Yanmar 2QM1. Head gasket leaking

[O32]

Originally Posted by Wotname

^^, I'm one of the interested ones!

2QM15 oil circuit pdf attached

[charliehows]

last time i bothered asking, the price for a replacement external oil line was around $200 - i always thought it was a poor design anachronism, now i'm wondering why the 2qm15 has an internal oilway where the other engines dont - only explanations i can think of is the oilway was found to be too narrow for sufficient oil flow for the bigger engines or the oil line gives a feed to the top of the rockers where the internal oilway has to force it up from below...seems unlikely given the tiny difference between the 2qm15 and the 2qm20.

[O32]

Removed head today. Not difficult once I got rest of stuff out of way.

Exhaust pipe flange bolts were tight, so I removed manifold along with exhaust mixing elbow.

Noticed red color inside block where push rods come up. Also saw this in pics on another sailor's engine dismantled. Seems likely it is iron oxide, but water does not show up in oil (even recent oil analysis). Thinking water only escapes when engine is hot and then vaporizes when it hits hot metal and oil?

My exhaust U-shaped mixing elbow is corroded and needs replacement. It is not original - it's made up from standard threaded pipe fittings plus a welded CW injection pipe. The OE type is expensive and from what I have read, not very long lasting. What have others used when the elbow fails? Seems it could be any generic type seeing it's not really engine specific.

[Wotname]

Originally Posted by O32

.....

Noticed red color inside block where push rods come up. Also saw this in pics on another sailor's engine dismantled. Seems likely it is iron oxide, but water does not show up in oil (even recent oil analysis). Thinking water only escapes when engine is hot and then vaporizes when it hits hot metal and oil?

......

Many engines are red inside, I have always assumed it is some type of "inside engine paint" or a manufacturing protective coating - I'm sure it has a proper name.

[a64pilot]

Way back when, and I mean back before overhead valves, engines interiors were painted with Glyptol paint I think the name was.
Most likely it was to seal rough poor casting from leaking and possibly to seal in loose casting sand that may still be in the rough castings.
I think it was red lead paint.
Then later hot rod days it was considered to be smart to polish the inside of the galley and or paint the interior on the theory that the smooth surface would help oil flow back to the pan quicker, about this time windage trays were fitted to high performance engines to keep the oil away from the crankshaft. High volume oil pumps and high RPM can pump a large amount of oil to the top end of an engine, there is some truth to it needs to get back to the pan unimpeded if possible.

I used to turbocharge 900 Kawasaki’s a long time ago, and because we had to bump the oil pressure way high to make the turbo live, filling the head with oil was a real problem.

Why on a Marine Diesel? My guess and it’s only a guess is the seal the block part, or maybe because it’s the way it’s always been done.
I’m going with seal the block and maybe prevent oil seepage on a few engines, but I’m guessing.

[a64pilot]

Glyptal not glyptol sorry.
https://www.eastwood.com/glyptal-red-enamel.html

[Wotname]

Originally Posted by a64pilot

........
Why on a Marine Diesel? My guess and it’s only a guess is the seal the block part, or maybe because it’s the way it’s always been done.
I’m going with seal the block and maybe prevent oil seepage on a few engines, but I’m guessing.

Yep, sure makes it look like a "proper" engine.

Thanks for providing the name of the product (Glyptal) - always wanted to know what it was.

[a64pilot]

I want to think it’s the same reddish paint that is used on alternator and electric motor wiring as an insulator, at least that is what I used as a kid in the 70’s building my motor.
Now I think it was a waste of time, but then I was pretty gullible.

[Perna]

Originally Posted by O32

Removed head today. Not difficult once I got rest of stuff out of way.

Exhaust pipe flange bolts were tight, so I removed manifold along with exhaust mixing elbow.

Noticed red color inside block where push rods come up. Also saw this in pics on another sailor's engine dismantled. Seems likely it is iron oxide, but water does not show up in oil (even recent oil analysis). Thinking water only escapes when engine is hot and then vaporizes when it hits hot metal and oil?

My exhaust U-shaped mixing elbow is corroded and needs replacement. It is not original - it's made up from standard threaded pipe fittings plus a welded CW injection pipe. The OE type is expensive and from what I have read, not very long lasting. What have others used when the elbow fails? Seems it could be any generic type seeing it's not really engine specific.

Don't know about the rust/paint. As for the mixing elbow if the original worked and it is made from pipe fittings can you not just take it to a plumber or remake it yourself?

[O32]

Originally Posted by Perna

As for the mixing elbow if the original worked and it is made from pipe fittings can you not just take it to a plumber or remake it yourself?

That is one option. I would use stainless fittings.

Another option is to use the Yanmar mixing elbow that just turns downwards. (I can get one for a good price) But then, I think I would need a vented loop on the water line to the elbow . And I should put one on exhaust line from lift pot to transom too.

Another problem. I bought a valve cover gasket. Didn't know there are two types. One (mine) is an o-ring (124060-11311) and the other is just a flat gasket 124060-11310. I wondered if I could fill the groove with sealant I have for my 98 Mercedes breather covers, but really I guess I should get the proper part. (Takes forever for them to deliver!)

[charliehows]

FWIW my exhaust is constructed from heavy but apparently standard plumbing pipe - 90 degree elbow straight up, about a metre of rise with a flat steel support mounted to the rear head galley cover to keep some of the weight off the manifold, at the top a 120-ish degree fitting, a short pipe and then into flex rubber exh. pipe; the water exhaust is fitted to the short pipe below the peak. I've had the elbow off for inspection a few times over the last 8 yrs, still looks like new(ish). If I was replacing it, i would also consider s/s.

[Cheechako]

Originally Posted by O32

That is one option. I would use stainless fittings.

Another option is to use the Yanmar mixing elbow that just turns downwards. (I can get one for a good price) But then, I think I would need a vented loop on the water line to the elbow . And I should put one on exhaust line from lift pot to transom too.

Another problem. I bought a valve cover gasket. Didn't know there are two types. One (mine) is an o-ring (124060-11311) and the other is just a flat gasket 124060-11310. I wondered if I could fill the groove with sealant I have for my 98 Mercedes breather covers, but really I guess I should get the proper part. (Takes forever for them to deliver!)

Cast iron or black iron may last longer than SS in a salt mixed exhaust. Just throwing that out.

[O32]

My immediate challenge, is to get the old pipe out of the manifold flange. It's been soaked with WD-40 and PBlaster for 24 hours, but shows no sign of moving using a big pipe wrench on the pipe.

I can get the flange off the manifold, so one option is to heat the flange, but then not so easy to grip it in vice.

Last resort unless someone has better ideas, is to saw pipe off and then try and saw from inside out and hopefully not damage the flange threads.

[O32]

Originally Posted by Cheechako

Cast iron or black iron may last longer than SS in a salt mixed exhaust. Just throwing that out.

Could be, but we are in Great Lakes. Nevertheless, it is a thought. Mind you, the aftermarket mixing elbows are S/S.

One thing I recall from my engineering days, is to only use sched 80 when threading pipe. My exhaust would probably still be there if Sched 80 had been used instead of 40. There is not much wall left when Sched 40 is threaded.

[a64pilot]

No, remove the pipe and flange as a whole, then put one or the other in a big vise and use heat, as in acetylene rose bud to heat it and then with a big pipe wrench, I heat until just starting to get some color max, then let Cool for a min before I put real torque on it.
First try heating not as hot, then if you have to get it real hot, get it real hot to bust the rust, but when it’s that hot, it’s too soft to take much force, so that is why you let it cool some.
Replacing with black iron would be my preference and cost less too. I think it would likely last longer than SS.
Bronze or cupronickel is the Gold standard, but hard to come by and really maybe not needed.