Valve Job Yanmar 3HM35F

[NYSail]

Hello all.... I have a 1986 3HM35F. Engine runs good however I have not done a value job in the 6 years I have owned her and I would be the p/o did not either. Any event I want to do this job. I hear this is a fairly simple and read the manual regarding the adjustments. However when speaking with people they talk about value adjustments however do not refer to any marks on the fly wheel that have to be lined up as the manual indicates....

I am going to have an experienced mechanic do the job but like to know what the steps are so I can monitor his work as well... hate when guys think they can cut corners and this guy is primarily a gas mechanic and does not have extensive experience with Yanmars. I will be there watching while he does this.

Thanks!!

 

[anchorclanker]

.. hate when guys think they can cut corners and this guy is primarily a gas mechanic and does not have extensive experience with Yanmars. I will be there watching while he does this.

Thanks!!

A "valve job" is a mechanical repair to damaged and worn valves requiring removal of the cylinder head, and is a major repair. What your actually referring to is a valve adjustment as part of regular maintenance, and as you have come to understand, is a relatively minor and easy procedure.

The procedure is outlined in the owners manual and both you, and your mechanic should read it thoroughly before proceeding. As to your mechanics ability, no one can answer that but you. Can your gas engine guy adjust the valves on a your diesel? I have no idea, can he do it correctly on a gas engine? Does he know how to use feeler gauge's correctly (there is a knack to learning the proper "feel")?

However, while you have the starter removed to read the flywheel marks to adjust the valves, it would also be a good idea to check injection timing (also explained in the manual). You could also remove the injectors and clean them. And again, as the manual shows, you can attach them onto the lines out of the engine, but turned away, and crank the engine slowly while you observe the spray pattern (being careful not to inject fuel into your skin).

 

[NYSail]

thanks.... yes i have taken care of the injectors already, pulled and had them rebuilt. dont have to remove starter to read flywheel marks... 3hm has a port for this.
mechanic is good with gas engines.... i just like to know as much as possible before i have anything done.... read the manual already and "adjusting" the valves sounds pretty straight forward and easy. i always like peoples opinions and thoughts to suppliment the words in the book.
thanks...

 

[anchorclanker]

You likely dont need a mechanic, its a pretty simple job and its quite a simple engine. Perhaps ask your mechanic to assist you, allowing you to do the job yourself, while preventing you from making any big "boo boo's". Might want to get a new rocker cover gasket beforehand, and just replace it on principle.

 

[Benny17441]

There are no time limits or time requirements for adjusting the valve lash on the engine. If the engine is running smooth and there is no tappet noise you may likely not need to do anything. What you may do is just check the gap to confirm it is not tighter than the recommended spec yet not loose enough to produce a loud tap. I check the valve lash about once a year but have not adjusted any probably in the last 5 years.

 

[anchorclanker]

Yanmar calls for valve adjustment every 500 hours.

Valves just as often wear in the valve seat and close up clearance, eventually leading to burned valves, loss of compression, and occasionally, catastrophic engine damage.

 

[NYSail]

Thanks all for the info. Yes I hear tapping and would not be suprised if this has never been done. I have ordered the gasket and will be doing the job this weekend.

Again thanks all!

 

[sailaway78]

Instead of timing marks

If you use the timing marks be sure to remember that on at least some Yanmars, the #1 cylinder it the rear, not the front one. Easier than worrying about the timing marks, is turn the engine over till a valve opens, then adjust the other valve for that cylinder. Fool proof. Might take a few minutes longer, but probably not, and much simpler.