[Sur la Mer]

Hi all...I'm new here. Long story with important questions follows:

I recently bought a 1975 Santana 30 with I believe the original engine. Prior owner had her for 30 years and had the engine professionally rebuilt but I'm not sure exactly how many years or hours ago. Its not been used much at all the past few years, but I need to deliver the boat in the next couple of weeks for winter storage and that will include transiting the East River in NYC...so a healthy motor is required.

I'm not familiar with marine diesels (yet) so each use I've verified cooling water flow as shown by the PO. No functional gauges - tach, oil pressure and temp are all inoperable. Two engine uses ago I didn't see flow so I inspected the impeller and it looked good. Opened sea clock and water flowed well. Reassembled and observed water coming out with exhaust as PO advised was normal. As we were returning to mooring under power I noticed white smoke/steam building out exhaust...then motor rpm slowed by itself. I put it in neutral and the rpm came back up. Since we were close to the mooring and in a tight spot, I put it back in gear to get to the mooring. Engine slowed, then stalled and won't restart.

So far I have removed the thermostat (rusted mess), exhaust manifold (plugged with iron oxide and carbon) and the head (looks like it's a bit warped on the non - cam side and has been weeping seawater down the block for quite awhile). Pistons, valves and cylinders look great. No funny or bad noises. No water in oil and doesn't seem to be oil in the water.

Before pulling the head I could easily turn the flywheel through many revolutions by hand regardless of the decompression lever position. This scared me into pulling the head but there's nothing obviously wrong so far...????

Money and time are serious hurdles at the moment (but I know I'm not the only one in that boat :-D)

Thoughts????

Thanks in advance,

-Keith

 

[Minnewaska]

Not sure anyone can give too specific thought. Here are some big picture thoughts.

Rebuilds have zero standards, so who knows what was done, let alone when. It's useless.

White smoke is water, often vaporized by overheating. Overheating could warp your head, which will need to be machined. The water dripping down the case, could also be dripping inside the oil pathways, which is really bad.

Clearly you need a new exhaust elbow and/or heat exchanger, wasn't sure which you meant. Both probably need cleaning at least.

If you could easily pull it through the compression cycle, I would guess there is something wrong with the valves. Did you hear any hissing? Like air leaking?

Your prob does not seem very compatible with a tight budget.

 

[RichH]

Although it may not be the cause ... that you mentioned a fouled exhaust manifold ... so, include in your check: for a stuck exhaust valve due to a pin hole leak (between the cooling side and the gas side) in that manifold. If there is a pin hole leak in the exhaust manifold and water is now (or has been) 'back-flowing' into a cylinder it will surely 'rust' the valve stem on an exhaust valve and possibly cause it to 'stick' in the open position. You can check for a stuck valve stem by simply removing the valve cover, hand cranking the engine while watching for movement of the valve stems and rocker arms.
If a stuck valve stem, there are many ways to get it free again and without a 'rip-down' (penetrating oil on the sticking stem, etc.)

If an exhaust valve stem is stuck or not closing correctly, you will get 'white' exhaust due to the unburned fuel due to the insufficient or NO compression due the valve not closing completely/correctly or not at all.

If the manifold has developed 'slab rust' (BIG flakes of rust breaking loose from the manifold internals and which block the manifold water outlet, you can easily have cooling issues. Such rust-slabs usually will fall back to the bottom of the water chamber of the manifold when the flow is stopped. This may not be the cause of non-running engine, but may be the cause that initiated that failure - back flow of water into a cylinder. The way to quick check for internal leaks on an exhaust manifold is to attach a pressure water source to the inlet nipple, block the exit nipple, apply pressure, and either watch for water from 'gas side' or with a valve at the inlet water side close it, and see if the pressure applied 'holds constant'.

Also be aware that during a high humidity day during cool fall/autumn weather, that water vapor can condense into 'visible water aerosols' AT the outlet/overboard exhaust port of the boat ... the hotter the exhaust water the greater the 'white cloud' effect.

Most of all, do your checks and analysis for the problem in an ordered and logical progression - simple things which dont require 'disassembly' --- first!

From your quite brief description, I would be inclined towards the following:

1. blown head gasket or stuck exhaust valve, etc. (compression)
if blown head gasket 'between cylinders' and also involving the cooling passages to the head, etc. would include 'white' exhaust (steam).
2. fuel system problem (a routine standard-practice 'usually high probability' with diesels)
3. Blocked fuel injection elbow to the water lift muffler (but wouldnt yield low compression, just high 'back pressure' to ALL cylinders).
4. cracked engine block, or cracked or warped cylinder head.

As stated above ... with marine diesels, always check for blockage, etc. in the fuel delivery system - FIRST.

hope this helps. Good luck.

 

[miatapaul]

If you have the head off already take it to a machine shop, does not have to be marine, but must have experience with small diesels. Ask them to do a basic check to see if it has a problem and if so can it be salvaged. Nice thing about a non marine machine shop is they do not make anything by you getting a new motor, so they are more likely to help. Marine shops these days seem only interested in putting in new motors, at the tune of likely 4 or 5 times what you paid for the boat. You may not be able to see cracks in the head without dye. They may be able to plane the head if it is warped. If it is fine, then it is the block giving you issues. The whole manifold and exhaust elbow are likely suspect and are expensive. Best route may be to have a machine shop make one up for you, unless you are a good welder. I think at this point your best option is likely to look for a yard on the current side of Hells Gate as I would not want to go through it with anything but a known good motor. If you have tow boat/seatow unlimited you might see if they can get the boat to it's new home. Are you going to LIS or trying to get to the Hudson/NJ?

Keep in mind that parts for a 40 year old diesel will often not be easy to get, and expensive especially a Volvo. But most may be available with quite a bit of searching and ingenuity.

 

[capta]

I think those above have shown you that your "healthy motor is required" probably won't happen before your winter haul out. You might want to check out Sea Tow or BoatUS to get you to the yard. Keep in mind that a free or cheap tow might very well cost you your boat, whereas the professionals can get your boat where it needs to go with a minimum of risk. Good luck.

 

[miatapaul]

I think those above have shown you that your "healthy motor is required" probably won't happen before your winter haul out. You might want to check out Sea Tow or BoatUS to get you to the yard. Keep in mind that a free or cheap tow might very well cost you your boat, whereas the professionals can get your boat where it needs to go with a minimum of risk. Good luck.

Yea, it might be cheaper to find a local yard to keep it in for this winter while he gets the motor straightened out. That is why I was wondering which way he was going, as he might get some good referrals.

 

[Sur la Mer]

Thank you all for the suggestions. Today I cleaned and inspected the parts I had already taken off Friday (before posting):

-Intake mesh 'filter' and breather filter - very oily.
-Exhaust manifold - corrosion, deposits and rust chunks in water passages as expected. Minor carbon deposits. Carefully opened clogged water passages with Dremel then blew them out with my power washer and compressed air.
-Head - valves move fine and are all closed. Lifters and rockers look fine. Head is surprisingly flat against steel straightedge (couldn't get feeler gauge underneath). The three external head studs had seriously frozen nuts however so the studs unscrewed rather than the nuts. I heated and removed the nuts thinking perhaps they hadn't allowed that side of the head to seat quite enough.
-exhaust elbow - no evidence of blockage.
-thermostat - garbage.
-gaskets - Head and exhaust gaskets showed no obvious signs of failure.

I've started to wonder about sticking rings as a cause for the compression loss since the motor has just been idled periodically for a few seasons but I will do a proper pressure check and fuel system check upon reassembly.

MINNEWASKA - I listened closely but did not hear (or feel) any hissing while rotating the flywheel.

RichH - the block didn't have obvious internal rust but I will try your water pressure test after reassembly.

MiataPaul - I'm going from Bridgeport CT to my new club on the Hudson River. I have unlimited SeaTow so may sail the boat to City Island then have SeaTow take it the rest of the way. In the interest of yankee ingenuity/wasting time I'll try putting the head back on without machining since it looks visually good...but regardless of whether it runs again this year or not will get it to an automotive machine shop for imspection. The points about getting it professionally towed even if it does restart are duly noted...hate the idea of my first transit to be on a tow line but GREATLY prefer that to having my first transit end at the bottom of the Gate!!

 

[Thai]

I have a md6a.
I pulled the valve cover to check valves
The air filter is full of oil . And smoke from the head when running ?
Checked the injectors I crack one and the motor wants to die good right , the other one will not do and thing
Assuming I have a dead cyl I hear hissing or air leak when I had crank it over but all valves are moveing, maybe not sitting correctly ? Could it be a manafold problem
Maybe a head gasket
White smoke ! Fuel smell and shean on water
Unburnt fuel
A over heating issue acured prior
And I checked no thermostat , wtf
That's not right
It is in a islander 32. I think the motor is to small for her!
Any and all comment would help much
Thanks!