1,000 hours?????

[Chad Flaugher]

I bought my I/O Tri Hull '74 Cobalt last July. It had 988 hours on all the original OMC motor and Outdrive. Between then and September, I managed to get that number up around 1,020 hours. There are no leaks, no ticks, no smoke, no water in the oil/gear cases.... She starts right up, and purrs like a kitten. (5.0L ford) My question is this... A car with 200,000 miles is usually just about done.... What is that benchmark in hours with marine engines? I realize it varies greatly on proper storage, maintenance, and winterizing. I believe I'm the third owner. The previous owner had it for 12 years. He fogged it, drained the water and filled it with antifreeze, and changed the grearcase lube and engine oil every fall... By the overall condition of the boat, I can only assume the original owner took pretty good care of it as well. 1020 hours seems very low to me, but what do all you seasoned boaters think? Thanks!

 

[dingbat]

http://boatsafe.com/nauticalknowhow/enginelife.htm

 

[Bondo]

I bought my I/O Tri Hull '74 Cobalt last July. It had 988 hours on all the original OMC motor and Outdrive. Between then and September, I managed to get that number up around 1,020 hours. There are no leaks, no ticks, no smoke, no water in the oil/gear cases.... She starts right up, and purrs like a kitten. (5.0L ford) My question is this... A car with 200,000 miles is usually just about done.... What is that benchmark in hours with marine engines? I realize it varies greatly on proper storage, maintenance, and winterizing. I believe I'm the third owner. The previous owner had it for 12 years. He fogged it, drained the water and filled it with antifreeze, and changed the grearcase lube and engine oil every fall... By the overall condition of the boat, I can only assume the original owner took pretty good care of it as well. 1020 hours seems very low to me, but what do all you seasoned boaters think? Thanks!

Ayuh,.... Motor Hours means little to Nothing,....

Do a Compression Test to find out the health of yer motor,.....

Boat motors rarely wear out, they're usually Killed by bad maintenance,...

My little 4.3l is pushin' 2,000 hours, 'n still has solid compression,....

 

[Chad Flaugher]

That 4.3 L is a steller motor no matter what it's in! Thanks for the input!

 

[HT32BSX115]

I bought my I/O Tri Hull '74 Cobalt last July. It had 988 hours on all the original OMC motor and Outdrive. Between then and September, I managed to get that number up around 1,020 hours. (5.0L ford).........1020 hours seems very low to me, but what do all you seasoned boaters think? Thanks!

Howdy,

Taken care of, it really is "low" hours.......My last boat (230 cu-in 6) had 1500 hours on it in the 1980's when the hour-meter quit working.
My dad bought the boat new in 1966, I sold it in 2005 and it still ran good.

I couldn't tell you how many hrs it REALLY had on it but it didn't seem to make a huge difference!

Regards,


Rick

 

[Chad Flaugher]

Hey, thanks Rick! That's good news!

 

[Silvertip]

Let's run some numbers and compare 200,000 "miles" in a car with 2000 "hours" on a the equivalent marine engine. First, understand that we will be dealing with total engine revolutions over the period, not miles because miles are simply not comparable here. Remember also that a car has multiple gears whereas a boat does not so we will use only high gear rpm in this comparison. So let's calculate the number of times a car engine rotates in 200,000 miles. Most cars today will turn in the vicinity of 2,000 rpm at 60 - 70 mph. So 2,000 rpm = 120,000 rpm/hour. At an average speed of 60 MPH (nearly impossible to achieve over 200,000 miles without a gazillion speeding tickets) that would equate to 3,333 hours to log those miles. So 120,000 rpm/hr x 3,333 hours = 399,960,000 total revolutions in 200,000 miles.

An auto-based I/O will likely spend most of it's life in the 3,000 rpm range and again remember there is no transmission. Since we are comparing engine revs over a 2,000 hour period, we can easily calculate that 3,000 rpm x 60 (min/hour) = 189,000 rpm/hour. 180,000 rpm/hour over 2,000 hours = 360,000,000 total revs.

Isn't it ironic that 2000 hours on a boat is the same (or very nearly the same) revs as 200,000 miles on a car. And the boat engine had to work a TON harder than the engine in the car. Now consider the average boat sees 50 hours of use each season. Obviously those in temperate climates use their boats a lot more than those of us in the tundra as do those on big water vs those on inland waters. But -- the average has been determined by folks other than me. So 50 hours/year/2,000 hours = 40 years of lifetime out of the boat engine. My Impala has 110,000 miles and is eight years old. My Yukon is 14 years old and has 134,000 miles. So it will take about 16 years to theoretically wear out my Impala and 28 years to wear out my Yukon as I expect both of them will easily make 200,000. Aren't numbers fun to work with??

Let the arguments begin.

 

[Chad Flaugher]

I start my trucks @ 20 below zero. I drive in traffic at 107 degrees with the A/C blasting pulling a trailer. All that being said, one of my trucks is running strong at 217K miles. If you COULD run vehicle at 60 mph stopping only for refueling, you could easily reach 400K to 500K before major repairs in most cases. The commuter vehicles, such as my step fathers truck or a Honda I once owned (Both well over 300K and still running) are mostly highway miles. It would be fair to say a marine motor runs similar to Highway miles with long steady runs at a steady RPM although it being higher.... I feel that there are so many variables in the "Marine to Auto" comparison, that experience would provide a better answer than math. I am however, quite impressed with your breakdown!

I would think that the biggest enemy to an older marine engine other than maintenance, would be the raw lake water in the engine leading to faster rust development as opposed to an engine filled with antifreeze.

 

[Silvertip]

Your original post asked about a comparison between 1000 marine engine hours vs 200,000 auto miles so that was the basis for discussion. There are certainly many marine engines that far surpass the 1000 hour mark as a couple on this forum have indicated. While operating a car/truck in extreme weather and pulling a trailer are valid points, keep in mind a marine engine has no transmission so it must push a 3500+ pound boats on plane using high gear only. Try to start your truck or car in high gear (if you could) on a regular basis and see what happens. As for 1000 hours, properly cared for I would consider that low hours just like 150,000 - 250,000 miles on vehicles today is getting quite normal. Although some folks can turn a new vehicle to trash in 50,000 miles or a new boat to trash in less than 500 hours..

 

[Chad Flaugher]

The "high gear" analogy is kind of flawed... Although there is no transmission, the water acts as a clutch. Kind of like spinning your tires on a gravel road until your momentum reaches your wheel speed. The lack of a transmission causes for higher RPM at cruising speed vs. a car, and I would agree that would cause wear and tear above the 2,100 RPM cruising speed of an average car. That's how my mind perceives it anyhow, don't mean I'm right! If I knew the answer I wouldn't have asked! I love the simple act of discussion, and theory. Good times, and thanks for the input!

 

[Silvertip]

I would again disagree with the spinning wheels theory. Without a transmission, your land based vehicle stands zero chance of moving an inch or spinning a wheel on any surface other than glare ice in high gear. Secondly, the water is not acting like a clutch. It is acting as a load. Tie your boat to the dock (a sturdy one) and hammer the throttle. If the water was acting like a clutch the engine would easily rev to red line. Water is acting as a load and so long as the prop doesn't lose bite (blow out) the engine will rev to perhaps 2500 - 3000 rpm depending on the prop. You experience the same thing if you tied your car to a post and hammered the throttle in any gear. Provided the wheels didn't spin, you would see engine revs only to the point of the torque converter stall speed which will be in the neighborhood of 2000 rpm. How much different the loading is on a boat vs a car can be determined crudely with a vacuum gauge. On a car at 50 mph you would typically see somewhere between 12 and 14 inches of vacuum. If you are old enough to remember some of the "Economy Gauges" cars had in the 70's, those gauges were nothing more than a vacuum gauge calibrated for good, bad, excellent. The excellent portion of the gauge would be seen only down hill with your foot off the gas. Although I haven't actually tried this, I'd wager you see much less vacuum on the boat. Remember, the more loading (more throttle) the less vacuum there is -- not the other way around. To keep a car moving on flat road and zero head wind it takes probably 30 - 40 hp. That won't cut it with a boat of equivalent weight. It is because of this loading issue that you do not see a vacuum advance unit and only mechanical advance on a marine distributor on older engines. Without sufficient vacuum, that unit would be non-functional most of the time. But -- as with many discussions of this type, opinions are just that. We can agree to disagree but the fact remains, boat engines take a beating that you just don't see in a land based vehicle unless they fall into the abuse category which generally involves lack of care and maintenance.

 

[HT32BSX115]

Water is acting as a load and so long as the prop doesn't lose bite (blow out) the engine will rev to perhaps 2500 - 3000 rpm depending on the prop. You experience the same thing if you tied your car to a post and hammered the throttle in any gear.

You're right! if you used an automatic transmission and the torque converter produced the same stall speed as you got in the boat tethered to dock at full throttle at (the same) "static" RPM................

Cruising along in a boat.........The (drag of the) water is the "load" .......... In a car, the "load" is the rolling resistance and aerodynamic drag driving down the road at a constant speed.

If the comparison is made at relative cruising speed, say 65-70 mph in a car, and 35-40 mph in a similarly powered boat, There's little comparison....

We can agree to disagree but the fact remains, boat engines take a beating that you just don't see in a land based vehicle

"Abso-tively" correct!

The engine in the boat is producing FAR more HP and torque (& wear and tear) than it would be producing in a car cruising along at 65-70mph.

The only fair comparison would be to put the boat on a trailer behind the same car, and tow it up a hill (A LONG HILL!)


Regards,


Rick

 

[Chad Flaugher]

So many variables to consider here... 6,800lb truck with a V8 vs 2,500lb boat with a V8. Maine engine with a never ending supply of cool water, auto with a constant supply of hot water. Marine with constant RPM operation VS Truck engine in stop and go traffic (very hard on engines!) Many many many more cold starts on an auto VS marine. More airborne pollution (dust, exhaust, pollen, chemicals) on the road, Blah blah blah so on and so forth...

I think agreeing to disagree would sum it up. I think the vast majority of destroyed marine engines come from frozen blocks, over heated cracked blocks (Change yer impellers!), and plain and simple maintenance neglect! Many more auto engines get run to death by miles simply because it is so much more convenient to stop at a Jiffy Lube for a 20 minute oil change and fluid check.

All engines are designed to generate torque and horse power. That does not necessarily constitute wear and tear unless excess heat is generated. I like Silvertip's use of RPM as a measure of wear and tear. It's all about engine temp, and lubrication during each revolution that counts. Variables such as load, weight, RPM, temp, start ups, start up temps, etc. all play into the overall life of any engine. Thanks for playing, we're all winners!

 

[Silvertip]

One last thought. You seem to be comparing apples to oranges in your last post. 2500# I/O's are on the light side for purposes of this discussion while a 6800# truck is on the heavy end of the vehicle comparison. Cars and trucks have air filters. Boats do not. Raw water cooled boats run in salt and brackish water while cars have closed systems. Here is a test for you -- next time you are in the water, with the flat of your hand vertical in the water, as quickly as you can, make a sweeping motion. What you feel is water resistance at a speed of about 1 mph. Next time you are in your car/truck, stick your hand out the window with the palm into the wind. You would need to be traveling about 30 mph or faster to even come close to that amount of resistance. Lastly, not all of the boats with auto-based engines are planing hulls. It takes a bunch of power to move a larger cruiser such as 6800# unit and would likely have not one but two engines. My last and really final comment here is that if loading was not an issue on a boat there would be no need for 6, 7 and 8L engines on boats in the high 20 foot and larger range.

 

[Maclin]

The load a boat faces as it gets up on plane is basically like a reverse tractor pull contest.