Official Cummins 6cta 450C thread

SeaCruiser · Jan 19, 2019

And congratulations on the cleanliness of the engines.

SeaCruiser · Feb 9, 2019

my3sons, I am working on the setup. There is one thing I dont fully understand, the overheat switch in the exhaust manifold, is this 200DegF? It seems too low to me, there is coolant flowing in there?
I just re-read your message, OMG 8000 miles! I did not grasp that the first time I read it! What are your cruising speeds and RPMs?

ZZ13 · Feb 9, 2019

I am experimenting with removed fuel coolers per discussions I have had with the folks at sbmar.com. I replaced the pipe with a 1.75" wired exhaust hose and then coupled the two hose ends together. It took a little trial and error to make the coupling. The hose from the block is a 3/8" ORFS fitting and the hose going back to the tank is a 3/8" flare fitting (due to the weird adapter Sea Ray put on that end of the cooler). Originally I assumed it was a 3/8" JIC fitting so I bought a JIC to ORFS adapter online. When I got it and tried to connect it I found the threads were too small. Sea Ray used a hardware store off the shelf 3/8" flare fitting. The attached picture shows the size difference between the flare and the JIC. I couldn't find a flare to ORFS fitting anywhere so I bought a flare to FIP from the hardware store and bought a MIP to ORFS online (picture attached of the two coupled). I'll take some temp readings of the line and the tank when it gets hot this summer to see how it compares to the readings with a cooler (I have those from my3sons).

PMC · Feb 9, 2019

Bill, im curious on the fuel cooler removal. I havent heard of this, and would like to understsnd the pros / cons of this modification. Is this to solve an existing problem?

ZZ13 · Feb 9, 2019

PMC said:
Bill, im curious on the fuel cooler removal. I havent heard of this, and would like to understsnd the pros / cons of this modification. Is this to solve an existing problem?

No real problem. The coolers were 18 years old and in salt that means end of life soon. So rather than spring for two new ones at $200 each, I removed them. According to sbmar and some fellow boaters that have removed them, they aren't needed unless you boat in the desert, much like the air grid heaters aren't needed where I boat as well (I removed them several years ago).

Advantages: one less part to worry about failing, two less hose connections to potentially leak, larger diameter path for seawater to flow from pump to aftercooler.

Disadvantages: none, pending hot weather testing.

PMC · Feb 11, 2019

Generally curious, how do the fuel coolers typically fail? Leak fuel? Leek raw water on engine? Leak water into fuel system? Are there any early detection signs of a soon to fail cooler?

I replaced the trans cooler after inspecting, and finding a green solder joint....i felt I dodged a bullet. A dock mate, with mechanical "B's" was not so lucky, and ended up flushing the trannies to remove salt water.

carterchapman · Feb 11, 2019

My dockmate's Pacemaker with two Detroits was getting water in his fuel tanks - it was the fuel cooler...

ZZ13 · Feb 11, 2019

According to sbmar.com, Cummins specs the max input temp of the fuel to be at 160F for our mechanical engines. sbmar.com recommends to use a cooler if its above 120F, so as not to affect horsepower produced when at cruise rpms. I'll shoot a temp gun at the input fittings when its hot this summer to see what I get. Right now, it won't be a concern. Interesting that Sea Ray put the cooler on the fuel returning back to the fuel tank, not on the fuel going into the engine. I assume so that any water that gets in the line from a cooler failure goes into the tank and not into the engine. So I'll take temp readings at the new fitting I put in (output temp), at the tank, and at the fuel input to the fuel pump.

my3sons · Feb 11, 2019

SeaCruiser said:
my3sons, I am working on the setup. There is one thing I dont fully understand, the overheat switch in the exhaust manifold, is this 200DegF? It seems too low to me, there is coolant flowing in there?
I just re-read your message, OMG 8000 miles! I did not grasp that the first time I read it! What are your cruising speeds and RPMs?

Yes, 200 F. The thermostats are 160 degree. They begin to open at 160 and are fully open at 182. Under full load my coolant temperatures are right around 170 degrees.The coolant temps are a little warmer in the exhaust manifold, but if they get anywhere near 200, there’s problems somewhere.

My preferred cruising speed is around 10 mph. But there are times when we go 25. At 10 mph it runs 1150 rpm. At 25 it turns about 2350 loaded down, 2325 not loaded down. When we crossed to the Bahamas last week it was a little choppy so slow gets uncomfortable so we ran for a few hours. We were so heavy with provisions and full tankage that we actually ran a little faster. It sits up on the water better and frees up, exhaust gas temps actually fall off a little when it goes from 2350 to 2375. Props are 22.3

Steve Barrett · Feb 12, 2019

PMC said:
Generally curious, how do the fuel coolers typically fail? Leak fuel? Leek raw water on engine? Leak water into fuel system? Are there any early detection signs of a soon to fail cooler?

I replaced the trans cooler after inspecting, and finding a green solder joint....i felt I dodged a bullet. A dock mate, with mechanical "B's" was not so lucky, and ended up flushing the trannies to remove salt water.

I had a leaking fuel cooler replaced last fall. First sign I noticed was every time I would start the engine there would be sheen of diesel fuel on top of the water. Second sign was having to drain water from the Racor more often then usual.

LMBoat · Feb 12, 2019

I believe the fuel cooler is less likely to fail as it is a simplier design (no tube bundle). If the cooler were on the intake side of the fuel plumbing, and there was a seawater leak in the fuel cooler, saltwater would go straight into the engine. Which pressure is higher? Fuel return or seawater?

Jaybeaux · Feb 13, 2019

Engine Coolant question. Is this the proper coolant for the 6CTA's?

Blueone · Feb 13, 2019

This is what I bought this summer from a Cummins dealer. I bought 17 total for both engines. Looks like the same stuff only I bought premixed, it's just easier to deal with you have the concentrate in the pic.. I got a can of engine paint when I was there too... Part numbers below

Jaybeaux · Feb 13, 2019

Thanks Blueone....yes. I got the concentrate. I'm going to mix with distilled water. Reading on the QuickServe site today, I am led to believe that since 2013, coolant filters are no longer required. Do you agree with that?

Thanks for helping me confirm the coolant.

Jaybeaux

Blueone · Feb 13, 2019

I have heard that about the Coolant filters but I changed them any way

Engine Coolant Filter WF2071 Cummins
Item# 391574644494

$15.99 USD

2

$31.98 USD

Jaybeaux · Feb 13, 2019

Appreciate that. This is where I get confused.....

My existing coolant filter is a Donaldson P554073 which has 8 units SCA.

The Fleetguard WF2071 has 16 units SCA.

I'd think with brand new coolant, I wouldn't have to add any SCA units. I wonder if there is just a "plain" filter? Am I over thinking this?

ZZ13 · Feb 13, 2019

Jaybeaux said:
Thanks Blueone....yes. I got the concentrate. I'm going to mix with distilled water. Reading on the QuickServe site today, I am led to believe that since 2013, coolant filters are no longer required. Do you agree with that?

Thanks for helping me confirm the coolant.

Jaybeaux

Do you have a link to that? The coolant is pre charged with the additive that coats the metal parts to protect them from cavitation damage. But the coolant still needs to be tested periodically to see how much (if any) additive needs to be added to maintain that protection. New filters containing the additive are a user friendly way to provide that additive.

Blueone · Feb 13, 2019

Jaybeaux said:
Appreciate that. This is where I get confused..... Am I over thinking this?

January 10, 2017 at 8:57 pm#14364
In reply to: Advice on Coolant for 6CTA 450 Mechanical

Tony Athens
Moderator
Vessel Name: Local Banks
Engines: QSL9 405
Location: Oxnard, CA
Country: USA
Join Date: Nov 2015
Offline
Topics: 1
Replies: 1511
JBB,

What I say here is based on real field experience (not the “book”) with this engine since it released in the mid to late 80’s………..

The 6CTA 8.3 base engine has a modern mid-stop liner design, and obviously, is also made from superior quality materials, plus has a coolant flow design that when all put together, seems to make this engine very tolerant of something less then a “school book” coolant make up..

So I say this————Use any brand name 50-50 EG coolant, use a WF2073 or WF 2074 filter when you change, and then change the coolant every 3000-4000 hours or 5-7 yrs, which ever come first.. Go fishing and don’t worry about the rest..

Tony

Tony Athens
Seaboard Founder

Jaybeaux · Feb 13, 2019

ZZ13......From the QuickServe site, my engine serial numbers. I misread it. Referring to engines built AFTER Jan 2013. Thanks for the catch.

https://quickserve.cummins.com/qs3/portal/service/manual/en/5411406/

General Information
Beginning in January 2013, all Cummins® engines are Organic Acid Technology (OAT)/Extended Life coolant compatible. Coolant filters are now optional.

Most Cummins® engines built prior to January 1, 2013 were manufactured with a coolant filter head. Use of a coolant filter is recommended. After January 1, 2013, coolant filters are only standard equipment on Cummins® engines greater than 15 liters in displacement. If desired, an aftermarket engine coolant filter head from Cummins Filtration™ can be easily installed on most engines with displacement less than 15 liters.

Several types of coolant filters are available for use on Cummins® engines. The choice of coolant filter type will depend on choice of coolant formulation and choice of service interval. If coolants capable of an extended service interval are used, an extended service interval coolant filter must also be used.

Chemical Filters

Some coolant filters contain additives for Supplemental Coolant Additive (SCA) replenishment. These filters, usually referred to as chemical filters, should onlybe used with conventional and hybrid coolants that require SCA replenishment.

Chemical-Free Filters

OAT coolants do not require SCA replenishment, and must use chemical-free coolant filters.

Blueone · Feb 13, 2019

Good link on different filters W2071, W2073, W2074

https://www.cumminsfiltration.com/s...nical Information Catalogue Water Filters.pdf

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