Engine life expectancy

[Tony Walker]

Hi all,

I keep seeing references to low engine hours on the different adds for used boats.

Our 2006 right now has north of 800 hours and we plan to use the boat lots more and run these things out.  Then replace or rebuild.

Our engines behave the same way they did on day one.  I have yet to put the first drop of oil between changes in either of them.  They have lots of trawler speed hours on them.  They have almost no WOT time on them.  Measure WOT time in minutes.

Anyone have any idea what engines do when they get to their endpoint?  And how many hours that might be?

Tony
Salt Shaker 342

[alswagg]

Prior to fuel injection, 1,000 hrs was about the end, similar to cars with 100,000 miles.  Now, with computer controled fuel air mixtures, better oils, better metals, you should see around 2,000 hrs.   This fall I serviced a Merc 4.3lt mpi with 2,900 hrs.  Only problem was worn out valves.  We replaced both heads and it is running great again.  This is on a pier service boat.  Oh, it is also running the Alpha drive.
Many inboard skier guys are seeing 1,500 hrs typically easy and then trading off.
The GM Vortec motors are great, but if you do have to replace, don't bother with rebuilding, just replace with a new GM rotating assy and then install the new Marine cam.  Nearly the same as a rebuilt motor and much better.
Al

[Rinker342]

Great info, Al, as always.   

[hanzelvh]

Hi Al,

What is your experience with Volvo diesel engines, we have now 600 hours on our 2007 cruiser.
On average we throttle at least once a day to 3000 rpm's to keep turbo and compressor "alive".
Same as Tony also our engine do not take any oil (except diesel oil  ) in between the yearly service and behave like the first day.
We have it serviced every year and put Startron in the fuel to avoid problems with water or bacteries.

[step 2]

Hi Al,
Why do you say not to rebuild the Chevy Vortec motors?  My local engine builder says they're the motors to look for when replacing a 350 sbc (5.7l).  My current Mercruiser 350 is going to be replaced this spring with a rebuilt.  Is there something wrong with the blocks, some or all, that makes them weaker or otherwise not as good as a new motor?  The engine builder also told me that I can easily get 300 hp out of a Vortec while also getting better fuel economy compared to a non Vortec motor.  Any thoughts on this will be helpful as I haven't located a block to start building yet... ounce of prevention pound of cure, you know.