Compatability of GM 2.5L and GM 3.0L

[Senior B]

A good friend of mine has a 1997 Wellcraft 185 bow rider that came with a Volvo 3.0L and the SX drive. He didn't winterise at all last year and the state of his boats motor this past spring wasn't condusive to any days on the water. Had all the water he could stand in his oil pan and the motor was siezed. The search for a good used 3.0L motor here in the tidewater area has been unsuccessful and he doesn't want to spent a lot of $$. My question is would a 2.5L mount up? They are fairly easy to come by and not very expensive to buy from the local auto parts store and change the freeze plugs. I'm sure the fly wheel would be different but he still has all the parts and brackets from the 3.0L. Thankyou.

 

[rodbolt]

Re: Compatability of GM 2.5L and GM 3.0L

thats a tough one as both versions have many variables.
you can buy a NEW 3.0 long block assy for less than 2000 dollars and be done with it.

 

[car5car]

Re: Compatability of GM 2.5L and GM 3.0L

Take many pics of yor engine and meagure it, then go to junk yard and take a look, take pictres, don't forget ruler. Good luck.

 

[car5car]

Re: Compatability of GM 2.5L and GM 3.0L

Find the crack first, somebody said you can weld block with bronze stick or glue it. Or just sell me the boat

 

[180shabah]

Re: Compatability of GM 2.5L and GM 3.0L

My question is would a 2.5L mount up? They are fairly easy to come by and not very expensive to buy from the local auto parts store and change the freeze plugs.

I assume the 2.5 your are refering to is the automotive engine(S-10's, Grand Ams, etc.)

No this will not work, they are different blocks completely.

 

[Bondo]

Re: Compatability of GM 2.5L and GM 3.0L

As stated by Shabah,.......

The 2.5l motors that you've been looking at,......
Are NOT the same motor,......
They share the same Displacement,+ Nothing Else.......

And,.......
You can forget about Car Car's Idea as Well,......
The 3.0l,+ the 2.5l used in Boats,......
Hasn't been used in automotive applications........

 

[whywhyzed]

Re: Compatability of GM 2.5L and GM 3.0L

1964 thru 69 or 70 Chevy II (Nova) was the last automotive application of the OMC/Merc/VP compatible 2.5/153 cu in Chevy. Most of those have been already rummaged for marine use.

 

[Senior B]

Re: Compatability of GM 2.5L and GM 3.0L

Thankyou all for your replys. Guess he will have to spend the $$. This is another testement to the wisdom of proper winterazation.

 

[rodbolt]

Re: Compatability of GM 2.5L and GM 3.0L

mail jeeps used the 153 until the mid 70's anyway.
but most are long ago gone.
yep proper winter storage is a tad important.
I get at least 4 per year that the customer says he did not think it got cold enough to freeze here or they simply got busy with the holidays and forgot about the boat out back.
it can get expensive, you may wish to pressure test the block/head assy before dissasembly and test the manifold assy for cracks as well. the riser I would throw away on general principle.

 

[Senior B]

Re: Compatability of GM 2.5L and GM 3.0L

mail jeeps used the 153 until the mid 70's anyway.
but most are long ago gone.
yep proper winter storage is a tad important.
I get at least 4 per year that the customer says he did not think it got cold enough to freeze here or they simply got busy with the holidays and forgot about the boat out back.
it can get expensive, you may wish to pressure test the block/head assy before dissasembly and test the manifold assy for cracks as well. the riser I would throw away on general principle.

He doesn't have the old motor anymore. Got rid of it when he got a used motor from a boat junk yard here called Budget Boats. His combo Intake/exhaust manifold is probably cracked as that used motor had a milk shake in the oil pan after a couple test runs on the muffs. He took it back to the joint and got his $$ back. Said the head gasket was blown but I think it was from his manifold. Now the boat just sits with no motor at all. Quite a waste as the hull, outdrive and interior are in excellent shape. He just doesn't want to spend the $$ on a good rebuilt motor and there is always my boat that runs like a top.

 

[Don S]

Re: Compatability of GM 2.5L and GM 3.0L

A cracked manifold will not put water into the engine oil while it's running or make the oil milky after only a couple of runs on the muffs.. It may leak a little on top of the piston if the valve is open, but that would be just a little bit. If the manifold cracked from freezing, so did the block, and a cracked block will dump water directly into the oil very quickly.

 

[rodbolt]

Re: Compatability of GM 2.5L and GM 3.0L

didnt know budjet junk was still in business.
never saw anything come out of there that worked anyway.
for around 3 grand you can buy a new long block assy with manifold and carb and riser with the ign components and it even comes with a flywheel.

 

[180shabah]

Re: Compatability of GM 2.5L and GM 3.0L

This one came from Budget

 

[Senior B]

Re: Compatability of GM 2.5L and GM 3.0L

[]didnt know budjet junk was still in business.
never saw anything come out of there that worked anyway.
for around 3 grand you can buy a new long block assy with manifold and carb and riser with the ign components and it even comes with a flywheel.
[/quote]
I see that you're just down the road a piece. Can they be gotten down there for that much? That isn't a bad price for a drop in motor with most everything on it. Don't think I've seen anything for that price up here.

 

[Reel Poor]

Re: Compatability of GM 2.5L and GM 3.0L

Here is an engine package, comes as you see it in the ad.

copy/past
www.dougrussell.com/Products/index.cfm?fuseaction=ProductDetails&ProductID=5&Category=6&Brand=70

 

[rodbolt]

Re: Compatability of GM 2.5L and GM 3.0L

do some searching, I found a complete new merc bobtail 3.0 for 3100 for a friend last summer, I also found another friend a complete long block assy,new, with ign system and flywheel and balancer for 1800. if you buy used either get a very good warrenty or better seatrial it first.