Official Cummins 6cta 450C thread

Can't seem to find an indepth write up but there is some info to be found at this link: http://clubsearay.com/index.php?threads/official-cummins-6cta-450c-thread.77886/page-12#post-1019780

We did remove an alternator on one engine but then fought a bolt going back on. But if you're changing alternators anyway, that's the way to go in my book.

Drain the coolant off of one of the lines from the coolant filter going back to the low point on the block. Remove the hose at the filter. If memory serves, you shouldn't have to drain too much just to replace the thermostats (yes, two per engine) but if you're changing anyway, then drain the whole thing.

I bought my T-stats from sbmar. They were the 160 Deg F versions. Kits came with gaskets, etc need for job.

If you have any questions, fire away.

Jaybeaux
Yup, read up on that post but just a couple of questions. Have had the thermostats for a few years now and just getting around to swapping. They are 160. I think I have down the process to drain the AF but not clear on getting access to the thermostat without removing unnecessary components. I saw you asked about removing the thermostat housing vs fishing them out after removing the outlet connection to the hose. Assuming you had to remove the housing? Lastly, once the alternator is out of the way does it allow you to "slide" the housing out without undoing the small hoses connecting to the AF fill "tank" ? I'm just eye balling it now so I know what I'm in for once I start.
 
Remove the housing. It makes for a simple job. The housing that I'm referring to is just the "hunk of metal" about 5"X3" and 3" thick. If memory serves, it is four bolts to remove. One bolt, again if memory serves, is blocked by the alternator in some fashion. I"m not sure if this picture will help, and don't ask how I came to have a picture like this :D. The cylinder head and exhaust manifolds are removed. You see where the alternator bolts on? That is the thermostat housing. The small hoses at the top of the AF fill tank are ok as they are above the level of the AF.
20210716_150405.jpg
 
Remove the housing. It makes for a simple job. The housing that I'm referring to is just the "hunk of metal" about 5"X3" and 3" thick. If memory serves, it is four bolts to remove. One bolt, again if memory serves, is blocked by the alternator in some fashion. I"m not sure if this picture will help, and don't ask how I came to have a picture like this :D. The cylinder head and exhaust manifolds are removed. You see where the alternator bolts on? That is the thermostat housing. The small hoses at the top of the AF fill tank are ok as they are above the level of the AF.View attachment 116545
I just starred at that pic for an hour, thanks.
No questions asked. Ouch!
 
Remove the housing. It makes for a simple job. The housing that I'm referring to is just the "hunk of metal" about 5"X3" and 3" thick. If memory serves, it is four bolts to remove. One bolt, again if memory serves, is blocked by the alternator in some fashion. I"m not sure if this picture will help, and don't ask how I came to have a picture like this :D. The cylinder head and exhaust manifolds are removed. You see where the alternator bolts on? That is the thermostat housing. The small hoses at the top of the AF fill tank are ok as they are above the level of the AF.View attachment 116545
This pic should be labeled “forum porn”…. No one should have to see this without a disclaimer first
 
Remove the housing. It makes for a simple job. The housing that I'm referring to is just the "hunk of metal" about 5"X3" and 3" thick. If memory serves, it is four bolts to remove. One bolt, again if memory serves, is blocked by the alternator in some fashion. I"m not sure if this picture will help, and don't ask how I came to have a picture like this :D. The cylinder head and exhaust manifolds are removed. You see where the alternator bolts on? That is the thermostat housing. The small hoses at the top of the AF fill tank are ok as they are above the level of the AF.View attachment 116545
Thanks, wow!…I won’t ask..lol.
 
While the aftercoolers are off I removed the grid heater circuitry. They are fried and didn't work and I don't really need them down here. I thought I'd post this in case anyone else wants to do this. Process was straight forward. Remove the two power and one ground wires and temp sensor connector at the grid block. Disconnect the three control connections - one for power control, one for preheat and one from rpm pickup. Remove the main power cable from the starter lug. Remove the two bolts holding the bracket on. That's it. Lots of room there now.
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Is this grid heater fused? Want to see how much smoke I have in early spring with them off before I make a decision to remove.
 
Is this grid heater fused? Want to see how much smoke I have in early spring with them off before I make a decision to remove.
There is one heavy wire going across engine you can disconnect if there isn’t a fuse(I never saw one)… just do one engine the starboard would be easiest and you can compare.
That’s what I did in the fall and noticed no difference at 40deg
 
Is this grid heater fused? Want to see how much smoke I have in early spring with them off before I make a decision to remove.
Yes it is. If you look in the picture you referenced, you can see the white fuse holder where a couple of the connections branch off the main harness. I removed those fuses on mine a few years before I finally removed everything.
 
Yes it is. If you look in the picture you referenced, you can see the white fuse holder where a couple of the connections branch off the main harness. I removed those fuses on mine a few years before I finally removed everything.
Thanks, I think I see it now.
 
I changed out the impeller including the cover oring. Now when engine running there is a small leak from the cover. Took cover off and cleaned everything out again to retry but ran out of time before had to leave. My question- should I be using any gasket maker as well, or is there anything else I’m missing?
I also saved old oring to try if new one still leaking when I get home Monday.
 
I changed out the impeller including the cover oring. Now when engine running there is a small leak from the cover. Took cover off and cleaned everything out again to retry but ran out of time before had to leave. My question- should I be using any gasket maker as well, or is there anything else I’m missing?
I also saved old oring to try if new one still leaking when I get home Monday.
Maybe it wasn’t quite sitting in the groove. I’ve never had one leak. I put a little grease on the o ring so it will stay stuck in the groove until I bolt in the cover. Also make sure the cover is nice and smooth. Use some high grit sand paper (300 grit or above) or a scotch bright pad on it. Also make sure impeller is all the way in.
 
Ok thanks. I’ll double check all the suggestions and try again next week.
 
Remove the housing. It makes for a simple job. The housing that I'm referring to is just the "hunk of metal" about 5"X3" and 3" thick. If memory serves, it is four bolts to remove. One bolt, again if memory serves, is blocked by the alternator in some fashion. I"m not sure if this picture will help, and don't ask how I came to have a picture like this :D. The cylinder head and exhaust manifolds are removed. You see where the alternator bolts on? That is the thermostat housing. The small hoses at the top of the AF fill tank are ok as they are above the level of the AF.View attachment 116545
Alternator or belt tensioner? I believe I had to remove the belt tensioner, behind it was a flat head bolt that had to come out.
 
Yup, read up on that post but just a couple of questions. Have had the thermostats for a few years now and just getting around to swapping. They are 160. I think I have down the process to drain the AF but not clear on getting access to the thermostat without removing unnecessary components. I saw you asked about removing the thermostat housing vs fishing them out after removing the outlet connection to the hose. Assuming you had to remove the housing? Lastly, once the alternator is out of the way does it allow you to "slide" the housing out without undoing the small hoses connecting to the AF fill "tank" ? I'm just eye balling it now so I know what I'm in for once I start.
I was able to slide it out. Didn't unhook the little hoses. I did loosen one hose clamp and slide it out of the way to prevent getting sliced up by it, but didn't remove the hose itself.
DSCN2938.JPG
 
I was able to slide it out. Didn't unhook the little hoses. I did loosen one hose clamp and slide it out of the way to prevent getting sliced up by it, but didn't remove the hose itself.
View attachment 116739
Well done. How much coolant did you take out? I’ve been putting this job off over and over. I’ve had 4 new sbmar T-stats for several years now. I intended to do it a few years ago when I changed the coolant. But didn’t. Next coolant change is in a few years. Although temp keeps holding at 160 on the original T-stats.
 
Well done. How much coolant did you take out? I’ve been putting this job off over and over. I’ve had 4 new sbmar T-stats for several years now. I intended to do it a few years ago when I changed the coolant. But didn’t. Next coolant change is in a few years. Although temp keeps holding at 160 on the original T-stats.
I unhooked a hose at the coolant filter, drained coolant from there. I don't remember how much, but 3-5gals, coolant was still running from the hose when I figured I must have it down enough.
 
Alternator or belt tensioner? I believe I had to remove the belt tensioner, behind it was a flat head bolt that had to come out.
Woody, I’m talking with my bilge buddy and we can’t remember exactly what we did. But sounds like you got it.

Jaybeaux
 
Maybe it wasn’t quite sitting in the groove. I’ve never had one leak. I put a little grease on the o ring so it will stay stuck in the groove until I bolt in the cover. Also make sure the cover is nice and smooth. Use some high grit sand paper (300 grit or above) or a scotch bright pad on it. Also make sure impeller is all the way in.
Re cleaned it all again and re assembled and test ran. So far bone dry. Not sure if it didn't seat right or there was a part not properly cleaned.
Thanks
 
Merry Christmas everyone!

I hate when I break stuff. I serviced my port aftercooler last week. Put everything back on and started her up. Tach signal is dead. Reads 0. I think the pickup is right there at the aftercooler on top of the transmission. Is that correct? Hopefully I just banged a wire and broke it. We leave Monday to cruise to FL so guess I’ll be working on it tomorrow. Worst case I go south without a port tach reading. Stay by this thread tomorrow to quickly answer all of my questions. Ha! Why are there two wires coming out of the pickup? Only one signal wire on the gauge.
 

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