Thread: Anyone we know here?

Originally Posted by PerthDisco

I had a pair of TAMD70Ds in a boat and they were similarly brilliant, simple, economical and underdressed engines (270hp / 900kg). They went out of production in 1981 becoming the 71D. Eventually though after 30+ years micro corrosion caused a piece of a valve to drop off and totally destroy one of them. We totally rebuilt it (just) as parts getting rare and very expensive. Moral of the story, yes the bottom end will go forever in a recreational boat (rust is a bigger problem) but do the heads as that’s what eventually fails as salt air is always on the back of the exhaust valves when you are not running. We then also rebuilt the head on the other side.

We had a pair of 70s before we replaced them with the 71s. Cracks and warping in the heads of the 70s is what finished those off. The heads in the 71s are quite a bit more robust and tolerant of small cracks. The other thing we routinely struggled with on the 70s was the heat exchangers. The 71s are a lot easier to work on from that perspective.

Originally Posted by BradC

We had a pair of 70s before we replaced them with the 71s. Cracks and warping in the heads of the 70s is what finished those off. The heads in the 71s are quite a bit more robust and tolerant of small cracks. The other thing we routinely struggled with on the 70s was the heat exchangers. The 71s are a lot easier to work on from that perspective.

If they’re keepers and 30+ years old rebuild the heads is my sincere warning. Literally a 10 cent size chip of valve fell off out of the blue due to pitting corrosion. That led to cracked liners destroyed pistons, new turbo over $40k full rebuild. A full head rebuild is <$10k.

Everything else is bulletproof and easily serviceable as you say.

Problem is, to replace/ upgrade to two new engines is going to be $150k as leads to new everything- gearbox, exhausts, props, ancillaries.