Official Cummins 6cta 450C thread

saopm said:
I agree, I’m pretty sure it would start. My next question is getting it to stop. Perhaps I can get it to shut down by tripping the ignition breaker on the Main 12V DC panel in the bilge. Can anyone confirm?
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You could test that by tripping the breaker and watching the solenoid go from the up to down position.

My CBs are in the salon, so not convenient. Might as well head to the bridge.

My boat had two remote panels in the ER with a full set of gauges, key, start button, etc., but the previous owners mechanic bypassed them both...ughh.
 
saopm said:
I agree, I’m pretty sure it would start. My next question is getting it to stop. Perhaps I can get it to shut down by tripping the ignition breaker on the Main 12V DC panel in the bilge. Can anyone confirm?
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Just turn the Racor to off to stop fuel flow.
 
ZZ13 said:
Just turn the Racor to off to stop fuel flow.
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It won't shutoff immediately by shutting off the Racor. It will continue to run until the vacuum builds up enough between the Racor and the lift pump, and the engine will run pretty rough for a bit until it dies.
 
Forrestkk said:
1999 450EB, 430 HP w/V-drives.

Valve Clearnace and belt tensioner.

1. I am going to adjust valves this year because I think they might not have been done at the 1200 hour interval (or maybe not evero_O). The tag on my port engine is under the remote oil filter, and unreadable. My starboard is a recently replaced engine and legible. Can I use the valve lash on the newer engine or are each engine/year different?
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Mine are at 1100 hrs and I was just thinking of the valve lashing. I looked but haven't found any procedures for our engine - would you have one? I've not done this service (on this engine) before ... is it considered easy or difficult?
 
Tomco said:
Mine are at 1100 hrs and I was just thinking of the valve lashing. I looked but haven't found any procedures for our engine - would you have one? I've not done this service (on this engine) before ... is it considered easy or difficult?
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Depending on access, valves are not too hard, and since we don't have mechanical unitized injectors under the valve cover we don't have to do those at the same time.

Just to level set so you know my viewpoint, I have adjusted valves on many other engines.

Our engines are pretty simple.
1. Take off the valve cover
2. Use the alternator pully to manually rotate the engine until #1 is at Top Dead Center (TDC). There is a timing pin just above the raw water pump to confirm the position (this is not an engine lock, it will break if it is depressed and you rotate the engine).
3. Adjust valve lash by loosening retaining nut and use a feeler gauge to set the gap between the top of the valve and the rocker arm so there is a slight drag on the guage for each valves specified lash.
4. While keeping the the adjustable piece at the correct setting, tighten the reataining nut and re-confirm meausurement.
5. Rotate engine and repeat steps 3 and 4 in cylinder firing order (note: you can adjust more than one cylinder at a time but you have to be sure that the there is no lift at all from the cam lobe).
6. Once all valves are adjusted, Re-install valve cover.
 
This is probably a simple job if you are familiar as stated above. I do my own aftercooler servicing and the majority of everything else but I farmed out the valve lashing to the pros as it was relatively cheap and I've never done it in the past. My cost was $500 for both mains and the gen.
 
Familiarity is the key point ... I'm comfortable doing most maintenance work (have some mechanic background but not on diesel) but always a little hesitant on the first go on it. I contacted our local Cummins and their estimate was $3500 (both mains and the genny) - if it was $500 I'd probably let them do it and watch.
 
Tomco said:
Familiarity is the key point ... I'm comfortable doing most maintenance work (have some mechanic background but not on diesel) but always a little hesitant on the first go on it. I contacted our local Cummins and their estimate was $3500 (both mains and the genny) - if it was $500 I'd probably let them do it and watch.
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If they were sending 4 techs from Miami to your boat maybe I could see $3500.Thats insane.
 
Irie308 said:
If they were sending 4 techs from Miami to your boat maybe I could see $3500.Thats insane.
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Yeah, $3,500 is a bunch. As I have vdrives, to do the work a mechanic may insist on pulling the cockpit floor, which is a chore. I am just doing the work the hard way between the floor and the top of the engine which makes the job longer, but overall a lot less time consuming. Is it an access issue for your boat?

FWIW on the genny, I called Phasor, and managed to get to speak with their lead tech and he said they stopped adjusting valves because they have never found them out, even at 5,000+ hours. They use Kubota engines. Not sure if other brands are more finicky on the valve train.
 
Miami ... maybe that is what they were planning! The estimate included about $1k for travel and $1.5k for labour.
Forrestkk, opening the interior hatch and the engines lay out in front of you ... easy access to the head covers and everything is done standing up.
 
Forrestkk said:
Yeah, $3,500 is a bunch. As I have vdrives, to do the work a mechanic may insist on pulling the cockpit floor, which is a chore. I am just doing the work the hard way between the floor and the top of the engine which makes the job longer, but overall a lot less time consuming. Is it an access issue for your boat?

FWIW on the genny, I called Phasor, and managed to get to speak with their lead tech and he said they stopped adjusting valves because they have never found them out, even at 5,000+ hours. They use Kubota engines. Not sure if other brands are more finicky on the valve train.
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After having my gen done at 1k hours the tech said they don't have many clients that do the lash on the gen since they run at a constant rpm.
 
Last edited:
So, in the midst of changing tstats as previously mentioned...down to the last bolt to get the housing loose and here is the last bolt....booo. Drilling and easy outs ahead. Then I have to find the replacement bolt, which sits right behind the tensioner.

20220112_165733.jpg
 
Forrestkk said:
Depending on access, valves are not too hard, and since we don't have mechanical unitized injectors under the valve cover we don't have to do those at the same time.

Just to level set so you know my viewpoint, I have adjusted valves on many other engines.

Our engines are pretty simple.
1. Take off the valve cover
2. Use the alternator pully to manually rotate the engine until #1 is at Top Dead Center (TDC). There is a timing pin just above the raw water pump to confirm the position (this is not an engine lock, it will break if it is depressed and you rotate the engine).
3. Adjust valve lash by loosening retaining nut and use a feeler gauge to set the gap between the top of the valve and the rocker arm so there is a slight drag on the guage for each valves specified lash.
4. While keeping the the adjustable piece at the correct setting, tighten the reataining nut and re-confirm meausurement.
5. Rotate engine and repeat steps 3 and 4 in cylinder firing order (note: you can adjust more than one cylinder at a time but you have to be sure that the there is no lift at all from the cam lobe).
6. Once all valves are adjusted, Re-install valve cover.
Click to expand...

I did find the Operations and Maintenance Manual for the 6CTA C8.3 series engines - it was only available page-by-page. I did some copying (a few years ago) and have the section on valve lashing. It looks like you do the entire set of valves in two steps ... haven't had time to compare to your note above or the YouTube link provided. If you want a copy, just send me a DM. It includes torque spec for the rocker nuts and the valve clearance specs (.012" Intake, .024" exhaust).
 
Forrestkk said:
So, in the midst of changing tstats as previously mentioned...down to the last bolt to get the housing loose and here is the last bolt....booo. Drilling and easy outs ahead. Then I have to find the replacement bolt, which sits right behind the tensioner.

View attachment 118329
Click to expand...
Its always the last one!
 
For reference, I was told by Cummins that the relevant documents for my engine were:
3381968 Operations and Maintenance Manual C8.3 Recreational Marine Engine; and
4915514 Owners Manual C8.3 Recreational Marine Engine
There is some overlap between them, the maintenance manual is the more detailed one. I got them off the Cummins quickserve site ... this was a few years ago and I think they moved to a new platform since but would think they are still available (pag-by-page vs a download). The valve lashing procedure is in the maintenance manual.
 
Forrestkk said:
Depending on access, valves are not too hard, and since we don't have mechanical unitized injectors under the valve cover we don't have to do those at the same time.

Just to level set so you know my viewpoint, I have adjusted valves on many other engines.

Our engines are pretty simple.
1. Take off the valve cover
2. Use the alternator pully to manually rotate the engine until #1 is at Top Dead Center (TDC). There is a timing pin just above the raw water pump to confirm the position (this is not an engine lock, it will break if it is depressed and you rotate the engine).
3. Adjust valve lash by loosening retaining nut and use a feeler gauge to set the gap between the top of the valve and the rocker arm so there is a slight drag on the guage for each valves specified lash.
4. While keeping the the adjustable piece at the correct setting, tighten the reataining nut and re-confirm meausurement.
5. Rotate engine and repeat steps 3 and 4 in cylinder firing order (note: you can adjust more than one cylinder at a time but you have to be sure that the there is no lift at all from the cam lobe).
6. Once all valves are adjusted, Re-install valve cover.
Click to expand...
Adjust Hot or Cold?
 
Tomco said:
Its always the last one!
Click to expand...

3 T40 Torx bits, 4 drill bits, 2 Easy Outs, and half a can of Kroil and finally, I got my thermostats out! A little corrosion control needed, and my first real supply chain issue as I am waiting on a hose from Cummins.

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20220123_114807.jpg


20220123_114932.jpg


20220123_114853.jpg
 
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