WayoutMatt
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Marine Power 454 gas engines
- Thread starter WayoutMatt
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The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
WayoutMatt
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Sorry for my ignorance, but what are NA diesels?
diver dave
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Naturally aspirated. Non-turbo
ranger58sb
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Ah. Later '90s, "motor yachts"... was thinking you meant their original "trawler-ish" cruisers from the late '70s-early '80s.
-Chris
WayoutMatt
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That is actually a good point for me to think about. To research the difference in hull design, if any, for comparison purposes.
WayoutMatt
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The time to sell has been the last year before inflation and risk of recession became such an issue. I am not in a hurry as I think it will take about 6 months before sellers realize they missed the boat on selling at inflated prices.
I am seeing markdowns pop up frequently now, and listings not moving.
JRO
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As far as pistons going up and down and cranks going around and around… The GM 454 is a solid, dependable long living motor that has respectable efficiency for its output.
What is important is what company made it a marine application and what components they used.
As far as fuel use… Look it up. There are facts and figures in the owners manual. Making a boat go any speed you need far more info than “it’s a 454”.
What is important is what company made it a marine application and what components they used.
As far as fuel use… Look it up. There are facts and figures in the owners manual. Making a boat go any speed you need far more info than “it’s a 454”.
foggysail
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I have a 1990 40' Silverton aft cabin with a pair of 454s. We purchased the boat after 25 years at 4-6K in my old reliable Hunter 30 sailboat.
Yes--- we had years of experience cruising very slowly, getting there is half the fun sometimes. So back to the 454s. Unless there is a rush or sloppy water, I usually cruise using one engine going out and the other engine returning. I run the engines at around 1800RPM which consumes between 1.4-1.5 miles/gallon. Cruising at 2800RPM with both engines I get about 0.5MPG on each engine.
Risers!!!! Don't screw with them and do not believe someone telling ''OH, they look just fine!" or listening to somebody telling ''I pulled a riser and it looked just fine!'' NONSENSE!!! THERE IS NO WAY TO SEE THROUGH THE CORROSION. As mentioned earlier, a failed riser will kill an engine. I do not put much engine time on our boat now so I stretch my replacements out to 10 years and no more. The recommended time is only 5.
Yes--- we had years of experience cruising very slowly, getting there is half the fun sometimes. So back to the 454s. Unless there is a rush or sloppy water, I usually cruise using one engine going out and the other engine returning. I run the engines at around 1800RPM which consumes between 1.4-1.5 miles/gallon. Cruising at 2800RPM with both engines I get about 0.5MPG on each engine.
Risers!!!! Don't screw with them and do not believe someone telling ''OH, they look just fine!" or listening to somebody telling ''I pulled a riser and it looked just fine!'' NONSENSE!!! THERE IS NO WAY TO SEE THROUGH THE CORROSION. As mentioned earlier, a failed riser will kill an engine. I do not put much engine time on our boat now so I stretch my replacements out to 10 years and no more. The recommended time is only 5.
Well, after 3 or 4 454s over the years, you couldn't pay me to have another.
Yes, they are good engines, but gassers typically have more maintenance and issues than diesels.
My gassers where several times more maintenance and unscheduled issues, and they sure burned a LOT more fuel than the diesel.
Yes, they are good engines, but gassers typically have more maintenance and issues than diesels.
My gassers where several times more maintenance and unscheduled issues, and they sure burned a LOT more fuel than the diesel.
rslifkin
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A lot lot fuel, absolutely. But other than an occasional spark plug, cap, and rotor change I can't think of any maintenance mine have that diesels don't. Most of the "gas engines are unreliable" issues seem to come from older stuff with less than reliable ignition systems. Good ignition systems make things much better.
Correct about electronic ignition system reliabilities. Also fuel injection systems.
Our Tolly's twin 350 cids have well tuned Rochester Quadrajet carbs and retrofit electric ignitions.
General maintenance: Occasional oil change. Long term - plugs, wires.
Coolant refresh every once in a while.
All in all... bullet proof if not run too hard, hour after hour!
Good point, but those are the things that fail. Seems like the gassers are just not a robust, and need:
Plugs
Wires
Ignition
Manifolds
Risers
Elbows
(above 3, every three years)
Lift pumps
Carb (on some)
Fuel pressure adjustment (on others)
Oil
Filters
Belts
Hoses
On the diesel:
Oil Lasts a lot longer
Filters Lasts a lot longer
Belts
Hoses
Some require a intercooler cleaning, but about the schedule where a gasser needs an engine replacement.
You're not going to convince me (perhaps most of us) about the reliability and cost of gassers, after having several over the years. Just the manifolds, risers and elbows cost more that several oil changes of the diesels. Yes, they "can" be reliable.... maybe. There's a reason most looper boats and bigger cruisers have diesel engines.
For a gasser, I could argue for an outboard, and when they don't do the job, get a diesel.
rslifkin
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Only one of those that's a regular concern on any well designed closed cooling setup is the riser/elbow (which are 1 unit on my engines). The manifolds are in the coolant loop, so same as a diesel, just inspect when changing the risers. Better exhaust setups are available, but they're semi-custom and rather pricey.
You also mention belts and hoses as if that's any different than belts and hoses on a diesel.
I'll say most diesels are better marinized than most gas engines. But other than the extra maintenance of shorter lived exhaust parts and the ignition system, I can't see why they're any less reliable in between maintenance periods unless there's something wrong with the design or install.
I mentioned hoses and belts on the diesel.
But all those things are a good reason that the gassers are not more reliable... too many "parts" and some critical.
We can agree to disagree, but having some 19 gasser boats over the years, and I'm a mechanic and they were well maintained, I have some credibility. I've got 1000s of gasser hours and most of the time they work fine.... until they don't. Don't have that issue with diesels.
psneeld
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Wait for the shoe to drop and the diesel repair/replacement prices will kick one in the teeth. Like in investments, past performance is not a good indicator of future performance.
They all have "bolt ons" that go. If you change things and clean things like aftercoolers on some diesels as often as siggested...the maintenance and costs stack against diesels big time unless you mess with it all (and replacement costs you really can't change).
Before I got into the commercial marine world I was convinced of the great advantage of diesels...and that is true for bigger faster heavier boats...you know the ones many are starting to put outboards on.
No longer do I believe that there is any great advantage in many applications.
No real need to argue much, heck the next generation of old codger boaters will be discussing pros and cons over 2 completely different types of propulsion.
They all have "bolt ons" that go. If you change things and clean things like aftercoolers on some diesels as often as siggested...the maintenance and costs stack against diesels big time unless you mess with it all (and replacement costs you really can't change).
Before I got into the commercial marine world I was convinced of the great advantage of diesels...and that is true for bigger faster heavier boats...you know the ones many are starting to put outboards on.
No longer do I believe that there is any great advantage in many applications.
No real need to argue much, heck the next generation of old codger boaters will be discussing pros and cons over 2 completely different types of propulsion.
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Boat engine comparisons on TF have become similar to many boys' dad's army boots, muscles and attitudes while the boy was in 3rd grade... i.e., bigger, better and badder that other boys.
Kinda silly.
MOF - All good quality engines kept well serviced have their deserved place in the boating world.
IMO... It's good to relay in posts what we each might find as details, needs or improvements... regarding engines we own and use or are familiar with from past experiences.
But - To consistently post disparaging remarks/items about other's engines - is - well, kinda 3rd grade like.
Kinda silly.
MOF - All good quality engines kept well serviced have their deserved place in the boating world.
IMO... It's good to relay in posts what we each might find as details, needs or improvements... regarding engines we own and use or are familiar with from past experiences.
But - To consistently post disparaging remarks/items about other's engines - is - well, kinda 3rd grade like.
kthoennes
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Yep, might as well debate anchors. Lots of factors and rationale on both sides I'm sure, but in my mind, for me, it comes down to two things: (1) I simply personally understand and know gas engines far better than diesels, ever since I rebuilt my 1974 Nova SS 307 when I was in high school. I'm a little more comfortable with diesels now, but they're still mostly an exotic foreign territory to me. And (2), parts and getting them serviced. Sure, diesels might last longer, be generally more robust, better on fuel, etc., but that does you no good if you can't find a marine diesel mechanic for 9,000 miles. My 454's might be gas hogs and might not run for 52,000 hours, but at least I can still relatively easily get parts and service, or even whole replacements. The nearest marine diesel service is 260 miles away in Minneapolis, if they're even able to schedule the work or find the parts. Meanwhile I can go to the NAPA auto store in Yankton, SD and get almost all the parts same day or next day.
diver dave
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Ok. Past the five page rule…
I am still in shock. Previous boat was twin 454 Crusaders. Current boat is 29 HP VOLVO diesels. If you exclude electric and hydrogen engines, hard to imagine a larger leap. [emoji41]
Examples: in 15 minutes i could drive my 454 block to a shop that could turn it into a 2000 HP dragster motor.
My Volvo?? The friggin 1” dia formed coolant hose is flown in from japan and cost me $120. Yeah, one bend and maybe 12” long. No, not stainless over teflon, just rubber. [emoji30]
I am still in shock. Previous boat was twin 454 Crusaders. Current boat is 29 HP VOLVO diesels. If you exclude electric and hydrogen engines, hard to imagine a larger leap. [emoji41]
Examples: in 15 minutes i could drive my 454 block to a shop that could turn it into a 2000 HP dragster motor.
My Volvo?? The friggin 1” dia formed coolant hose is flown in from japan and cost me $120. Yeah, one bend and maybe 12” long. No, not stainless over teflon, just rubber. [emoji30]
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foggysail
Guru
Did you give consideration to making up your own hose instead? Easily done in most cases using standard copper or even plastic fittings to make the bends instead of having to spend $120 for the proper replacement
Datenight
Guru
Can also go to NAPA and compare the hose to what is in stock. May have to cut some off if a leg is too long.
Went to NAPA to get new hoses for the Perkins 6-354 in the green boat. Hoses were downstairs. The said leave the hoses and come back this afternoon. They matched all the bends. I did have to trim some. Great service from the store in Groton, CT. It was about 12 years ago…
Rob
rslifkin
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In my mind, there are reasons (1 big, 1 medium-size) why I'd prefer diesels in my boat. The big one is fuel consumption. From the numbers I've run, at 17 kts, my fuel burn would go from ~30 gph to ~20. And at 6.5 kts, my fuel burn would go from 5 gph to 2 - 2.5 gph. Not carrying 400+ gallons of very flammable fuel would be nice too.
Beyond those, the gassers move the boat along just fine, they've been reliable, etc. So in actual usage, fuel efficiency is really the only thing I can complain about.
Beyond those, the gassers move the boat along just fine, they've been reliable, etc. So in actual usage, fuel efficiency is really the only thing I can complain about.
diver dave
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Not that you'd want to do this as long as your fuel thursty 454 cid's are running well, but:
Would you consider simply replacing with new high-tech filled 350 cid's! Cost to do so would be minimal compared to putting in diesels.
Know that your Chris is a bit bigger/heaver than our Tolly, and not knowing its performance with 350's, I can only guess at what nmpg you'd get at various speeds. However, I will guess that as long as the 350's were rated at ample hp and torque [some offered do have considerable power stats] that you'd be happy with performance and your fuel bill would be greatly decreased.
Happy Boating Daze! - Art
Browny
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Not that you'd want to do this as long as your fuel thursty 454 cid's are running well, but:
Would you consider simply replacing with new high-tech filled 350 cid's! Cost to do so would be minimal compared to putting in diesels.
Know that your Chris is a bit bigger/heaver than our Tolly, and not knowing its performance with 350's, I can only guess at what nmpg you'd get at various speeds. However, I will guess that as long as the 350's were rated at ample hp and torque [some offered do have considerable power stats] that you'd be happy with performance and your fuel bill would be greatly decreased.
Happy Boating Daze! - Art
I'm not sure how that would work, in big heavy boats. The old saying, there's no replacement for displacement, is hard to argue with (until you tie off to the gas dock!). My big blocks push my 36' Hatt along, but I'm not sure I'd want to go with any smaller engines.
I'm with you and RS, have a big-ish boat, heavy for gasser's but they start, run, don't burn oil, and move the boat along. Yes its costs my a few dollars a minute on plane, but the savings going gassers vs. diesel in my boat was enormous. The exact same boat as mine with diesels was $60k more.
Even at the current $6.60 in our marina, I can buy a lot of gas for $60K. Hell, I can buy/rebuild two new big blocks AND a lot of gas for $60K.
99.99995% of the charter captains on the Great Lakes run big block engines... for 1000's of hours.
rslifkin
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Not that you'd want to do this as long as your fuel thursty 454 cid's are running well, but:
Would you consider simply replacing with new high-tech filled 350 cid's! Cost to do so would be minimal compared to putting in diesels.
Know that your Chris is a bit bigger/heaver than our Tolly, and not knowing its performance with 350's, I can only guess at what nmpg you'd get at various speeds. However, I will guess that as long as the 350's were rated at ample hp and torque [some offered do have considerable power stats] that you'd be happy with performance and your fuel bill would be greatly decreased.
Happy Boating Daze! - Art
I don't think I could reasonably put small blocks in my boat. Just not enough power to move this hull (a bit over 27k lbs loaded without people and not the lowest drag hull out there) and still provide a good lifespan. If I were to repower other than diesels, I'd probably do custom built big blocks with higher compression, EFI and try for efficiency, at least at low RPM. A pair of small blocks would basically turn my boat into displacement speed only, as they'd be near WOT to keep the thing on plane and would live a very short life unless I went for some of the more souped-up small blocks (and those would likely be short on low rpm torque and have trouble getting the thing out of the hole, plus they'd still be short lived). Basically anything that isn't happy putting out ~200 hp continuously would be insufficient for this boat.
As-is, 3000 RPM is pretty much minimum planing speed with the 454s (~14 kts) and 3300 is typical planing cruise at 17 kts (with 3400 as max continuous, WOT around 4200).
The only real issue with the 454s is low rpm fuel burn (~5 gal/hr total at 1300 rpm). Small blocks wouldn't save much on plane, but at slow cruise they'd burn a bit less.
