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Thread: Need Advise on Breaking in new pistons and rings

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    Default Need Advise on Breaking in new pistons and rings

    Bored my Merc triple block .040 over and installed all new Wiseco pistons and rings. Since it was a "bit expensive", I looked up Wiseco's break in procedure and intended to follow it to the letter.

    However...They recommend 5 HOURS of idle time, followed by a few hours of below 1,500 rpm in gear, followed by an hour or so of 2,500 rpm in gear.

    Are they serious?

    The 5 idle hours I can do easily--just let the fool thing idle away--but the rest of their procedure will be hard to do--especially the in gear 2,500 rpms deal: that's hanging on plane throttle settings.

    So...what do you guys recommend? Naturally, I'll run 20:1 oil and keep an eye on temps.

    Thanks,

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

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    Default Breakin new pistons

    Quote Originally Posted by Fastjeff57 View Post
    Bored my Merc triple block .040 over and installed all new Wiseco pistons and rings. Since it was a "bit expensive", I looked up Wiseco's break in procedure and intended to follow it to the letter.

    However...They recommend 5 HOURS of idle time, followed by a few hours of below 1,500 rpm in gear, followed by an hour or so of 2,500 rpm in gear.

    Are they serious?

    The 5 idle hours I can do easily--just let the fool thing idle away--but the rest of their procedure will be hard to do--especially the in gear 2,500 rpms deal: that's hanging on plane throttle settings.

    So...what do you guys recommend? Naturally, I'll run 20:1 oil and keep an eye on temps.

    Thanks,

    Jeff
    Jeff, here is what i have learned over the 45+ years doing this
    Start the engine, verify it is cooling correctly. Only idle as long as it take for general check over. Make sure spark timing is with in conservative range
    Load the engine right away with out allowing it to turn up in rpm. tied on the trailer works.
    If you are at a ramp tied to the trailer works well
    2000 rpms for 15 minutes about 1/3 throttle. Opening the throttle to let air in to fill the cylinder. a full cylinder will put pressure on the rings to help seat.
    If you just idle for 5 hours, the rings will glaze over and never seat.
    I give engine 1 minute idle cool down
    Then go to 2500 rpm at half throttle. 15 minutes. Lug and loading engine is best.
    1 minute cool down idle
    3000 rpms 3/4 throttle 15 minutes
    1 minute cool down idle.
    3500 rpm. full throttle 10 min
    1 minute cool down idle.
    4000 WOT 10 min
    1 minute cool down idle.
    lugging to engine and loading it will seat the ring fantastic. This is how we break in on the dyno.
    Work your way up in rpm at shorter times.. If you break in an engine badly, it will never perform to its potential. If you are conservative, do the hole thing over again. But idle with no load does no good.
    This loads the engne at low rpm so pistons can wear to fit the bores and the rings will mate with the bores or bests seating.
    Good luck
    Thanks Ron Hill, hydrospeed77, slowJEEP thanked for this post
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    Wow! Thanks for your advice--which sure is different from theirs (as different can get!)I'd better make up lots of gas!

    For the 3/4 throttle and full throttle runs I might have change props (don't have a dyno) to achieve the rpm/ throttle settings required. . Should be interesting. Also, I can't hog the launching ramp so long and may have to do this in sequences of 15 minutes apiece.

    Again, thanks for your advice.

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

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    Jeff

    What piston skirt to wall clearance and ring end gaps did you use for the Wiseco's? Are these cast or forged? High silicon?
    Not experienced with Wiseco's, don't have a dino and do not hog the launch ramp. The variable loading to push the rings to the wall is the important part and some cool down. Pretty much similar process Mike notes except I do out in the water. When I break in new Merc cast pistons and rings (with proper clearances) on the race engines with a used bored block (or just new rings on seasoned pistons on used block), very little idle just to verify cooling, leaks, etc, ignition retarded some, extra non syn oil, plane over quick watch revs doing this then do the variable rpm loading to mid rpm with short blasts to full revs back to mid, do several cycles for 10 min or so. Come in for a cool down. Then repeat several times, then I do full revs. Never had a failure and engine works well, even compression in cylinders.
    Have fun
    Pete
    " Three may keep a secret if two of them are dead" Ben Franklin

    Location: SW Orlando, Fl

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    As I recall, the bozo who did the block set clearance around .005 inched.

    These are forged slugs.

    Your procedure sounds like it does the same thing, but not hogging the ramp, which may not be as much of a problem since the watermen around here having major problems caused by a lack of crabs and stupidity in Annapolis (politicians).

    Thanks!

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

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    Jeff

    Like I said not familiar with forged pistons or if the 0.005 clearance is what is required for your engine, with forged I have been told warm up is critical so they do not stick.

    Does Wiseco have specs on recommended clearance for your final bore size for the alloy used in you pistons? A bit late if more than 0.005 required?

    My break in process in for race jobs on a hydro and works for pleasure rigs.

    Pete
    " Three may keep a secret if two of them are dead" Ben Franklin

    Location: SW Orlando, Fl

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    This is the dyno break used by WPT for Tohatsu Sport C two cylinder.
    Break in setup

    Main Jets # 220
    Spark Advance 1/8 back from stop
    Fuel 93
    Oil Ratio 16:01

    The goal is to load the engine with a large prop so that you have a lot of
    Carb opening and the engine is lugging at these rpms. It takes gas pressure
    behind the rings to seat them well.

    Idle 1 minutes
    2000 10 minutes
    Idle 1 minutes
    2500 10 minutes
    Idle 1 minutes
    3000 10 minutes
    Idle 1 minutes
    3500 10 minutes
    Idle 1 minutes
    4000 10 minutes
    Idle 1 minutes
    4500 10 minutes
    Idle 1 minutes
    5000 - 5500 10 minutes Varying throttle
    Idle 1 minutes
    5500 - 6000 10 minutes Varying throttle
    Idle 1 minutes
    6000 - 6500 10 minutes Varying throttle
    Idle 1 minutes
    6500 - 7000 10 minutes Varying throttle
    Idle 1 minutes
    7500 - full 10 minutes Varying throttle


    Race Set Up
    Oil Ratio 20:1 Mercury Racing Oil p/n 8M0078011
    Main Jet # 215 High elevation jet
    Spark Advance Maximum
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    When doing three cylinder engines like OMC 50 cu or SST60 type engine be carfull of the engine vibration at 4000 rpms. We avoid that rpm.
    run 3500 at 3/4 throttle
    1 minute idle
    3500 at WOT
    1 minute idle
    4800 at 3/4 thottle
    1 minute idle
    4800 at WOT
    Do no run at the vibration points, parts will shake right off the engine.
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    Quote Originally Posted by Mike Wienandt View Post
    Jeff, here is what i have learned over the 45+ years doing this
    Start the engine, verify it is cooling correctly. Only idle as long as it take for general check over. Make sure spark timing is with in conservative range
    Load the engine right away with out allowing it to turn up in rpm. tied on the trailer works.
    If you are at a ramp tied to the trailer works well
    2000 rpms for 15 minutes about 1/3 throttle. Opening the throttle to let air in to fill the cylinder. a full cylinder will put pressure on the rings to help seat.
    If you just idle for 5 hours, the rings will glaze over and never seat.
    I give engine 1 minute idle cool down
    Then go to 2500 rpm at half throttle. 15 minutes. Lug and loading engine is best.
    1 minute cool down idle
    3000 rpms 3/4 throttle 15 minutes
    1 minute cool down idle.
    3500 rpm. full throttle 10 min
    1 minute cool down idle.
    4000 WOT 10 min
    1 minute cool down idle.
    lugging to engine and loading it will seat the ring fantastic. This is how we break in on the dyno.
    Work your way up in rpm at shorter times.. If you break in an engine badly, it will never perform to its potential. If you are conservative, do the hole thing over again. But idle with no load does no good.
    This loads the engne at low rpm so pistons can wear to fit the bores and the rings will mate with the bores or bests seating.
    Good luck
    Nice
    FYI
    very similar to the old Factory when building OMC F1 V8's but they were a little more aggressive with 30 sec under load and 30 sec cool off up at all revs working up to 7500. that takes about 45 min then a full power run to 9500+
    Thinner rings in the F1 v8 though.

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    Quote Originally Posted by Powerabout View Post
    Nice
    FYI
    very similar to the old Factory when building OMC F1 V8's but they were a little more aggressive with 30 sec under load and 30 sec cool off up at all revs working up to 7500. that takes about 45 min then a full power run to 9500+
    Thinner rings in the F1 v8 though.
    I used to work at Mercury Racing. That is where I learned the system. They used a 30min total on all 2.5 race engines. It was a hurry out the door issue yet verifying everything was going to right direction.

    When I was developing engines for the Military Drone program I referenced that style but extended time to ensure everything was best. Lots of inspections on the way. All the race engine I prepare now, use some type of system like this.

    When you think Break-In. What does that really mean. This is my opinion:

    You are trying to prepare the parts to work together to perform best for longest time. Pistons will always wear. I want to wear them in, not out. Rings must seat to the bore as to seal primary and secondary compression and importantly transfer heat from the piston to the bore. If the rings glaze over they will never perform to optimum. Rings that are not seated correctly have hotter/ more risk in the piston. It takes gas pressure above the ring to push the ring against the bore in over to mate/seat. This can only be done with the throttle open to fill the cylinder. You want to load the engine heavy at low rpm as to avoid friction. Wear the engine in, not out. Make the parts comfortable to running loaded at low rpm before you get to higher rpms and added friction.
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