[overbored]

Yammer casts the block to be used for several applications the ports that are blocked with the head gasket on the marine engine is by design. they cast the opening in the block and then design the head gasket to block or partially block the passages as required for the cooling needed on the engine depending on the application of the engine. make sure you get a new gasket for the marine application it may be different then the tractor model. also make sure you know if the piston you have is the standard size or the over size piston there are different head gaskets for the different pistons sizes.
If the valves are wet with oil then the then valve stem seals are leaking if the oil is on the combustion side of the valve when it is closed then the valve seats are leaking

 

[Rockter]

Get yourself a valve spring compressor and re-grind the valves.

The strange blind-end "ports" are of no consequence. Just leave them. You must check that the new head gasket is the same!
Put new valve stem seals on there too. They are probably in the gasket kit anyway.

Even after grinding, do not expect perfect sealing of the valve seats. They do not always hold perfectly - they are supposed to, but not always perfectly.
I test with kerosine. Gasoline and alcohol are rather thin and, in 40 years, I have rarely got more than about a 3 minute seal with those.
Don't over-grind the valves. Grind until you have an unbroken grey ring in there. Clean off all of the waste grinding paste.

Use a torque wrench for re-assembly.
Check your valve clearances on re-assembly too.

In very cold weather, run a fan heater in the engine compartment for your first start after re-build. Direct it over the air intakes. Switch it off the moment the motor starts. Warmer air really does help the first start in very cold weather.

If you find that it still does not start, then (in desperation) try spraying WD40 in to the air intake to encourage first start. Do not do that often as the motor will become addicted to it.

Let us know how you get on.

 

[nigell]

Next part of the story ...

Since my last post, I was able to grind valves and cleaned them. I have also changed valve stem seals. After cleaning all, I instaled new head gasket (according to a dealer, the missing holes in head gasket are really part of the Yanmar design!) and mount engine together. Changed filters, changed oil, did bleeding, adjusted valve heads clearance, checked if the governor is sending fuel to injectors (by putting full speed and when manually rotating engine by handle observed if diesel is coming from piping next to injectors - sorry, here I am missing English words, so are words "cranking the engine" the same as I described by words "manually rotate engine"? Here also I have to note that when doing the same procedure with piping attached to injectors, I hear short "squeezing sound" periodically repeating 3 times per one turn of the engine. My thoughts are this is governor trying to push diesel through injectors. Am I right?)

Than started engine (as Rockter adviced, I heated the engine by fan heater and later also used the trick with spraying WD40 to air intake) and nothing. Engine not started. On the very beginning he shortly fired (I think, it was diesel deposits left on pistons and in piston holes after final cleaning). But then nothing. Tried several times.

Also noticed white smoke from air intake again (as in one of my previous posts). So I removed the rocker arm chamber to see what is going on with valves. I noticed that some white smoke is coming from the area of pushing rods (see picture). It is interesting it corresponds to the cylinder which was (after removing cylinder head) dry and without any oil leaks around valves.

Now I am starting to be a little desperate since I have no idea what next. Any experience or advice?

 

[Chas H]

are words "cranking the engine" the same as I described by words "manually rotate engine"?

Cranking the engine typically means using the cranking/starter motor. Manually rotating means turning it over by hand.

Can valve timing be adjusted?

Have you adjusted the injector timing after setting valve clearance?

boatdiesel.com may be helpful.

 

[PhilCarlson]

You're past my level of experience here. The only experience of value that I can add is that every time I've had to bleed my fuel line, I've only had to bleed it to the end of the last flexible line (the shielded line leaving the filter). After that it drew fuel into the cylinders and fired just fine, but it took a while; 15-20 seconds of cranking to get there.

Not sure if WD-40 has what it takes to ignite. I would think it would take a lot.

Don't panic, take a breath. It's a simple engine and a simple solution will sort it out.

 

[RegisteredUser]

Sounds like there is somerhing missing in the...path.
Engine needs to be ready to accept the fuel and air....chased forward from the tank.

 

[contrarian]

I have heard of spaying Diesel Fuel into the air intake while engine is being cranked but not WD40. Anyone else use WD40 this way ???
This project is way beyond my comfort level. Maybe time to check with a certified Yanmar mechanic. Doesn't have to be marine, one of those tractor guys can probably fix you up just as well. The best marine mechanics in my neck of the woods work for a company that mainly does heavy equipment and Semi Tractors. I'm really curious as to how this works out. Please post the results so that those of us with the 3gm30 can have more information for our arsenal.

 

[Capt Len]

That squeak sound is the high pressure pump preforming its duty. Have you checked the injectors.? Usually you can take them out of the head and connect them to the high pressure line upside down. Crank engine ,observe spray pattern Be careful of squirt as it can blind you or cause nasty as it penetrates skin .Watch for blowing out any copper crush washers while doing this. but you'll want to replace them.

 

[boatsurgeon]

For a diesel to run, it needs a properly compressed air fuel mixture. That's it.

1. Make sure the engine stop control lever is not in the stop position, and you are feeding good clean fuel.

2. Turn the engine over slowly (one full rotation per minute) with a ratchet on the crank pulley nut. It should be quite an effort, and equal for each cylinder, to overcome the compression stroke. If not, find out why compression is so low. If so...

3. Loosen the connections one at a time on the high pressure pump and make sure they are peeing out fuel as you turn the engine over with the starter.

If not, find out why you are not getting fuel to the high pressure pump.

If so,

4. Tighten the pump connections, shut of the seawater intake and crank (by starter) that puppy for 30 seconds.

If it doesn't start, let it sit a few minutes and then crank another 30 seconds.

If it starts at any time,

4. Open the seawater intake. All is good and is long as it has a properly compressed fuel air mixture, it should continue running forever.

If it doesn't start,

5. Repeat the high pressure pump test. If that proves the high pressure pump is delivering fuel,

6. Find out why your injectors aren't injecting.

7. If your compression strokes are compressing, and your injectors are injecting clean fuel, and the engine has clean air, and the exhaust is not blocked, the only thing remaining that could prevent the engine from running is injector timing (and I have never had this problem unless someone removed the injector pump and didn't put the shims back in right).

 

[Sailorjane]

One day I will also understand something about engines...

sorry

 

[nigell]

Hi guys, forced to left Denmark to my home country for one medical treatment. So cannot continue on the engine until next month. But there are not many possibilities left. So next step will be injectors functionality checking, re-calibration of valves timing and if these will be fine then cylinder pressure measurements.

But still not understand where is the white smoke around pushing rods is coming from and if this is a real problem or not. Studied manual and figures of the engine and cannot find the way for smoke getting to a camshaft and around pushing rods. Thought about broken rings, therefore not sealing and letting smoke to go around piston down and further, but it does not make sense since it would be much more easier for smoke to go through the open exhaust valve.

But I will know more next month and then I will continue with bringing news again.

 

[Capt Len]

Beginning to sound like a professional compression test is in order. (blowby getting around the rings) A thoughtful amount of lube oil squirted in the cylinder will temporarily seal faulty rings but have no effect on cracks in head or block or leaky valves .

 

[boatsurgeon]

Hi guys, forced to left Denmark to my home country for one medical treatment. So cannot continue on the engine until next month. But there are not many possibilities left. So next step will be injectors functionality checking, re-calibration of valves timing and if these will be fine then cylinder pressure measurements.

But still not understand where is the white smoke around pushing rods is coming from and if this is a real problem or not. Studied manual and figures of the engine and cannot find the way for smoke getting to a camshaft and around pushing rods. Thought about broken rings, therefore not sealing and letting smoke to go around piston down and further, but it does not make sense since it would be much more easier for smoke to go through the open exhaust valve.

But I will know more next month and then I will continue with bringing news again.

Any chance this engine seem to loose coolant from the reservoir?

If so, does the exhaust gases smell sweet (like sugar)?