I was Bored so Pulled the Head on my Yanmar

[sailorchic34]

My yanmar 3gm30F engine with 1100 hours on it which has been hard starting for over a year and using oil (approx. 0.8 quarts per 12 hours). I had thought I had resolved it a few times. But it was getting worst and worst. Would only start with #3 decompressed. Plus would sometimes die when going to idle, even after 2 hours running. So annoying when that happens waiting for a bridge to open too.

So today I pulled the head and heat exchanger/manifold off. Lots O fun. So #1 (aft end) had carbon buildup, lots O carbon. #2 and #3 looks clean with a very light carbon dusting that wiped off. The head gasket did not look that bad, but was oil soaked from 9 to 12 o-clock at #1 (far left in photo's), which corresponded to the carbon on the head at #1. Cylinder walls in all three are fine. Can still see cross hatching on the walls.

#3 pre-combustion chamber was lighter then #1 and #2. Have a friend bringing a pop off tester for the injectors tomorrow. So with luck I can fine out if #3 is bad. #3 takes 20-30 seconds once the engine is running and decompression lever released to start firing. But no carbon buildup on #3 at all. I'm thinking #3 injector may be bad/leaking.

Oh I pulled the caps on the heat exchanger and rodded out the tubes. Really was not bad, with only a light buildup towards the middle.

My only concern is rings, as I can't really check them unless I pull my engine out and thats going to be a lot of work. Is there another reason why the head gasket would be oil soaked. BTW the oil galley to the valve train is exterior and connects to the head at #3 at 7 O-clock, which is dry.

So that was my day....

[ohdrinkboy]

i'm in awe of sailorchic

[Bash]

Originally Posted by ohdrinkboy

i'm in awe of sailorchic

Gimme a break! It was only a three-banger.

[skipmac]

Originally Posted by Bash

Gimme a break! It was only a three-banger.

Yea! I've got a four cylinder she can try. Lets see if she can move up to the big leagues.

[miketo]

I'm in awe, too. SailorChic is smart, and smart people rock.

[lonesoldier0408]

The problems you describe seem to be due to either worpage or surface prep from the previous work performed on the engine. Torque specs should be followed closely on re-assembly. Also worpage of the head should be milled out. Although accessive wear to the block caused by assembly prep is possible, it is unlikely. Although I have heard others talk of installing two head-gaskets, I don't recomend this, nor have I ever seen it. Try to determine if the seapage is on the head or block side of the head gasket and work that part.

[foggysail]

Hey!! Good for you Chick! And another 'ATTAGIRL' for rodding out the heat exchanger. That works, found that the radiator shop technique did not clean anything other than remove paint from my heat exchangers.

[Boracay]

In the good old days heads needed to be torqued twice. Initially and then after run in.

When you replace the head check if this is something you should do.

[bobconnie]

SailorChic, be sure to have the head cked for flatness! resurface if needed! never use 2 gaskets ever! It looks to me that your on the right track with that injector! and I believe from the pics that the head needs surfaceing! but that means little LOL please ck it !! If you dont have a torque lay out for that head, just start in the middle and work your way out counterclock wise! always works for me! Let us know how things work out! also do you have a flat level and some feeler gauges? if ya do you can ck the head yourself !! have fun!you have more guts then many on here LOL

[sy_gilana]

Agree with all others to check flatness.
Did you do a compression check before?
IF injectors test out well, you're worried about rings but don't want to pull the crank, an experiment might show up a difference between cylinders. You are going to change the oil anyway. Get the 3 pistons exactly to the same height. Pour in exactly the same amount of diesel, say 50cc. Leave overnight. If levels are similar in morning leave as is, if there is difference, pull the crankshaft.
The carbon build up is a result of incomplete combustion. This can be due to air restriction coming in, exhaust restriction going out, loss of compression, or excess fuel. Do a valve job while you're headless. Get the head crack - tested, and give it a surface grind anyway, but check the block for flatness. I would blue it. Good luck.

[cheoah]

Nice work! Hope you find something conclusive, and agree it is worth going over as much as you can while its out.

Thanks for pics and look forward to updates

[sailorchic34]

I did an eyeball check for flatness on the head this afternoon with a piece of angle aluminum extrusion. I was too pooped this afternoon to find the feeler gauges. I'll get my feeler gauges out tomorrow is check for flatness of the head and block. I think I have two (well at least two issues) with the engine. #3 has a delayed firing, like its not getting fuel. Possible bad injector. #1 has carbon, but is it head or rings.

The head gasket was soaked at that end, where as the rest of the head gasket was dry as a bone. OH I was wrong about the oil connection to the head. It is at 10 o-clock at #3, right where the oil on the gasket is. Thing is the connection is at the top of the head and I don't think there is a pass thru to the bottom edge of the head, but maybe there is. no coolant in oil or vise versa. #2 is the cylinder that's still fine and runs. I will do the oil in the cylinder trick for sure.

I do have the yanmar manuals and torque sequences. I believe that heads should be retorqued and pretty sure this engine never was. BTW, this is the first tear down on the head, since yanmar built it.

Oh I've done a complete rebuild of a inline 6 as well as a few 4 cylinders. But this is my first diesel tear down.

I was really surprised at how clean #2 and #3 were. Before the photo of the head, I just did a very light wipe with a cloth to #2 & #3 domes. #1 on the other hand needed to be scraped clean of carbon, mainly on the oil galley side of the head.

I should note that I could hear a tone (noise) from the engine when it was idling. I think I read somewhere/ sometime that that was a possible sign of a bad head gasket.

[sailorchic34]

Originally Posted by bobconnie

you have more guts then many on here LOL

Not so much guts as an amazing lack of funds, So I have to do it myself. Luckily my dad taught me a thing or two about engines.

I should mention that I did not get a compression check done. With a 1/2 quart of oil used every 5 hours of motoring and the hard starting, I knew I had compression and or fuel issues.

I did show the head gasket to a master mechanic and his option was it had to be rings. Which I really don't like to hear. Its going to be a royal you know what, pulling the engine out (its a V drive).. Oh not that bad, gee half the engine is apart already. But it will be annoying if I pull the pistons and find the rings in spec.

[roverhi]

The GM30 is a pretty light diesel. Pulled mine with transmission using a come along and 4x4 over the companionway. Pulled it out by myself but took two people to push it back in and drop it onto the mounts. Set it on the sole on a piece of scrap plywood. Was able to slide it around without too much difficulty to get at it from all sides. Even lighter if you take it out without the V drive.

My engine was fine but the PO's installation to replace an A4 was crap. Engine was so far out of line it ate stern bearings in less than a 100 hours and was about a foot farther forward jutting into the galley than the A4. Had to carve away at the engine beds and relocate the mounts to move it back into the engine space and out of the galley. Took it out and put it back in at least 5 times trying to get clearance for flywheel and bell housing and proper height for the beds so it would align.

Since you've got the head off, would definitely have a machine shop check out the head for flatness and mill if necessary, replace the valve guides and do a valve job. Should cost well less than a boat unit to have that done. Two head gaskets with decrease the compression significantly and is a no no without miling the head to take off a corresponding amount of medal to compensate for the extra head gasket. Even then, don't know how it would work with the high compression of a diesel. It would be a last resort fix in utter desperation if you had to do it.

If the cylinder walls show no sign of wear, highly doubtful that the rings are a problem. Rings usually quit ceiling because the cylinder bores get ovaled by wear. With only 1100 hours on the engine would be wiling to bet your problem is an injector or injector pump problem if there are no other issues with the head. The engine may be fed oil externally but it falls back to the sump through the head and block. If the gasket was soaked in oil, could have been a problem with the gasket. Not completely out of the realm of possibility that an oil passage was not cut out properly on the gasket, BTDT. Assume the cylinder seals on the gasket did not show signs of gas leaks.

New style head gaskets usually don't require or is retorqueing reccomended after initial installation. They seal properly on installation torqueing and can be deformed by retorqueing and shorten the life. after run in. The original style gaskets on Series Landrovers were copper and required retorquing after run in. New gaskets are a composite material with metal insert seals around the cylinders, etc. Retorqueing verbotten on the new style. Check with Yanmar for their reccomendations.

[Navatech]

Originally Posted by sailorchic34

but is it head or rings

What you SHOULD have done is do a compression test BEFORE pulling the head...