1075 sci
 

So how long do they last? How long before top ends need to be done? How long before complete rebuilds ? Looking at a change and comes with 1075 sci with 52 hrs. 50 hrs are under 5000 rpm and would like to know where I stand in the big money maintenance time line.

I know my buddy put 160 hours on theirs before total
rebuild. And then your at $22,000 each side. But those hours
are not the norm.

I would say that is the norm!
I plan on getting 200 hours. I have a lot of idle time and don't hold it wide open.
Owners that buy new from the start don't care as much and usually run their stuff much harder.

Thanks for info guys . No other 1075 sci owner out there that are willing to chime in ? All info would be very appreciated . Thanks

After 50 hours its not uncommon to have the heads rebuilt, and a complete engine inspection performed. This may not be an oficial Mercury maintenence plan, but its a good way to help prevent a complete engine faiure in the future. I have seen a 1075sci blow at around 50 hours and also know people who have run into the 150 hour range before any real problems. As with any high perf motor change fluid and filters often, and I would recomend at 25 hour intervals.

That is what i thought . In my other big engines i have always done top ends at 75 hrs. With complete rebuilds at 150 hrs. Please keep the info coming if you own 1075 's and have other thought or experiences .

Agreed. Also find yourself a very good Hi-Performance Tech and use him. Around the 50 hour if you dont pull the heads have your tech pull the valve covers and check the rocker arm adjustment. Most failures start in the valve train. Regular oil and filter changes with recommended oils and you should be good. Fuel is also a big issue, make sure you buy good fuel at a reputable gas pump.

Good luck!!

With good maintaince, Oil changes, Valve lash checked regularly. Most guys are getting about 125hrs before needing top ends. Somewhere before 125hrs, I would have the lifters, springs, and timing belts changed. Your probably good for another 100+ hrs at that point. Theses motors have a very small cam, around .630 lift.
All the failures that I know of have been Lifters or Timing belts between 130-135 hrs. These were also very hard hrs run in open waters in Florida.

So to sum the 1075 sci question if you have a owned a set of 1075 sci would own a second set ? Love to here what current and previous owners think.

I would stick with 1075's

Also valve lash oil changes every 15 hours and record changes.

assume these numbers are about the same for the Merc 850's? most likely will end up with a pair of those in a boat in the future.

Ours have been great so far, they have 115 hours on them. Did a refresh when we bought the boat last year. They run great and are very dock friendly for the size of motors. Would definatley have them again in the future. The lifespan all depends on the throttle position and routine maintenance.

thats great to hear. nice that higher HP engines are finally proving reliable

Arent they solid rollers in the 1075's?

What type oil use in these motors?

We ran amsoil then switched to schaffers on the next boat

This thread sheds light on a bunch of things. Great read!! I also heard the valve train is the most common problem with these engines

Yep that sums it up

Two 1075s
 

If you are looking to purchase good, solid running 1075s, we have two for sale (they were pulled out of our boat January 2016 because we upgraded to 1350s) and they are located in Sanford, Florida.
The intake valves are custom titanium and some other parts have been upgraded.
These engines have been expertly maintained by Bruce Baker / Express Engines and we have all of the documentation about their maintenance.
Hours on Port 111.4
Hours on Stbd 108.1
75K