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  1. #1
    Lieutenant trendsetter240's Avatar
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    Default Wiseco Piston Break In Process

    I'm currently breaking in my 1995 Evinrude 70hp ELEO after a complete rebuild. I installed wiseco forged pistons as part of the rebuild.

    My mechanic today told me that I need to follow a more extensive break in process for the Wiseco pistons than I would with the OEM pistons.

    Does anyone know what the proper break in procedure is? I have currently ran the engine at idle varying between 650 and 1200 rpm for 1.5 hours. VRO pump has been disabled and I am running 25:1, 91 octane ethanol free gasoline.

    Thanks for your help.

  2. #2
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    Default Re: Wiseco Piston Break In Process

    Call Wiseco and ask to talk to the Marine Manager. PLEASE let us know what they say. This should be good.....

  3. #3
    Lieutenant trendsetter240's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by Dhadley View Post
    Call Wiseco and ask to talk to the Marine Manager. PLEASE let us know what they say. This should be good.....
    Well, there is no one available there right now, it's after 5:00pm pacific time now. I will call them again on Monday.

    I looked in the boxes that the pistons came in and there is an insert that states "refer to your service manual for break in procedure".

    I guess for the time being I will go with my mechanic's advice and what i've gathered from the net. That is to run a 4 - 8 hour idle/fast idle warm up process before following the OEM break in process for the next 10 hours.

    I also found on the net (unconfirmed) that forged pistons need up to 12 heat cycles before they will begin to seat. That's 12 times being brought to operating temperature at idle and run for 30 minutes.

    Anyone has any experience with Wiseco please chime in. I'm looking for all the info I can get.

  4. #4
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    Default Re: Wiseco Piston Break In Process

    it might be a technicality, but I am sure you are seating the RINGS and not the piston.....

    good luck

    bob

  5. #5
    Vice Admiral bktheking's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by bob johnson View Post
    it might be a technicality, but I am sure you are seating the RINGS and not the piston.....

    good luck

    bob
    Second that.
    Signature- If you have fuel and spark- Have you checked compression?

  6. #6
    Petty Officer 1st Class billy4hp's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by bktheking View Post
    Second that.

    Not necessarily true, Wiesco pistons have a much different cam cut on their piston skirts compared to an OEM piston and some have anti-friction skirt coatings... The cam cut is usually much narrower than stock with less skirt to wall contact to reduce friction in the engine and these pistons are usually ran with a tighter piston to wall clearance compared to an OEM piston... Also being forged they have a much different expansion rate compared to an OEM cast piston... Since the contact area is smaller it carries more load (and thus the need for the skirt coatings in some applications) and carries a greater risk of sticking or galling a piston when the engine is cold...

    Without getting over complicated, during break in, the engine should be ran double oiled (just like it's done during OEM break in) and it is imperative the engine is brought up to operating temperature before attempting to plane out, heavy load, etc. My personal experience is also to not let a new engine with forged pistons to idle for a long period of time during break in, I always liked to vary the engine rpm 200 to 300 rpm during the first 1/2 hour of operation...

    Over 10 years I built over 500 high performance engines, of the ones I also tore down for freshing, the engines that received the most care during break in had the best looking piston skirts (among the other high load components)...

    I am sure Dhadley has had much for experience with forged pistons in outboards than I have. Most of my experience with them has been with I/O's but I have done my fair share of two strokes..


    JMHO...



    My $.02....
    1973 Glasply 21' Camper Cutty --- AKA Mean Green

    Originally Mercuiser 888
    Rebuilt FWC SBF
    SEI 106 Upper and Lower

  7. #7
    Vice Admiral bktheking's Avatar
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    Default Re: Wiseco Piston Break In Process

    PDF on their site makes no mention of special break in procedures other than "refer to your service manual". A phone call would clear up any doubt.
    Signature- If you have fuel and spark- Have you checked compression?

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    Default Re: Wiseco Piston Break In Process

    I would think the break-in would be the same for forged or cast pistons, however, the boring tolerance is different due to different expansion characteristics.

    OK - What the heck is cam cut?

  9. #9
    Petty Officer 1st Class billy4hp's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by Chris1956 View Post
    I would think the break-in would be the same for forged or cast pistons, however, the boring tolerance is different due to different expansion characteristics.

    OK - What the heck is cam cut?
    Cam cut refers to the machined shape of the piston skirt. In high performance pistons the cam cut is manipulated to control piston rock at the top and bottom stroke (referred to as piston dwell) and is often reduced to decrease friction....

    Break in can vary depending on skirt coating, cam cut, cylinder liner coatings (Nikasil, Chrome, etc) as well as piston ring material (Cast, Coated, Stainless, etc)...

    If it were me, I would be kinda pissed at the original posters "mechanic" that started this whole can of proverbial worms as they spec'd the Wiesco pistons so they should know what should be done to break in this engine without causing unnecessary damage...

    I have heard time and time again from people who have rebuilt engines with good forged pistons state "boy are those forged pistons noisy until they warm up". Inevitably these engines are short lived as the "noisy pistons" have excessive clearance from improper machining and are basically beating themselves to death until the pistons grow enough to take up the excessive clearance a well meaning machinist "put in" the engine.

    I agree a call should be given to both the "mechanic" to get the clearances they set up this engine with as well as Wiesco on any special recommendations and to verify if this engine was machined properly for these particular pistons... They may simply be forged replacements for OEM pistons that require nothing special, or they might be "the piston of the month" wazoo units... That I don't know...

    It's really easy to trash a set of high end pistons if things are not done properly including machining, assembly and break in...

    Here's hoping for an easy solution for the original poster...

    JMHO...
    1973 Glasply 21' Camper Cutty --- AKA Mean Green

    Originally Mercuiser 888
    Rebuilt FWC SBF
    SEI 106 Upper and Lower

  10. #10
    Lieutenant trendsetter240's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by billy4hp View Post
    Cam cut refers to the machined shape of the piston skirt. In high performance pistons the cam cut is manipulated to control piston rock at the top and bottom stroke (referred to as piston dwell) and is often reduced to decrease friction....

    Break in can vary depending on skirt coating, cam cut, cylinder liner coatings (Nikasil, Chrome, etc) as well as piston ring material (Cast, Coated, Stainless, etc)...

    If it were me, I would be kinda pissed at the original posters "mechanic" that started this whole can of proverbial worms as they spec'd the Wiesco pistons so they should know what should be done to break in this engine without causing unnecessary damage...

    I have heard time and time again from people who have rebuilt engines with good forged pistons state "boy are those forged pistons noisy until they warm up". Inevitably these engines are short lived as the "noisy pistons" have excessive clearance from improper machining and are basically beating themselves to death until the pistons grow enough to take up the excessive clearance a well meaning machinist "put in" the engine.

    I agree a call should be given to both the "mechanic" to get the clearances they set up this engine with as well as Wiesco on any special recommendations and to verify if this engine was machined properly for these particular pistons... They may simply be forged replacements for OEM pistons that require nothing special, or they might be "the piston of the month" wazoo units... That I don't know...

    It's really easy to trash a set of high end pistons if things are not done properly including machining, assembly and break in...

    Here's hoping for an easy solution for the original poster...

    JMHO...
    Thanks for all the info guys.

    Some background on this: I brought the block into a machine shop, not my mechanic, where they bored each cylinder to match the pistons. The pistons and rings came from the machine shop also. They are 3100 series, forged marine pistons (1 is 3172P3, 2 are 3172P4).

    The bore clearance is .0005 on each cylinder.

    After I had built the motor I was in my mechanics shop pickup up some engine mounting hardware and I asked him about the break in process. He said that with forged pistons you need to follow a more extensive break in process and that I should find out from the machine shop or online. By this time everyone was closed for the weekend so I was hoping to find out from some of the experts on here.

    So..You mentiond that you don't like to idle forged pistons during the break in process..do you recomend I continue on with the OEM break in steps in my service manual? With the only exception being that I allow the engine to warm up longer before going above 1000rpm?

    Thanks again guys.

  11. #11
    Petty Officer 1st Class billy4hp's Avatar
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    Default Re: Wiseco Piston Break In Process

    Unfortunately, in your situation of having to break in the engine without the aid of a dyno, it's going to have to idle sometime. I just wouldn't let it sit their and idle for a long period (like fire it up and let it idle for 10 or 20 minutes with no load).

    If you are forced into a situation where it has to sit and idle for any length of time. I would vary the engine RPM manually w/ the throttle control a couple 100 rpm up and down.

    The varying of the engine RPM aids in break in by changing the load every so slightly on the piston skirts, rings, bearings, etc.

    JMHO, good luck with your project...
    1973 Glasply 21' Camper Cutty --- AKA Mean Green

    Originally Mercuiser 888
    Rebuilt FWC SBF
    SEI 106 Upper and Lower

  12. #12
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    Default Re: Wiseco Piston Break In Process

    Call them again an Monday and let us know what the Marine Manager says. Ask to speak directly to him. If he's not available get his extension number.

  13. #13
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    Default Re: Wiseco Piston Break In Process

    Ask for Marie LaVoe. She managed a company down in, or around the south swamp country. Later went to Wiseco. Funny idea's about break in. Just don't argue, and wear the dead chicken around the neck as instructed.

  14. #14
    Lieutenant trendsetter240's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by billy4hp View Post
    Unfortunately, in your situation of having to break in the engine without the aid of a dyno, it's going to have to idle sometime. I just wouldn't let it sit their and idle for a long period (like fire it up and let it idle for 10 or 20 minutes with no load).

    If you are forced into a situation where it has to sit and idle for any length of time. I would vary the engine RPM manually w/ the throttle control a couple 100 rpm up and down.

    The varying of the engine RPM aids in break in by changing the load every so slightly on the piston skirts, rings, bearings, etc.

    JMHO, good luck with your project...
    Hey billy4hp, thanks for your reply.

    I just got back from about 3 hours runtime on the river. Basically what I am doing is the OEM break in process times 3. i.e. oem says first hour do not operate over 3500 RPM and vary the throttle. I did that for the first 3 hours.

    After about 2.5 hours on the water today (4 hours into the break in period) I brought it up to full throttle and planed the boat then pulled back to 3500rpm. I did this 4 times and checked the water temp from the tell tale each time. Water was warm but not hot.

    I think I will continue along this path for now and I will talk to Wiseco on Monday.

    Cheers.

  15. #15
    Petty Officer 1st Class billy4hp's Avatar
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    Thumbs up Re: Wiseco Piston Break In Process

    Quote Originally Posted by trendsetter240 View Post
    Hey billy4hp, thanks for your reply.

    I just got back from about 3 hours runtime on the river. Basically what I am doing is the OEM break in process times 3. i.e. oem says first hour do not operate over 3500 RPM and vary the throttle. I did that for the first 3 hours.

    After about 2.5 hours on the water today (4 hours into the break in period) I brought it up to full throttle and planed the boat then pulled back to 3500rpm. I did this 4 times and checked the water temp from the tell tale each time. Water was warm but not hot.

    I think I will continue along this path for now and I will talk to Wiseco on Monday.

    Cheers.
    Trendsetter 240,

    Sounds like you have things under control... Enjoy your newley rebuilt outboard....

    Billy
    1973 Glasply 21' Camper Cutty --- AKA Mean Green

    Originally Mercuiser 888
    Rebuilt FWC SBF
    SEI 106 Upper and Lower

  16. #16
    Lieutenant trendsetter240's Avatar
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    Default Re: Wiseco Piston Break In Process

    Well, just had a good long conversation with a tech at Wiseco followed by a good long conversation with the Machinist that bored my block and sold me the pistons.

    The conclusion: forged OEM replacement pistons should be broken in following the standard OEM break in process. (With a few bits of advice from both the Wiseco tech and the Machinist)

    Both advised to follow the standard break in process with the following additional comments.


    Advice from Wiseco Tech:

    1. Use standard 2-stroke oil, not synthetic, at the double rate (25:1) during the break in process. Synthetic oil can lead to glazing of the cylinder walls before the rings have set.

    2. Avoid extended idle periods after the initial 10 - 20 minute startup of the motor.

    3. Throughout the life of the pistons, always provide a 5 minute warm up period at or near idle before running WOT.


    Advice from Machinist:

    1. Low load during first 1/2 hour, vary the throttle.

    2. No WOT during the first 3 hours of the break in period.
    (Service manual says 2 hours, I waited 4 hours.)

    3. Examine spark plugs periodically during break in process for signs of differences between cylinders.


    So I guess that settles it. Not sure why my mechanic told me that I needed a different break in process. I suspect that they had failures in the past and put it down to the forged pistons. The tech at Wiseco did tell me that they have changed the shape and dimensions of the marine pistons over the years to compensate for some of the “issues” that they had in the past.

    Regardless..I’m happy and my motor is running great. I don’t mind having to warm it up for 5 minutes whenever I cold start it.


    Cheers and thanks for your help guys.

  17. #17
    Petty Officer 1st Class billy4hp's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by trendsetter240 View Post
    Well, just had a good long conversation with a tech at Wiseco followed by a good long conversation with the Machinist that bored my block and sold me the pistons.

    The conclusion: forged OEM replacement pistons should be broken in following the standard OEM break in process. (With a few bits of advice from both the Wiseco tech and the Machinist)

    Both advised to follow the standard break in process with the following additional comments.


    Advice from Wiseco Tech:

    1. Use standard 2-stroke oil, not synthetic, at the double rate (25:1) during the break in process. Synthetic oil can lead to glazing of the cylinder walls before the rings have set.

    2. Avoid extended idle periods after the initial 10 - 20 minute startup of the motor.

    3. Throughout the life of the pistons, always provide a 5 minute warm up period at or near idle before running WOT.


    Advice from Machinist:

    1. Low load during first 1/2 hour, vary the throttle.

    2. No WOT during the first 3 hours of the break in period.
    (Service manual says 2 hours, I waited 4 hours.)

    3. Examine spark plugs periodically during break in process for signs of differences between cylinders.


    So I guess that settles it. Not sure why my mechanic told me that I needed a different break in process. I suspect that they had failures in the past and put it down to the forged pistons. The tech at Wiseco did tell me that they have changed the shape and dimensions of the marine pistons over the years to compensate for some of the “issues” that they had in the past.

    Regardless..I’m happy and my motor is running great. I don’t mind having to warm it up for 5 minutes whenever I cold start it.


    Cheers and thanks for your help guys.
    Glad to hear you got some "straight from the horses mouth" info....

    IMHO , it's always a good idea to let any engine warm up before you lay the throttle to it....

    Have fun.....

    Billy
    1973 Glasply 21' Camper Cutty --- AKA Mean Green

    Originally Mercuiser 888
    Rebuilt FWC SBF
    SEI 106 Upper and Lower

  18. #18
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    Default Re: Wiseco Piston Break In Process

    Coming in late on this discussion, is piston to cylinder clearance of .0005 correct? My 1990 60 hp Johnson and my 1993 90 hp Johnson factory manuals both show more like .005 which is 10X your spec. Seems like a lot of difference.

  19. #19
    Lieutenant trendsetter240's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by GeneH View Post
    Coming in late on this discussion, is piston to cylinder clearance of .0005 correct? My 1990 60 hp Johnson and my 1993 90 hp Johnson factory manuals both show more like .005 which is 10X your spec. Seems like a lot of difference.
    Hey Gene, I'm no machinist but I do trust mine. The label on the block said bore was 3.2275 and the label on the piston box says bore: 3.2270.

    That's where I came up with the .0005 clearance. Please correct me if I am reading this wrong.

    Cheers!

  20. #20
    Lieutenant Mark_VTfisherman's Avatar
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    Default Re: Wiseco Piston Break In Process

    <irrelevant answer>
    Last edited by Mark_VTfisherman; January 28th, 2010 at 10:22 PM. Reason: I posted when I should have been in bed!

  21. #21
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    Default Re: Wiseco Piston Break In Process

    If the tolerances you mention is correct, the forged pistons will be a lot quieter than the casted. All motors should iddle at least 5 mins before running wot, thats what owner manual says too. Congratulations with your rebuild, well done !!!

  22. #22
    Petty Officer 1st Class billy4hp's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by Mark_VTfisherman View Post
    .0005 seems pretty tight to me... an "interference fit." .035- .045 sounds better.
    Huh? An interference fit would mean they would be pressed together? And thirty five thousandsth's clearance is spark plug gap territory....

    http://www.mcwdn.org/Decimals/Thousandths.html
    1973 Glasply 21' Camper Cutty --- AKA Mean Green

    Originally Mercuiser 888
    Rebuilt FWC SBF
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  23. #23
    Lieutenant Mark_VTfisherman's Avatar
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by billy4hp View Post
    Huh? An interference fit would mean they would be pressed together? And thirty five thousandth's clearance is spark plug gap territory....
    Hi- just read your response, and looked at mine again. I apparently missed zeros after the decimal; however, I don't know why I even responded. I posted that at 11:20pm and I can't even explain my answer: .0005 is not as tight as .00035

    It's 10:30 pm, and I am going to bed now before I say something dumb tonight, too

  24. #24
    Supreme Mariner Frank Acampora's Avatar
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    Default Re: Wiseco Piston Break In Process

    WELL, My 2 cents: I have rebuilt a number of different brands of 2 cycle outboards and if possible, I always use Wiseco. They are amazingly well made and worth every buck you pay for them.

    NOW: from necessity, when the owner picks-up his rig, I take it out on the water with him. With only about 5 minutes running time, It is necessary for me to use full throttle to set timing. HOWEVER: Once timing is checked and confirmed as correct, the engine no longer sees full throttle. I caution the owner to not exceed 3/4 throttle or 3500 RPM until at least two 6 gal tanks of double oil mix has been run through the engine. On the larger engines, this works out to somewhere around 4 hours. Say, 1,000,000 cycles

    I have never had a return or complaint, and all my personal engines run "like a top."

    ALL outboard engine pistons are cam ground because the cooling water cools the cylinder unevenly. This also causes the piston skirt to heat and expand unevenly. Thus, when the engine warms up, the piston becomes more nearly circular and it and the cylinder now match in shape. Engine tolerances vary from manufacturer to manufacturer. For example, while OMC uses .005 clearance, Force uses .002. AND total wear allowed in the cylinder for taper, out of round, or oversize is .005 on OMC and .002 on Force. THUS if your Force engine has only .002 wear, it is necessary to bore .010 over. AND- the listed clearance is hot clearance--wiggle a cold piston in a cold cylinder--amazing how much slop there is, especially at the crown which gets way more heat than the skirt.

    Since racing applications or higher power modifications usually result in more cylinder pressure and higher temperatures, and since the aluminum piston expands to a greater degree than the steel cylinder liner, these applications require a bit more clearance. Engine runs like crap until it warms up but racing engines are not meant to run cool or slow.

    NOW: My personal opinion--- 3000 RPM works out to 180,000 cycles per hour. If rings aint seated and it aint broke in by then, it aint never gunna be.

  25. #25
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    Default Re: Wiseco Piston Break In Process

    Quote Originally Posted by trendsetter240 View Post
    Well, just had a good long conversation with a tech at Wiseco followed by a good long conversation with the Machinist that bored my block and sold me the pistons.

    The conclusion: forged OEM replacement pistons should be broken in following the standard OEM break in process. (With a few bits of advice from both the Wiseco tech and the Machinist)

    Both advised to follow the standard break in process with the following additional comments.


    Advice from Wiseco Tech:

    1. Use standard 2-stroke oil, not synthetic, at the double rate (25:1) during the break in process. Synthetic oil can lead to glazing of the cylinder walls before the rings have set.

    2. Avoid extended idle periods after the initial 10 - 20 minute startup of the motor.

    3. Throughout the life of the pistons, always provide a 5 minute warm up period at or near idle before running WOT.

    So you never got to the Marine Manager? What sort of Marine background does the tech have?

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