Official Cummins 6cta 450C thread

scooper321 said:
The engines have about 1400 hours, so I can't believe they are the original ones. The prev owner is actually a friend and was anal about engine maintenance. We talked a bit about the air cleaners as we went over the boat. I just don't remember if they are original. I did get about 4 of those cleaning kits with the boat, however! But you're right. I do plan on swapping them for new ones. I'm thinking I'll wait until I winterize, as that's the next time I'll have the hatches open for easier access to the airseps.
Click to expand...

Had a nice cruise down the Bay last weekend and my first mate reported that on acceleration we still had black smoke. Happened after about 10 mins of no wake crushing to get into open waters. So the engines were almost up to temp, if not fully. But I guess my airsep cleaning didn’t do the trick. The bottom had just been cleaned and the after coolers were cleaned this spring.

My mate doesn’t know anything about turbos spooling up, etc. She just said we got black smoke when we accelerated. Oddly, I was look as I accelerated and didn’t see it, but she was in the cabin so she had a better view.

Is this smoke normal during acceleration, before the turbos kick in? I get no smoke while running, or while idling. It’s just during acceleration. I’ve read things about injectors, turbos bring rebuilt, being over propped, poor Cummins exhaust layouts, so my head is spinning with possible solutions. But I don’t even know if I actually have a problem?
 
Can you post some other details?

is the black smoke every time you come into plane or just the first?

What is your WOT rpm?

When was the last time you cleaned your aftercoolers? And we’re they properly cleaned by disassembling not just rodded out?
 
EKM said:
Attempted trip to Newport and found out trans on the Port side was slipping. So not the starboard engine.
At high idle, both hit 3000rpm which checks out the tachs are accurate. Talking to Twin Disc this am to troubleshoot but sound like trans needs to be pulled. Turbo, aftercoolers need to come out too.
Click to expand...

OK....trans rebuilt (pulled it on Tuesday and was back in by Friday). Took the turbo charger and exhaust elbow out as one piece to allow trans removal. All back together again but the turbo charger to exhaust manifold is leaking antifreeze (new gasket installed). Will order another gasket and replace. Planning to block sand exhaust manifold and turbo flange and will re-install with high temp silicone.

Any other suggestions on how to reseal this flange?
Thanks....Ed
 
EKM said:
Thanks....reinforces that this is typical and high temp silicone will help seal.
thanks again! Was so disappointing to work on my boat for the whole day and upon start up, see it dripping antifreeze!
Click to expand...
Actually that's not the link I wanted, I changed it. check it out.
Still the same how to though.
 
EKM said:
OK....trans rebuilt (pulled it on Tuesday and was back in by Friday). Took the turbo charger and exhaust elbow out as one piece to allow trans removal. All back together again but the turbo charger to exhaust manifold is leaking antifreeze (new gasket installed). Will order another gasket and replace. Planning to block sand exhaust manifold and turbo flange and will re-install with high temp silicone.

Any other suggestions on how to reseal this flange?
Thanks....Ed
Click to expand...

Big Tony fan but I would recommend to stuff all passage ways with rags, removing the studs and then using the best file you can buy, true both mating surfaces evenly, remove all corrosion then using https://www.amazon.com/Permatex-205...ocphy=9007455&hvtargid=pla-571549195137&psc=1
or
https://www.jetlube.com/deacon-flange-gasket-sealants/

Then reassemble using proper torque spec and just as important sequence, ie 1-3-2-4 X pattern.
 
NotHerDecision said:
Can you post some other details?

is the black smoke every time you come into plane or just the first?

What is your WOT rpm?

When was the last time you cleaned your aftercoolers? And we’re they properly cleaned by disassembling not just rodded out?
Click to expand...

I only noticed at the first acceleration. But then I cruised the rest of the trip. No additional smoke seen.
The Ac’s were removed and cleaned this year.
I haven’t checked my RPM’s on the engine since survey (a year ago March). They were about 2700 then but it is something on my list to do. The previous owner was religious about keeping his props tuned to Sea Ray specs. And so the boat is likely a little over propped. That’s why I’ve been cruising at 2100 this season. I will check the rpms before the season ends and get the props tuned before next season.
 
I wouldn’t worry about a little smoke the first time you get up on plane. And yes I would check the wot Rpms. I keep my at 2700 and boat runs like a top
 
EKM said:
Great....I don't remember seeing a coolant filter but will look tomorrow.
Thanks. Anything special to fill the coolant system and purge the air?
Click to expand...
Open the petcock at the top of the pipe connected to the heat exchanger. Then fill it up until coolant comes out that petcock. Then close it and then top off the tank. Then fill overflow jug about 1/3 - 1/2 full. Then go boating. It'll take a few rides before any trapped air works it's way out so don't be alarmed if the overflow jug level drops down.
 
ZZ13 said:
Open the petcock at the top of the pipe connected to the heat exchanger. Then fill it up until coolant comes out that petcock. Then close it and then top off the tank. Then fill overflow jug about 1/3 - 1/2 full. Then go boating. It'll take a few rides before any trapped air works it's way out so don't be alarmed if the overflow jug level drops down.
Click to expand...
I don't see a coolant filter....maybe this was added to later models? Also no bleed petcock mounted at the top either.
 
EKM said:
I don't see a coolant filter....maybe this was added to later models? Also no bleed petcock mounted at the top either.
Click to expand...

Could be yours are different. Also filters get moved around to "remote" locations depending on boat models and engine room access. Generally the filters are going to be located on the inside of the motors (between them) for access.
Assuming you have straight drives, try looking in the following locations:

Red=bleed petcock, green=coolant filter, Yellow=coolant drain point (HX side of engine it is at the bottom of the oil cooler which is just in front of the oil filter if the filter is in it's natural position (not remote). Injection pump side I remove a coolant line from the coolant filter housing to drain the system like Bill said.

Injection pump side of starboard engine
IMG_0823_LI.jpg

In this file photo above, I was actually getting ready to drain the coolant. See the hose clamp that is already loosened and slid up the hose at the yellow arrow? The vise grip is clamping off the line just above it, getting ready to pull the line off the coolant filter housing.

same engine
IMG_0827_LI.jpg


HX side of engine, port engine
IMG_0828_LI.jpg


Good Luck
 
So I brag here about the SMX seawater pumps. The first one I bought just under 6 years ago may be leaking. I just finished 22 hour slow cruise to Fernandina FL. 1.5 quarts of seawater under port engine from seawater pump area. That works out to two ounces (1/4 cup) per hour. Most likely the pump but I'll check other possibles such as failed or loose hose clamp (had recently replaced fuel cooler with a hose) or loose impeller cover (had recently replaced impeller). It's port engine on straight drive so pump area is against sidewall. Real hard to debug. Might try to rig up my phone and a light to video it while I run the engine.

Guess I'll call sbmar and find out if I should go with new pump or theirrebuild kit (which is still $300+).
 
ZZ13 said:
So I brag here about the SMX seawater pumps. The first one I bought just under 6 years ago may be leaking. I just finished 22 hour slow cruise to Fernandina FL. 1.5 quarts of seawater under port engine from seawater pump area. That works out to two ounces (1/4 cup) per hour. Most likely the pump but I'll check other possibles such as failed or loose hose clamp (had recently replaced fuel cooler with a hose) or loose impeller cover (had recently replaced impeller). It's port engine on straight drive so pump area is against sidewall. Real hard to debug. Might try to rig up my phone and a light to video it while I run the engine.

Guess I'll call sbmar and find out if I should go with new pump or theirrebuild kit (which is still $300+).
Click to expand...
I've had the SMX pumps since 2011 and agree with you on their performance. Easy impeller changes, the impellers last three boating seasons and maybe longer (in the Great Lakes), never had a vane damaged, plus they simply pump a lot of water. I'll be interested in what you find because my experience is that they perform perfectly.
 
Well, it's the pump. Pictures of good starboard pump and suspect port pump. Notice port pump has green all around water weep holes to drain water when water seal fails. Starboard pump is pristine there. So I plugged the bottom most weep hole with a dry paper towel and left it there for five minutes with engine running. When I took it out the inside of the towel was wet.
 

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my3sons said:
Could be yours are different. Also filters get moved around to "remote" locations depending on boat models and engine room access. Generally the filters are going to be located on the inside of the motors (between them) for access.
Assuming you have straight drives, try looking in the following locations:

Red=bleed petcock, green=coolant filter, Yellow=coolant drain point (HX side of engine it is at the bottom of the oil cooler which is just in front of the oil filter if the filter is in it's natural position (not remote). Injection pump side I remove a coolant line from the coolant filter housing to drain the system like Bill said.

Injection pump side of starboard engine
View attachment 91308
In this file photo above, I was actually getting ready to drain the coolant. See the hose clamp that is already loosened and slid up the hose at the yellow arrow? The vise grip is clamping off the line just above it, getting ready to pull the line off the coolant filter housing.

same engine
View attachment 91309

HX side of engine, port engine
View attachment 91310

Good Luck
Click to expand...
My engines do not have the drain valves or bleed valves.
If you pull the small hose off the hold up tank mounted on the engine, it drains the block (hold your finger over the tank). When the block is drained, you reconnect to the tank and the tank drains into the block so pull of the hose again and drain. Held about 5 gallons to be drained. Im using a 4 gallon jug and siphon from the jug to tank for refill. Get to be an expert on draining.
Big issues is my turbo to exhaust manifold is still leaking after new gasket, new studs and sealant....very depressing
 
EKM said:
My engines do not have the drain valves or bleed valves.
If you pull the small hose off the hold up tank mounted on the engine, it drains the block (hold your finger over the tank). When the block is drained, you reconnect to the tank and the tank drains into the block so pull of the hose again and drain. Held about 5 gallons to be drained. Im using a 4 gallon jug and siphon from the jug to tank for refill. Get to be an expert on draining.
Big issues is my turbo to exhaust manifold is still leaking after new gasket, new studs and sealant....very depressing
Click to expand...
When I broke my factory turbo to manifold seal it was to have the turbo rebuilt. Part of that was honing the mating surface on the turbo. I reinstalled it with a new gasket without rtv and it leaked slightly when on plane. So I took it off and cleaned manifold side really well, put in new mounting studs and new gasket with rtv. That worked. Just sharing an experience you might find something useful in.
 
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