Blown: Need to Rebuild

[LMannyR]

I finally got a project boat. It's a 1983 Wellcraft Aft Cabin 230 with what seams to be a blown engine.

Batteries are fully charged and when I try to start the engine, I get one loud THUMP! I pulled the plugs and tried turning the crank with a rachet. It will only move about 1/8 of a turn and...THUMP (much quieter of coarse).

The seller said "plan to rebuild as it needs carb work."

I'm assuming it's toast. Or are there other checks?

Block Cast ID = 10066036

I'd like to rebuild but with EFI, mecm, vortec, etc. I'd like to pull an engine out of a wrecked truck to do this.

Can someone walk me through this? Stonebreaker? Maybe I should put this in DIY Marinizing.


Thanks.

[stonebreaker]

What's your budget, and what are your performance goals? And are you rebuilding yourself for fun or to save money?

[Frosty]

Take the heads of and tell what you see. It may not be dead!!

[LMannyR]

This boat previously had some 220 hp I think. For some reason, I think this is not the original motor.

Anyway, Stonebreaker thanks for the quick response. I'll do the rebuild myself. Saving $$$ is always nice. I would like to get 300hp reliably. Truthfully, I'm not sure what the performance of an engine on this type of boat should be. What is a must is MECM, Fuel Injection, closed cooling system, and or dry stack?

Dry stack is when the water does not go through the exhaust right? So this means the o2 sensor can stay. How does the exhaust get muffled in this case?

Frosty, I'll take pics. I'll have to do it place since I don't have an 8' cherry picker to clear the stern. I'll need to build one soon.

[Zackman]

Whoa, there cowboy... What engine and drive do you have in that there boat?

[lazeyjack]

the first thing on any damaged motor, is to pull off the oil filter, and cut the element in half, spread the filter paper out and look for either copper or alluminium, which will tell you if its bearings or pistons
I does sound like seizure or broken crank
Before Istarted boatbuilding, I was a field service engineer for Cummins Eng Co, and this was our procedure,
its A pocees of elimination, dont start yanking the thing to bits, yet!

[LMannyR]

I pulled a hose at the bottom of one of the exhaust mani. and black water poured out. I'm assuming this is not normal. I'll drain the oil next and see what it looks like.

Zackman,

The carb cover said Merc 5.0. 305 The block cast id 10066036 indicates 350. Which leads me to believe this motor has been messed with already.

Thanks

[gonzo]

Black rusty water from the bottom of the manifold is normal. The fuel injection system and other electrics from a truck are not for marine use. You may have an engine with a dropped valve or valve seat. A long block with warranty is about $2200.00 shipped. Ar you looking for a complete fuel injection system?

[Beech2000]

Performance comes with steep price. Stay with OEM configuration as much as possible. It will allow for worry free fun on the water. Trust me I know..

[LMannyR]

I pulled the engine a few days ago. Stripped it down. The only pieces left are the crank, a couple brass plugs on the rear, and cam.

I'm planning on honing, decking it down .005, baked and peed, and check for cracks. I'll have them inspect the crank and hopefully it's reusable. If the crank is not reusable, I'll stroke it for 383 cubes with same pistons.

I didn't do much research before removing the head and did not tag the rockers nor the push rods. Not sure what to do there. I might also port and polish the heads while at the machine shop.

Possibly new push rods and rockers.
New piston rings (not sure what brand or size yet)
New gaskets
New water pump
new oil pump
MSD Ignition
All new hoses.

Anyone know what kind of hp/tq improvements this will yield?

[switlikbob]

I did basically the same thing you are doing, minus the crank modification. My motor went from 260 HP to a whopping 280 HP yielding me a massive 7mph gain in top speed!!!!