I have an 83 300sd with 260 miles... slow on take off...
when do you all plan on rebuilding your engines... I am happy with it...
but I am starting the rebuild planning phase...

have you run a compression check?

no i have not done a compression check...

i am just planning on rebuilding at a certian mileage...

i am sure you will receive advice that may be contrary to that game plan.

well my reason and logic for just rebuilding at a stated mileage is
that I dont want to buy pistons... they are now 1200 bucks... and if
you rebuild before you start hearing a knock or something like that then
your rebuild is basically just rings, and bearings... verses oil pumps and
pistons, and cranks...

First of all, rebuilding a 617 engine from the bottom up usually makes no sense. The cost of this endeavor is well over $3K to do the job properly and the value of the car is probably just below this number. It makes far more sense to find a good used engine with about 150K on the clock. Costs less and is far less work.

Secondly, unless you have plenty of time and can toss away money, you don't rebuild an engine on mileage alone. Have a proper compression check done. You may be surprised at what you find.

What's the blowby situation?

Is everything else to spec.....camshaft timing.....injection timing?

Maybe a new set of valves and prechambers are in order? My SD runs like a brand new vehicle after I put $1K into the head. I'm thrilled with it.

Once the engine forces you to get into the bottom end........it's a losing proposition.

Naturally, if you have a show car and money is no option, just purchase a rebuilt long block from Metric Motors:

http://www.mercedesengines.net/products.asp?cat=40


For $5750. you get everything from the top of the valve cover to the bottom of the oil pan.

well,
i just rebuilt an m103... and my thouhts were running like this...
If I rebuild say around 300k i can do rings, and valve guides and sleves,
I figured I could leave off the oil pump... and the pistons... and that is where
the money is... 1200 for the pistons, and 800 bucks for the oil pump..
but if i just diy the rebuild then the money is pretty low,
timing chain and guides 200,
rings 150,
sleaves 150,
bearings 100,
head redone 250,

So I can probably do it for 1000, if i avoid the turbo, vac pump, oil pump
and pistons...

When something major breaks, ie she spins a bearing, or loses compression, snaps the oil pump chain, ect.

I don't plan on rebuilding, if the time ever comes I will order a new or rebuilt long block and just swap everything over. That way my labor costs are $0 since I an unable to do a rebuild myself. Engine swap no sweat.

I will price out a new long block from MB, those come with a 4 year warranty. I will then price you a rebuilt long block from Metric.

Then deside based on price and warranty.

If the engine runs good why touch it? Just keep driving it!

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200