Upgrading older Englines?

[drew.ward]

I am looking at a few classic motor yachts and many of them have either cats or detroit diesels. One boat has two strongly running, well maintained 12 cyl detroits.

They've proven themselves a great fit for the boat for 40 some odd years. Now I understand the whole idea of not messing with a good thing, but I can't help but wonder if there are some sorts of upgrades that have become available for these thirsty beasts that could be integrated into the existing setup to up the fuel economy / performance.

Is this even a plausible idea?

You can put fuel injection or better engine controls or a new carb or exhaust on older car engines. So does the same apply with these bigger marine engines?

[Pblais]

but I can't help but wonder if there are some sorts of upgrades that have become available for these thirsty beasts that could be integrated into the existing setup to up the fuel economy / performance.

I'm not sure what your expectations are.

You can put fuel injection or better engine controls or a new carb or exhaust on older car engines. So does the same apply with these bigger marine engines?

Turbo chargers do a lot for performance but just about nothing for economy. Diesels already have fuel injection. Classic boats get that way because of what they were not because you can make them more fuel efficient. Last I checked a carb on a diesel just is never going to help, work, or even be possible at least in a functional sense.

The concept of fuel efficiency along with improved performance is not something you can get in a boat. They tend to be very fuel inefficient. It's not all bad because the fuel costs are the cheap part of the operation. The analogy between cars and boats really is not very telling.

[drew.ward]

I wasn't actually trying to say putting a carb on a marine engine...just pointing out that there are tons of upgrades for older auto engines. It certainly seems likely that in 50 years there would be some technological advances that would be applicable.

[Pblais]

just pointing out that there are tons of upgrades for older auto engines.

I'm not aware of any refits for any older engines of any type that actually make a difference so long as we stick with just the engine. As for tons I think you need to make a list. Newer engines tend to be from the top down and bottom up - newer.

They may be cheaper, lighter, or they may have some properties about them that make an advantage, but I wouldn't say they fundamentally changed anything or that you can refit older engines to make them something different in a better way.