Official Cummins 6cta 450C thread

Yes, there is coolant intrusion but the boat sat for a long time between the incident and the discovery. The coolant might have drained in. I've been distracted and in California and trying to deal with this long distance due to my daughter's health problems. It's a real s....show!!

Sorry to hear about your daughter.

To be honest, with those issues I would pull the engine if it were mine. If the head got hot enough to crack and water got in the oil I would either want the block magnafluxed or replaced. My starboard got hot with the previous owner and was re-powered with a crate engine from Cummins. $36k plus install and came with 2 year warranty.
 
Take a picture of the installed belt before you remove it. You'll likely have to refer to it when installing the new one. I sure did. Easy to get a bit confused with the routing.
 
Take a picture of the installed belt before you remove it. You'll likely have to refer to it when installing the new one. I sure did. Easy to get a bit confused with the routing.

Thanks. That’s a freakin brilliant reminder. And no sarcasm implied. I do take pics of a lot of stuff when disassembling but I hadn’t yet thought about doing it here. Been more concerned with how to properly set the tension. But thanks for the tip!
 
Thanks. That’s a freakin brilliant reminder. And no sarcasm implied. I do take pics of a lot of stuff when disassembling but I hadn’t yet thought about doing it here. Been more concerned with how to properly set the tension. But thanks for the tip!
The tensioner does that. Using a 1/2” breaker bar into the center of the tensioner, move the tensioner to give slack to get belt off and on.
 
Take a picture of the installed belt before you remove it. You'll likely have to refer to it when installing the new one. I sure did. Easy to get a bit confused with the routing.
I just put a performance kit in my golf cart…. The cart nazi was coaching me over the phone and said take a pic of the throttle linkage and governor linkage…. I said I am good ….. he said we are not proceeding until you do. What ever so took some damn pics without a lot of thought. Took everything apart altered a bunch of stuff…. Put it back together without pics. He said now try this ..I did, told him the result and he says you put it back together wrong. I said no way…. He says that’s why I told you to take pics…. He said now fix it and call me back when you do ….. click.
Now I am looking at my shitty pics going damn it…. Got it in the end. Yes take pics
 
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I just put a performance kit in my golf cart…. The cart nazi said take a pic of the throttle linkage and governor linkage…. I said I am good ….. he said we are not proceeding until you do. What ever so took some damn pics without a lot of thought. Took everything apart altered a bunch of stuff…. Put it back together without pics. He said now try this ..I did, told him the result and he says you put it back together wrong. I said no way…. He says that’s why I told you to take pics…. He said now fix it and call me back when you do ….. click.
Now I am looking at my shitty pics going damn it…. Got it in the end. Yes take pics
You put wheelie bars on that thing yet?
 
My son in law came to the house and said so this is the 31mph golf cart…. (The only one in the garage)…. He says I see you put seatbelts in…(need them to be street legal).. he says good thing because I’m using those …..I said if your wearing those seatbelts you can’t go for a ride

View attachment 123391
Well, you did say son in law so,...

Great thread sorry for the highjack.
 
I just put a performance kit in my golf cart…. The cart nazi was coaching me over the phone and said take a pic of the throttle linkage and governor linkage…. I said I am good ….. he said we are not proceeding until you do. What ever so took some damn pics without a lot of thought. Took everything apart altered a bunch of stuff…. Put it back together without pics. He said now try this ..I did, told him the result and he says you put it back together wrong. I said no way…. He says that’s why I told you to take pics…. He said now fix it and call me back when you do ….. click.
Now I am looking at my shitty pics going damn it…. Got it in the end. Yes take pics

Just had a dock neighbor isolate an electrical issue to his main AC breaker. He pulled it out and was showing to me. It was a three pole, single throw breaker. I had a sudden panic. “Did you take pictures of the wiring before you took it off?” He assured me he had. He got the replacement breaker and has power again, so all appears well. Whew!
 
The tensioner does that. Using a 1/2” breaker bar into the center of the tensioner, move the tensioner to give slack to get belt off and on.

I have one of those. Do I rotate clockwise to remove tension? That looks like it may be the way... will it spring back with force once I get the belt free? And what’s a good fulcrum point for the bar? The nut on the tensioner bolt? Last question, how hard is it to get the belt cover off? Access looks tight.
 
I have one of those. Do I rotate clockwise to remove tension? That looks like it may be the way... will it spring back with force once I get the belt free? And what’s a good fulcrum point for the bar? The nut on the tensioner bolt? Last question, how hard is it to get the belt cover off? Access looks tight.

1. If I remember correctly as you look at the front of the motor, it is CCW to move the tensioner to release tension. It will be apparent as one way the tensioner is pushing on the belt and the other will relieve tension.

2. Yes, it will spring back, but not very far and it has an internal stop. So, once the belt is slipped off the tensioner you can slowly relieve pressure until the tensioner stops and remove the driver.

3. No fulcrum required. It isn't that hard to rotate against the spring with a 1/2" driver (on my port engine it was surprisingly a 3/8" driver). Just stick the square portion of a ratchet or breaker bar in casting (circled in blue below) of the tensioner and push away from the belt to relieve tension.

Screenshot_20220329-051956_DuckDuckGo.jpg


4. To remove the belt cover there are three bolts. If I remember correctly, there are two 10mm bolts and one 15mm. If looking at the front of the engine, there is one 10mm bolt that is going into the thermostat housing from left to right at about 10 o'clock, another going into the block at about the 3 o'clock position, and the 15mm is at the 7 o'clock position. There is a spacer on the 15mm bolt you will want to catch.

This is a pretty easy job. Should take about 15 to 20 mins per engine.

Other things to do while it is apart is clean out rubber dust, check for corrosion, especially inside the belt covers, and inspect all the pulleys and harmonic balancer.

I wiped down the whole area with Fluid Film (being careful not to get any on where the belt touches) after removing some light corrosion and repainting
 
I have one of those. Do I rotate clockwise to remove tension? That looks like it may be the way... will it spring back with force once I get the belt free? And what’s a good fulcrum point for the bar? The nut on the tensioner bolt? Last question, how hard is it to get the belt cover off? Access looks tight.
Forrest took care of you. On the 400DB the bottom bolt on the belt guard on the starboard engine is a long reach. Ok to get out but fiddly to get back on. I have to tape the bolt to the socket to slide it in and start turning it to tighten. It takes the 15mm socket. I also have to remove the coolant overflow jug to be able to slide the guard out of the way. But if you are just doing the belt, you can change it just by dropping the guard down and forward, and not sliding it out.
 
Forrest took care of you. On the 400DB the bottom bolt on the belt guard on the starboard engine is a long reach. Ok to get out but fiddly to get back on. I have to tape the bolt to the socket to slide it in and start turning it to tighten. It takes the 15mm socket. I also have to remove the coolant overflow jug to be able to slide the guard out of the way. But if you are just doing the belt, you can change it just by dropping the guard down and forward, and not sliding it out.

Bill and Forrest, thanks! Very helpful. And yep, I’ve used the tape on the bolt trick many times!
 
Hi Guys,

I am chasing a phantom coolant leak.

My port engine is dropping an ounce or two every few hours. I find it below the engine, but very frustratingly I cannot find the source. It is not coming out of any of the hoses, petcock, or the banjo fitting on the turbo.

I just did the thermostats on this motor (nope, not leaking at the housing) and I got 10 hours with no leaks and now this little annoyance, but it seems to be getting a bit worse each run which concerns me because something may eventually cause a large leak.

Any thoughts?
 
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Hi Guys,

I am chasing a phantom coolant leak.

My port engine is dropping an ounce or two every few hours. I find it below the engine, but very frustratingly I cannot find the source. It is not coming ot of any of the hoses, peacock, or the banjo fitting on the Turbo.

I just did the thermostats on this motor (nope, not leaking at the housing) and I got 10 hours with no leaks and now this little annoyance, but it seems to be getting a bit worse each run which concerns me because something may eventually cause a large leak.

Any thoughts?
Turbo to exhaust manifold gasket can leak. For me it was hard to find because it seemed to dry off really fast. I wrapped it with a paper towel to find it.
 
Turbo to exhaust manifold gasket can leak. For me it was hard to find because it seemed to dry off really fast. I wrapped it with a paper towel to find it.

Good info. Curious, how much coolant did you have to drain to change that?
 
i just had to do the turbo to exh manifold gasket for same reason. I could see my leak. I was not sure how much coolant to drain, so I just drained it all (and put it back in after repair). As engine repairs go, not bad. And leak is fixed.
 

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