6V92tac possible rebuild on 45C

[worldsaway]

I also have a 45C with the 535hp 692s. The factory sent those boats out with the 4blade 30X33 Nibrals and 2:1 gears. Mine have been rebuilt and will turn full rpm. I have been considering taking an inch of pitch out based on Genesis advise to be able to hit 2350rpm under full load. I get the full load 2300rpm but thats all. From what I know with 2500 hrs you're in that rebuild zone for sure. What a great boat though.

[jim rosenthal]

Hear, hear, on removing the engines. The job is better quality all around, and like Jim says, it gives you something to do with your boat while the engines are away getting rebuilt. Plus, having spent all that time and effort to make your engine room look new, you will spend the effort to keep it that way. And think about killing anyone who gets it dirty....

[Megalodon45C]

I have a 2:1 reduction, with the 4 blade rolla 30*33 the best i ever turned was 2250 when i bought the boat in 98 with 1200hrs on them. I am starting the N-frame overhaul tommorrow morning the price is 23 grand, he told me that parts are 18 G's and labor will be 5 G's with a year warranty. He guarantees the 2300 rpms at WOT, I Love this boat, if i pull engines out i would have to replace with inline 6's. thanks for all the help will ley you guys know how it turns out.

[garyd]

If you're going to pull them, I would consider cutting opening around the back bulkhead and taking them out whole transmissions and all.

The repair of the bulkhead these days is no big deal. You can also take the engines on a trailer to anyone you want to have them rebuilt. After they are done you can put them back in the boat.

This saves a bunch of time, money and mess.

I did this on my 41C, we put them both back in the boat (posistioned) in less than 3 hours. We used a crane with the engines held tight against the boom. Stuck them in (one at a time) inside lowered them down and done. No part of the engines touched the boat. Didn't have to build a rail system or use a A frame and the engines were completely assembled, the only thing we left out was oil.

Good luck have fun boating
garyd

[Genesis]

When you get those done go for a run with full water, fuel, provisions and every guy you ever take fishing with you.

If you can't hit 2350 loaded like that you're overpropped.

BTW what's this "major" include? How's your hot oil pressure at idle?

[TedZ]

Am i reading this right?

The suggestion is to take out 6V92's...rebuild them and replace an engine that needs rebuilds in 2000 to 2500 hours for $36,000 rebuilds only? And this does not include the bulkhead or whatever repair? And you have the pleasure in the 2500 hours of burning at least 20% more fuel than a modern engine would burn, not to mention the ability to use a greater percentage of the available power without engine damage?

Doesn't this mean that you can spend $72,000 plus on 5000 hour engines and save about 15,000 gallons of fuel assuming an average burn rate of about 30 gallons an hour for both of the 6V92's? Not to mention the oil consumption which is many more thousands differance.

A Cummins 610 HP QSM-11 would not only be a great choice it would improve the resale of the boat by at least half of the cost.

When all factors are considered...

Ted

[Genesis]

The last quote on a repower with 550 QSM11s was in the $130k range, all-up. Engines and gears were just over $100k.

The 600s were more, of course.

Does this change your computation any?

Oh, by the way, I've never seen a repower end up adding more than 30% of the cost to the value of the boat. If you repower, do it because you want to and intend to keep the boat - not for resale value.

[TedZ]

I buy the 30%...better to set the expectation low.

Do you need new gears? I haven't looked at the torque difference. Are the existing gears close to maxed out torque?

To be honest with you i thought the QSM-11's could be bought cheaper than you quote. Maybe i'm wrong but i would shop for bobtail engines.

I was in Charleston, SC at Cummins marine facility a couple of months ago. Lot of testing on QSM's. Some dealer is getting cheap, lightly used engines.

The part that i can't get by is on a 2300 max rpm engine, at 2100 rpm's they are burning 22.3 gph. I don't have the curves but i'm sure there is a burn at near max torque using even less fuel. Using the engines 2500 hours, that is hard to beat at today's prices. If one looks at 5000 hours (lot of fishing!) the savings is going to be unbelievable at future prices for fuel thinking it could take 10 years to put 5000 hours on the boat.

I was struck by the rebuild cost for 6V92's. First, make sure they need it. Then if you have the time, do it yourself. It is a very easy engine to put kits in if the block is ok. The heads are a bit of a pain...get a DD mechanic for them and you are done.

BTW, we didn't even talk about the weight savings!

Thanks for the response.

Ted

[Genesis]

Yeah, the gears are part of the deal, mostly because the Allisons are wet flywheel. Plus they almost certainly wouldn't hold together with a QSM on the other end of them....

Problem is that this "5000 hour" thing is fallacious for most of us. If you run 500 hours a year, then ok, it makes sense. But most of us don't; we run a couple hundred hours.

10 years before major work is not bad on any engine. Time is just as bad as hours, and most recreational engines die not from overuse, but either disuse or abuse. There are exceptions of course, but the guy who is wailing about 1000 hours TBO is forgetting that he only put 100 hours on a year, that he could only reach 2100 RPM with a rated WOT of 2300, and that he overheated a couple of times because he wasn't cleaning the heat exchangers every year or two.....

The marine engine market is full of wild markups. It sucks too - that same engine in a truck or stationary piece of machinery doesn't cost that kind of money. If I could do a repower with the QSMs for $60-70k, all-up, I'd have 'em in my boat by now. At $130 I'll pass; $60,000 is a LOT of fuel, even at today's prices.

[TedZ]

Yes, the $130,000 number is a stunner.

I am sooo impressed by the QSM-11's i wet the rug when i see them!! Guess it affects my judgement!

I would still call a Cummins dealer and tell them you want some engines that have come out of the dyno test cells. They can only say no!

Ted