Hello again ,
I went to pickup the machined block and pistons today from the engine builder.
I asked what he set the piston to wall clearance to ?
He says .oo5 ?
I say I have been told to run .0065 to.008 .
He said we did what wiseco recommended in the instruction paper.
where should the clearance be set for this motor ?
Looking for real experience here .
Also what type of is material is the evinrude block sleeve made of Nik or steel?
Thanks in advance Cj
Contact Wiseco tech support to be sure. They will steer you in the right direction. Be careful with tight clearances with "forged" Wiseco pistons...easy to seize it up while cold or breaking in. Go with what Wiseco says.Originally Posted by veryspeedy
Age and treachery will always overcome youth and skill !!
I was planning on calling the this morn, just was wondering if .005 was enough.
Not sure manufacturer is not aware of the cooling tendency of the early ficht motors.
My machine shop Builder says he builds I/O engines with .005 all the time but those are four stroke.
I did a 175 Ficht and bored and honed to the high side of tolerance. That was 300 hrs ago and still going strong.
Ed
What pistons and what was the high side of tolerance? Pleas be more specific!I did a 175 Ficht and bored and honed to the high side of tolerance. That was 300 hrs ago and still going strong.
Ed
Once you figure out the right clearances/specs, insure the underlying problem/problems that toasted the motor before are resolved.
Age and treachery will always overcome youth and skill !!
Make sure you check the alignment pins for the rings before you install the pistons. I know that in my industry motorcycles. atv's, and snowmobiles they have a problem with those pins failing out and causing problems.
2004 Ranger 521VX with 2019 Evinrude G2 250 H.O.
Pistons I used was Wiseco,I do not remember the tolerance range,I did this in 2008 and sold the boat in 2015 to a friend and sent the manual with it. I remember recording all info in the back of the manual, don’t remember exact numbers. Typically 50/60% of tolerance for the bottom range. ie +.004 -0 ,I would do +.002 to+.0025 for the min. And very important to chamfer all port edges and use a quality hone to produce cross hatch and a good ball hone to finish port chamfers.
Ed
yes thanks , my engine builder honed to the nominal bore size which is recommended by wiseco.
The clearance was right at .004 which is what Wiseco also told me to set them at.
it sounds tight .
I assembled today and is feeling real good turns over very nice by hand .
I did speek to Wiseco the said the new pistons they sell should be installed at the exact nominal recommended bore size.
They also said that adding clearance was not recommended.
the said adding clearance on the new stuff is worse than tight.
guess well see..
Follow their instructions on start up and running your motor for break in.
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