On Jan 31, 2:22 pm, "Eisboch" wrote:
"Reginald P. Smithers III" wrote in messagenews:jKmdnWhUN9ChR13YnZ2dnUVZ_sWdnZ2d@comca st.com...



At what point does it become more economical to replace a diesel versus a
rebuild?

Sorta depends on what's wrong with it. Many diesels have replaceable
cylinder sleeves, so when the engine "wears out" the sleeves can be
replaced ... often without removing the engine from the boat and at a
fraction of the cost of new engines.

Other engines ... the Cat 3208 V8 (I believe) do not have replaceable
sleeves and, although they are good engines, are considered by some to be
"throw aways" when the time comes for rebuilding.

The DD 67-1 series (non turbo) live forever with occasional bolt-on
component replacements. I have a friend with a pair in his old Hatteras.
They've had injectors replaced, cracked manifolds fixed, but they still chug
along with over 10,000 hours on them.

Eisboch

This is a little off subject, but engines that have removable
cylinders are typically much heaver than those that don't. This is
because the block that has cast in cylinders gets a lot of stiffness
from those cylinders being part of the block. But a block with
removable cylinders gets no added strength from the cylinders, so the
block has to be made much heavier so it won't flex. So it's a coin
toss, bigger and heaver (and slower), or smaller, lighter and faster,
but it wears out sooner. By the way, 3208's can be rebuilt, they just
need to be removed from the boat and bored out (I wouldn't be
surprised if a sleeve is then pressed in as well) in a machine shop.
Most of your smaller high output engines today have cast in cylinders
for light weight and speed. By the time the engine needs to be
replaced most people move up to higher HP anyway.

John