Engine Swap - 1988 Merc 5.0 to a 1981 Merc 228

[Keith & Tonya Sheets]

I am getting ready to change the Merc 5.0 motor in my 1988 Celebrity 19 ft to a Merc 228 motor from a 1981 Celebrity 21 ft. I have noticed that the exhaust manifold are different (risers in rear on the 1981, in the middle on the 1988). The block was cracked on the original motor. Would it be better to swap the accessories onto the 228? What other difference/challenges can I expect? This is my first I/O swap so I am learning as I go. The 1988 motor was a very smooth running motor despite the fist size hole in the block from freeze damage. Thanks in advance...

 

[Bt Doctur]

simply remove the log manifolds and therm housing and swap the manifolds (if un-damaged) and therm housing from the 5.0 . to the 228

 

[Bondo]

What other difference/challenges can I expect?

Ayuh,.... Welcome Aboard,... The crank shaft bolt pattern is different, which will cause problems with the flywheels, 'n couplers,....

The change happened in '86,...

 

[Keith & Tonya Sheets]

Is there a work-around for the crankshaft pattern?

 

[Keith & Tonya Sheets]

I pulled the original motor as a complete unit, where does the crankshaft bolts come into play? Will it prevent the outdrive from slipping into place? Is their a different process in pulling the 228 out of the original boat? I pulled 4 engine mounts and disconnected everything (linkage, lines, electrical, etc.).

 

[Bt Doctur]

What is the distance between the rear mounting bolt holes? If there the same the coupler is not an issue.

 

[Lou C]

The older engine has a 2 piece main seal and the newer one has the 2 piece. You'd have to research what other changes took place to see if you can swap just the flywheels, or if you really need a newer engine with the same flywheel as the one you are replacing.

 

[Keith & Tonya Sheets]

Thanks guys, I will measure the distance of the rear mounts when I get the other motor out this afternoon. Hopefully they match up.

 

[Bt Doctur]

flywheels are 12 3/4 and 14 inch the larger flywheel uses a 2 inch larger spread.between the mounts and you cant just change the flywheel ,

 

[Scott Danforth]

why not simply get a proper late-model vortec running long-block and use that? degrading to the 81 block and heads doesnt make sense.

 

[Keith & Tonya Sheets]

Depends on how it is looked at. The boat I got it from was damaged, the motor, interior and other pieces are in very good condition. Plus I got them all for $500. The least expensive complete motor I could find was almost $2000. Even if the motor doesn't work out, I still got my money's worth in the interior and other usable parts.

 

[Bondo]

Ayuh,.... You got a Great Deal,.... Nothin' wrong with older iron,....

Once ya get the flywheel thing behind ya, it'll be just fine,....

Things to scope out,....
Flywheel diameter is determined by the starter bolt drillin's in the block,.....
Many are drilled for either starter,... Many are also drilled with only 1 pattern drillin's,...
The straight across pattern is for the 12" flywheel,...
The staggered pattern is for the 14" flywheels,...

Yer coupler has to mate to the flywheel, 'n the flywheel cover, which are not all the same,....
How wide the rear motor mounts are on the 228hp will determine whether it's useable with yer later drive, 'n transom housin',...

 

[Keith & Tonya Sheets]

'nuther question, if I use the outdrive that came with 228 motor and assemble everything as a comlete unit, would that make a difference. I had the outdrive checked out and it appears to be in great condition. Everything bolts back together same as when it was in the wrecked boat, the flywheel size shouldn't be a factor, or am I missing something? Don't mean to ask dumb questions, as I said I am learning as i go.

 

[Keith & Tonya Sheets]

When I get the motor out of the wrecked boat i will take a couple pictures of back side of motor assembly and take some measurements. This is a great project for me. Learning a lot. I do have the say, my outboard days was a little simpler.

 

[Bondo]

Ayuh,..... Any differences yer gonna find have to do with the inner transom plate, 'n the flywheel cover,...

I wouldn't worry 'bout it, til ya got it settin' on the floor, 'n measure the rear motor mount spacin',....

 

[Scott Danforth]

Depends on how it is looked at. The boat I got it from was damaged, the motor, interior and other pieces are in very good condition. Plus I got them all for $500. The least expensive complete motor I could find was almost $2000. Even if the motor doesn't work out, I still got my money's worth in the interior and other usable parts.

if all your dealing with is a cracked block and most likely exhaust manifolds. running 5.0's and 5.7's longblocks are about $300 used ($1200 reman/$2k new). new manifolds and elbows another $500. the rest of your stuff will swap over.

To me, its easier to fix what is broken vs playing musical parts. I would drop in a post '86 5.7 with vortec heads and not worry about the transom plate or flywheel housing.