Rebuild Detroit 671's or re-power with Cummins?

DOUGNASH · Post by **DOUGNASH** » Sat Dec 15, 2012 7:45 pm

This is what I am dealing with right now.

The detroits would be re-built by a professional who has been in the business a long time. He does all the work himself. He uses non-turbo injectors (forgot the number) but he says this will minimize most of the smoke and many owners are happy with the results. includes wiring and gauges.
He offers a full 2 year warranty on all work and would stay on the job until everything performes perfectly. He has references that have his rebuilds running 15 years later.
His price is in the 20k per motor range.

I also have a friend who works for the local Detroit dealer, mostly works on generators though, but he has young kids and doesn't have time. But his buddies would rebuild and use all factory Detroit parts in their spare time, a couple of guys coming and going doing here and there as their schedule allows.
Probably a little cheaper but I question warranty and just dealing with multiple people, but I also hear they do really good work, as they should working for Detroit.

What about the capital gears?
Multiple people told me they are junk.. They work fine for me, both sides have the same 1 or 2 second pause before engaging in either direction.
Rebuild em or replace with what or just re-install and wait for issues.

I actually like the sound of the detroits at all speeds, my boat before this was a 33 well craft coastal with 3116 turbo Cats, those turbos would whine under load with awesome torque, miss that one..

Cummins would be factory rebuilds 450 hp mechanicals, about 25k per motor, new harness and gauges, with 2 year warranty. New gears about 4k each, installation about 10k.

The cummins are 1500 lbs lighter and burn 30% less.

I love the boat and have put much $ into upgrades already.

But I would like to upgrade to a sport fish soon.

14 meter Trojan or a 50 post.

I basically live on the boat may through September and do a lot of entertaining so a bigger boat more room 2 heads would be nice.

I thought cummins would be better for resale?

DOUGNASH · Post by **DOUGNASH** » Sat Dec 15, 2012 7:56 pm

This is the old BLACKJACK from Florida (I know you asked RWS on other thread)
Since owning these are the major upgrades I have done

Atlantic hard top
Garmin 7212 GPS
Garmin auto pilot, 2 garmin 300 VHF w/ digital antennas
3000 watt JL audio sound system
Xantex 60 amp battery charger
12 gallon air tank w/ comps and an awesome real train horn that fires at 200psi
New upholstery on seats in cockpit

The reason I ask is, since I am looking to get a bigger boat, do I try to sell the boat as is, not fix the motors, cut my losses and take the money I have saved and use that as a deposit on the bigger boat?

georgepet · Post by **georgepet** » Sat Dec 15, 2012 8:20 pm

My own advice which has nothing to do with the boating elements is to wait until at least February to see what the fiscal cliff negotiations produce - unless you have a buyer on the hook right now. In some way, those negotiations will affect people's optimism and hence willingness to entertain purchases in an uncertain environment. If I was buying, I'd be hammering on every advantage I could gain, it'll truly be a buyers market yet again....and at least knowing what the fiscal landscape is, would make for a more informed decision

DOUGNASH · Post by **DOUGNASH** » Sat Dec 15, 2012 8:33 pm

Makes sense
Won't be making any decisions on this until March-ish.
Right now just saving my $

prowlersfish · Post by **prowlersfish** » Sat Dec 15, 2012 9:01 pm

Doug reading your post I would say do nothing or fix the detroits , the extra money spent on the cummins would not add enough to the valve for you to recoup the money spent . Also they will only be about 10% better on fuel . As far using non turbo injectors you won't get the power as they won't deliver as much fuel . also the turbo motor will smoke more cold due to lower compression of a turbo engine. Or course the should clear up pretty quick assuming the engine is in good shape . Block heater help also .

As far as the 14 meter and the Post , you may want to look at the Ocean 48 better on fuel then the 14 meter and a ton of room .

Capital gears they seem to be a good gear. The set in the 45 Viking I run have been a good gear , some delay but thats due to the electronic controls on the Viking . Do you have cable or electronic controls

DOUGNASH · Post by **DOUGNASH** » Wed Dec 19, 2012 11:42 am

I thought the cummins would help with resale, not so much as in higher price, but I thought the boat would seller quicker.

I am talking to a lot of people about this.

Also I am sure with the cummins there are a lot of un knowns with getting everything fit right and aligned properly. COuld turn into thousands more than original quote.

This boat means too much to me to just walk away and sell as is, so I guess now I am leaning towards rebuilds detroits.

ALso I spoke with rebuilder again and questioned him about the injectors.

WHat he does is put a non-turbo sleeve in with a turbo dome, which either increases compression or decreases from 17 to 18.5 or visa versa in-turn reduces much of the smoke.

The gears are cable driven. I also understand that capital is out of business and parts are hard to come by..

(please bare with me I obviously do not know much about this stuff)

Oceans are beautiful boats inside and out, but I just dont like the lines on the boat and couldnt picture myself owning one (just a personal thing thats all)

DOUGNASH · Post by **DOUGNASH** » Wed Dec 19, 2012 11:42 am

I thought the cummins would help with resale, not so much as in higher price, but I thought the boat would seller quicker.

I am talking to a lot of people about this.

Also I am sure with the cummins there are a lot of un knowns with getting everything fit right and aligned properly. COuld turn into thousands more than original quote.

This boat means too much to me to just walk away and sell as is, so I guess now I am leaning towards rebuilds detroits.

ALso I spoke with rebuilder again and questioned him about the injectors.

WHat he does is put a non-turbo sleeve in with a turbo dome, which either increases compression or decreases from 17 to 18.5 or visa versa in-turn reduces much of the smoke.

The gears are cable driven. I also understand that capital is out of business and parts are hard to come by..

(please bare with me I obviously do not know much about this stuff)

Oceans are beautiful boats inside and out, but I just dont like the lines on the boat and couldnt picture myself owning one (just a personal thing thats all)

DOUGNASH · Post by **DOUGNASH** » Wed Dec 19, 2012 11:43 am

I thought the cummins would help with resale, not so much as in higher price, but I thought the boat would seller quicker.

I am talking to a lot of people about this.

Also I am sure with the cummins there are a lot of un knowns with getting everything fit right and aligned properly. COuld turn into thousands more than original quote.

This boat means too much to me to just walk away and sell as is, so I guess now I am leaning towards rebuilds detroits.

ALso I spoke with rebuilder again and questioned him about the injectors.

WHat he does is put a non-turbo sleeve in with a turbo dome, which either increases compression or decreases from 17 to 18.5 or visa versa in-turn reduces much of the smoke.

The gears are cable driven. I also understand that capital is out of business and parts are hard to come by..

(please bare with me I obviously do not know much about this stuff)

Oceans are beautiful boats inside and out, but I just dont like the lines on the boat and couldnt picture myself owning one (just a personal thing thats all)

prowlersfish · Post by **prowlersfish** » Thu Dec 20, 2012 6:55 am

Doug your engine guy scares me .. yes higher compression with reduce smoke and help starting . .But with the turbos and after cooler , lower compression is needed . this is true on all engines . When J&T started hot roding these engines do you thing they lowered the compression for no reason ? Do you thing DD Cummins Cat etc Got it wrong with there High output engines ? Think about it .