Official Cummins 6cta 450C thread

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That's what I thought. IDK about DAs, but this number doesn't match the actual weight of DBs. We had this discussion several years ago and few 400DB and 420DB owners posted that they were in the range of 35-36K. Thus, back then we've concluded that the specs had wrong data.
 
Alex F said:
Is this actual or from the specs doc?

This is why I said we're comparing apples and oranges. Few years ago I checked the weight of mine and it was 40K. And this was about 75-80% of what I call fully loaded. The yard guys swore that the scale on the travel lift was accurate.
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Alex, I had yard tell me we were 35k in the slings at the end of season with very little fuel or water. Dinghy was on the platform. So 40k sounds accurate to me. Definitely a heavier boat. I’ve run with a 42 DA with CTA and I had to push her 2350 to keep up with him at 2150 and he was still running well ahead of us. A 10k difference in weight is quite possible.
 
Going into winter storage. Not much in it but fuel was full.
32700+/-
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420 DB would definitely be more.
 
Thanks guys. Your data proves my point.

Here's what's posted in the specs for 420DB and 44DB.

420DB:
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44DB:
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Here's an interesting comparison to 2012 450DB

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Do I really believe that 450DB is ~38K and 44DB 22K? Is there really 16K difference? Absolutely not! If someone can prove my thought process wrong, you have the stage.
 
Alex F said:
Would you mind sharing the weight numbers?

44DA with a hard top and 450Cs....that's new to me. Didn't SR made the model switch from 420 DAs and DBs to 44s and upgraded the engines to QSC500s in 2006?
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ok. My mistakes. It's not a 44DA. It's a 2004 420DA. Basically the same boat. But yes, 450C's. But v drives where my 400 DB is straight. His dry weight with hard top is 23000.
 
scooper321 said:
ok. My mistakes. It's not a 44DA. It's a 2004 420DA. Basically the same boat. But yes, 450C's. But v drives where my 400 DB is straight. His dry weight with hard top is 23000.
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'04 420DA with 450Cs, we're on the same page now. Was his 23K weight on the actual scale?

I just pulled up the specs from SR site and it states 25.5K

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Alex F said:
'04 420DA with 450Cs, we're on the same page now. Was his 23K weight on the actual scale?

I just pulled up the specs from SR site and it states 25.5K

View attachment 145702
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Beats me. You know how we talk on the docks... sometimes we don't remember all the figures exact!

So his is 25.5K and mine "says" 22K. That's "about" the same in my book. But the point above about the specs on the 400 being wrong is interesting. Never heard that before. But it makes sense. Even with the hardtop on the DA there's still a lot more fiberglass on the DB!
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Woody said:
A couple years ago one of the crew said I was 'pushin' 30,000#. I don't know where that number came from though.
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I believe it as it sounds as very realistic number.

I just confirmed with a friend on 420DA (hard top) numbers and with full fuel and heavy dinghy he was pushing 31K.

The more data we collect, the more we can conclude that same years (e.g. 2004-2005) DA vs. DB, DBs are heavier by good 5K-8K. With the same LWL DBs generate extra drag, which costing us (DB guys) few knots at the same RPMs.

Here's another observation that relates to performance. Since DAs are a bit lighter, they swing slightly larger diameter props still allowing them to meet desired WOT. So, combination of lighter weight and larger props is the logical explanation why DAs can push back 150-200RPMs and still run at the same speed or even 1-2kts faster.
 
I changed my 3 racors and both spin on engine fuel filters this weekend. Used the orings that came with the racors. Ran all three engines for quite a while….. no leaks nothing out of the ordinary.

I then cleaned out the bildge washed the engines down scrubbed everything. I also took the air filters and washed those out.

I then find two thick black orings on the floor about 1” in diameter about 1/4 thick by 1/4” wall thickness. Cross section of the ring is square not round like a typical oring.

Do you guys think this is related to the spin ons or racors ?… I have done this before and never came across these.
 
Blueone said:
I changed my 3 racors and both spin on engine fuel filters this weekend. Used the orings that came with the racors. Ran all three engines for quite a while….. no leaks nothing out of the ordinary.

I then cleaned out the bildge washed the engines down scrubbed everything. I also took the air filters and washed those out.

I then find two thick black orings on the floor about 1” in diameter about 1/4 thick by 1/4” wall thickness. Cross section of the ring is square not round like a typical oring.

Do you guys think this is related to the spin ons or racors ?… I have done this before and never came across these.
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A new o ring comes packaged with the spin on filter. When you remove the old spin on you have to then remove the o ring from the threaded post. It’s not easy to get off by hand. It’s jammed up to the top and I have to hook it with something pointy to pull it down and off. Then you push on the new o ring and then spin on the new filter. Did you do this exact process?
 
ZZ13 said:
A new o ring comes packaged with the spin on filter. When you remove the old spin on you have to then remove the o ring from the threaded post. It’s not easy to get off by hand. It’s jammed up to the top and I have to hook it with something pointy to pull it down and off. Then you push on the new o ring and then spin on the new filter. Did you do this exact process?
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God damn it…… I wonder if those two o rings didn’t fall out of the pkg as I wasn’t looking for another oring and the old ones are still up in there. I know for sure the bigger oring came off with the filter because I always check to make sure it doesn’t get stuck to the flange but never looked for the smaller one….. and I would have seen the smaller one in the drip pan…
No big deal will swap them out….. thanks for the quick response
 
Blueone said:
God damn it…… I wonder if those two o rings didn’t fall out of the pkg as I wasn’t looking for another oring and the old ones are still up in there. I know for sure the bigger oring came off with the filter because I always check to make sure it doesn’t get stuck to the flange but never looked for the smaller one.
No big deal will swap them out….. thanks for the quick response
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Yup. Those are the new ones you found. Probably be fine with the old ones another year but I know all about not sleeping good unless you fix it.
 
So what coolant filter is everyone running in their Cummins 450s? My boatyard is recommending WF2122 (recommended by Cummins) but that's not one of the WF207x numbers that we've long discussed on here. From a quick interne search it appears the WF207x filters are paper filters and the WF2122 is not. So that's a plus. But I have no idea if the WF2122 has any additive or not, like the WF207x's do.

Are we running additives with our filters or do we just use coolant with additive?
 
I test with the test strips in the fall when I change my oil a few days ahead of lay up.
If the results indicate that it could use some sca, I wait until spring to do it. There is no reason to put sca into the system just to let it sit all winter. The sca depletes from time and use. I add the sca by installing the filters with the additive tablets inside the filters. I use WF 2071 which is 4 units. The rule of thumb is to use the filter with half the number of units as the cooling system capacity is in gallons. Our system is approx 32 qts so I use the 4 unit filter. Has worked perfectly for my boat and for all of the 8.3 motors in trucks our company owned in my previous life. If your system has not been maintained and the nitrite and moly numbers are way down, you can use a 6 or 8 unit or add the sca liquid or change the coolant with a coolant that has the additive in it and run a blank filter to start and then do your strip testing at each oil change. I use the fleetguard ES Complete coolant. It’s preloaded with sca.
 
my3sons said:
I test with the test strips in the fall when I change my oil a few days ahead of lay up.
If the results indicate that it could use some sca, I wait until spring to do it. There is no reason to put sca into the system just to let it sit all winter. The sca depletes from time and use. I add the sca by installing the filters with the additive tablets inside the filters. I use WF 2071 which is 4 units. The rule of thumb is to use the filter with half the number of units as the cooling system capacity is in gallons. Our system is approx 32 qts so I use the 4 unit filter. Has worked perfectly for my boat and for all of the 8.3 motors in trucks our company owned in my previous life. If your system has not been maintained and the nitrite and moly numbers are way down, you can use a 6 or 8 unit or add the sca liquid or change the coolant with a coolant that has the additive in it and run a blank filter to start and then do your strip testing at each oil change. I use the fleetguard ES Complete coolant. It’s preloaded with sca.
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Thanks. Where in the system do you take the strip sample ?
 
scooper321 said:
Thanks. Where in the system do you take the strip sample ?
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You pretty much can’t go wrong just putting a new WF2071 on each year. Like Mark, that’s how mine tests out every year and that’s what I swap in every oil change annually.

But I just take the tank top off and dip it in there. Can’t tell you if that’s right or wrong.
 
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