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Discussion Starter · #1 ·
I have a Westebeke 33 that has a cracked piston. On inspection by mechanic I have been told that because the cylinder walls are slightly pitted (hard to see but cylinder walls are not smooth and shinny) that the engine would need to be rebuilt. This would include reboring the cylinder walls.

The rub is that mechanic thinks this is not possible since cylinder wall tolerences on W 33 are too little to allow reboring. I need to verify that this information sounds reasonable because I do not have a clue and the only option is to buy a new engine, which is what the mechanic wants to do.

Opinions and comments please.
 

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You can discuss your engine with the support staff at Hansen Marine Hansen Marine Marblehead MA. They know their Westerbekes. They would charge about $6,500 to rebuild that engine if you ship it to them. My advice would be to consider a Yanmar.
 

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I went to a web site for westerbekes engine parts and they showed pistons in two larger piston sizes than stock.:)

If the walls are so thin why then does the manufacture offer over size pistons and rings??:eek:

Makes ya wanna say---HUMMMM:rolleyes:
 

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What you should do is price re-building the Westerbreke and compare that with replacing it with a more reasonable cost engine, like a Beta Marine, Kubota-based one... if there isn't a big difference, it might make more sense to buy new than to rebuild. Westerbreke tends to have fairly expensive parts IIRC.
 

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For me, this comes down to usage pattern and access. You never just think of it as a rebuild or a new diesel, because a new diesel might need work on the stringers, new glassing, new alignment, new stern tube, new mounts, new wire runs, new hoses and so on.

Then you think: Am I going to feed this beautiful new engine from my nasty old tanks? So tear 'em out. New hoses, new tanks, new filters, new vents.

Then you think: My power band is different. Shouldn't I have a new prop? New shaft? PSS? Thrust bearing? Drive Saver? Insulated engine box? New venting and fans? Bigger alternator? Entire set of spares?

Before you know it, you've put 20 grand into some old boat that's going to look pretty silly with its oxidized gelcoat and wire halyards and ancient rebuilt head and poorly insulated icebox and...

...time to get a new boat?

Here's a pro-tip: Find out if the W-33 is in fact a "marinized" version of a Mitsubishi or Isuzu tractor diesel. My W-52 is the same engine as a Mazda R2 diesel as found in the B2200 series and Ford Ranger series of 1980s light pickups, for instance. Find rebuild kits for those engine (compare specs between your manual and the "other" diesels to confirm.

Then have an auto rebuilder do the job. Take a diesel course and do the basic disassembly yourself, but leave the injectors, pistons, cranks and bearings to the pros. Much cheaper, and the engine can go back into a cleaned up, repaired engine bay at a fraction of the cost. With the money you save, you can buy a new fuel system and maybe a folding prop!
 

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Val-

now you ruin all our fun with a sensible post.... meanie... :p
 

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Kerr :

A re-bore takes so very little material away, that I think your mechanic is telling wee stories. Classically, pistons are offered in oversizes and there will be a range available, typically in +0.25, +0.5, +1.00 mm on the standard diameter. You choose according to the amount of scoring on the cylinder walls, then look up the recommended piston-to-bore clearance, then you take your barrels to a machine shop, and they do it for you. It is not too expensive.... in 1997 it cost me about £20 per bore, and about £72 per piston (Mahle) and there were 3 of them.

Westerbeke will not make pistons, I understand. Pistons are made by others. Typically, if you turn the piston upside down and clean off the gum a bit you can see the part number on it and the manufacturer... Mahle is one of them I have seen.

Be careful, there may be a slim possibility that the motor might already have been re-bored, so you will have to measure the bores at present, then choose.

Could you send a wee picture of the piston and the bores? I was interested in what was meant by a "cracked" piston, and bores rarely score unless there is a lubrication failure, so it would be interesting to see them. Has the piston shed lumps of itself into the crankcase?

You might get away with just a single new standard piston (and no re-bore) if the scoring isn't too bad, which will be about $100 plus your gaskets, and for an older engine, it can run for years yet. As long as the bottom end is sound and you have not complained of excessive bottom end noise???, you will probably be OK.

I don't know your mechanic, but I have seen often in the past a doom-prophet promising to fix a motor at great expense when there isn't a lot wrong with it. Be careful.

Take some pictures for us. It would be interesting to see what this "pitting" looks like.

.
 

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I'm wondering what it is that made you call in a mechanic.

Did he look in the engine with a bore scope?
 

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Discussion Starter · #9 ·
thanks you all for your responses. The engine was removed from the boat, the head taken off and one piston was cracked completely across the top. The westerbeke 33 model has a history of cracked pistons, I guess it just finally caught up to me. Upon inspection, by eye, of the cylinder walls it was clear the walls were scratched and scarred, and some brown material that looked like rust, were in each cylinder.

I was told by mechanic that in his opinion the engine was shot and needed to be replaced. Again, according to him the tolerances of the engine made it difficult and unlikely to be successful. I have to trust what he tells me because I have not other way of knowing.

At this point we have identified a Westerbeke 44 to be the best replacement given dimensions, weight, power, etc. When I am done I will have spend the equililent of 33% of the boats value...not sure what else to say, or do, I am between the perverbial rock and a hard place. Again, thanks for your responese....Jim
 

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Kerri :

You must have more money than you have time.
What "tolerances" is he talking about? Does he mean that this motor cannot and could not ever be re-bored because the liners were too thin in the first place???
Maybe he is right, but could you find time to take a picture or two?

I am genuinely interested and want to learn too.
 

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thanks you all for your responses. The engine was removed from the boat, the head taken off and one piston was cracked completely across the top. The westerbeke 33 model has a history of cracked pistons, I guess it just finally caught up to me. Upon inspection, by eye, of the cylinder walls it was clear the walls were scratched and scarred, and some brown material that looked like rust, were in each cylinder.

I was told by mechanic that in his opinion the engine was shot and needed to be replaced. Again, according to him the tolerances of the engine made it difficult and unlikely to be successful. I have to trust what he tells me because I have not other way of knowing.

At this point we have identified a Westerbeke 44 to be the best replacement given dimensions, weight, power, etc. When I am done I will have spend the equililent of 33% of the boats value...not sure what else to say, or do, I am between the perverbial rock and a hard place. Again, thanks for your responese....Jim
If you get done all in for only 33%, you're doing pretty well...this is your chance to contribute to th eetensive lore that owning a boat is an expensive hobby...even ignoring the purchase price.

While the engine is out is the opportune time to pull and replace the fuel tank and the hot water tanks, two common problems on your boat, plus look closely at the radial drive and related gear, if you want a underdeck autopilot, put it in now. My bet is you'll break 50% before she gets wet again..
 

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I cannot believe that I could not rebuild any engine for for $500 a hole and make a good money doing it.

Why your mechanic wants to install a new engine---

engine list price $6,000
mechanic cost $4,800 list less 20%
profit for no work$1200 Didn't even get hands dirty

Still gets paid for r&r (Remove and replace)

And may even talk the owener into paying him to haul off old engine to a rebuilder for a core that the rebuilter will pay him (the mechanic) for.

The prices may be different but the results are the same.

I am flabergasted that in a world of Terabites, billions, and home computers that can run a small country that people are scared by .001 of and inch.. These are tollarances that machinests have been working with for over 100 years. just the ball bearings in your lawnmower have clearances to .0001.
 

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It is not really a tolerance issue, despite the claim. What the mechanic must be arguing is that there is not enough material in the cylinder liners to allow a re-bore. This is very questionable to me.

What the mechainc could be arguing is that the pitting is so deep that a re-bore to the max allowable would not reclaim the surfaces. If so, then drift in some new liners and use standard pistons.

It does not make sense, hence the wish to see some pictures.
 

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Rockter

That is what I think.

Scrap an engine just because it scored a cylinder wall??

Boreing and then installing a sleve and then boreing the new sleve is not something that is new for the automotive machinest.
 

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Most mechanics are not machinists, and most machinists are not mechanics- Have a machinist look at the engine and determine whether you have enough beef left in the cylinders to be able to trim the fat. a couple of minutes with a micrometer will tell the tale.
 

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Kerri :

Was the bottom end sound? Was the gearbox OK? Was it statrting OK before the engine failure? Were there many hours on it? Was it using oil before the failure?
 

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Ran across this thread on google, just figured I'd throw in my .02 from exp with the westerbeke 33. It should be rebuildable, we had ours rebuilt about 2 years ago, due to 2 cracked pistons. Almost no engine is un-rebuildable, the question is how much are you willing to spend to rebuild it. If yours has never been rebuilt, and it only cracked a piston and the crank/rods/etc are in good shape, and the cylinder isn't torn up (probably isn't), it shouldn't be too big of a deal to rebuild it at a reputable rebuilder who's capable of dealing with diesels. Cylinder overboring isn't a big deal as long as pistons are available and they are. The 33 tech manual lists .025, .050, and .075 overbore pistons. The greatest expense with rebuilding the 33 is that you generally have to get all the parts from westerbeke, which is very expensive. I would suggest taking the engine to an engine rebuilder and find out what they would want to replace, and what they'd charge. You should be able to get parts numbers and prices from your westerbeke dealer. From what I understand it's pretty much impossible to get a discount on parts.

The only other thing to be concerned with when rebuilding is if the cracked pistons are the only thing wrong with it. If they are, great, but if you have more serious issues (in particular with the injection pump, which as I recall wasn't rebuildable, or possibly was for $3000 or something ridiculous, we were going to replace the engine if the injection pump had gone bad).

The 33 is a mitsubishi built diesel, but we've never been able to track down what mitsubishi model it is. The only way we found it was mitsubishi was the new pistons from westerbeke have the mitsubishi logo stamped on the underside. There were no mitsu part numbers to be found anywhere. On the plus side, the new pistons were redesigned to improve combustion and made an incredible difference in starting the engine (although not having cracks in the pistons makes a big difference as well :) )
 

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like a Beta Marine, Kubota-based one...
the engine is based on the tractor engine not a marine engine.

might be the best option since you can go to the local tractor store and buy parts for a lot less than a marina would charge for the same part.
 

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"The 33 is a mitsubishi built diesel, but we've never been able to track down what mitsubishi model it is."
If you can find out how many cubic inches (or liters) the displacement is, you can probably pick it out from any good list of Mitsu's diesels, there can't be all that many in any given size.

The hard truth can be determined by using a caliper to find out the cylinder bore now, the cylinder wall thickness, and the depth of the pitting. As they said on the X-Files, "The truth is out there" and this should be a matter of numbers, not opinions.

OTOH if that engine is infamous for cracked cylinders--it might just be worth getting rid of bad news. And no rebuild is worth considering unless it comes with an outstanding warranty, which will include servicing on the boat--or the cost of pulling & hauling to the shop again.

"Westerbeke" is said to be an Elbonian word for "A red engine made by someone else for the lowest price."
 
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