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HELP PLEASE!!! Purchasing New Boat Detroit 8V53

LeeroyB

New member
Hi Guys,

Really appreciate any help you can offer in advance. I have no practical mechanical knowledge and 2 small kids that cant swim.

Ive found a 45 Foot boat I want to purchase that has 2 x 1971 Detroit 8v53 285Hp Engines.

These are my concerns;

1) They look in good condition (Fresh paint all over) and Ive told have been rebuilt in last 10 years but have no proof.
2) havent been used much for the last few years
3) Went for a sea-trial yesterday and boat put out a fair bit of whitetish smoke under load mainly (Boat Broker told me its normal for not being used for awhile)
4) Had oil change in last 6 months and hardly been used.
5) I want to get an oil sample analysis (expensive) but my concern is engines havent really been used since Oil change.

Questions;

1) Is it still worth taking it for a half hour run and then getting an oil sample analysis ?
2) Anything else thats really important to check for ?

Side note:

When we did sea-trial one engine made a loud pop, tonnes of smoke and sea-water stopped coming from one exhaust. At the time we were WOT
and hauling at 18 knots. (45 foot boat).

We limped back on one engine and Im being told its being repaired shortly to determine fault. Most likely just impellor I was told.

Please I welcome all thoughts ?>


Cheers,

Lee
 
50 year old engines that have been out of production almost as long.
If you talk yourself into this purchase, you are probably going to learn WAY more about mechanics than you ever wanted.

While the DD 8-53 is a venerable, reliable workhorse, finding parts and knowledgeable, skilled Detroit mechanics to help you is getting to be harder every day. Your first, best move after the buy would be to get the shop manual and start reading.

Just my opinion.
 
2X what jgmo said!!!

I'll also add if you don't have a marine surveyor involved, you will learn WAY MORE about boat systems and structures and their costs, too!!
 
Thanks guys for all your help. It seems like the consensus from both sites is too run away :) (Not in those words)


Im actually really surprised because I would have thought these type of 2 stroke detroit engines were super simple to run and bulletproof.
Feel free to educate me because thats why im here.

I did see lots of sites selling parts for them including rebuild kits.

Update from mechanic today: Turns out the exhaust clamp came off (so that was the loud pop). And the water impellor broke into pieces. (I have photos for everything). So they are replacing both impellors now and oil filters.

Please feel free to comment your thoughts
 
I've used Detroits most of my life, about 60 years. They're the only engine of it's size I will use on the ocean. But good engines or not, you need to have a mechanical survey by a real Detroit mechanic, not the usual marina mechanic.
My current boat has twin 671s built in 1947. I had no problem getting parts. Before overhaul the engines had somewhere above 30,000 hours.
If you or some mechanic you know can successfully rebuild a gas engine, you can rebuilt a Detroit with a shop manual. That's how I learned 50+ years ago.
Once the valves, injectors and governor are adjusted, they go years without problems.
 
Yes...you can find SOME parts....liners, pistons, rods, bearings, injectors.But you probably can't find a new block or cylinder head if you need one. Why? Because they haven't been cast since sometime in the 1980's or before. So finding a reliable "scrapper" that has stockpiled some would have to be an option. I used to have a resource in San Diego for obsolete Detroit parts but he was old in the 90's and the business is probably long gone now.

Yes, these engines are "simple" in design AND function but not to an inexperienced mechanic. Just one read of setting up the Roots type blower in the shop manual will reveal that fact. Setting up the fuel injection system and governor for proper operation and reliability is actually a "precise" endeavor using precision (some special) tools and not a small amount of practice. As is rebuild parts selection and installation.

Here's a little riddle for you to solve and to ask of any prospective tech you're considering letting in the engine room:
Where is the "restricted fitting" and what is it's function?

That question alone should weed out about 95% of today's Detroit 2 stroke "experts"

What type of cooling system? Closed, recirculating, fresh water or raw sea water?
Big difference here in maintenance and PROCEDURES to keep the boat safe!

I will close with this.....
People are trying fairly diligently to sell you on this vessel. It is safe to assume that they had faith it would pass the "sea trial". It didn't! You have already seen failures occurring!....ok....stuff happens.

BUT....clouds of white smoke on startup is RAW FUEL or WATER (steam)

If it's raw fuel....low compression. Yes. It is common to see on engines that are halfway worn out but "freshly" ( use ANY adjective you like here, "recent", "low hours") overhauled??? Maybe....probably not.

Oh well...no biggie....these will run a long time like that. IF you can get them started!
Might not be so easy in northern winters.

If it's STEAM....(you really need to find out which BEFORE jumping in)...then it's WATER in one or more cylinders. WATER?... where did that come from?

Well....if it's raw water cooled....it can come in through a poorly engineered or maintained exhaust system!....HMMMM...better check THAT out!

I'm not trying to rain on your dream but you asked and I'm answering. No dog in this brawl and all that.

But, I mentioned earlier the owner's or broker's faith....

How much faith do you have? If you go offshore in this boat I hope you carry with you much more than faith.

Whatever you decide,

Good luck.
 
Believe me this advice is exactly why I came to this forum and wont be ignored.

Thanks for taking the time to type it all out.

I have a “supposed” Detroit expert calling me this morning. Ill have a chat and ask him what you sent.
 
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