Merc 700sci hrs/lifespan before rebuild
12-21-2014, 05:21 PM
#12
I have a newly purchased boat with staggered merc 700's about 190-195 hrs on them, smartcraft shows over 100 hrs below 1500 and less than 2.5 hrs above 3500 rpm. Did leakdowns on motors came out good, Pressure checked headers and thats all good.
What can some of you tell me about your experience with these motors as far as reliability, attention needed, valve train lasting, misc. other things to watch and what kind of rebuild times are most seeing and expecting.
Are the week links on these motors the valve train (rocker arms, valve springs) or??
I assume the bottom ends are pretty well built for this kind of HP range?
What can some of you tell me about your experience with these motors as far as reliability, attention needed, valve train lasting, misc. other things to watch and what kind of rebuild times are most seeing and expecting.
Are the week links on these motors the valve train (rocker arms, valve springs) or??
I assume the bottom ends are pretty well built for this kind of HP range?
12-23-2014, 03:02 PM
#14
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12-23-2014, 03:14 PM
#15
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I took pulled things apart to inspect and had a rocker on on #3 cylinder starting to come apart.
I didnt get much response on here so I called out to Teague. Bob told me you can replace them all if you like but its not needed it was probably a fluke and anything can fail earlier than supposed to. They are a good quality rocker arm and it was probably a fluke. He said he'd like to take my money but in his opinion its not needed. (he did say it depends on how the motors were used also but with the history on the smartcraft it shouldnt be needed) If he were to sell me rocker arms it would be there brand wich is a copy apparently of the design on the Cranes that come in the motors stock.
I just assume replace them all now if need be but he convinced me no need.
As far as rebuilds: They recomend 350 hr valve train and bottoms should be good for 600hrs with proper maintenance and decent driving habits.
My plan at this point would be run them to approx 300 hrs, pull motors, replace valve train and inspect the rest of the stuff and hopefully put back together for some more hrs and time.
Who told you to replace the rocker arms?
Anybody have any further knowledge on this?
Last edited by hustlerguy; 12-23-2014 at 03:20 PM.
12-24-2014, 06:23 AM
#16
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Search and look at the threads on the 525's valve springs. Lots of good information there. Since cams in the 700's are more mild, the situation is not exactly the same. But similar enough for me to draw some general conclusion on the 700's. Seems like the general consensus there was that the rocker issues are really caused by springs that are to weak on the seat. Most in the thread advocated replacing the stock springs and upgrading to some of the new generation SS rockers.
12-24-2014, 06:55 AM
#17
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Do the 700's run the crane gold like the 525's
How many hours are on your engines bengtb
How many hours are on your engines bengtb
Last edited by F-2 Speedy; 12-24-2014 at 06:58 AM.
12-24-2014, 10:52 AM
#18
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I was drawing that same conclusion but after talking to tegue he convinced me different.
700's dont run the same cam, I also asked about running different springs (better springs) I'd just assume spend the money and put the best stuff in. Was told the PAC springs are top dollar springs and fit that combo really nicely and as long as leaving the cam stock would not recomend anything else.
Sooo...
Seems like there pretty sure of the combo.
Yes the 700's do run the same crane Gold rockers.
700's dont run the same cam, I also asked about running different springs (better springs) I'd just assume spend the money and put the best stuff in. Was told the PAC springs are top dollar springs and fit that combo really nicely and as long as leaving the cam stock would not recomend anything else.
Sooo...
Seems like there pretty sure of the combo.
Yes the 700's do run the same crane Gold rockers.
12-24-2014, 03:23 PM
#19
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It has been suggested that the 2008 gold Crane rockers on the 700's were made in Mexico and quality was questionable. Problems with the needle bearings failing, working there way thru the engine and destroying it. I would definitely change them, but that's just my opinion.
