,725 when the boat is full and heavy.

[George Samaha]

Jeff, yes, ideally it should be 13.6GPH at 2200RPM according to Tony’s recommendation, but ours can be completely different, it all depends on weight/drag and props, so we need to find a method to measure the actual consumption without having flow meters or smart electronics… And also to be sure the RPMs are accurate while we are testing. It seems the gauges are not that accurate.

[Jeff Capretto]

Philip and George,

Thanks this chart has great details.

[Jeff Capretto]

Fuel Burn

Philip,

Thanks much, this boat does not have Smartcraft. Is there another way to track the fuel flow as you increase the RPM? Guessing a Cummins diesel tech who does the engine inspection will have a computer to attach and record?

Thanks

[George Samaha]

I may have the least experience here, but I can say that I had mine (which are discolored) checked by a local mechanic, apparently he did not care much about the color, he only checked for “play” of the turbo fan on its axis and said they are still good. We recently cleaned the bottom and did about 33MPH, so I am happy the engines are giving all their power. I LOVE THESE ENGINES. You should see the waves we created behind us 🙂

BTW guys, now that the hull is clean, how can I check for GPH consumption? At 33MPH, the old analogue RPM gauges were showing 2600+RPM. I got a digital tachometer but dont know where to point it at! The belt covers are in a very tight place and seem very difficult to remove. Props are Hy Torq 22R24 L-CUP NI. Other owners of the same boat/engines have pitched them down to 23 and even 22.5 degrees. I prefer to reduce some weight from the boat rather than messing with the props.

[Philip]

They look a little dark to me but the fuel vs rpm graph will tell the whole story.

Make sure to get the fuel burn at every 200 rpm from idle to max rpm along with the max rpm and we can tell more.

Phil

[Jeff Capretto]

2002 SeaRay 42 with 355 hours

Tony, Rob and George,

Thank you I’ve been learning a lot reading through this thread. We are traveling to TN to look at a 2002 42 SeaRay with 355 hours on it. The boat has very little time as it spends most time taking quick trips to anchor and run the genset for AC. I have attached a picture below in reference to the discoloration of the turbo’s. In your opinion do they appear properly discolored for the time on the boat? The Port engine papers to have more discoloration.
Is there any issues with the boat only having under 400 hours over 15 years?
If the boat is clean and has service records we are going to press with a survey, sea trail and engine inspection with samples etc.

Thanks for your time and help.

[George Samaha]

Thank you Rob.

[Rob Schepis]

Timing pin. There is a retaining clip holding the pin in the housing and then two seals – one on either side of the housing.

[George Samaha]

What is this part?

What is this part in the 6CTA above the water pump (under the fuel pump)? It leaks oil on both engines.. Any suggestions how to fix it?

[George Samaha]

Scary!!!

OMG! I will sure open them. Any suggestion how we can unlock those rusty screws? good old WD40 or is there anything better in this case?

If I understand right, by making it safer you mean adding a dry riser after the turbo that goes higher than the water lift mufler’s riser. “inherently safe” as Tony calls it?

[Rob Schepis]

Could be safer — Water lift muffler setup is only inherently safe when there is a riser off the turbo, without a riser the turbo/exhaust manifold/engine are always at risk. Here’s the difference between your Cummins book lift muffler setup and the Seaboard way.

As to that OEM wet elbow – it is for sure not a forever item. Here’s one of the ones I pulled off of my current boat and these were several years younger than yours. Don’t let the outside conditions be an indicator, you can see the ones I pulled were “as new” externally but trashed internally. You need to pull your elbow off the turbo and see what’s going on inside….

1 user thanked author for this post.

David R

[George Samaha]

Turbo seeing water?

You’re great Rob. Seems like water is going back in the turbo? Is this exhaust doomed to fail?

[Rob Schepis]

Sure why not but don’t let that stop you from servicing all coolers properly…

[George Samaha]

About seawater pressure testing, I am thinking of making a special hose fitting with air pressure gauge to test the whole seawater side pressure in one shot. Like descaling, would disconnect the water pump output (to insert a fitting with air pressure in the hose. max 30psi) and disconnect the wet exhaust input (to connect the fitting with gauge) and do the test… will have to block the hose going to the dripless shaft seals (if any). In case of leaks, listen or drip some water on hose connections to see if/where it bubbles. If still there is a leak, disassemble the parts and test each separately. Bad idea?

[George Samaha]

Thanks again Rob.

[Rob Schepis]

Gear Coolers

George,

Here’s more info on the subject and replacement option. If you buy locally or elsewhere be sure they meet the specs described here..

https://www.sbmar.com/product-category/engine-components/gear-oil-coolers/

[George Samaha]

Thank you Rob for the pointers about the gear cooler. Yes apparently original and no zinc! 17yrs old… It seems like bronze to me, but when you said fitting, and from the pinkish color where the fitting broke, maybe that was a brass fitting someone put there.

Yes removed the aftercooler core and cleaned water and air side. Waiting for metalube to put if back together. The air side was full of thick oil! OMG I did not expect so muchI Guess this is blowby sucked back in (CC and air filters are very close together).

[Author]

Replies