i think my 3.0 is blown. can i go to a 5.7?

[erikgreen]

Re: i think my 3.0 is blown. can i go to a 5.7?

I realize you want to use the 5.7, but do it right if you're going to do it. You can't use non marine alternator, distributor, or starter for a very good reason... unlike a car or truck, the engine compartment of a boat is usually nearly airtight. Gasoline, oil, and hydraulic fumes can collect in there, and unless your bolt-ons are ignition protected marine components there's a good chance you'll end your life with a loud boom.

Check to see if your starter will work on the 5.7 engine.. if the bendix gear is the wrong size or the bolts are positioned wrong you're going to need a new one. The alternator should be able to be clamped on without too much trouble, as long as it's got enough capacity to power everything.

The sterndrive gears effectively can't be changed. You can buy them suitable for the old drive, but the gear and shim setup is very specific to the drive case you use. If you swap the drive gear in the upper to get a different ratio without the special Mercruiser assembly/shimming tools, you'll get a gear set with a very short life. They have to mesh exactly right. Better to buy a used upper with the ratio you need, or a new one from SEI (about $600).

Note that the risk you're taking with this engine swap isn't just personal, it's legal. If you put more power in the boat than it should have per the manufacturer then get in an accident, you're sunk. Any lawyer for anyone/anything you hit, or who is injured riding in your boat or while near your boat can sue you and win, because they can prove you overpowered the boat.

Like others have said... repair the old engine with replacement parts and sell it, or even sell it as is and buy a boat suitable for a 5.7L engine. There's a ton of bigger boats on the market now, suitable for a repair job and a nice big engine. Get one cheap and go to town.

Erik

 

[alilley]

Re: i think my 3.0 is blown. can i go to a 5.7?

ok so lets set the v8 swap to the side for a little bit here. i have been doing some checking on some things and talked to a few machine shops in my area that have shed a little light on things for me and raised a few questions. to start off with i will explain what is going on.
-- getting water into the oil (looks like a thined out wendy's frosty),
-- engine block is cracked to the out side for sure,
-- motor runs up to 4000 rpm to just under wide open throtle (if i go to full then it boggs and hesitates) with norm load
-- getting blow by through the crank case vent tube
-- noticing exhaust smell when up to speed but not as noticable when at idle/nowake
-- plug wires keep falling off during ruff water as they fit loose in the cap


i was then suggested to get the head magna fluxed to make sure that it was not cracked. as that might be here i am getting water in the oil from. if that is the case then what i would do is get a rebuild kit for .030 over standard bore. weld the block back shut, have the deck planed to ensure trueness. so that would button up the bottom. then find a differant head which would be a lot easier to find then a new block

what other then the head being crack could cause the water in the oil issue?
i hae had the manifold and riser off and all appiear to be good an not cracked and many thanks again as i was not tryin g to get people fired up was just trying to go the least expensive way out to get boat back on the water

 

[zbnutcase]

Re: i think my 3.0 is blown. can i go to a 5.7?

A cheap boat is never a bargain!!

 

[erikgreen]

Re: i think my 3.0 is blown. can i go to a 5.7?

You have much experience welding cast iron?

 

[alilley]

Re: i think my 3.0 is blown. can i go to a 5.7?

i do not, but my father does.

i am trying to figure out how the water is getting into the oil. is there any other way other then a crack in the block, head, or a blown head gasket (which i know is unlikely but they do happen).?

i had put a few hours on the motor will on muffs with fresh oil. i checked it before foing out the first time and it still looked like oil. we went out 3 time that may have totaled less then 5 hours. we did both full throtle and no wake speeds. the last time we took it out we started noticing that it was cutting out which was caused by the loose plug wires. wile i was fixing that i noticed that there was somthing sprayed on the bottom side of the engine cover. coresponding to somthing being sprayed over the top of the riser, the bottom or the carb and top of the manifold. as soon as i seen it i knew it was oil, i pulled the dip stick and sure enough over full and as i described earlier it looks like a thined out frosty. pull the plug out of the valve cover (where you put the oil in at) to look inside there and sure enough foam/froth under pulg, top of the rockers and about any where it can settle. at that point we took it back to our dock and tied her off. that is where she has sat for since monday. i will be pulling it out of the water once i get back in on saturday

 

[BAproject]

Re: i think my 3.0 is blown. can i go to a 5.7?

If your boat is filling up with water that quickly I would most certainly check the bellows, if you have a rip or hole in the drive bellows, water can go into both the engine and the bilge. Have you checked this....you might be able to save the engine. But drain everything asap and squirt marvel mystery oil into all the cylinders, cross your fingers

 

[erikgreen]

Re: i think my 3.0 is blown. can i go to a 5.7?

Yes... do check the bellows, and also all the hoses on the engine... run the engine on muffs and a hose and see if you see where the leaks are.

What you need to do for the engine is run a leakdown test... basically one cylinder at a time you pump in compressed air via the spark plug hole.. where you hear hissing tells you more about what the problem is.

Good explanation of compression and leak down testing here:
http://www.wcengineering.com/articles/leakdown.html

Erik

 

[alilley]

Re: i think my 3.0 is blown. can i go to a 5.7?

the water coming into the bilge area is coming from a crack in the block to the outside. it is located just about an inch to inch and a half below where the head would match up to the block. that is why i mentioned earlier if i were to have dad weld it i would have that part resurfaced to make sure it would be true when rebolting the head back on. right now i am concerned with getting water into the oil. and i have ran it on muffs as well ran it sitting in the dock. the only water i am getting in the bilge area right now is from the crack as mentioned.

 

[Bondo]

Re: i think my 3.0 is blown. can i go to a 5.7?

Ayuh,... My guess is the crack is on the inside wall, down low, behind the drain hole by the pan rail....