I also have a DD 6v53 in the basement. I have done all the work on it for
30 years and 38K miles of voyaging so I am quite familiar with it.
I presume you have the manual. I studied mine for weeks even before I took
delivery of the engine.
I suggest you use only Rotella SAE30 or SAE40. I have been specifically
warned against multi-grades. Rotella is a low ash oil needed in the DD
two-cycle engines.
To tune the injectors I use a infrared laser pointer thermometer and note
the temps of each exhaust elbow when the engine is running under load.
Then when it is cold adjust each injector accordingly. It has taken about
eight passes but I have all the cylinders within about 20 degrees of each
other for a nicely balanced engine.
The DD fuel system is a blessing and I have taken full advantage of it.
Since I built the boat I have modified the fuel system over the years to
eliminate all fuel system problems and now I have none. I am dismayed at
the crappy fuel systems built in to most boats at the factory. Ninety
percent of diesel engine problems are fuel system related and most come
with the boat.
Specific to the DD, I installed a brass check valve across the lift pump
(the gear type fuel pump on the engine) so that when I turn on my electric
fuel pump fuel bypasses this pump and is rapidly circulated through the
engine and back to the tank quickly flushing any pockets of air and filling
the entire system with fresh clean fuel before I hit the Start switch.
I did have a major problem once that shut down the engine but fortunately I
was only five miles from Bellhaven NC and towed the boat there with the
dinghy on the hip.
The shaft that spins the blower shattered into four pieces. It is about 6"
long and connects the timing gears to the blower. It is accessed through a
cover plate just above the port, rear, camshaft power takeoff. It is easy
to get to but take great care not to drop *anything* inside this opening or
you will begin a long tour of the timing gear area. I even had to remove
my raw water pump (which was driven by this camshaft) and it took me only
about 30 minutes to install the new shaft. The original shaft was about
1/2" diameter (the shank part, not the ends), but the replacement was about
5/8".
I strongly suggest you check these shafts and replace them if they are the
skinny ones. SO much easier to do when tied to the dock. The shafts are
not expensive, but the price of a failure is. Fortunately DD had put a
shield around the shaft that caught my four pieces before they fell into
the timing gears, otherwise I would be replacing many large and expensive
parts throughout the engine.
DDs use lots of oil. Mine uses a gallon of Rotella SAE 30 for every 24
hours of running time. I don't change oil. I just add oil and change the
filter yearly.
I have heard of the glop that is supposed to lurk in engines, but always
from people wanting to sell something to get rid of it. I recall vividly
removing the DD oil pan to drill and tap a hole for the Pre Start Lube Oil
Pump suction and finding no glop in the bottom of the pan. Turns out that
modern high detergent oils and oil filters keep everything quite clean
(except for soot apparently).
I have often read the 80% of the wear on an engine comes at start-up so I
installed a Pre-Start Lube Oil Pump. A Jabsco Gear Puppy @ $220, it sucks
from the oil pan and feeds through a checkvalve into a fitting on the oil
filter bracket. I turn this pump on (as well as the electric fuel pump)
just before I hit the start switch. It gives me 30 psi oil pressure before
the engine spins. The pump has a relay to feed it (it can pull to 15 amps)
and don't forget the 15 amps fuse (don't ask me why I know, but to rewind
the pump's armature is $120 plus shipping). Also use a momentary switch
for this pump because once the engine starts the 40 or more psi of the cold
engine oil pressure locks up the Gear Puppy and will blow the fuse (or let
the $120 magic smoke out if you forget to install a fuse). On my
reinstallation, I am installing a 15A self-resetting circuit breaker (plugs
into a 2-blade fuseholder) from NAPA. I am considering also installing a
relief valve around the Gear Puppy so I can leave it on with the engine
running so I can use it as an emergency lube oil pump. I installed a
similar system on my 8KW genset years ago hooked to the glow plug circuit.
Personally, I think every engine should have one.
I am not one to change seawater impellers yearly. I can't remember the
last time I changed the main engine impeller. But I do remove the cover
when hauled out and look at the blades when I renew the zincs and clean the
heat exchangers. I found a good place for zincs: USAzincs.com
I have removed the intake "silencer" that come stock with these engines and
replaced it with two pleated paper type air cleaners (stacked one element
on top of the other) from the NAPA store. I wasn't really happy with the
filtering ability of the original. I use two stacked two elements to let
it breathe easier and replace them yearly.
These big diesels can be sluggish to start, especially in cold weather. A
block heater would be a wise addition (and one I have yet to add). Also I
have doubled up on the battery-to-starter cables: cuts the wire resistance
in half. When I first got the engine I has some trouble starting so I
pulled the starter, took it completely apart (except for the fields) and
carefully put it back together. Loose brush pigtails where an obvious
problem. I filed and/or sanded (don't use emery cloth around electrics,
the abrasive dust conducts) all the current carrying parts, especially the
brush pigtail lugs and their mating surfaces, to make more contact area. I
cleaned everything thoroughly with brushes and compressed air, especially
making sure the brushes moved freely. I used an electrical anti-corrosion
glop (like Never-Seeze but with copper) on all the current carrying
connections. It has worked fine for 30 years.
I came across an air shutdown device somewhere and installed it. It is a
big aluminum piece with a flap valve inside that fits between the blower
and the air filter. It is used to stop air flow in the case of a worn
engine that starts sucking lube oil past the rings and runs away
uncontrollably. I have never rigged a remote control (solenoid or pull
wire) on it. Now I close it manually only as an anti-theft device. I also
have two semi-hidden ball valves (with the handles removed) on the fuel
lines for anti-theft and to isolate the engine part of the fuel system when
desired when working on the engine and wanting to use the genset. (also
have similar valves on the genset fuel lines too)
I can't put my hands on one of my many fuel system essays, but I'll try to
hit the high points.
1. Suck the fuel from the VERY BOTTOM of the fuel tank. A well of some
sort in the bottom of the tank to collect water and glop before sucking it
out would be even better. The concept is to suck out EVERYTHING that sinks
to the bottom of the tank with the normal fuel suction pipe so it ends up
in the primary filter rather than accumulate in the bottom of the tank
waiting to rise up and kill the engine (and possibly you) some dark and
stormy night. The Conventional Wisdom of putting the bottom of the suction
pipe a bit above the tank bottom is DEAD WRONG and can even be FATAL! I
personally know of boats that were lost because of this common factory
installed defect.
Special Note to German Engineers: DO NOT put fuel screens in the bottom of
Mercedes fuel tanks!!!
2. Install an electric fuel pump between the suction manifold and the
primary filter. I use a NAPA Balkamp BK.610-1016 impulse type unit @ $120.
The size of a beer can, it has two pipe fittings and a wire and stops at
about 7 psi. It has a built-in, easily removable screen to protect itself
so you should mount it screen end down for easy cleaning. You must install
it with a bypass valve because the screen can get plugged up. It is a
fairly large screen but it is up-stream from the primary filter so it
catches everything that comes out of the tank if there is no bypass valve
to pass the crap on to the primary filter. I use a swing-gate check valve
for automatic bypassing but some folks use a ball valve. Buy an extra one.
After an installed one has proven itself, put the extra one it its place
and keep the proven one as a spare. I have had an early failure. Make the
pipe connections to the pump with unions or hoses so the pump can be easily
replaced. A tricky trouble can be the collapse of the rubber liner inside
a rubber fuel hose. The hose can look fine on the outside, but the inner
liner can come loose and pinch off flow under suction.
3. Put ball valves everywhere, especially between the output of the
primary filter and the return manifold (so you can clean your own fuel).
You also want to be able to close the return line, pump up 7psi pressure,
then close the suction line. If you loose pressure you have a leak
somewhere. Find it and fix it. You cannot find where a fuel system is
sucking air any other way (don't ask me how I know...).
4. Put gauges downstream of anything that has a filtering effect to see
the degree of the restriction (especially the primary and secondary
filters) so you don't go "Easter egging" - changing perfectly serviceable
filters out of ignorance. You may not have the time to waste some dark and
stormy night! Use 15-0-15psi gauges: they work under both pressure and
vacuum. I use stainless case, brass guts, 2 1/2" (2" is available but I
can see the 2 1/2" across the engine room at night with a flashlight)
glycerin filled. I like the Wika brand because they are solid built and
because of the little pressure relieving valve at the top of the case. I
got the latest batch (DFS-gauges.com PN 4269986 $15) dry yet "fillable"
and will fill them myself to save $4 (hey - that can be a 6-pack in some
stores!).
I have heard of people installing a spring-type check valve backwards on
the fuel return line after it leaves the engine. By backwards I mean so
the return fuel can push against the spring to return to the tank. This is
supposed to prevent the fuel from draining out of the engine when it is
shut off and make for easier starts.
If you have any question don't hesitate to contact me.
Norm
S/V Bandersnatch
Lying Julington Creek FL
N30 07.68 W081 38.47
>
> Always looking to learn more. The DD 6v53 are new to me, but for the
> most part, a diesel, is a diesel. Give it plenty of clean fuel, keep
> it cooled, and lubed and all will generally be well. The 2 strokes
> have some extra issues, and as always, details vary, but they are
> pretty straight forward.
>
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