Official Cummins 6cta 450C thread

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Here is the mixing elbow leak. It was a pretty good stream when on plane. Steady drip at idle.
 
I shipped the old elbow to them today. I chatted with them on the phone to learn why the elbow pits so bad. He explained that the chemical reaction of the exhaust with the salt water creates an acid that eats at the metal. He said the new alloy they use is almost impervious to that acid. He said we will get a long life out of these new ones.
 
Are the Port & Starboard elbows the same, or are they "mirror images" of each other? I'm not and the boat, and I can't remember.

Did you ask him about a "group buy"?

Are you replacing both sides? I'm guessing yes.

Jaybeaux
 
Jaybeaux said:
Are the Port & Starboard elbows the same, or are they "mirror images" of each other? I'm not and the boat, and I can't remember.

Did you ask him about a "group buy"?

Are you replacing both sides? I'm guessing yes.

Jaybeaux
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Both sides are exactly the same. I am expecting the quote today.
 
$1400 each. The material cost is the driver. That's the best price he will do. I don't know if it'll go up if you buy separately at a later date. He's off all next week. If you want to order now call them at 954-763-3005 and reference work order number 20886.
 
I put this in a gas engine thread without realizing it.

After installing the Aetna digital tachs on my Cummins 6CTA engines, now that I know the tach reading is spot on I took a look at the synch module and synch gauge accuracy. I found my synch gauge needle was pushed port of center staring at about 800 rpm and got progressively worse as rpm increased (with the new gauges). Almost an entire notch on the gauge at 2200 rpm cruise. After reading up on how they work, I tested the voltages out of the module. I found the module is off, not the gauge. At same rpm it is putting out more voltage to the starboard side of the synch gauge. That's why my gauge leans left. At 1000rpm it put out 4.7v to port and 5.3v to stbd. Bigger difference at 2000 rpm. There is a centering screw so I played with it. That solved the problem. I didn't have to move it much. Now the module puts out about 5.1v to both sides at 1000 rpm.
 

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Ok, they arrived today. I did notice the hose lip on the water hose is less pronounced. I'll probably double clamp that connection as a result.

Fernando, if you are reading did you paint yours? Dave said no need to, so I may just leave it the shiney bling look
 
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Bill, are the shower heads the same?
Do they have the small holes? Same size holes?
 
my3sons said:
Bill, are the shower heads the same?
Do they have the small holes? Same size holes?
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Holes are about the same size. Old holes are 9/32 and new holes are 8/32. Although the holes along the perimeter may be a bit larger. Old shower has 30 holes. New shower has 20 holes. Not sure why. I'll check with them on Monday. I looked at Fernando's pictures and they put 24 holes in his. Looks like it would be very straightforward to drill holes larger or drill 10 more holes if needed. I'll see what they say.

Other than that, the size, shape and orientation of the new mixer is a perfect match for the original.
 

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Does anyone know what this small pipe is coming off the turbo and going to the oil pan area of the engine? At the turbo it connects between the two turbo shells. It has a little too much rust corrosion for my liking. Its fastened by silicon boots and hose clamps at both ends. Has anyone changed this and has any guidance?
 
It’s the oil return line. Oil is sent to the turbo bearings under pressure and that pipe returns it.
Just went down to take a look. Changing it should be straight forward.
 
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my3sons said:
It’s the oil return line. Oil is sent to the turbo bearings under pressure and that pipe returns it.
Just went down to take a look. Changing it should be straight forward.
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Being it's not pressurized when not running, do you think it would be a clean simple job at the dock? I was only worried about oil draining out at the bottom once I remove it. I guess I could tend to it when I change the oil and the engine is empty if this is an issue.
 
craigswardmtb said:
View attachment 75335 View attachment 75333 View attachment 75334 Does anyone know what this small pipe is coming off the turbo and going to the oil pan area of the engine? At the turbo it connects between the two turbo shells. It has a little too much rust corrosion for my liking. Its fastened by silicon boots and hose clamps at both ends. Has anyone changed this and has any guidance?
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It's a normal rust spot for us salt boats. Usually it comes from a very slow drip out of the heat exchanger endcaps. Mine was like that. I took it off, sanded it clean and repainted it and put it back on, after I replaced my heat exchanger end cap gaskets. Oil will not run out if you remove it.
 
craigswardmtb said:
Being it's not pressurized when not running, do you think it would be a clean simple job at the dock? I was only worried about oil draining out at the bottom once I remove it. I guess I could tend to it when I change the oil and the engine is empty if this is an issue.
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I have seen that tube removed during a turbo seal test by a Cummins mechanic. There will be a small amount of left over oil but most drains back after shut off.
 
Like they said, straight forward. It’s time to change those hoses at the ends anyway
 
Can you estimate how many hours these engines can give us when properly maintained and run? What are the max hours you guys have seen on them and how often you push them over 2300RPM?
 
SeaCruiser

I’m going to respond in reverse. The 6CTA cruise RPM is 2200. You shouldn’t run them over that unless you’re doing a WOT test because really you’re just wasting fuel at that point as you have diminishing returns. If you look at the Cummins answer it is the the engine can be ran at WOT 1 hour every 8 hours but I think most members here do it much less. Personally, I run my engines up to WOT every 60 days or so but only for a minute just to make sure all is well.

As far as hours: I’ve seen 13k hours but there are examples of 20k hours on the blocks. It’s my opinion the more hours in a recreational setting then better. Diesels just don’t like to sit and that’s where the problem starts so unlike a gas engine hours are not a percentage of use of the engine. If you find a well maintained 3k hour boat then buy it you will be replacing things like the ac well before worrying about a block.
 
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