In situ rebuild.....

[oscarvan]

As I continue my studies I have a question for the old hats......:p

Question applies to a 53/54/56 or 58MY

It's been pointed out that the 8V71 or 8V92 can be rebuilt in situ, as in without removing it from the boat. I'm curious as to whether it has to come up?

I can't imagine dropping the pan and removing rod caps and crank shaft bearings/shaft while it's sitting on the mounts..not to mention getting under there with the torque wrench..... but I would like to know.

Thanks.

[racclarkson@gmail.com]

As I continue my studies I have a question for the old hats......:pQuestion applies to a 53/54/56 or 58MYIt's been pointed out that the 8V71 or 8V92 can be rebuilt in situ, as in without removing it from the boat. I'm curious as to whether it has to come up?I can't imagine dropping the pan and removing rod caps and crank shaft bearings/shaft while it's sitting on the mounts..not to mention getting under there with the torque wrench..... but I would like to know.Thanks. Are you aware there is an upper pan as well as the lower one?

[whoover]

Hello Oscar,

After removing and rebuilding both of my cummins 903s in my 42c I would say that it is easier to take them out. I realize that the motoryachts would have more room to do the work I think the extra time spent working in a small space would be close to taking them out. I also feel that a better quality rebuild can be had off the boat.

It took too of us to lift the crank shaft in and I had the block bottom up. We spent two hours just torqueing the heads and we were pretty much finished physically after that. I had a very well equipped workshop and a lot of room to work.

This is a pic of the starboard just before test running it to check for oil and gear oil pressure.

This is just my opinion and others will say otherwise. Also a DD is a different beast than a cummins so maybe apples to oranges comparison.

Walt Hoover

[oscarvan]

Are you aware there is an upper pan as well as the lower one?

I am now, thanks.

And Walt, I agree that having it out is waaay easier. That said, getting it out of a MY can be a seriously large operation.

So.... can it be done on the mounts or does it need to come up?

[Pascal]

I can’t imagine how you could do the bottom end without lifting the engines as the stringers are in the way

On the 53 and 58 MY/YF, with big hatches, getting them out is no big deal. On the 58 MY with the galley above the ER... it s an other issue

When I repowered my 53 2 years ago, it took maybe two to three hours to lift each engine out of the hatches and move them to aft deck. There was also a few hours of prep including setting up reinforcement for the aft deck to take the weight. The crane at the yard could t reach all the way in but with a big forklift it would have been easier

Here is a video of the removal

https://youtu.be/c4S4jQzh0P4

There are couple more on my channel, scroll down to 2018...
https://m.youtube.com/user/SandBARhopper

[Westfield 11]

I was under the impression that the engine was jacked up within the engine room to make room beneath it. But looking at the 12v71’s in mine I am questioning that now. Also are we talking about the 1510’s or the later 56/58s?

[oscarvan]

Thanks Pascal. Yes, the 58 with galley up would be a major demo for removal.


I was under the impression that the engine was jacked up within the engine room to make room beneath it. But looking at the 12v71’s in mine I am questioning that now. Also are we talking about the 1510’s or the later 56/58s?

Either, although I am aware that the 53/58 will be a lot tighter than the 54/56

[rsmith]

I rebuilt both my 12/71s in place with both pans out it’s no problem to lay under the engine and roll new bearings in. The engines had 9000 hours at the time and the bearings measured to near new specs. Unless there was a catastrophic failure like loss of oil or severe over heat in a 71 or 92 Detroit I’d do inframe and just heads cylinders and liners. Just like a hot section rebuild in a turbo prop or jet engines don’t have to be lifted

[racclarkson@gmail.com]

I was under the impression that the engine was jacked up within the engine room to make room beneath it. But looking at the 12v71’s in mine I am questioning that now. Also are we talking about the 1510’s or the later 56/58s?A lot depends on the boat, of course. I have no headroom in my ER, that is, until the air induction components are removed. And removing the motors from a convertible begs the question: Why not repower?

Aslan has some higher hours on her starboard motor. Yet, it holds very nice oil pressure. So, I would agree that a top end rebuild would likely be the appropriate course of action when the time comes. Naturally, it could be a different story once inside the beast. But, not breaking the engine from the gear (or jacking engine) has advantages.

[edward]

I guess a good engine survey would indicate if a rebuild is necessary ?

[racclarkson@gmail.com]

I guess a good engine survey would indicate if a rebuild is necessary ?Cheap insurance.

[rsmith]

I guess a good engine survey would indicate if a rebuild is necessary ?

Not always, my boat was 9 years old with 500 hours when we bought it. It had bad engine survey from Sun diesel in Lauderdale. We were able to lowball the price based on rebuild of both engines. Took the boat to RPM diesel in Lauderdale who checked for stuck rings and ring tension. Determination was to give it a good run and recheck compression after valves and rings reseated. After 100 hours of hard running wot went from 1800-2350 both engines and smoke cleared up.

[oscarvan]

Although high time engines MAY have many years left in them if they were run and maintained, generally speaking a rebuild is, or should be, figured into the price. Fresh engines command a premium and may or may not perform accordingly.

Knowing what is involved in any amount of rebuild and slowly arriving at the conclusion that doing it myself in situ when it becomes necessary is very feasible I can figure that into the decision making process.

[oscarvan]

Not always, my boat was 9 years old with 500 hours when we bought it. It had bad engine survey from Sun diesel in Lauderdale. We were able to lowball the price based on rebuild of both engines. Took the boat to RPM diesel in Lauderdale who checked for stuck rings and ring tension. Determination was to give it a good run and recheck compression after valves and rings reseated. After 100 hours of hard running wot went from 1800-2350 both engines and smoke cleared up.

Did you add a few qts of Marvel Mystery oil to that process?..... I had the exact same scenario with an automotive engine that sat for a long time and the Marvel and 1000 miles was all it took.

[snakey george]

My engines had to be raised to do the bottom end. 1987 53 YF.

George

[oscarvan]

Ah, thanks.

And Pascal, was finally able to watch your vids (didn't work on the airplane lol). Very interesting. And bookmarked.

[dottieshusband]

I was under the impression that the engine was jacked up within the engine room to make room beneath it. But looking at the 12v71’s in mine I am questioning that now. Also are we talking about the 1510’s or the later 56/58s?
The 63 MY can be done inframe, without lifting. There is room to remove the upper oil pan, which provides working room for the bottom end.