Wiseco Piston Break In Process

trendsetter240

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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.
 

Dhadley

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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.....
 

trendsetter240

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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.....

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.
 

bob johnson

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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
 

billy4hp

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Re: Wiseco Piston Break In Process

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....
 

bktheking

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5,057
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.
 

Chris1956

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Mar 25, 2004
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27,031
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?
 

billy4hp

Petty Officer 1st Class
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Messages
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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?

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...
 

trendsetter240

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Re: Wiseco Piston Break In Process

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.
 

billy4hp

Petty Officer 1st Class
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Messages
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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...
 

Dhadley

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Joined
Feb 4, 2001
Messages
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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.
 

R.Johnson

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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.
 

trendsetter240

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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...

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.
 

billy4hp

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Messages
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Re: Wiseco Piston Break In Process

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.... :cool:

Billy
 

trendsetter240

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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.
 

billy4hp

Petty Officer 1st Class
Joined
Jan 31, 2009
Messages
245
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.

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
 

GeneH

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Sep 1, 2007
Messages
109
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.
 

trendsetter240

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Messages
1,458
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.

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!
 
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