Broken Rocker Arm Shaft Mounts

[GrahamHO]

Originally Posted by Celestialsailor

A little contradiction there.
Ya... he was delivering but did you check the water and thermostat after the engine work was done. From what i read, you were the last guy to touch it.


Good point and also piston clearance. On my Westerbeke W46 there was .010" (Ten thousands of an inch) from the top of the piston to the bottom of the head. Any resurfacing of the head is going to change the dynamics of the function of the engine. This is why it pays to read the specs from the engine manual as to what can be machined safely.

Diesel engines with their high compression ratios around 22:1 have much smaller combustion chambers than petrol / gasoline engines in cars which are now around 9.5:1. This means that clearance between the valve head and the piston crown is much smaller in diesel engines. Anything planed off the cylinder head will reduce this clearance further bringing the overhead valves closer to the piston by the amount removed.

It's possible that a workshop used to machining car cylinder heads might have taken too much off. It's also possible that this may have been the second time it was planed.

My suggestion of the wrong valve clearance was an objective / constructive observation not a personal criticism. It is certainly one of the possibilities.

Obviously something was wrong.

[skipmac]

Originally Posted by jonahmcg

hey guys, i did adjust the tappets of course. but thanks for the insults. i didn't check the cooling because i wasn't on the boat. he was delivering it. so sort of hard to get into the engine and check things out. ya know.

Hey Jonah,

Just ignore the insults. Always find a couple like that almost anywhere you go, even Cruisersforum.

Do keep us posted on what you find. I'm very interested to learn the answer to this little puzzle.

[GrahamHO]

Originally Posted by skipmac

Hey Jonah,

Just ignore the insults. Always find a couple like that almost anywhere you go, even Cruisersforum.

Do keep us posted on what you find. I'm very interested to learn the answer to this little puzzle.

Hey Jonah,
These are not personal insults! People are trying to help you. Someone, somewhere has done something wrong. These things don't happen by themselves.
Here is another possible scenario. There should be an oil line taking the engine oil from the engine block to the cylinder head and into the rocker shaft. On disassembly and head removal this oil line has to be removed. It has short hollow banjo bolts at each end. If those bolts had been screwed back into their respective holes for safe keeping, and if the oil line had been omitted on reassembly the valve gear would seize up after say 15 minutes ( as it apparently has). There would be no oil leak as the banjo bolts were put back into their holes for safe keeping.
On my Yanmar, that oil line runs from near the air intake but on the block; then around behind the engine and up into the back of the cylinder head.
Likewise on your engine there may be another way to transfer the oil to the head? It could be an oil way in the block matching an oil way in the head; perhaps. This would necessarily be through a hole in the head gasket. If that were blocked with gasket goo for example the valve gear would seize. I doubt that it is possible to replace the head gasket the wrong way up but it may be possible and that may obstruct the oil way.

[Cheechako]

Originally Posted by a64pilot

In any event I'd pull the head, just because I strongly suspect bent valves and I would have to rule that out.
Of course an easy way to check for a bent valve is once the head is off, lay it on it's side and fill the intake or exhaust ports with alcohol, a bent valve will leak badly.
Look for shiny spots on the pistons, usually looks like little crescent moons.

I've seen a few hydro locked motors, but never seen the valve train damaged by a hydro lock, not bent pushrods etc.

I had it happen on my Perkins 4-236. Motor had less than 500 hours on it. The exhaust was large (3") and the muffler small. The Exhaust outlet was half submerged at the water line. Evidently when I parked it for the night at a marina, the wind chop direction was putting just a bit of water in the exhaust with each lapping wave. When we started it up in the am it cranked very hard, started and then had a problem.
After a lot of screwing around we removed the rocker cover and found one pushrod off the rocker on the aft/lowest cylinder. Not sure how that happened but it seemed to be from some water in the cylinder. Maybe when it fired off with some water in there (non compressible) as opposed to all gas it forced the valve up and bent the pushrod off the rocker. Go figure. I had a custom exhaust loop made after that.

[GrahamHO]

Originally Posted by Cheechako

I had it happen on my Perkins 4-236. Motor had less than 500 hours on it. The exhaust was large (3") and the muffler small. The Exhaust outlet was half submerged at the water line. Evidently when I parked it for the night at a marina, the wind chop direction was putting just a bit of water in the exhaust with each lapping wave. When we started it up in the am it cranked very hard, started and then had a problem.
After a lot of screwing around we removed the rocker cover and found one pushrod off the rocker on the aft/lowest cylinder. Not sure how that happened but it seemed to be from some water in the cylinder. Maybe when it fired off with some water in there (non compressible) as opposed to all gas it forced the valve up and bent the pushrod off the rocker. Go figure. I had a custom exhaust loop made after that.

I'm sure you have corrected the muffler / water lock size by now. Also you need a high loop in the exhaust pipe before the exit.
I made a little flapper valve out of a small sheet of copper on a plastic hinge for the end of my pipe outside the transom. It's cut on a 45* angle so it closes, like you see on truck exhausts. It's mainly to stop the salty air blowing through the pipe into the engine. The water lock should prevent that but it's an extra precaution for if the boat is sitting unused for a while.

[Terra Nova]

Originally Posted by GrahamHO

...you need a high loop in the exhaust pipe before the exit...

From the water lift muffler the exhaust should rise as directly as possible to the high loop, and then continually downward to the outlet.

[Celestialsailor]

I feel I need to address the hurt feelings and insult issue. Ultimately we are responsible for our choice in life and with our property. Personally, I run into it all the time. Examples are:1) Having a friend move my boat from the slip to the marina hoist, while I'm at work. The starter stuck that I had problems with it prior. I forgot to tell my friend this information. I assumed if it stuck they could discern the sound of a stuck starter from that of the diesel engine. They couldn't or didn't. Price: New starter. I blamed them in my mind for about 10 minutes until I realized it was me that set that scenario up. So I was wrong, not them.
2) I had head work done on the head of a diesel. Got it back without the valve stem caps. I swore it was their fault (again in my mind) until I looked in every box in my shop and found them under a flap of a box. This, when the guy doing the valves distinctly told me not to disassemble the head myself. But I did, thinking I could save a few bucks.
One thing I know...if I touch it, I have a possible part in it's demise. I've learned not to go on the Internet with my blame thrower pointing fingers. If I was having someone delivering a boat for me, I would do what I could to minimize problems. It's not the delivery persons responsibility to make sure the engine installer properly tested the engine for any water locks, thermostat or any related malady that could occur. Sure, it would be nice if the person could keep and eye on things but he is part of the human condition and with that we get what we get.
One thing not mentioned...that is...almost every engine panel I know has a high temp alarm. That was never mentioned going off. Why is that? Maybe the installer (new owner) neglected to hook it up. Maybe it was faulty and untested. Again, the responsibility of the owner. If I'm being labeled here as "having a bad day"...forget it. I'm not. Over time and being self sufficient, I tire of people blaming and then asking for help. That's a victims role not a self sufficient sailor. Sorry for the rant. Just wanted to clear the air on this one.

[Terra Nova]

Cs--good post.

[model 10]

Yes and it relates to always blaming the mechanic right away, too.

[GrahamHO]

Originally Posted by Terra Nova

From the water lift muffler the exhaust should rise as directly as possible to the high loop, and then continually downward to the outlet.

Exactly, and the loop should be in line with the boat and not off to one side assuming a transom exit. If it loops to one side and you are motor-sailing, water can collect in the loop if you are heeled that way. Then you shut down the motor and tack, and the water in the loop is now on the high side and can cascade back into the engine.
You need to work out all the possibilities for your own boat. A side exit is different again.

[GrahamHO]

Celestialsailor we all learn by mistakes and we have all made them.
It can be a good 💡 idea if you are going to disassemble anything new, to take some cellphone photos of the different stages to refer to on reassembly.

It's not a bad principle to do things yourself and get a specialist to do what you can't. I do that all the time and save lots of money.
Right now I'm finishing making a short prod for an asymmetric gennaker.
I cut all the SS components and took them to a welder to weld. He knows I wont blame him if I get it wrong.

[jimbunyard]

Originally Posted by jonahmcg

So here's the story, Bought a sailboat this summer, guy delivering it didn't check the cooling water, blew a head gasket on the way up. Got the head skimmer, put a new gasket in, reconnecting everything. Ran it for fifteen minutes, changed the oil. Seemed to run fine, Tried to start it again, a loud banging was happened every two or three seconds. Took the rocker cover off and found 2 bend pushrods and two of the mounts for the rocker arm shaft have split in two.

any ideas on why/how this would happened.

Sounds to me like a basic synopsis, no blame inferred. When I get on a boat I'm unfamiliar with, I don't leave until I'm confident in its' ability. The captain is responsible for the boat, the owner is responsible for the bills for running the boat.

Originally Posted by jonahmcg

i didn't do any valve adjustment.

Im at the point in the process now where i've ordered new parts and am going to take the head back off, check the piston clearances, and put it back together. still havent diagnosed why it happened though so a little worried i might just happen all over again.

Originally Posted by jonahmcg

is this something that could have happened if someone tried to start the motor too long with the seacock open, and the water from the exhaust backed into the engine?

Originally Posted by Celestialsailor

That's exactly what happened. You didn't adjust to make up the difference the head lost. BTW nice job blaming the chap that didn't check the cooling system...you didn't? Why not?

Celestial Sailor, Good job, god. Wish I had your all-knowing prescience.

Originally Posted by jonahmcg

hey guys, i did adjust the tappets of course. but thanks for the insults. i didn't check the cooling because i wasn't on the boat. he was delivering it. so sort of hard to get into the engine and check things out. ya know.

Originally Posted by Celestialsailor

I feel I need to address the hurt feelings and insult issue. Ultimately we are responsible for our choice in life and with our property. Personally, I run into it all the time. Examples are:1) Having a friend move my boat from the slip to the marina hoist, while I'm at work. The starter stuck that I had problems with it prior. I forgot to tell my friend this information. I assumed if it stuck they could discern the sound of a stuck starter from that of the diesel engine. They couldn't or didn't. Price: New starter. I blamed them in my mind for about 10 minutes until I realized it was me that set that scenario up. So I was wrong, not them.
2) I had head work done on the head of a diesel. Got it back without the valve stem caps. I swore it was their fault (again in my mind) until I looked in every box in my shop and found them under a flap of a box. This, when the guy doing the valves distinctly told me not to disassemble the head myself. But I did, thinking I could save a few bucks.
One thing I know...if I touch it, I have a possible part in it's demise. I've learned not to go on the Internet with my blame thrower pointing fingers.(then why are you doing it?) If I was having someone delivering a boat for me, I would do what I could to minimize problems. It's not the delivery persons responsibility to make sure the engine installer properly tested the engine for any water locks, thermostat or any related malady that could occur. Sure, it would be nice if the person could keep and eye on things but he is part of the human condition and with that we get what we get.
One thing not mentioned...that is...almost every engine panel I know has a high temp alarm. That was never mentioned going off. Why is that? Maybe the installer (new owner) neglected to hook it up. Maybe it was faulty and untested. Again, the responsibility of the owner. If I'm being labeled here as "having a bad day"...forget it. I'm not. Over time and being self sufficient, I tire of people blaming and then asking for help. That's a victims role not a self sufficient sailor. Sorry for the rant. Just wanted to clear the air on this one.

Feeling a little guilty? Good. Rant all you want. The introductory post states very clearly that the OP bought a boat and arranged for someone to deliver it to him. Since we can't know if the owner told the captain that the boat was competent to make the trip, the worst case is to assume that he didn't. If that is so (and actually, even if he did say it was competent), the responsibility is on the skipper to make sure that the boat could survive the trip, if only in the interest of self-preservation. If he didn't, and the worst thing that happened is he burned up the engine, he should consider himself lucky, and, as appears to be the case, hope that the owner doesn't hold him responsible in some way. (Assume I'll get some flack on that one though...)

Of course, it seems a moot point, since it doesn't appear he's coming back. Again, good job, experts.

Originally Posted by GrahamHO

Celestialsailor we all learn by mistakes and we have all made them.
It can be a good �� idea if you are going to disassemble anything new, to take some cellphone photos of the different stages to refer to on reassembly.

It's not a bad principle to do things yourself and get a specialist to do what you can't. I do that all the time and save lots of money.
Right now I'm finishing making a short prod for an asymmetric gennaker.
I cut all the SS components and took them to a welder to weld. He knows I wont blame him if I get it wrong.

Always nice to hear some calm good sense.

[Celestialsailor]

Originally Posted by jimbunyard

Sounds to me like a basic synopsis, no blame inferred. When I get on a boat I'm unfamiliar with, I don't leave until I'm confident in its' ability. The captain is responsible for the boat, the owner is responsible for the bills for running the boat.







Celestial Sailor, Good job, god. Wish I had your all-knowing prescience.
Your little reverse psychology bs means nothing other than "yeah for our side". What you didn't attach speaks volumes as to trying to "win" your way to pointless position. The OP stated first he didn't adjust the valves then a few posts later...of course I adjusted the valves. So if your little sly stab of "Wish I had your all-knowing prescience", then I wish you had so some knowing prescience to put 2=2 together.





Feeling a little guilty? Good. Rant all you want. The introductory post states very clearly that the OP bought a boat and arranged for someone to deliver it to him. Since we can't know if the owner told the captain that the boat was competent to make the trip, the worst case is to assume that he didn't. If that is so (and actually, even if he did say it was competent), the responsibility is on the skipper to make sure that the boat could survive the trip, if only in the interest of self-preservation. If he didn't, and the worst thing that happened is he burned up the engine, he should consider himself lucky, and, as appears to be the case, hope that the owner doesn't hold him responsible in some way. (Assume I'll get some flack on that one though...)
Why would I feel guilty about pulling someones covers while trying to blame someone for his inability to make sure all was in order. I make the point again. All good installations have temp. alarms. You conveniently avoided that little detail.

Of course, it seems a moot point, since it doesn't appear he's coming back. Again, good job, experts.
...and again...yeah for our side.





Always nice to hear some calm good sense.

My so called rant was to bring awareness to the op of taking responsibility for his boat. Not merely responsible for the bills of his vessel. One of the more stupid statements you've come up with.

[jimbunyard]

Originally Posted by Celestialsailor

My so called rant was to bring awareness to the op of taking responsibility for his boat. Not merely responsible for the bills of his vessel. One of the more stupid statements you've come up with.

Always love being called stupid. (oh, and by the way you (f you remember) called it a rant...


Also, by the way, what exactly didn't I attach? If I were (as you so memorably put it) pulling out my blame throwers, I wouldn't be so coy as to leave that out...


And please, don't answer, or, if you do, don't expect a reply....

[HappyMdRSailor]

Seriously guys... Cut the crap...

None of this has anything to do with the OP's actual question...

"Why did this happen?"

I suggest that some of the replies could have been put in a more polite manner... And the heated debate was completely unnecessary...

The OP has 7 posts total, six here and one more OP that didn't even get one answer... If the goal was to chase of a new inexperienced vessel owner looking for help... I tend to think WE ALL just might have succeeded...

If the OP EVER comes back, our answers should be positive, direct and helpful...