1988 3.0 blown head gasket

[hadaveha]

I am going to look at a 1988 searay donor boat with a 3.0 donor motor and outdrive, seller says it has a blown head gasket

the second choice is a 1982 3.0 running with a crack in the block but no water getting into the oil

and choice number 3 1987 chevy 305 running but cracks in the manifold
anyone got any advice before I leave out on this donor boat quest this weekend

 

[alldodge]

Re: 1988 3.0 blown head gasket

I am going to look at a 1988 searay donor boat with a 3.0 donor motor and outdrive, seller says it has a blown head gasket

the second choice is a 1982 3.0 running with a crack in the block but no water getting into the oil

and choice number 3 1987 chevy 305 running but cracks in the manifold
anyone got any advice before I leave out on this donor boat quest this weekend

Choice 1 and 2 are 3.0L, and choice 3 is a 5.0L, what is the actual question your asking? Which one to use to replace something what ever the something else is. Little help

 

[hadaveha]

Re: 1988 3.0 blown head gasket

Im sorry I should have made it clearer Im looking for advice as far as one with a blown head gasket, cracked block, or 305 with cracked manifolds, would be the safest quickest turn around, does any of them sound like stay aways, they all are within a 100 bucks of each other

 

[fishrdan]

Re: 1988 3.0 blown head gasket

Those sound like they should be "free" boats to me...

I don't see any of them as being a "good" donor candidate as they all have mechanical issues. A good donor boat would have a thrashed hull/interior with the owner not recognizing the value of the excellent running drivetrain.

Just a guess, but I bet those boats are going to cost more to fix than they are worth. Cracked anything on the engine and I would suspect everything is cracked until proven otherwise. The best of the bunch would be the blown head gasket 3.0, but is it really a blown head gasket, or something else ($$$)?

 

[alldodge]

Re: 1988 3.0 blown head gasket

+1 with fishrdan and will add, Since none are running you don't know if there could be other issues and with the drive, electrical, etc

 

[hadaveha]

Re: 1988 3.0 blown head gasket

well we can run the one with the blown head gasket, and the one with the cracked block, but for just a very short time. All the donor boats I can find are ether older early 70,s, or priced like boats that are in perfect shape, or boats like these, I understand its a bit of a crap shoot.

 

[Bondo]

Re: 1988 3.0 blown head gasket

Those sound like they should be "free" boats to me...

I don't see any of them as being a "good" donor candidate as they all have mechanical issues. A good donor boat would have a thrashed hull/interior with the owner not recognizing the value of the excellent running drivetrain.

Just a guess, but I bet those boats are going to cost more to fix than they are worth. Cracked anything on the engine and I would suspect everything is cracked until proven otherwise. The best of the bunch would be the blown head gasket 3.0, but is it really a blown head gasket, or something else ($$$)?

Ayuh,.... I completely Agree, sounds like 3 piles of junk,...

A blown head gasket usually takes the head and/ or block with it,...

A Donor boat, by definition is a Rotten boat, with a Runnin' driveline,...
Anything else is just a pile of parts, at Best,...

 

[hadaveha]

Re: 1988 3.0 blown head gasket

ok guys thanku ill be skipping on all 3 of these

 

[hadaveha]

Re: 1988 3.0 blown head gasket

I wouldn't mind finding a good buildable 3.0, Im just trying to get away from this 470 every time I turn around its robbing my wallet, So to rebuild a good 3.0 would seem like a walk in the park opposed to that aluminum demon

 

[fishrdan]

Re: 1988 3.0 blown head gasket

I doubt you'll be happy with a 3.0 after having the 470, performance wise anyway. 130-140HP compared to 165-190HP, 25% less power is going to be a big difference.

It would be better to look for a 4.3L, and swap everything over. I've been keeping my feelers out for a donor 4.3L boat.....

 

[thumpar]

Re: 1988 3.0 blown head gasket

Going from a 470 to a 3.0 is going to be a lot of work. I would do as fishrdan said if you are going to switch to something else. With either the 3.0 or 4.3 you will need to redo mounts. You could even get a 4.3 donor with bad motor and buy a 4.3 from a wrecked truck/van add the brass core plugs and use the rest of the parts from the donor boat.

If it was me I would do one of 2 things.

1 Figure out why you are having so many issues with the 470.

2 Sell the boat and buy one that fits what you want.

 

[aerobat]

Re: 1988 3.0 blown head gasket

I doubt you'll be happy with a 3.0 after having the 470, performance wise anyway. 130-140HP compared to 165-190HP, 25% less power is going to be a big difference.

there were threads about it and fact is that the 3.0 pushes 135hp at the prop where the other is rated at the flywheel. so after the losses in the drive the factual output at the prop is very similar , some claim the 470 is even weaker than the 3.0 . in any case not a big difference.

i would look for the boat in best overall shape and be prepared to change the engine - if you can manage to get some more seasons out of it you have a net win !

 

[thumpar]

Re: 1988 3.0 blown head gasket

there were threads about it and fact is that the 3.0 pushes 135hp at the prop where the other is rated at the flywheel. so after the losses in the drive the factual output at the prop is very similar , some claim the 470 is even weaker than the 3.0 . in any case not a big difference.

i would look for the boat in best overall shape and be prepared to change the engine - if you can manage to get some more seasons out of it you have a net win !

That is probably correct but if you are going to redo mounts for a new motor why not go up? If he went to a 4.3l the outdrive would still have the correct ratio so no added cost there.

 

[Bondo]

Re: 1988 3.0 blown head gasket

That is probably correct but if you are going to redo mounts for a new motor why not go up? If he went to a 4.3l the outdrive would still have the correct ratio so no added cost there.

Ayuh,.... 'n you'd be in the 200/ 225hp window,...

 

[fishrdan]

Re: 1988 3.0 blown head gasket

there were threads about it and fact is that the 3.0 pushes 135hp at the prop where the other is rated at the flywheel. so after the losses in the drive the factual output at the prop is very similar , some claim the 470 is even weaker than the 3.0 . in any case not a big difference.

For a newer 3.0L engine, 135HP at the prop is correct, or at least that's what Mercruiser says, but that's not what the OP is looking at. (I kind of doubt 135HP at the prop since GM says 140HP for the newest Vortec 3.0L, why wouldn't Mercruiser say 140 HP? Is it actually less than 140HP? Only loosing 5 HP through the drive? I dunno..) The 3.0L, 3.0LX, 140HP HP ratings were all over the place, different compression, heads, pistons, carbs, manifolds, etc. 3.0L vs 3.0LX... Prop vs crank HP rating. Actual HP ratings at the prop were something like 115-135, depending on vintage. At one point they slapped a 2.5L (siamesed port) head on a 3.0L that one had to kill power a bit.

The OP is looking at 80's 3.0L/140HP engines (not newer high performance prop rated 3.0L engines) so it's an apples to apples comparison between his 470 and those older engines, horse power wise. I don't remember when they changed from crank to prop HP, (late 80's?) but don't think it's applicable for the engines the OP is looking at.

 

[hadaveha]

Re: 1988 3.0 blown head gasket

the only reason I was looking at the 3.0 was if I get 30 mph Im going to be very happy, I had a 3.0 in a 19ft bayliner cuddy full of wet foam, and I reached 30 without going into max rpms, I think the bayliners listed weight for that boat was 1900lbs, the boat that currently has the 470 is aluminum, Crrestliners listed weight 1850lbs so I would think I would get atleast as good performance as I had in the 1988 bayliner

 

[aerobat]

Re: 1988 3.0 blown head gasket

when you are looking for 30 mph in a 1850 lbs boat the 3.0 will do the job easily for sure, even an older one. but are you currently looking for a new boat or are you looking to replace your old 470 in your current boat ?

@fishrdan : i agree that the power ratings are a mysterium somewhere , i think its only a rough number for the customer to know in which power class his engine is. and you are right its depends what version of the 3.0 the OP is about to install.

but at least the newer vortec H.O 3.0 versions are more powerful than somebody might believe and i don,t think he will go with an old tired 470 somewhere where a decent 3.0 has never been.

 

[Starcraft5834]

Re: 1988 3.0 blown head gasket

hada.. I have a 1987 3.0 GM 140hp and pushs my 20 ft cuddy 32 gps... it's over 2500lbs,,, is my boat underpowered? yep... am I happy with it as is, yep.......good luck and fix it up........

 

[hadaveha]

Re: 1988 3.0 blown head gasket

aero Im just at a point where I need to spend some money on the 470 and I thinks its more than I want to spend on the 470. Id like to make a change to something alittle less moody, not to rattle the 470 guys. I would like to have something simple that I can do the maintenance on. Im not looking for tuns of horse power, to be honest fuel economy would be second to reliability, if I can reach 30 to 32 and cruise between 18 and 22 Id be very happy.

The three boats I was asking about I know wasn't great donor boats, but I wasn't looking for something that I didn't expect to do some work to, if I could get my hands on a donor with a good base to overhaul from Id be fine. The boats I was looking at was in the 300.00 to 500.00 range, and I might could even ebay or CL some the parts or the trailers and put that back into my engine work. I was truly only asking of the 3 just from what info I have now would be atleast taking a run at for say 300.00

Imperial I know that old bayliner would just run all weekend on a tank of gas to, very easy on the ears also.

 

[alldodge]

Re: 1988 3.0 blown head gasket

The three boats I was asking about I know wasn't great donor boats, but I wasn't looking for something that I didn't expect to do some work to, if I could get my hands on a donor with a good base to overhaul from Id be fine. The boats I was looking at was in the 300.00 to 500.00 range, and I might could even ebay or CL some the parts or the trailers and put that back into my engine work. I was truly only asking of the 3 just from what info I have now would be atleast taking a run at for say 300.00
.

Hey why not roll the dice it could be worth 500 to have a go at it. I picked up a D3 dozer for 4500 just last year and after getting to work on it found it just could be something not worth the trouble. The more I got into it the more I started thinking, this may have been a bad idea. I'm now half way in and things are looking a whole lot better. If it turns out 500 was a bad idea, well that's the way it goes, but some times it works out.