Yanmar Engine Rebuild

[Ken Hunter]

Yanmar 3GMF has broken rings & piston in #3 Cyl. At the very least I would like to replace all 3 pistons, rings, rods & rod bearings. Does anyone now of any particular do's & don'ts for this operation? The cylinder liners measure out ok and are not scored. Should the liners be honed or replaced? Thanks for your help, Ken

 

[Larry]

Hone works for us.

We honed the cylinder walls of a Yanmar diesel once, and it worked well. (We replaced rings only. All went well.)It was an easy rebuild job, especially since no one else locally would touch the Yanmar.

 

[Henry Weber]

Yanmar rebuild

KenA few months ago I rebuilt my Yanmar YSB12. The shop that did the machining on the head advised that I remove the liner for examination even though the bore was within spec and not scored. I am fortunate that I took his advice because we found that corrosion from the salt raw water had caused serious eroding of the cylinder wall which was undetectable without removal. In several places the wall was eaten away about 80% of its thickness. I have about 150 hours on the new engine and so far I am happy. Don't know if my situation was unique or not. Just wanted to pass it on to you. good luck with the rebuild.Henry