Rebuild vs Repower

Ask for all bills and invoices and then have a mechanic check out the rebuild.

That is good advice.

You will also need to make sure it turns the same way as yours.

If it's a twin engine application I would absolutely rebuild yours. 6-71's came in several different HP applications and of course J+T's made the most power. So unless you know what this rebuild engine is, chances are it's not the same engine/hp. Also, how long ago was this rebuilt engine rebuilt, and who did the work. Detroit Diesel only offers a 6 month warranty on parts.........so if the engine you buy comes apart at 20 hours, your SOL.

In yachting those trying to save money always lose money. Those focusing on spending wisely always come ahead.

If you try and purchase a motor (used or new) from a major known motor manufacturer or dealer you will find they do not like to stock motors on the shelf and they are mostly built to order. This is because motors laying around can develop internal issues with corrosion or moisture and other problems. The reputable company's do not want to deal with those potetional hazards and sell those liabilities to there customers.

I would only buy that used motor from the man with the fleet if I was planning on rebuilding that motor and making sure it was suitable for the expense of installation. So if a motor needs to get rebuilt it might as well be yours that you already own. I very much agree with Capt J's statements.

Get three quotes and get'er done. And then invite me fishing

I was reading this thread and wanted to ask a question of all you 6-71TIB owners. Any of you familiar with Capitol Transmissions model 11-200? I am looking at purchasing a vessel with these and am quite concerned because parts are scarce as well as mechanics. I am looking into new transmissions, like ZF.

Any comments or thoughts are appreciated. What new transmissions would be best or has anyone every done this?

Thanks
Stuart

The only way to go with a full rebuild is from a large dealer that has the financial ability to stand behind the rebuild. A rebuilt engine can mean anything. My dad was owned boat yards forever and I spent more years than I care to remember following him around. None of that is really important but I have seen this situation end badly more times than I've seen the owner save money. Pulling the engine is no big deal. Just take the time to put paneling or heavy cardboard on the floor and walls. The yard should have a stinger bar made up and it takes about an hour to drop the straps on the travel lift and switch over. A 671 is relatively narrow, you may have to remove the exhaust to get it through the door. Only way to know is take a tape measure. Not to be rude but I've never seen a charter company with the funds to keep spare rebuilds that were anything I'd be interested in using. I'm sure there are exceptions.

shop around and get estimates and recommendations.

Those are great engines that can last a long long time if well cared for and they dont require a someone with a PHD or computer science and engineering degree to change the oil.

be advided that an in-frame rebuild can mean everything from changing one or two kits to the full monte:
kits, rebuilt heads, mic-ed rolled in bearings, turbo, blower, injectors, cooling system.....

get written and signed estimates of work to be performed and parts to be used replaced or rebuilt.

Getting the engine out of your boat to overhaul it on the stand isn't as bad as it seems. If you could find other owners who have had overhauls from the facility you intend to use, that would be very helpful.

I had an in frame overhaul done in Orange Beach and it failed immediately. $65k down the tube. Suing those crooks for what it's worth.

Ultimately, the pro who got me going by overhauling the engine again was John Carey from Carey's Diesel in Leipsic DE. He was excellent. That is not in your area but I'm sharing my experience to be helpful.

The Guarantee from most might as well be written on a piece of toilet paper.

Safest bet is get one of the original mfr's dealers to do the rebuild.

How many hours are on the engine? I lost the water on a 6-71 while fishing and when I checked my gauges it was pegged. It cracked the head and cooked some of the seals between the head and the block. We put a new head on and it has run fine for years. I personally wouldn't try to rebuild it in the boat. A mechanic with a helper should be able to get that engine out in 4-5 hours. A shop that can run it on a dyno or a test stand at the very least would be desirable.

Yes ... my second time around, the engine was removed and built on the stand in the shop. It's just so much nicer that way. The completed engine went right in through the back window.

I agree that it is more preferable to rebuild the engine outside of the boat. It's easier to get all of your torque specs perfect on rod bolts and main bolts, easier to assure all of the bearings are in place, and just a lot better working conditions to be meticulous. But, It adds a lot of labor to remove and re-install the engine (if it's even possible without cutting a big hole in some boats), versus doing an in-frame rebuild. If the engine got very hot, chances are the bores will need to be line bored and are probably out of round and egg shaped and the deck might have to be milled. A lot of DD bores weren't exactly true to start with. I had a guy that owned a machine shop that used to build race engines, he had a dedicated room that was a/c'ed and totally enclosed from the rest of the shop, just for building engines and he kept the floors/walls/work benches meticulously clean and would basically lock the sliding glass door, turn on the radio, and work without any interruptions.

That being said, I have seen LOTS of engines rebuilt in place and have then lived a very successful life without any issues. OTO, I've seen 1 last 4 months and under 150 hours, due to a (reliabilt) bad injector that washed a liner out......and 4 other injectors on their way out. This was a few years back and DD tried their best not to cover it under warranty and only covered most of the expense. Even though it was done by a DD dealer and within 6 months.

Pulling the engine to rebuild it is adding more complexity to the job than it needs. Pulling the salon apart and removing the salon back window to rebuild instead of in frame is a decision you'll have to make, I'd have it rebuilt as she sits unless you get several other opinions from shops which say it's better to pull the engine. Some shops will have the experience to pull and some will not. It's not rocket science to rebuild a 6-71 in frame and since you really do not have the full details about the other already rebuilt engine I'd stick with rebuilding yours.