268 Sundancer 1987 engine mystery

S

Simonas

New Member
Jun 23, 2015
14
Lithuania
Boat Info
268 Sundancer 1987
Engines
Mercruiser
Hello all,
We are about to buy a boat with broken engine. Interesting thing is that this boat is powered with a single 5.4 Mercruiser and Alpha drive. For me it sounds underpowered, maybe that is the reason why engine is broken. From that point, seems like we have to buy complete drop in engine 454 7.4, or is there other opportunities? Maybe newer model 6.4, or twin 5.4?
Thanks.
 
It is underpowered. Its how standard sea rays roll. There are some out there w 454's / alphas but they were blowing up the alpha drives.

383cu is the replacement for the 454's by the way and they have more low end torque which is really what you want.

then find the best prop i.e. smaller pitch 4 blade.
 
Thank You.
Today we have bought that boat. So question became must to solve.
Does that 383 comes with injection, or carbureted?
IF, we'll buy injected engine, is there many adjustment to be made to make it run?
Does Alpha drive works with 383? Or take it another way, which engines alpha will work with?
Thanks.
 
That's might be good solution, but very expensive. Maybe I'll found something cheaper, but before I have to know what I should look for?
 
Hello again. Now I found 6.2 Monoinjected engine, which was under flood (not hydrolock, just boat sunk after huricane, or so). Engine was reasembled, cylinder honingated (not sure if it's right word). Price is extreemely good. Question what kind of difficulties I will face, if I will decide to put that engine instead of 5.7 Does it take a lot of work to connect mono injected engine? What else should I consider before buying it?
Thanks.
 
Holiday weekend in US. Are you seriously looking at an engine that has been submerged?. I would rather have a rebuilt engine, too many possible issues with a sunk motor IMO.
 
SCORPIO said:
Holiday weekend in US. Are you seriously looking at an engine that has been submerged?. I would rather have a rebuilt engine, too many possible issues with a sunk motor IMO.
Click to expand...

Thanks for Your answer.
Actually, I've bought that engine, because it was dissasembled cylinders cleaned, some parts changed, heads serviced. And the price was extreemely low. If it would last for two seasons, I would be very happy.
That engine has no exhaust manifolds, nor alternator, starter, but I have everything from "broken" engine.
The biggest problem is that 5.7 "broken" engine was carburated, and 6.2 I bought is EFI. I also got some wiring cables for 6.2
1.) Should I work a lot on wiring and make EFi work, or should I downgrade it to carb?
2.) Where can I find information how to connect all wiring?
3.) Do I need additional fuel pump? Now I have SAE J1171 from 5.7 engine.
4.) Do I need risers for 6.2 engine? Seems it was not installed on 5.7.
Thanks in advance.
 
Here's my $.02

1. If you're ok with the effort and expense of the efi system, it's definitely the way to go. You will be much happier with the way the engine runs. However, the carb system is much simpler and less expensive, and obviously is a tried and true system as well.
2. I would think your best bet here is to get the mercruiser manual for the current and also the new engine. Some here may be able to help you with a source for those online.
3. The fuel pump you'll need depends on what you decide for #1.
4. I believe these will be completely different from the 5.7 ones.
 
1.) I don't see much of expense, because I need only fuel pump, as far as I understand.
2.) Got both.
4.) Maybe, I'm not sure. Question do I need that for 6.2 engine?

Today I've check the engine I bought and I think it's MPI, not EFI. If You could tell me difference between two, I could judge it 100%.
IF it's MPI it's even more pity to replace it with carb, but if I'll not be able to run wiring, I have to do so.
One more question:
if I go for carb instead of MPI, I just have to change intake manifold, or something else?
Thanks.
 
The 6.2ltr is a newer LS motor and I've never seen one that was normally aspirated (carburetor). I believe they are all fuel injected motors that require a computer. Does your new motor come with the brain box and everything ready to instal?

I do know this for a fact, the LS motors (6.0 ltr, 6.2 ltr) have absolutely nothing in common with the older style small block engines 305CID and 350CID (5.0 and 5.7ltr).

A conversion to the LS motor will require a bell housing change as well as even engine mounting provisions. It is a complete change from the original engine.

Also, the Alpha drive is rated for 300hp. I have an Alpha behind my 454BB which is rated at 330HP. The Alpha drive on my boat is the original and has survived the higher horsepower, however, the original owner and I have been easy on the throttle up and throttle down. They are tough drives, but I would suggest being easy on them with the higher hp motors.
 
Last edited:
It's very interesting, because when I bought that engine, owner told me, that everything is the same. Now I looked at the engine, and it's 5.7 block. As far as I heard it's only different heads, or something to bring more HP.
Engine came with complete wiring and computer. But I think, that it's not from the exact engine, because wiring doesn't look like, that ever got under water.
Now I'm confused. I don't know how to find out what kind of engines do I have. :)
Is there any way to check it?

Getaway said:
The 6.2ltr is a newer LS motor and I've never seen one that was normally aspirated (carburetor). I believe they are all fuel injected motors that require a computer. Does your new motor come with the brain box and everything ready to instal?

I do know this for a fact, the LS motors (6.0 ltr, 6.2 ltr) have absolutely nothing in common with the older style small block engines 305CID and 350CID (5.0 and 5.7ltr).

A conversion to the LS motor will require a bell housing change as well as even engine mounting provisions. It is a complete change from the original engine.

Also, the Alpha drive is rated for 300hp. I have an Alpha behind my 454BB which is rated at 330HP. The Alpha drive on my boat is the original and has survived the higher horsepower, however, the original owner and I have been easy on the throttle up and throttle down. They are tough drives, but I would suggest being easy on them with the higher hp motors.
Click to expand...
 
One quick way to tell if it is the older Chevy motor or a newer LS engine is the exhaust ports.

Older small block has "Siamese bores" where the center two exhaust ports are closer together and not evenly spaced.

350%20block_zps6vkset2m.jpg


Note on the LS motor that the exhaust ports are evenly spaced.

6.2%20ltr%20chevy%20motor_zpscwjjegqt.jpg


There should be some numbers on your block you can Google to find out what block and year you have.
 
probably a 383ci "stroker" - it uses the 5.7 block (not LS based) with a longer stroke crankshaft to up the ci (therfore torque and HP) - if you did not get the ecu's with the motors (those would be toast if they were submerged), I would just go to carb - I'm not sure what year each motor is, but intake manifold mounting has changed over the years - your new motor may have the vortec pattern - carbed intakes are available from the aftermarket - also you would probably need to switch the ignition system too (make sure the distributor drive gear is compatible with the new motors camshaft (roller?)......MPI is a more advanced form of EFI where each cylinder or port has an injector.....EFI often generically refers to a throttle body injection or TBI type of a setup...
 
Lets make this simple...Post some pics of the engine you bought. Being a submerged engine is not an issue as long as the rust internally was dealt with properly, Marine electronics are designed to get dunked....don't worry if the harnesses and connectors got wet. As long as there aren't any signs of corrosion, you will be fine. We need pics here to guide you better.
 
I will post some pics later today.
Yesterday I've decided to swich intake manifolds, and make it carburated. Their bolt places in intake canals are the same. The problem came, when I took off intake manifold, and saw, that cooling canals are rusty and dirty. I've decided to take of head covers, and than I saw, that some bolts are missing, and even 2 pushrods!!! I bet machanic who assembled that engine was dead drunk. Thanks god, I've decided to check it. Than I've decided to dissasemble the whole engine and check, because it's not turning properly. Yesterday took off heads, they are serviced, but not cleaned from rust. Today I will take off bottom and check why it's not turning. Yes, I know, I've got what I payed for. But not complaining, I like that kind of work.
I will also take the numbers from the blocks.

How to make sure if distributor drive gear is compatible?
 
Hello again,
Today I have released the bolts of connecting rods, engine turns 1/5 of the turn, and than stops. Seems like it lean on something. Any ideas?
No photos, cause bouth engines are now teared down, so no point.
 
Today finally I've found why engine were stuck. I have removed chain cover, and found small part is bend, which prevented chain from moving. I don't know what is the purpose of that part. Is it possible to make it straight, or should I order new one? Photo attached. (only one, because it's the most complicated way to upload photos I've ever seen). I'll try to upload second one in another post.
 

Attachments

  • photo 11.jpg
    photo 11.jpg
    36.9 KB · Views: 149
You must log in or register to reply here.

Forum statistics

Threads
113,214
Messages
1,428,713
Members
61,110
Latest member
rvlewis
Back
Top