The day our engines
arrived Ray and I were working on removing the mechanical fuel shut-off cables
that were used to turn off the Perkins engines.
We understood that the Cummins had an electrical fuel shut-off for
turning off the engines, so these wouldn't be needed. We stopped to watch the engines being
unloaded, and looking at the fuel injector pumps we noticed two control levers,
not one. Although there was an electric
solenoid shut-off, there was also a mechanical lever. We hadn't pulled those control cables out
completely, so just put them back where they were.
The cables came over the front of the engines
on the Perkins, while the Cummins brackets were designed for the cables to come
from the rear. We weren't sure if our
cable length would work or not, but with a lazy S route under the engines it
turned out just right. We were short by
one double cable housing clip, and that thing was nearly $20. After a few fruitless excursions to the
Second Wave marine consignment store and some forays on Ebay I conceded defeat
and bought one at Fisheries. We needed a longer bracket to accommodate the
length from the end of the cable housing to the connector, so Ray fashioned a pair
of those in his shop. We also removed
the control levers for the fuel shut-off so Ray could weld on an offset
extension for a better connection. We
ended up with this nice looking installation.
The boat has exhaust pipes
running from the engine room all the way back to the stern – these pipes are in
excellent shape, as we replaced them a few years back with fiberglass and hose
connecters. The new engines have exhaust water injection elbows which we
need to connect to these existing exhaust pipes. The new elbows are 5” in
diameter, while the boat’s exhaust system is 4.5” in diameter, so some
adjustment is necessary. There are some commercially made “reducers” available,
but the only ones we saw are straight, which would introduce some complications
with a bit too much length. Also, it would then require purchasing a
couple of additional 5” elbows to route the exhaust from the engine to the
pipes. We decided we would build our own reducers, by enlarging one end
of the existing 4.5” elbows we have now. I purchased a one foot section
of 5” fiberglass pipe that we could cut in two to make our modifications.
As I was hoping, the store had a 3’ long remnant and just handed that
over for the price of 1’ – a little extra material in case we need it.
We also purchased a quart
can of fiberglass resin and a small bottle of catalyst, as well as about 10’ of
4” wide fiberglass cloth. With one end of our 4 1/2" elbow cleaned
and sanded, Ray added an O ring he made from some tubing to prevent the resin
from running down the elbow. Our plan
was to wrap the fiberglass cloth around one end of our elbow to bring its
diameter up to where the 5” extension would just fit over it. The
directions for the resin/catalyst ratio were for a full quart, way more than we
needed, so we used syringes to extract 4 oz. of resin and 3 or 4 ml of
catalyst. The syringe used for the catalyst scaled down to only 5 ml, so
that was a bit of a guess, plus the ratio changes quite a bit with the ambient
room temperature.
We
decided about 3 wraps around the cylinder would be about right, cut off the
proper length of cloth, mixed our resin and went right to work, as we knew we’d
have a limited working life with the resin. We were just finishing up the
3rd wrap when the remainder, about half of what we started with,
solidified in our cup. It quickly generated enough heat that we couldn’t
hold it by the bottom – we set it outside away from the house just in case it
was going to burst into flame. It didn’t. When the cloth set up we
tried the 5” tube over it and decided a couple more wraps would make for a good
tight fit. With our next session working with the resin we used a bit
less catalyst, applied the extra wraps and overlaid the 5” tube onto the piece
just before we had our next lump of solid leftover resin. We had used
most of the 10’ of cloth, so purchased some more for the second elbow.
With even less catalyst this time, we got the entire wrap plus the 5”
tube on the second elbow in one session.
Our new elbows provided for the 90 degree turn to the bulkhead on each
side, as well as the reduction in diameter.
On the deck you can see
the old 4.5" plug that kept water from entering the boat while the exhaust
is disconnected, and clamped to our new reducer elbow via a length of hose is
the new 5" wood plug that serves the same purpose. Both sets of plugs will remain on the boat in
case they're needed during some future exhaust work.
Some of you may be
wondering what the heck we’re doing using fiberglass for exhaust piping.
Although the exhaust directly out of the engine can run up to 850
degrees, this is quickly cooled when the raw cooling water is injected into the
exhaust at the water injection elbow. This is now a common material to
use for marine water-cooled exhaust – much cheaper than copper (the previous
pipes on the Potentate) or even hose, and with a much longer lifespan.
I had also purchased some
5" diameter stainless steel exhaust elbows on Ebay, thinking they would
come in handy for routing the exhaust from the engine. Using one of the stainless elbows and short
lengths of hose for connecting, I hooked up the starboard exhaust from the
water injection elbow all the way to the bulkhead. I didn't like the looks of it at all. It just didn't look like very much
slope. The raw water used for cooling
exits through the exhaust, and with this slight of a slope I was concerned that
water could backwash up the exhaust into the engine if the boat were rocked the
wrong way. This would be a very bad
thing, especially with salt water.
I did
some research and read somewhere that the exhaust elbow should be at least
12" above the waterline. By
sighting a nearby thru-hull fitting from the outside and inside we estimated
that we had just around half that elevation.
I took the connection apart and put the wooden plug back in. We took a trip to Broomfield's Marine Exhaust
in Ballard to see what sort of riser might be available. He had a couple of 90 degree elbows designed
for Cummins, and we borrowed those to better estimate what we'd need. I bolted them together with a 90 degree
offset, then clamped on our exhaust elbow with some vicegrips for a
visualization.
We could see that we could
do another two or three inches of elevation, and that we'd also need the riser
to extend away from the turbocharger another 3 inches so as to clear the raw
water outlet pipe from the heat exchanger.
We ordered two risers made from elbows with a straight piece welded
in. They were ready in a week or so. I put them in the trunk and made the next stop
at Ballard Insulation, where I had heat shields made for them. These aren't water cooled, so can get up to
800 degrees depending on the load on the engines. The small threaded fittings are for the
pyrometer sensors. These riser were not
cheap, but are a lot less expensive than having salt water inside your engine.
We also got some pieces of
high temperature gasket material while at Broomfield's, and Ray cut out a
couple of gaskets for the risers with his scroll saw. Here they are sandwiched between a couple
pieces of wood to prevent the material from fraying.
In yet more Ebay shopping
I had acquired a box of stainless steel T-bar clamps and a couple of high temp
silicone exhaust hose couplings, so we were ready to assemble our exhaust
system and see how it all fit together.
We had the steel exhaust gaskets that came with the engines, and we used
those between the turbochargers and the new risers. The gaskets Ray made we used between the
risers and the water injection elbows.
We put a thin layer of white lithium grease on the joining surfaces as
well. I had learned earlier from
Broomfield's how that helps with the seal while we were working on the Perkins
exhaust system. The extra 2 feet of
5" fiberglass pipe we had was just the right length for the port side run
from the injection elbow to our newly made reduction elbow. The insulating pads are held on with
stainless steel wire, laced together not unlike a boot.
We found it was easier to put the pads on
before connecting the raw water hose from the heat exchanger to the elbow. The starboard side went together in a similar
fashion, with a shorter run to the reduction elbow. The hose from the heat exchanger to the elbow
is wire reinforced, and also repurposed.
It's from sections of the hose I removed from the raw water through-hull
fittings to the engines and replaced with new.
In between our steps of
getting the exhaust parts fabricated and aligned to our satisfaction, we’ve
also been doing some other necessary stuff, like connecting fuel input and
return lines, raw water hose, battery cables, painting the new stringer blocks,
filling the engines with coolant (the coolant that was in the engines didn’t
have much anti-freeze in it – a result of having engines shipped up from
Florida!), and reinstalling the boat’s hot water tank, which is now plumbed
into the starboard engine’s coolant system for heating our water while cruising.
The tank fit back in its original spot, with about an inch or two of clearance
from the starboard engine’s crankshaft pulley.
Despite all that we’ve
done to date it seems like there’s just as much stuff left to do as ever, but
we’ll eventually be to the point where we’re
ready to turn the key(s) and push start(s) to see what happens. After
that comes another list of tasks, including fixing that big hole in the
ceiling!
We
have been enjoying our short work days, with equal amounts of pondering to go with
the actual work – and with occasional lunch breaks at Voula’s or the Salmon Bay
Café as well.
In
the photo above you can also see the raw water pump below
the control cables, with no pipe attached. Sea water is pumped through a
heat exchanger to cool the engine’s coolant, similar to a radiator cooling a
car engine – we just use water instead of air blowing through the grill.
In addition to the engine coolant, we also have to cool the transmission fluid
and reduction gear oil as well. The engines came equipped with
transmission coolers, but we opted to use the old ones that cooled the transmissions
when the Perkins were driving them. They are larger and serviceable – Ray
had previously disassembled and cleaned them, so they were ready for duty.
With
the additional circuit for cooling the reduction gear, we had some rerouting to
do on the raw water plumbing. In addition, one of the pipes that came
attached to the starboard engine’s raw water pump was smaller than the port
side, as well as a bit shopworn. The pipe on the other engine was PVC,
and we decided to go that route on the starboard side as well. We
acquired some various universal flex hose lengths at an auto supply store, as
well as a couple of preformed elbows that were 1 ¾ inches in diameter – the
size needed to fit onto the transmission and gear coolers. The outside
diameter of the PVC pipe is an odd size not intended for clamping hose to – so
we fixed that by getting some PVC couplers, which Ray cut in half and turned
down to the proper outside diameter on his lathe. He also formed a ridge
at one end to better hold the hose.
Once
we cut the PVC sections to the proper length we used PVC cement to attach and
bond our custom fittings to the ends of the pipe. The raw water is now
routed across the back of the engine under the turbocharger into the
transmission cooler, then to the reduction gear box (which has its own water
jacket), and from there to the heat exchanger, where it cools the engine’s
internal coolant. From there the raw water is injected into the exhaust
elbow coming out of the turbocharger where it cools the exhaust and then exits
with the exhaust out through the transom.
With
the plumbing completed we turned our attention to the electrical
connections. Earlier I mentioned that I had located and acquired a pair
of brand new Cummins gauge panels complete with 30’ wiring harnesses. Ray
had made a new mahogany panel from an old cabinet door of mine that I’d set
aside nearly 40 years ago for this purpose, and I augmented the gauge set with
additional VDO gauges for turbo boost, pyrometer (exhaust temp) and
transmission pressure. We installed these on the helm a few months ago,
but we’re now ready to make the connections to light them up.
The turbo/boost gauge is
mechanical – no sending unit, just a small air hose from the intake manifold is
all that’s needed to actuate it. I had a length of plastic hose left over
from repairing the ice maker connection some time ago, and Ray had a length of
similar sized hose that he’d previously used for compressed air in his
shop. With that supply and some compression fittings we were able to make
connections, thread the hoses through the rear bulkhead and up the closet wall
to the gauge panel.
Next came the pyrometer gauge. When we had the
exhaust risers fabricated we had a threaded hole put in each one, to which we
could insert a temperature sensor. This sensor can detect temperatures up
to 1500 degrees, although the exhaust coming directly from the turbocharger
should never exceed about 850 degrees at wide open throttle. The sensor
has an electrical pigtail which attaches to a length of double wire that we
also routed through the firewall and up to the helm. These additional
gauges are also illuminated, as are the original panel gauges. We tapped
into the power and ground connections of one of those gauges to connect the
lights of the new gauges. The gauges have small clear bulbs, but also
came with green and red sleeves which could be put over the bulbs. I used
the red to match the other gauges. The transmission oil pressure gauges
we’ll hook up later, using a pair of unused wires that are in the harness.
Once this was done we
decided to turn on the battery switch for each engine so we could turn on the
ignition key to see if all the lights worked and if the gauge needles would set
to zero. I was at the helm and Ray was in the engine room to flip the
switch. He did starboard first, and the engine started cranking, even
though the key was off and I definitely wasn’t leaning on the starter
button. That was a bit unexpected and exciting, but Ray turned it back
off pronto. I thought something must be messed up between the gauge panel
and the wiring harness, so we disconnected the gauge panel completely from the
engine and tried it again – with the same result. We left starboard off
and turned our attention to the port side. We did not get that result
there, which was a bit reassuring. No sounds, smoke or smells occurred
when the battery switch was powered on, and when I turned on the key for the
port engine all the gauges lit up, and the low oil pressure light came on, as
well as the warning buzzer.
We
were about to leave the starboard snafu for the next day when we encountered
Randy Rice as we were leaving. He is another tenant at the marina who
repowered his boat several years ago using these same model engines. He
came to take a look at it, and surmised that maybe one of the wires from the
relay below the starter was crossed up. He disconnected it, then did some
testing with my voltmeter at several contacts. All was as it should have
been, and the wire he disconnected had belonged where it was. He put it
back to the same terminal; we turned on the battery switch and … nothing.
It behaved itself and when I subsequently turned on the key for the starboard
engine the gauges lit up, the buzzer sounded, etc. A light tap of the
starter button engaged the starter so all seemed okay. We could only
surmise that the load of spray paint that was put on the engine after it was
rebuilt had somehow been conductive, or something was making contact that
resolved itself with the removal and replacement of that wire. We weren’t
quite ready to start the engines then – still haven’t opened the seacocks for
the raw water inlet and there are some additional witnesses who may want to see
what happens when we turn the key for real.
