How can I tell if an engine is frozen or worth trying salvage?

[ConceptKreator]

So,a bit of background. I recently bought a sailboat and she came with a Volvo Penta MD7A. The guy I get her from said he never got her working, though also never really tried. Currently the boat has no battery installed, but all the wiring is in place and looks pretty fresh. The manual crank arm was found during in cockpit hatch and was super rusted. I got it all completely cleaned up and repainted only to discover that a part of the crank seems to have snapped off in the engine. There is some rust visible on the outside of the engine, but nothing horrible. I've tried moving the large flywheel by hand, and try as I might, I couldn't even get it budge. As I said there is not battery installed at present, I DO NOT have a key (though working around that is simple enough) and any fuel left in the tank is likely to be quite old. Given all that, and the crank arm being snapped off and covered in rust, as well as some surface rust on the exterior of the engine itself... My question is this:

is there anyway to know if the engine is frozen or is in any way worth trying to salvage?

 

[Richard19068]

is there anyway to know if the engine is frozen...

I don't know the engine but can you put a wrench on the crankshaft pulley nut and try to turn it?

 

[JamesG161]

Open each injector and pour in some Brake fluid to each Cylinder.

Wait a week to see if you can hand crank it.

You might repeat that 2 times before giving up.
Jim...

 

[DeniseO30]

The MD 7A is a pretty old engine I don't know if you can get parts for it but yes, taking the injectors out getting brake fluid or brake fluid and acetone or other rust breaking type fluids would be a good idea you can get what it's called a strap wrench on the flywheel or workout some kind of Leverage because you don't want to strip or break the nut that holds the flywheel i try for just a rocking motion rather than trying to rotate right away try it every few days keep rocking it back and forth 1/8" or so, use a marker on the flywheel and a spot near it so you can tell if it moved, if it breaks loose, great, if it probably never will, then you can decide to use more brute strength because you can cut your losses on something so old.

 

[DeniseO30]

May be worth reading https://boatdiesel.com/Forums/Search/Volvo-MD7-MD11-MD17-Forum-piston-ring-stuck.cfm

 

[ConceptKreator]

Thanks all. I'm thinking it may be a lost cause. The flywheel doesn't move AT ALL, not even the finest bit, even with leverage. I think I may rely on the outboard for now and look for a rebuilt Yammar or similar to reposer in the near future.

 

[JamesG161]

I'm thinking it may be a lost cause

"Don't give up the ship!".... John Paul Jones

There is a rebuild Kit from Perkins Elmer aka Volva Penta, if you are interested.

Jim...

 

[Benny17441]

You could always start disassembling it to determine the cause and at the same time clean up the space for when you might decide to repower.

 

[ConceptKreator]

Ya I think at this point I'm at the "I might as wen test it apart and see what I can see" stage... who knows... maybe she's salvageable.

 

[jssailem]

When faced with a similar challenge, I chose to remove the engine and have a mechanic rebuild the engine. We are in the middle of the process so can noot tell you if it was a good solution. We discovered 2 of the 4 cylinders had the pistons rusted in place. The mechanic was able to get the pistons free once he had the block in his shop.
See the A story of the engine that could.... Then didn't thread.

 

[kloudie1]

With it stuck so soundly, I might just pull the cylinder head then you can see pretty quickly if it can be revived. I am not familiar with that engine but it looks like it does not have cylinder sleeves. Pulling the head would quickly tell you if you have big pits in the bores, have a significant wear ridge.. and it would be a lot easier to work the pistons free. If it loolks like it can be revived, then do a valve re-seat and put it back together. If reclaiming, take the injectors to a shop for a rebuild/test..

 

[ConceptKreator]

Excellence ad ice. Thank you.