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  1. #1
    Join Date
    Jan 2003
    Location
    Warwick, Rhode Island
    Posts
    86

    Default Yanmar adjustment of Top Clearance of Intake/Exhust valves

    Now I know I really bored, I got out my service manual for the engine today and started reading it from front to back (a snow storm in April tends to do that to you). Anyway, I noticed a maintenance routine that I havenít done yet, that being the intake/exhaust valve clearance setting on my diesel. My question is should I try this on my own, since Iíve never rebuilt an engine or try to find a mechanic to watch/learn. I always do my own maintenance, however I'm concerned about the ďif it ain't broke don't fix itĒ, in addition to the bad comments about some of the mechanics people have used. Has anyone else done it? The book says it must be done every year or every 250 hours. Any comments would be appreciated.

    Thanks,

    Mike
    2002 270 Mackinaw
    315 Yanmar
    Warwick (Narragansett Bay), RI

  2. #2
    Join Date
    Jan 2003
    Location
    Wantagh, N.Y.
    Posts
    3,619

    Default

    This is a job I used to routinely do on my first Big Block Vette, whch had a solid lifter cam and therefore required close maintenance of the upper valvetrain, but is a job that I have never attempted on a diesel.

    Does your manual give specific clear instructions as to the Yanmar recommended proceedure or no? Check hot or cold? Intakes before the exhaust or after? You need very clear unambiguous instructions first time thru.

    If you have never done this job - even on a gas engine, the the smart bet would to pay a Yanmar-certified mechanic to do it the first time while you relentlessly peer over his shoulder during the operation.

    rgds, Leprechaun
    Three-fourths of the Earth's surface is water, and one-fourth is land. So it is quite clear that the good Lord intended us to spend triple the amount of time fishing as taking care of the lawn.

  3. #3
    Join Date
    Oct 2002
    Posts
    1,664

    Default

    Thanks for the reply Lep.

    Have any other diesel owners done this precedure yet, either yourself or a hired hand? :?:

  4. #4
    Join Date
    Jan 2003
    Location
    Warwick, Rhode Island
    Posts
    86

    Default

    Sorry, that was me above...
    2002 270 Mackinaw
    315 Yanmar
    Warwick (Narragansett Bay), RI

  5. #5
    Join Date
    Oct 2002
    Posts
    1,664

    Default valves

    Just some general info- It's like everything else, nothing like experience. First get a Yanmar service manual. It will show you where every thing is. You must have a feeler gauge for intake & exhaust. If it's a (4) cylinder you have (1) of each type valve per cylinder. What you are checking for are valves that get tight. (Some one once said when a diesel gets quiet look out for trouble) Any way, Because of the high heat produced in the combustion process, the exhaust valve is the one that will likely get tight. A little loose is acceptable, a little tight is not! Never advance the engine using the starter. Use a sockit wrench on the crank shaft pully. "Never turn in the opposite direction that the engine normally turns. The idea is to raise the lobe of each lifter as high as it will go then slide the appropiate feeler gauge in the little tiny space just under the lifter. The gauge should slide while feeling some resistance. If you do have to adjust a valve or two,pay attention to the amount of preasure it took to release the locking nut, and try to duplicate this same torque when tighting. If anyone feels I have incorrectly stated somthing "Please correct me" . Hope this helps
    Mel-slidell

  6. #6
    Join Date
    Oct 2002
    Posts
    1,664

    Default valves

    Some additional points. The reason for "not" using the starter is , it may start. If your diesel is like mine (1) rotation and and it not going to stop. The other reason is, you can not bump with any accuracy.
    The reason ''for not'' turning in the opposite direction of rotation, you may inadvertantly suck some carbon particles under the seat of one of the valves and produce a high spot, which we all know will make that cylinder loose compression. Good Luck Mel-slidell

  7. #7
    Join Date
    Feb 2003
    Location
    O C, California
    Posts
    22

    Default

    Mike go ahead and follow the procedure and check clearances. Don't make any adjustments unless your sure. I do a bit of Cummins work (equipment not marine applications) and their valve adjustment interval is 2000hrs, majority of the time all is ok at the 1st 2000hr svc. I haven't worked on a Yanmar but a valve adjustment at every 250hrs seems excessive and will sure increase the cost of ownership. Mel and Lep are right. If the manual calls for a cold engine follow the procedure to the letter and if you pass the timing mark where you are to check a clearance, don't back up, go around again because gear lash may throw off your measurments. Torque everything to spec if you do make any changes, and roll over the engine by hand one more time to be on the safe side. Wish I had some specific knowlege and could help more.
    Charles
    Education is what you get if you read, experience is what you get when you don't. :lol: I love to give our new mechanics a hard time when they jump right in and screw something up, especially when the info is on the shelf!

  8. #8
    Join Date
    Jan 2003
    Location
    Warwick, Rhode Island
    Posts
    86

    Default

    Thanks for the replys! I have the manual for the 6LP-STE and yes they state to check it cold. I think initially I'll just do the feeler gauge check myself as you recommended, then have a Yanmar mechanic do the actual adjustment. After that I'm sure I'll be able to handle it. Anyone know any good Yanmar techs in/around RI?
    2002 270 Mackinaw
    315 Yanmar
    Warwick (Narragansett Bay), RI

  9. #9
    Join Date
    Jan 2003
    Location
    Wantagh, N.Y.
    Posts
    3,619

    Default

    I remember a long article last year in Offshore magazine about Old Lyme Marina being a big player in yanmar installs and service - they are on the Conn River - can you get your boat there?

    Link:

    http://www.oldlymemarina.com/


    rgds, Leprechaun
    Three-fourths of the Earth's surface is water, and one-fourth is land. So it is quite clear that the good Lord intended us to spend triple the amount of time fishing as taking care of the lawn.

  10. #10
    Join Date
    Feb 2003
    Location
    Portsmouth, VA
    Posts
    380

    Default

    When we do valve lash adjustments on our diesels we generally have the valves in a no rock condition. This means that the valves are closed and on the base circle of the cam-not high on the lobe. This is where the rockers will be loose. You can double check this position because as you rotate the crank about 20į in either direction the valves will not move.
    At this point pick the correct feeler gauge and slide it between the valve and rocker. It should snug things up. Check snug by moving the rocker should have some resistance. Making the adjustment is no big deal, just take two hands and a steady eye. Loosen the lock nut, adjust the screw up or down while the gauge is between the two. When you get the clearance you want hold the adjustment screw and tighten the jam nut. There should be more than one cylinder in the no rock position at the same time.
    Some manuals give you the position of the crank relative to the position of the valves. To much info for me.
    Should be about a 2 hour/1/2 six pack job. Good luck.

    Tim

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