Crank Questions

[gottatanfl]

We recently aquired a 38 Hatteras, the engine blocks are in the boat the rest is disassembled in boxes. Prior owner started a rebuild and just left it.

671 Detroit, Question is the crank shaft has surface rust, can it be saved without pulling it from the boat?

 

[thoward]

Short answer is no....Why would you not pull it?

 

[gottatanfl]

the mechanic at the marina claims it can be saved and is much easier to rebuild from there than pulling it out.

they do not have the set-up to pull the engines we would have to have to boat towed about 40 miles away

 

[thoward]

Honestly, the engine has been sitting and you do not have a good history of its issues. I would have the crank pulled and check the journals properly. It is much more expensive to find out after the fact you had a problem!

 

[Boatsb]

First can the engines be rebuilt outside the boat? If so that is the best way to go. A good shop has all the tools and machines and is a controlled clean environment. If that is not an option than anything that can be removed should be brought out to a shop and checked or cleaned up. Rods may need resizing. Cranks may get polished. Anything like that will add to the reliability of the rebuild.

I had a crank cut for a V6 gas engine a wile ago for under $150.00 Its not worth cutting corners.

 

[captddis]

Depends on the rust, if it is light surface rust and a couple swipes with crocus cloth cleans it up fine. Anything more and it should come out.

 

[gottatanfl]

Had another Mechanic take a look this weekend, he says looks like we are starting from scratch.
New engines....Electrical...AC's, it all needs replaced.

We kinda fiqured that would be the answer. What's the best way to remove and replace these 671's? Companion way looks to small, windows maybe or cut a hole in the flybridge floor and take out that way.

 

[Genesis]

Cut the bulkhead at the rear of the ER and stick a stinger through the hole.

Are you sure they won't come out the door if you remove the door and accessories? I'm assuming this is a 38SF. On Gigabite my measurements said my 6V92s would come out that way if I removed the accessories and the door itself.

 

[Will]

Who ever is doing the work usually has experience with removing engines. With the head, blower, exhaust manifold, flywheel, bell housing and fwd end gears and plates removed, the block is much smaller than you might think. The block, crank, liners, pistons, cam and balance shafts can be done at the shop then reinstalled as a unit. The head, blower, etc. can be done in the shop too then attached to the block in the boat.

Everything is heavy and it's not easy. But it's frequently done that way. Cutting holes in the boat is extreme and should be considered as a last resort.

Will

 

[UNIQUE_NAME]

went thru this 2 years ago. no natural opening (window/door) is large enough because i wanted to assemble EVERYTHING and run them before i installed. much to my dismay, hatteras suggested the sawsall to the flying bridge floor route. as it turns out, this is relatively non invasive. the rug on the flying bridge covers all the exterior destruction, so true finish work isn't required. the inside headliner comes down and is re-installed relatively easy.
i seem to remember only having to splice 1 wire, all the rest under the headliner could just be moved. my headliner was tacked to the aft side of the wood supports in the salon, so i removed from the cabin entrance moving forward. hope this helps.

jim

 

[campbellde]

Looks like you've got the same boat as me, the double cabin motoryacht. I have the same setup as you with the 6-71's. I've often wondered the same thing about engine removal. I really don't think you can get them out.


The door is only about 21" wide if I remember correctly. The aft bulkhead is really short because of the rear cabin/ flybridge setup on this boat. I don't even think you could cut it to get the blocks out through this way.


I've wondered if removing the side windows would give you enough room to remove the stripped down blocks. Short of that you may have to cut a hole in the flybridge to get them out.


Although not the best option, surely there is some who can do a good rebuild with the blocks in the boat, if they are not too far gone.


Please keep us posted. Mine run great now, but I may be in the same situation as you one day. I'm planning changing my generator in the near future. It appears that it will come out of the door in pieces.


Dan

 

[thoward]

Had another Mechanic take a look this weekend, he says looks like we are starting from scratch.
New engines....Electrical...AC's, it all needs replaced.
QUOTE]


If this is the case I would think long and hard about spending a dime! I redid a 43'er and I will tell you you are much better to buy one that does not need that much work even if you got it free! You will have a ton of money in the boat and everything will have done to ABYC standards for it to pass a survey which you will need to get insurance. Good luck!

 

[Trojan]

The block must be really bad before you can't rebuild DD in the boat. Maybe the mechanics you had were not DD MARINE mechanics. Most mechanics don't have the structural equipment to do the in boat rebuilds.

BILL

 

[gottatanfl]

Quick update:

My husband and son worked on the boat this weekend and have all the lights, water and pumps working every thing in the galley is working but the stove top.
They replaced a few bilge pumps and the rest was switches needing replaced and some blown fuses.

Heads work but we are going to replace both the toilets as they just look bad.

The AC units we have not tried as they look like the have seen better days.

Still awaiting a couple more opinions on the blocks before we make big decissions there.

The wood work was mostly redone prior to our purchase, a few areas could use restored but it looks good overall. I will take a few pics of the blocks and post for opinions. They look REALLY rusted to me. BUT hey I'm just the wife.

 

[gottatanfl]

By the way does anyone know of a good diesel mechanic in North Central Florida????

 

[gottatanfl]

Attached picture of block

 

[Boss Lady]

Look up iron oxide, an excellent abrasive! Everything needs to get torn down and cleaned, surface rust on the cam lobes must be removed, the cylinders will get replaced during the rebuild. If your cam lobes are pitted you will be replacing those too.

 

[krush]

Hit those parts with some steel wool. If the rust comes right off, you're good. You just need to get in there and clean it up some. As long as it's just a thin film of rust and NO pitting, you may be ok.

 

[gottatanfl]

Can the crank be turned if we lift the engine, leaving it in the boat just lifting it to get the crank out then can a machine shop turn these?

 

[Genesis]

If you can get it out a good shop can clean it up.

Whether the damage is severe enough to condemn it is an open question and whether you want to do that with a high-performance engine is another question......

That engine needs to be torn completely down - the camshaft may look like that crank!