Challenge: Engine Diagnosis

[Celestialsailor]

I thought this would be a fun post and brain teaser. So here is the scenario...


I bought this boat recently for a very attractive price. It originally came from an Estate sale 2 years ago and was purchased by an individual who lived too far away and decided to sell it...hence my involvement.
Reportedly, the engine was seized. It's a Westerbeke W46 which is Mitsubishi based if I'm not mistaken. The bottom zincs had been long gone and there was damage to the thru-hulls. In another post under maintenance, I show the pictures. It is dry docked now and the last few weeks I have been tinkering around with some of the issues of the boat. One was no steering. It was hydraulic and out of fluid. I filled it and voila...steering. I looked for leaks and never found any...strange! Later while buying parts at a local chandlery, I happened upon a gentleman who knew the boat and the owner who had passed away. He told me that there was a bit of a feud between the diseaseds' friends who wanted the boat. Apparently they all parted with ill feelings. Also I learned they were trying to buy the boat from the executor for really cheap. This got me thinking...
There was no hydraulic oil in the bilge and no leaks...hmmm. Sure would be easy to buy a boat for cheap if the steering didn't work or a "seized engine"! So I charged a battery, replaced electrical cables and tried to turn the engine over. Sure enough....clunk...won't budge. So I got a socket for the crank nut and lo and behold it would rotate almost 180 degrees backwards where it clunked again and back forward with a clunk once more. I pulled the valve cover and the valve train looks good and moves as much as it should in 180 degrees. The engine is spotless as it should be with 450 hours on it. I feel there is a chance it could have been tampered with to look like a seized engine but who knows...maybe something internally let go.
It is a center cockpit boat and the sole hinges up, making engine removal a breeze. However, working on the sides or pan would take Houdini to dismantle anything. So I will pull the engine and take it to my Machine shop at home (lucky dog uh?). First I will remove the transmission to see if the flywheel is doing anything, then anything which drives off the engine.
So here we are looking for your speculations. Let’s have fun with this one...

[Kalinka1]

A couple of things come to mind. How long is your wrench handle and is it hitting the side of the boat preventing 360* transmission locked? If it goes 180* in both directions that adds up to 360* so really not seized. An interesting question will be interesting to see where this goes and what the final outcome will be.

[captain465]

I would venture to say that one of the rods/rod bearings/rod caps has been damaged/is loose/is bent, or the crank shaft has broken. It is vertually as bad as being seized if the access is as you say. Pull engine and drop pan to examine entire bottom end.

[Cheechako]

My maintenance guys used to say: "If it aint leakin, it aint hydraulic" It is strange that you cant see even a drip anywhere though.. you may be on the right track. Have you considerd that the starter gear might not be disengaged from the flywheel?

[James S]

Hmmm, well that is interesting.
I'm no motor head, so cant be of much help with the nuts and bolts of the thing...but I can bump the thread!

[brutb]

Does it look like someone pulled one of the injectors? May have had bolt inserted, I would look for marred paint on the injectors to see if one had been removed. The locked starter is also a good bet. Nice quality boat...

[Celestialsailor]

Originally Posted by Kalinka1

A couple of things come to mind. How long is your wrench handle and is it hitting the side of the boat preventing 360* transmission locked? If it goes 180* in both directions that adds up to 360* so really not seized. An interesting question will be interesting to see where this goes and what the final outcome will be.

Nope...The nut has 6 flats (hex nut). It will rotate 3 flats (or 180). Transmission in neutral...Good guess but try again...

[Celestialsailor]

Originally Posted by brutb

Does it look like someone pulled one of the injectors? May have had bolt inserted, I would look for marred paint on the injectors to see if one had been removed. The locked starter is also a good bet. Nice quality boat...

In the manual the injector is in a cavity, then a small channel where it looks like a metal object would have difficulty getting to the pistola. But remember...it's 180*...therefore the pistola is clunking at TDC and BDC...try again...

[Celestialsailor]

Originally Posted by Cheechako

My maintenance guys used to say: "If it aint leakin, it aint hydraulic" It is strange that you cant see even a drip anywhere though.. you may be on the right track. Have you considerd that the starter gear might not be disengaged from the flywheel?

I can here it engage and disengage...Remember 180 on the flywheel would be about 50 rotations on the starter

[PaulM]

Does the "clunk" sound internal or external. I would start by looking hard at the flywheel and crank pulley to see if there was an "extra" bolt that was a bit too long. I'm not very familar with exactly how injector pumps are powered, but it seems that the IP would be worth looking at.

Paul

[perchance]

Valve timing out of whack causing a piston to contact an open valve?

[perchance]

If you plan on pulling the engine anyway you could pull the head in situ and bar it over. That would eliminate a valve issue.

[Celestialsailor]

Paul M- The clunk is more of a feel on the wrench but yes...kind of internal
Perchance- The valve timing is controlled by gears. In the manual, the crank gear is 1/2 the size of the cam gear...2:1. It would be tough to envision it slipping but who knows...good guess.
"If you plan on pulling the engine anyway you could pull the head in situ and bar it over. That would eliminate a valve issue".
...or remove the injectors and loosen all the pushrod adjustment and rotate. Believe it or not...the head gasket is $200.

[Jim Cate]

Might check to see if one valve adjuster was screwed way down... valve never closes, hits piston as it nears TDC no matter which way you rotate the crank. Much easier for the dirty bastard to fix after he buys the disabled boat.

Cheers,

Jim

[DeepFrz]

It would have to be at least two valves screwed down in two cylinders to make it stop after 180 deg. rotation. For someone to take the valve cover off and screw down two valves would take quite a bit of time and effort.

Camshaft is 1:2 rotation with the crank so doubtful it has anything to do with the cam.

Can't really say why but I have a hunch its in the transmission.

See if you can locate the area where the clunk is coming from. A stethoscope would help you with that.