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Of
all the questions we are asked, one of the most frequent is which
gas engine is best.
I have some very definite opinions about that because I perform
a lot of gas engine surveys, as well as engine failure analysis
for insurance companies, meaning that my perspective is not based
on the "virtual reality" of dockside chat, but what happens
to this vital machinery in the real world based on thousands of
surveys. So let's get to it.
Hands down, I give my top award to the Crusader
Division of ThermoElectron Corporation for their Crusader line of
engines. Coming to this conclusion was easy because their engines
simply outperform all others in terms of service life. The fact
is that Crusader engines keep going long after others have had overhauls,
engine replacements, or replacements of expensive parts such as
manifolds, risers and cooling systems, often giving reliable service
life in excess of 100% over other engines.
But that's not all. Several years ago, I had the
opportunity to tear down a Crusader 454 engine and that of a competitor,
side by side on the bench, and make a detailed comparison.* I was
quite surprised to find that even the engine blocks were not the
same, for the Crusader block was considerably better.
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If
you don't think engines and how they are installed make a
difference, compare these two.
On left a pair of Mercruiser 454's installed in a Forumula
F-29; on right Crusader 454's in a Tiara 3100. Any guesses
as to the difference in maintenance costs? The striking things
about the Crusaders is how uncluttered they are. How would
you like to change plugs and oil filters on the Mercs? |
Start with the fact that the Crusader had 4-bolt,
stepped and stabilized main bearing caps, whereas the other engine
had a 2-bolt, unstepped, unstabilized main bearing caps. As some
of you may know, GM has long made two lines of basically the same
engine, the better of the two being named the "TargetMaster"
line of heavier duty, more precision engines for trucks. While I
don't claim to be intimate with the GM product line of engines -
the last time I personally rebuilt a TargetMaster was 10 years ago
- there isn't any doubt in my mind that Crusader is using the TargetMaster
line. The basic block was an all-around better block than it's competitor's.
The basic differences were in the lower end, as well as obviously
larger cooling passages.
Crusader's engines aren't widely used for race
boat engine conversions like its competitors engines are, probably
because Crusader doesn't get involved with the racing crowd. But
it is interesting to note that when its competitor's engines are
used by the race engine builders, they always add stabilizers to
the main bearing caps. Sort of makes you wonder why they don't just
use the better block in the first place, doesn't it? Well, part
of the answer is that this is a high performance, not a heavy duty
block, made for speed but not endurance.
Why not electronic ignitions and EFI fuel systems?
Quite simply because of cost and reliability. Crusader has strictly
avoided electronic systems, and rightly so because let's face it,
these engines get wet. Whether its leaking decks or hatches,
stuffing boxes throwing water or leaking hoses or whatnot, reliability
goes out the hatch when sensitive systems are involved. Experience
people know that the outstanding virtue is ruggedness and the ability
to survive the environment. So, too, ease and cost of servicing.
In that regard, you just can't beat the plain old carburetor and
standard ignition system. All decent mechanics (and many boat owners)
know how to fix these things, and at reasonable cost. When
you start adding digital electronics and delicate metering systems,
the cost can only go up, and the number of mechanics who work on
them goes down. No matter how much fuel a sophisticated system may
save, or improvements in efficiency or power, nothing compares to
reliability and low cost repairs. Its your money, take your choice.
In the real world, Crusader outperforms all others
in terms of reliability and longevity. Its not unusual for me to
find Crusader engines 15-20 years old that are still going strong
in the seawater environment, whereas its rather rare to find other
engines going this long. There are two primary reasons for this:
(1) better cooling system design, and (2) better gaskets.
One engine marinizer has had gasket and cooling
system problems for going on two decades now and still displays
no willingness to resolve the problem. Frankly, there's no excuse
for a line of engines in which the head gaskets go bad in 4-6 years,
but in 50% of all engines that I survey of this builder, I find
leaking head gaskets. Mostly on seawater cooled engines, but not
infrequently on FWC engines as well. And both of Crusader's main
competitors have exhaust risers that are almost guaranteed to go
bad in seawater use within 3-5 years. Its bad enough to have to
bear the cost of replacing leaking risers, but the real problem
with leaking risers is that when they corrode and start leaking,
the water goes into the engine, often causing major damage and costly
repairs.
Crusader solves this problem by including the cast
iron risers on the fresh water side of the cooling system, so that
without sea water going through them these risers can last ten years
or more. Yes, it does mean that Crusader engines are more sensitive
to overheating because more of the very hot exhaust system is being
cooled by the FWC side of the system. But that's a small price to
pay to avoid having to replace $2,000 worth of castings and risking
major engine damage. This doesn't mean that Crusader engines are
prone to overheating, at least not if you pay more attention to
cooling system maintenance. This is because any reduction in heat
transfer ability will result in a more rapid rise in temperature
simply because more of the engine is being cooled by the FWC system.
That means following instructions when mixing your
engine coolant with water to get the proper ratio. Did you know
that too much coolant (antifreeze) can actually be harmful to your
engine? Excessive amounts of ethylene glycol can cause the chemical
to gel on the sides of the cooling passages in hot spots like the
water jackets around the cylinders and exhaust manifolds. When this
happens, the antifreeze begins to retard heat transfer, and what
you get is uneven cooling - hotspots and cooler spots - resulting
in great differences in temperatures that can cause the block to
distort. This is one of the major causes of cracked blocks, manifolds
and cylinder heads, as well as ring wear and piston melting. The
same thing happens when you have too little, or no coolant; corrosion
within the cooling system retards heat transfer and results in hot
spots or higher internal temperatures.
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| Here's what happens when poor quality
head gaskets leak - water in the cylinder, but that's
not all. The water corrodes the metal surfaces of both
the block and cylinder head, meaning that the surface is no
longer flat and will not make a seal with new gaskets unless
these mating surfaces are re-milled. You can mill the
heads, but you can't re-mill the block. So what you end up
with is basically a ruined engine. For another
$100 in better quality gaskets, this would have been prevented.
This inexpensive (Hino) diesel was only 5 years old and obviously
had automotive gaskets. |
Other features with Crusader include better location
of components for servicing, better engine mounts, higher quality
transmission oil cooler with convenient front engine mount so that
its easy to check for leaks. And unlike some builders, their engines
aren't painted black but a nice medium blue color so that you can
identify and repair leaks quickly, whereas with black or dark gray
you usually don't notice water or oil leaks until its too late.
Better internal gasketing. Fuel pumps that almost never fail. Superior
belt drive system of peripherals such as water pumps and alternators.
A standard mechanical electrical system with no microprocessors
or other high tech BS to cause high tech headaches. A serviceable
heat exchanger tank with removable end plates so that the core can
be removed and cleaned, whereas most others are very expensive throwaways.
And yes, you should pull the cores and have them cleaned every two
years, as well as regasketing the system.
Now here's one of the best features: high rear
engine oil filter mounts on most models!!! Yep, not under the engine
where it can't be reached, but nice and high where with two hands
you can spin those little honeys off in a heartbeat. Now that's
what I call thoughtfulness. (Not included on V-6 models and optional
on most engines and available as a kit)
I give my 4 gold star award to Crusader Engines
for an overall superior product. Here's a manufacturer that obviously
cares about their customers. How do I know this? Because they have
gone the extra mile of taking the time to design these engines,
not only for longevity, but for ease of service. In an age when
most manufacturers could care less if servicing their products are
a nightmare, Crusader offers a product that is about as easy to
maintain as possible. Crusader costs more, but anything else is
penny-wise and pound-foolish.
* Model years were 1991
& 1992
Estimated engine service life,
FWC models: 12-15 years**
Estimated engine service life,
seawater models: 6-8 years**
Total engine service life, SWC
cooled engines with good maintenance: 10-12 years.
Total engine service life FWC
models with good maintenance: 15-20 years.***
** Before replacement of major
components such as risers, manifolds, heat exchangers, is required.
These estimates are based upon real world surveys and experience
of boats in south Florida that get full 12 month usage with no layup
periods.
*** This average includes major
replacements of heat exchangers, water pumps, regasketing and valve
jobs, etc.
Related Article: Gas -vs-
Diesel Part II
Posted in 1997
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