Replacement engine for 2001 Captiva 272 with 454 Mercury engine

madst3215

My engine lost pressure in one of the cylinders so I have a decision to make, repair this OEM engine or replace it.  What is the largest HP engine that can fit inside the engine compartment or the best economic one that is lighter but around 300_350 HP?  I don't know how to size one or where to begin looking for an engine replacement. Any advice?

Cableguy Greg

Welcome aboard!!!

Since you already have a big block, I would think that the boat would be able to fit another big block. If it was me, I would try to repair the existing engine first. Pull the heads and see what is going on. Worst case, get a long block and swap all of the other parts over from the old engine.

nascarnuts27

I purchased a 282 Captiva w/8.1 Volvo Penta knowing the engine was frozen as a mechanics special. I have 2 full service auto repair shops so even if we had to pull the engine and put in a reman I would come out ok $$ wise doing all the labor myself with some help from my mechanics. For 3 weeks we worked off/on trying to unfreeze the motor with no luck plus it had a spark plug broken off flush with the block. Pulled it out with my son-in-law forklift and got a cylinder head off only to discover it was trashed  actually grit inside the cylinders due to exhaust manifolds/risers that had not been flushed out and were rusted so bad the engine sucked crap back in the cylinders. Yes is was a salt water boat.....I had already priced a reman from Tri State Engines at $4800 (long block) and was about ready to order it when I found a local engine rebuild shop that rebuilds these engines (8.1 GM) for a nationally know rental and does them weekly. They quoted me $2600-$3000 so I went with them. Was supposed to be 3 weeks but ended up taking almost 3 months! They determined my old engine was so bad they didn't even want fool with it. So they started with another block (they have them in stock), bored it .030, and rebuilt it with stock components. I considered putting it high performance (after research determined that 5-8 extra MPH and increased fuel consumption wasn't worth it) with more compression/bigger cam/ etc but decided to just go stock  despite the extra parts involved they still kept me at $3000. Finally the engine is in and it sounds great still having some teething problems getting it to idle right and take throttle properly but mechanically the engine is sound. I'll post when I get it broke in how it does. The GPS is stuck at 49.3 max speed from previous owner so I hope it will do 50. 

Willhound

A suggestion on repair or replace is tough without knowing other details like total hours, any other issues, have you been satisfied with the performance of the original block? Any other work that needs to be done?
Edit: Oh, and welcome to the forum, just noticed it was your first post!

reneechris14

Welcome to the RBOC forum I think a rebuild would be your best option. A 454 block is usually a strong platform. 

madst3215

Thanks for the inputs.  Some more info: it has about 300 hours and I have been very happy with motor but I didn't winterize it while I was out of town and the freeze plugs popped a couple times in the last few years.  We were starting initial assessment when the bolt were so rusted we couldn't remove them without several hours of work. Now i are quoted at a couple grand to just get the engine open to determine the problem.  So I have been wondering if the initial few grand would be better spent on a new engine or suck it up and pull the original and take a chance.

skennelly

Not winterized?  Maybe the block is cracked

randy56

This about $3050, without shipping. if you can pull the other one out and bolt on your parts, then reinstall. If you have the ability or tools to do it your self. 

Crate Engine, Marine, Long Block, Assembled, External Balance, Cast Iron Heads, Chevy, 454, Each

(2)

Part Number: HME-DM25 More Detail...

madst3215

Thank you for your advice.  I don't believe the block is cracked but there is a slim chance.  I had it winterize this last year when I used it so I think the low pressure in the cylinder is the problem.  I will look into the two engines mentioned.  Those are much cheaper than the new ones I have seen online or my mechanic quoted me.  They are says 12k plus labor. They would give me $600 for the old engine but that seems low too. How do I determine what engine can fit in the current space?  ALSWAGG you said ensure its a Mark VI, where do I go to look at engines that fit and determine what is the max HP I can install? Do I call rinker or do crate engine companies have dealers that can quote me the information?

madst3215

Thanks for the comments. I will look to rebuild this engine and get more time out of it. This is a great forum to get knowledgeable about my boat. Thanks everyone. If anyone has more advice please let me know.

pistole

Al is always helpful

Dream_Inn

@madst3215 Please keep us updated on what you do and post some pictures.  You can definitely learn a lot from the people here, but we can learn from you.  Pictures from your rebuild, or whatever you decide, can help the next person making the same decision.  Good luck!

JoeStang

300 hours is very low hours for a big block, unless it wasnt maintained properly. I'd get a second quote on diagnosing the problem first, before pulling it out.

madst3215

I haven't made a decision yet. The last boat repair shop couldn't get the engine open due to rusted bolts. Now I have to find someone who can torch off the broken bolts to see what is wrong inside. More money it seems to me.  I am looking at a rebuild due to costs. 

madst3215

Thanks for your input.  I have been talking to other boat shops and some won't touch in season due to age. Others will do a rebuild but they say due to age and running in salt water for over 15 years they say total rebuild may be right move. I flushed and sprayed it religiously but know it's old and I want piece of mind. One marina quoted $11,700 383 for mag bravo and $2500 in labor. This is new engine with all new parts attached. Is that a good deal? Sounds high to me and past performance has been mediocre.

madst3215

The manifold bolts are rusted with a couple broken off. That stopped the last marina from making a full diagnosis.

madst3215

Update. I have some money coming in and am looking at getting a new engine. More I read about a 19 year old engine run in salt water the more they say replace the whole thing. I have a local boat mechanic looking for a good replacement for my 454 Mercury and am trying to find the best complete engine for the most horse power around 12-14k. Looking for advice or recommendations for pricing and getting most power from it.

madst3215

Update: I finally have scrapped money and time together and will get the boat fixed. I have decided to get a rebuilt engine to give me piece of mind. I am looking at a 454 mpi replacemnt with 325-350hp for $6500 and a 8.1 425hp rebuild waiting on pricing. Anyone have an opinion on power versus torque to be worth the extra money? I am going to make this boat as new as possible. Change all fluids, new gauges full detailing with new stickers and carpeting. I will get some before and after pics soon. I am getting a quote on each engine and will post that for advice. I want to put a new refrigerator in but not many comments on the value of doing it. Is it a DIY or just let mechanic do it? Thanks.

madst3215

Update: I bought a 2001 454 engine merc engine with less than 350 hours on it for $6500. I have my mechanic installing it with several other issues to fix since it's sat for so long. It's been several years since it ran last but should be getting it in a week. I will get pics when I get it.

PickleRick

I chimed in to late.  If you had 50 to 60k to spend the duramax 6.6 is being marinized now to replace BBC applications.


For a bravo application they need to be nerfed a bit but the race guys are pumping 700 plus hp reliably off shore for thousands of hours.

They weigh in at about 800 lbs fullly dressed.  Many are ditching turbos for blowers/super chargers or adding super chargers with turbos for race applications.

The adapter plate from chevy turns the back of them into a BBC.

The best years to use are about 2006 to 2007.5 due to ease of tuning/adapting/ upgraded injector design and there are already USA based companies that will make your ecu stand alone and custom tuned for your marine/hotrod applications. 

The price for the conversion is much less depending on what work you can do yourself.

Also, BBC engine mounts can be modded to fit the duramax.

The military is already utilizing these motors in marine applications.  The boats are set up with two power levels, much like a fancy sports car.  With the flip of a switch they go from 450 hp to 700 plus.  Slow patrol and all out for battle.