Re power

Hi,

If you can call going from 14l to 18l an increase of some 200 ci, overhead cam and full electronics and thinner liner walls minor changes, I would tend to agree with you.

The earliest thing to show itself for the C 18 compared to the 3406 for me is the clean burning of the former.

I have a client who has over 20,000 hrs on one as a genset, I have encouraged him and he is interested to see just how far one will go so then he knows when to expect the others to need attention.

Maybe more than minor changes, but the exterior footprint and for retrofitting purposes they're very similar.

The 3406 is a great engine, I agree. They're proven and last a very long time. At this point in the game you can find Re-manned C18's for a reasonable price. 3406's even cheaper.

a 715hp QSM 11 will push a 54' Bertram to a 20+ knot cruise.....that is the largest they make......weird thing is I maintain a set of those engines and on the engine plate on the motor it says they are rated for a 1000 hr service life?????

Sorry CaptJ, you won't see that kind of performance with a QSM11 in a 54 Bertram. You are just guessing, which doesn't help the OP.

Like I said before, a Series 60 rated 825 hp @ 2300 rpm will get you a 20 - 22 knot cruise. These repowers have already been done and the Bertram 54 is a heavy boat for its size. Cummins turned the screws up on the QSM11 from 2300 rpm to 2500rpm to get the rating up from 675hp to 715hp. I have installed both on the same vessels (2 different brands) and in all honesty, the 715hp version did not improve performance and burnt more fuel, was more expensive and did not make sense. It was just a quick way for them to get into the 700+hp rating game against their competitors and charge more $$$. Even at the highest allowed cruise of 2300 rpm for the QSM11 you are going to see 18 knots and have reduced life between overhauls. And there is little to no margin for full load conditions and heavy weather.

The 3406E is built on a proven platform, and IS significantly different than the newer modern C18. Footprint between a 3406E and a C18 doesn't matter to the OP unless it is relatively close to the 12V92's he is replacing. Otherwise, there will be additional costs involved in the repower in terms of modifying the Engine Mount locations.

Since the 3406E has been replaced by the C18, I imagine you can get a decent deal on someone's inventory or even a factory reman. You will most likely need a gear change and I hope the OP is factoring that into his budget as well as new propellers. I would say that $100/hp retail would be a target for Engines, Gears and a single Control Station but you may be able to do better if a distributor is sitting on some inventory.

Whats wrong the V-12's. You might better off to rebuild them for around 100,000.00. At 100.00 p/hp your going to in at least 300k. And probably more.

I'm rebuilding a 12 v 92 in a 54 right now. The cost of a repower vs. rebuild is considerable.

Ouch, so both motors are unrebuildable pretty much.....maybe that's why he's looking for repower.

If the block was cracked, its gotta come out. I would't waste a dime on on it, either a new DD short/long block or re power. If i was going to re power, my choice would be 8 cylinder 1000 hp MANs or 3412s, c 32 acerts, Big Cats.

With the latter, at that point, make sure you like the boat because you're married.......

Why Man's at 1000hp then Cat's? I would go C18 at 1000hp over the MAN's for that boat all day, everyday. That would be the easiest choice of the 4 as you can probably use existing shafts/struts/props (with a re-pitch) etc etc...Another option and cheap if he wants to step away from 12v92's is to find a set of rebuilt complete 12v71 TI's and cut the props a bit.

If you're going to spend the money on c32's or 3412's and installing them, you can find a much newer boat that already has them for the same money probably.....

What was the synopsis on the 12v92 of yours that had the coolant issues? What ended up being wrong with it? Head o-rings? I'm sort of involved with a boat with 16v92 DDECS that ate 2 cylinders from the head o-rings, they're doing a top end rebuild on it right now.

I digress, Big Cats are first choice but the smaller MANs are an attractive alternative. I think his least expensive route is replace block, rebuild then do the other engine. We all moan and groan about DD 92s, but they are dependable and simple- as are 71s-however never were as good as 71s.
I'm doing an in-frame overhaul due to a cracked liner and worn out cam, 24 years old and 2800 hours, can't ask for more out of those old beasts!

No. thats pretty good. What condition is the other motor in? These 16v92 DDECS were rebuilt/majored at 1050hrs, and 835hrs later, the stbd engine ate two pistons upon startup due to coolant in the cylinders....So they're doing all the cylinder kits and rebuilding the heads....the rod journals on the crankshaft look perfect.....it only started gaining coolant in the oil right at the time of this fiasco........question is...how are the o-rings in the other motor, but you can't ask the seller to do anymore.....I'm involved with the buyer.

No issues from the other engine but high hours dictate attention in the near future. I'm going to fish it this summer and probably rebuild the other one in the fall.
Hopefully she cooperates with my schedule.

It would be easiest to do them both at the same time if the funds allow.....much less downtime....and a little less labor......

Would like to get them both done now but mechanic's working me
In now and has other commitments elsewhere he's postponed. My issue just popped up recently.
I think I'm going to become a diesel mechanic!

Forget that......just dealing with the sheer weight of carrying that stuff in and out of engine rooms is enough of a deterrant.