Long lasting gas engines?

While on the no load thread this came up (see my own quote below) and we've talked a lot about how long a diesel engine can be expected to last and all know that the gasoline engine is considerably less long lived. But of how much importance is that? How many of us have had to rebuild gas engines in their previous boats? Not many I suspect. I think the long lasting reputation of diesels in pleasure boats is over played and most of us would be just as well off w gas engines IN THIS REGARD.
The actual life expectancy of gas engines is probably best represented in automotive histories but that's a different application than boats. But since there's so few starts in the total hours perhaps boat engines could last longer BUT boat engines work much harder ................................................?



Awww Al give him a break,
That means if I had a gas engine it'd be 2/3rds worn out .............NO WAY!
Diesel is nice'n safe and twice as economical (fuel only) BUT THAT's it.
Gas engines are MUCH smoother and quieter and last a long time. My 73 Buick has never had any serious maintenance .... Heads never been off and it's really strong. Could use a carb rebuild but it runs perfect all the time. If it sits for a week or so it looses it's prime but that all. It's seen new shocks, batteries, the usual break work ect but to say the car has lasted and gone the distance ( over 100K) is an understatement. 100K is not high millage now but in it's time it was. Did some numbers and you are closer than I thought. 100000 miles at 50 mph is 2000 hrs. Not all that much actually. I've gone half that w my Mitsu and consider it basically a new engine. I wonder what they're say'in a new 350 Crusader w fuel injection would do re life expectancy re hours? So it looks like a modern gas engine should go 5000hrs and. A diesel 10 to 15K. I'll start a new thread unless someone beats me to it ....... I'm at Barns & Noble on the I-pad.

Assistance towing carburated, 454's get an easy 5000 hrs (10-12 years) with the crap beat out of them. Dino oil, changed every 200 hrs. That's sitting in a deep wet bilge with minimal season and light winter maintenance.

If an assistance tower gets 5,000 hours out of a 454 gasser, then a displacement speed trawler should get more, but somehow they don't. Probably because there is no such thing as a displacement speed trawler with a gasser.

Assistance towing is tough duty on an engine: high speed planing to get to the caller, time spent at part throttle washing the silt out from under the grounded boat and light throttle 5 kt towing back to port.

Anectdotal stories says that gassers get 2-3000 hours before replacement.

David

djmarchand said:

If an assistance tower gets 5,000 hours out of a 454 gasser, then a displacement speed trawler should get more, but somehow they don't. Probably because there is no such thing as a displacement speed trawler with a gasser.

Assistance towing is tough duty on an engine: high speed planing to get to the caller, time spent at part throttle washing the silt out from under the grounded boat and light throttle 5 kt towing back to port.

Anectdotal stories says that gassers get 2-3000 hours before replacement.

David

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You wouldn't use a 454...you would use a straight six (like a Fort 300 cu in or even smaller) with a high reduction gear I would think.

In the 50s GM built a V6 small truck engine specifically for the trucks. Never saw service in a car. They had many special features in the cooling system, block, crankshaft, lube system such that they could be run at very heavy loads for long periods. They were big and heavy and about 304 cu in. I recall that they were great engines but they had a reputation for high fuel consumption. I'll bet they'd go the distance in a boat though. Too bad they burn so much fuel. Perhaps they can be "fixed". Have no idea if parts are available. It,s odd that the lightweight GM small block replaced them.

Another engine that would work well (not economically though) is an older Jaguar like a 3.8 or 4.2 L inline 6 w their billet crank. They weigh more that a big Buick V8 though. I hear if they are well taken care of they last forever.

What do some of the fleet trucks get out of the common GM 350? I remember driving old flatbed trucks w the GM 350 that had untold millage on them and the flatbeds (and others) had strong engines that ran great right up ther'e at max power and shifting only after they ran out of breath.

Psneeld I can see a 454 running 5000 hrs. Do you know if the 455 Buick and the 454 chevy are related more than being both GM?.

Monk used Chrysler Crowns and such in his "heavy cruisers" which were were sometimes displacement, other times semi displacement. There are still many around here in the PNW with the original gassers. When I was just burning time over-thinking my repower project, I was thinking that a slant 6 would have been a great engine for my purposes if it was marinized and supported. I do believe that gassers would last a lot longer on average if only they were cared for. Many folks with 30+ foot boats hit the marina, fire it up, get outside the no wake zone and put the hammer down because they can. Anecdotally I have a marina acquaintance who runs his single Volvo 5.7 at 4000 rpms as his cruise speed on a 28 footer. The mechanic loves him.

The PO of our Owens underwent a complete re-fit 2 seasons before we purchased it. Only 2 items where not replaced, the gas tank and the Velvet Drive and they where refurbished/rebuilt. Factory fresh 350 Chevy engine and brand new Osco marinazation kit. The old lump was a 283 Chevy that was by all accounts original to the boat.

I accept that my approach is that of a complete simpleton and that some will claim has no regard for the safety of my family. We figure that if that 283 lasted from 1967 to 2011 without exploding and vaporizing itself and all on board that we're pretty safe. There's also no reason not to believe that it has every opportunity to last another 40+ years in normal service with good maintenance.

If it does not, and we still own the boat, I'd gladly spend the $1,800 to replace it with another crate engine. http://www.summitracing.com/parts/nal-12568758?seid=google&gclid=CIrdtIvMmLYCFQxxQgodpgkAYQ It would take me and a friend an afternoon and a half to pull and replace it as if nothing ever happened. I challenge any owner of a deisel boat under 34 feet to make the same claim.

Having said all that, if we upsize to another cabin cruiser it will most likely be deisel. Not because gas engines are evil, just because there are fewer of them so equipped in the next size we are considering.

I think how long a gas engine will last depends not only on the maintenance being kept up, but also if it is freshwater cooled or raw water cooled... A raw water cooled engine if it lives in salt water...is going to need a lot more maintenance...and replacement of not only the risers and elbows...but quite possibly the main water pump.... It seems the cast iron risers and elbows have a limited life span....

Father-in-law had a 455 Olds FWC (no relation to 454 Chev) in his Dyer 29, it seemed to go on for ever, at least 20 years b/4 boat was sold and may ll be going yet for all I know.

In a 29'-30' boat a gas engine can make the difference between noisy and quiet, smooth and rough, & engine box or flushdeck; all serious considerations.

manyboats said:

Psneeld I can see a 454 running 5000 hrs. Do you know if the 455 Buick and the 454 chevy are related more than being both GM?.

Click to expand...

They are not.

My other boat had the 3 litre mercruiser sterndrive from 1975. I bought the boat in 2005 (i think) and ran it for one summer. It was going pretty strong but not 100% reliable. At the end of the summer it blew the headgasket and the boat was in any case due for a full renovation.

The engine was raw water cooled and not much care was put in the maintenance. So about 30 years of longevity, not bad.

Naturally I have no idea about the hours it had gone through but a typical average for that kind of boat per season is about 50 or so hours.

I still have the engine, in parts and mechanics told me it could be put back together. Block, head and pistons etc were nearly fine. Maybe it would need oversized pistons but you van imagine that there were not much left in the water pump...

It would take me and a friend an afternoon and a half to pull and replace it as if nothing ever happened.

PLUS a couple of cases of BEER!

Thanks I thought the 454 and 455 were different engines but thought it strange that the same company would make 2 engines the same size. I know nothing about the 454. Is it a lighter weight/higher performance engine? My 455 has loads of torque but when I push down on the throttle sometimes I'm going faster than intended real soon. Not that much screaming power (for it's size) even though it's got a big carb. It's no 10 mpg car either ... 13, 14 and more at times I'm sure.

I thought sea water cooled engines were basically a thing of the past and wasn't planning that to be part of this. I'm more curious about the basic engine.

psneeld talks about 5000 hrs "beating the crap out of them" (454) but I'll bet "beating" dosn't include poor maintenance. And I'll bet gas engined boats receive poorer maintenance than diesels. Perhaps much poorer. I'm more interested in how long an engine CAN last and I suspect that 5000 hours could be a high for gas .... but?

I wonder if sunchaser has accounts of gas engines running hard w good maintenance in the construction world? I'll bet there's some small truck fleets like vans running on propane or natural gas that go 300000 miles or more.

djmarchand wrote "Anectdotal stories says that gassers get 2-3000 hours before replacement." I'm guessing that includes very poor maintenance. I think air cooled motorcycles should last that long.

manyboats said:

Thanks I thought the 454 and 455 were different engines but thought it strange that the same company would make 2 engines the same size. I know nothing about the 454. Is it a lighter weight/higher performance engine? My 455 has loads of torque but when I push down on the throttle sometimes I'm going faster than intended real soon. Not that much screaming power (for it's size) even though it's got a big carb. It's no 10 mpg car either ... 13, 14 and more at times I'm sure.

I thought sea water cooled engines were basically a thing of the past and wasn't planning that to be part of this. I'm more curious about the basic engine.

psneeld talks about 5000 hrs "beating the crap out of them" (454) but I'll bet "beating" dosn't include poor maintenance. And I'll bet gas engined boats receive poorer maintenance than diesels. Perhaps much poorer. I'm more interested in how long an engine CAN last and I suspect that 5000 hours could be a high for gas .... but?

I wonder if sunchaser has accounts of gas engines running hard w good maintenance in the construction world? I'll bet there's some small truck fleets like vans running on propane or natural gas that go 300000 miles or more.

djmarchand wrote "Anectdotal stories says that gassers get 2-3000 hours before replacement." I'm guessing that includes very poor maintenance. I think air cooled motorcycles should last that long.

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Pretty much, the only maintenance the engines get is when they break...they get a replacement part. They get 200 hour oil changes with cheap dino oil. Get a shot of CRC 656 over the rusty parts a couple times a summer. And it's 4 boats rigged and treated the same.

psneeld,
OK good and this is the real world marine not propane powered fleet trucks.

manyboats said:

I wonder if sunchaser has accounts of gas engines running hard w good maintenance in the construction world? I'll bet there's some small truck fleets like vans running on propane or natural gas that go 300000 miles or more.

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Eric--- A co-worker has a Tahoe (I'm not a GM/Chevy fan so I have no clue what it has for an engine other than knowing it's a V-8) and it currently has well over 300,000 miles on it and to date has not needed an overhaul.

There's lot's of examples of gas engines going 250,000 plus miles out there..my sister's Honds is but just one...however...a boat engine it's not.

Boat and car engines operate differently.

Car engines are not under very much load most of the time.
How long does any car operate at full or 80% throttle?

A planning hull gas runabout operated above hull speed uses much more horsepower than the engine in a car.

When I was in the O/B-stern drive business, 2000 hours was about the life of a gas engine. Most small recreational boats average less than 100 hours per year, so that is 20 years of life.

Gas engines also require the exhaust elbows and sometimes the exhaust manifolds to be replaced every few years due to the high exhaust temps. (Gas engine exhaust is about 2000 degrees while diesel is about 900.)

For marine use, I would want a gas engine to be a long stroke, high torque engine like a Ford 460. The GM 454 is a short stroke engine and in my stern drive servicing experience did not last as long as a 460. However, the owners of the 454 engined speed boats were more likely to be 'full throttle' operators.

I think a high torque long stroke gas engine in a trawler using only 50 to 75 hp should last a long time if it gets proper maintenance.

Larry,
Long strokes have very little to do w torque. Buick V8 ultra short stroke engines developed more torque than straight 8 Buicks ever dreamed of having.
Look at the specs. You'll find all sorts of short stroke engines w lots of torque. I think that old wife's tale came from the probable fact that long stroke didn't develop much torque up in the engine speeds where most engines develop their max torque.

psneeld if the Honda was geared right it would probably make a decent boat engine.

Lots of small Bayliner boats didn't last long because of the way they got treated just like those engines you mentioned above Larry.

manyboats said:

psneeld if the Honda was geared right it would probably make a decent boat engine.

Click to expand...

It is my understanding--- but I could be wrong--- that the engines in Honda's larger outboards are simply marinized Accura engines (or some model of Honda automobile).

This is an interesting thread and something I think of often. My pickup has 5,101 hours on the motor at 140,000 miles and 6 years old. Unheard of in a maranized car engine. I compare that to my thirty year old Perkins with 2,500 hours. They seem barely broken in, hourwise.
Regarding outboards, I don't think I've seen one advertised with over 700 hours, so got me to wondering what is the typical life span, hour-wise of an outboard?

Max Simmons said:

This is an interesting thread and something I think of often. My pickup has 5,101 hours on the motor at 140,000 miles and 6 years old. Unheard of in a maranized car engine. I compare that to my thirty year old Perkins with 2,500 hours. They seem barely broken in, hourwise.
Regarding outboards, I don't think I've seen one advertised with over 700 hours, so got me to wondering what is the typical life span, hour-wise of an outboard?

Click to expand...

Not sure where you got your info or if you have read most of this thread...but marinized car engines have gone 5000+ hours in some boats and outboards also have easily surpassed 1000 hours.

Talk to commercial guys and don't nuch you read in boating magazines.

Well at least try national Fisherman mag instead of the glossy yacht mags...

Well at least try national Fisherman mag instead of the glossy yacht mags...

The guys in NF have a great setup , usually a roof hatch that will allow the engine to be removed straight up in minuets.

With the usual keel cooling and dry exhaust the hookups are minor.

Most will have a spare junk yard engine , so IF something untoward happens , its no big deal.

Remember many of these folks will run home loaded at full tilt , so the engine does get a workout!

In the 1960s Seamaster marinized the Ford 534 truck engine. This was a high torque relatively slow turning gasser. I believe that the top RPM was about 2800. Hatteras used some of these in their early sportfishers. I knew a guy who had the SeaBee, a 41 Hatteras. He said they were bullet proof. Not economical to run however.

In the late 50s we had a couple of GMC straight trucks with 20' boxes. They had the V-6 engines Eric was talking about. They were good trucks, and a big improvement over the old GM straight 6. Maybe it was just that they were newer. I don't remember about the fuel mileage. I wasn't paying for it. We also got our first International COE tractors at that time. They had the 220 hp Cummins. I will never forget the beautiful sound they made. After the screaming Jimmys they were a pleasure to drive. The Road Ranger transmission was also a big improvement.

This is an area that I've got unfortunately quite a bit of experience in.

First, Gas engines are generally found in planing hull boats.

The owners of these boats generally run them hard, up on plane.

What I've found over many years on both my own boats and watching the Bayliner Owners Club members trials and tribulations is that a gas engine is going to last approx 1,000 hours over a 10-15 year useful lifespan.

Thats not to say some last longer, and thats not to say that some last shorter, thats just what I've found.

This is also what David Pascoe found and documented in his writings on the subject of Gas Vs Diesel

Marine Engines : Power Options - Gas Versus Diesel

Now, down to the root cause of the failures. Do gas engines fail because of an internal problem, or do they fail because of an external problem.

I think its both.

Running an engine hard, like a boat up on plane makes everything critical. There is so much heat to dissipate that the smallest cooling system issue can lead to catastrophic engine failure. Timing issues or old gas can cause detonation which can ruin a gas engine extremely quickly.

Then you run into maintenance issues. Gas engines are often not maintained properly, with the largest issue being exhaust system corrosion and failure. Then you run into the issue of water ingestion. Stern drive installations do not use water lift mufflers, and the installation is often marginal at best when considering exhaust system rise. This makes water ingestion a major problem.

So, the long story is that in boats gas engines do not generally (but not always) have long lifespans, but its not really the engines fault.

A well maintained gas engine in a larger boat might last a very long time.

Looks to me at this point that gas engines suffer terribly from all manner of abuse. And most die off quickly.

What I wonder is what if someone ran a gas engine the way lots or even most of us run our diesels. From the text I'm hear'in on this forum most trawler engines lead a life that almost all gas engines can hardly dream about. And keep in mind that gas engines don't suffer from underloading. It seems to me that If I was to swap out my diesel for an excellent gas engine it should last at least half as long as the diesel.

Still looking for a fleet car or truck story but even that would be flawed by the fact that the engines would be operated by people that didn't own the engine. They'd run them hard cold and shut them down hot and do lots of other things not good for engines. But if fleet gas engines ran regularly 5000 hrs then one could assume one could get at least 8000 hrs if run and maintained well.

Max does your PU actually have an hourmeter? Did you install it? Sounds like you must have done a lot if idling.
I remember something thats kinda related to this. In th 50s and 60s Weyerhaeuser kept their OBs (50hp Mercury 4 cyl) for pond boats. They were run hard every day. Lots and lots of full throttle operation. The throttles probably performed much like an on/off valve. They rebuilt those engines often but because of the nature of the crankshaft it was probably not replaced. Interesting extreme performance of an OB.

Eric, I think the reason that the exclusive truck gas engines were discontinued was the expense of manufacturing. By the time forged parts, extra bearings, and bracing to hold the block together were added up the cost was approaching diesel. Diesel was becoming more favorable in the trucking industry. We even had some Mack gas tractors, but they were switched to diesel by the mid 60s.

It just cost too much to hold a gas engine together under the loads of commercial use. The cost factor got very near diesel.

Max does your PU actually have an hourmeter? Did you install it? Sounds like you must have done a lot if idling.

Yes, it came with an hour meter. I think this equates to an average of around 27 MPH. Lots of time spent in Seattle running between construction sites.

Growing up with gas engined boats, our 1967 31' Trojan had twin ford 302's I believe and we got roughly 1,200 hours out of them before re-building. Next boat was a 1976 36' Trojan, twin Mercs based on 350 block. One lasted 1,400 hours before replacemen and the other was still running when we sold it with a little over 1,500 hrs. It was going through oil quite a bit. My Dad always said that running these motors compared to driving over the pass with a full load and your foot to the floor.
Lately helping a friend find an outboard runabout, it seems that the boat with hour meters or mention them in ads have less than 500 or so hours. I don't recall seeing one listed as 1,200 hours, thus wondering what the life expectancy of outboards.

Max does your PU actually have an hourmeter? Did you install it? Sounds like you must have done a lot if idling.

I think most newer p/u probably have an hour meter included in the electronics.
My 2004 GMC Duramax has 187000 miles and approx 4500 hours mostly highway. My 1990 GMC 1/2 ton gasser (350) has 250000 miles so likely over 6000 hours although no hour meter. It still runs around the farm but does run pretty rough these days.
Average maintenance on both and I usually just start up and drive away even in our Canadian winters.
Bob

Still looking for a fleet car or truck story ,

Talk to the cops , lots of ideling , totally indifferent drivers but frequently pro fleet maint.

The best cop car engine I know of was the old Chrysler Canadian 318 which was a big block 440 engine cast to 318 CI.

They would easily go 300,000 miles ,in the 60's , tho the exhaust always leaked.
The exhaust manifold was not the problem , with enough heat the block warped enough for the thin sheet metal manifold gaskets to not seal.

The cops loved the reliability , but hated how old the cars were before replacement.