Repowering my boat

[79Glastron]

Hello everyone!
Boat: 79 Glastron SSV177LX, omc 3.0 140hp

I've been thinking about changing the engine in my boat, the 3.0 is in need of a rebuild, and the ball gears are worn out as well. I have been toying with the idea of putting a 250 six in its place, and of course keeping the omc style drive. I like the 250 six because its smooth, powerful and full of torque, and spreads the load better than a V6. Also, the 6 has the same bell housing as the 4 and uses the same type front engine mount, only a few more inches forward. I would have to get an 800 series drive and probably use a ratio made for the 3.8 V6, which is rated for 170HP which is very close to the 165HP rated 250. I think the biggest problem will be moving the front motor mount, and drilling the 6 new holes, everything else should be a "simple" swap. BTW, the boat is in really great shape, always kept inside, covered. Very sound boat, hate to lose it. .....Idea's.....suggestions?
Thanks
Randy

 

[Rob454]

Re: Repowering my boat

Moving the motor mounts forward is a simple thing really IMO. Jsut make sure the motor is striaght ahead not cocked to one side or the other. HP differences are minimal IMO. if it all bolts up the go for it.
Is the inline 6 a marine motor? cause if its not how are you gonna get marine exhaust manifolds
Rob

 

[79Glastron]

Re: Repowering my boat

Moving the motor mounts forward is a simple thing really IMO. Jsut make sure the motor is striaght ahead not cocked to one side or the other. HP differences are minimal IMO. if it all bolts up the go for it.
Is the inline 6 a marine motor? cause if its not how are you gonna get marine exhaust manifolds
Rob

Rob, yeah the 6 was used as a marine engine, I know omc used it, I'm not sure about merc. Its only a 25 hp gain, but why would they offer the boat in 120, 140, & 165 if the performance difference was little? I'd like to put a V8 in, but I am unsure if the boat would handle it, it might. I think the 302/351 fords are light engines? Don't know.......

 

[whywhyzed]

Re: Repowering my boat

I repowered my OMC stringer boat from a 4 to a V6.

Chev. I6 or V6 both share the same Chev bolt pattern, I would recommend looking for a donor boat, and then deciding which would be better to use based on what deal you may find. Also look what sort of room is in your engine compartment - V6 is about the same length as the 3.0 but wider, where the 165 has more length but same width as the 3.0

Inspect your Glastron's transom first with an ice pick - regardless of how new and well cared for the boat is... Glastrons had their share of issues....all fixable easily but if per chance the transom is soft - here's your time to go mercruiser conversion from a donor boat. Lots of 165 mercruisers around..e.g. boatangel type charities and such.

If transom is good and you are looking for a 3.8 OMC drive or 1985 4.3 stringer, might as well just look for a trashed 3.8 or 4.3 stringer boat and use both drive and engine. Look for 1983 or newer to get full mechanical shift and the 1985/86 4.3 would be the sweetest to find of course (hunting tip: 4.3 stringer drive and engine were painted silver instead of blue/white scheme)
The I6 165 was only used by OMC with electric shift stringer drives so you would need parts from at least 2 boats going that route- a lot of searching and you certainly don't want to go backwards to electric shift.

When I repowered my boat, I bought a 3.8 powered boat that was not winterized and the 800 series drive was in excellent shape- I bought the whole boat for $230 delivered to my driveway. I replaced the engine long block and manifolds etc.

More opportunity for power with a V6 due to availablity of 4 bbl manifolds. I upped my HP to 185 with the 4BBL conversion- couldn't have done that if I had used an I6.

I went from 120HP to 185HP and gained about 13 mph. (39mph before, 52 mph now)
140 to 165 conversion will only yield about a 3 or 4 mph gain max.

Additional discovery and selling point of going I6 as opposed to V6 I made the other day - THIS ONE IS IMPORTANT:
The intermediate housings for 4 cylinder OMC stringers only have an exhaust flapper in the PORT side, where a V6 would require a second flapper be added. Of course if a whole donor boat is used, any V6 intermediate would have both flappers. I always wondered if OMC had any foresight to be nice and simply put flappers in both sides of the 4 bangers intermediates (not to mention a safety bonus if the rubber cap/hoseclamp ever rotted starbord)....well the cheap buggers didn't....I poked down the starbord side of a 4 banger intermediate the other day - no flapper- the intermediate has to be taken apart and seperated from the bellhousing side to install a flapper starbord - bit of a pain

 

[79Glastron]

Re: Repowering my boat

Thanks for all the advice. If I was going to go the V6 route, I may as well go for a 4.3. I think they run 190hp with a two barrel.

 

[Dakota47]

Re: Repowering my boat

KjdKjd, what is so special about the 85/86 4.3 v-6 omc engines, my boat is a 1987 but the engine is a 1986, so what gives???

 

[whywhyzed]

Re: Repowering my boat

KjdKjd, what is so special about the 85/86 4.3 v-6 omc engines,

Nothing special about the engines, same as your 87, it's just that his boat has a big stringer hole in it's transom so if he's looking for a stringer donor boat, 1985 was the only year 4.3's were mated to stringers. Some were sold as 1986's

 

[Dakota47]

Re: Repowering my boat

Thanks, learn somthing new everyday...

 

[Skid-joe]

Re: Repowering my boat

Was just wondering, what is the weight difference in between the 4 banger 3.0 liter and the V6 4.3 liter.......

thanks for the info........joe

 

[whywhyzed]

Re: Repowering my boat

around 150-200 pounds with the mainfolds etc-
With my 4 banger, I stood on the back of the boat and marked a pencil line where the water line would be with an additional 195 lbs (me) added... after the swap it sat right at the line.

 

[Skid-joe]

Re: Repowering my boat

Cool....thanks

joe

 

[79Glastron]

Re: Repowering my boat

First off I wanted to say thank you all for the comments. I found some info on the weights of the engines. All info was taken from the same site, I'm not sure if they count acc or manifolds.
3.0: 350lbs
250 I6: 440lbs
4.3 V6: 425lbs
SBC: 535-550lbs

I kinda wanted to stay away from the 3.8, no insult to anyone...I think the 4.3 is more built for boat use (4.3 being a 350 with 2 cylinders cut off) and can get more hp, 2 bar 190, 4 bar 220.

I also think I'm going to go mercruiser, just because parts are going to be easy to find, and the resale value, if I ever sell will be higher, and hopefully won't break as much too. I guess my next question is how hard is it going to be to fix the large hole in the back? I know the merc hole is A LOT smaller, maybe this isn't the right forum for that question.
Thanks again

 

[whywhyzed]

Re: Repowering my boat

4 bar 220.

The 4.3 4 barrel is actually 205HP, not 220 unless you go to the vortec heads and roller cam and such- with Vortec it's up in that territory.

 

[Bondo]

Re: Repowering my boat

I also think I'm going to go mercruiser, just because parts are going to be easy to find, and the resale value,

Ayuh,............ You're starting to talk some Sense........

But,........ Now it's time for you to ask Yourself some Questions.........
This really Can't be done for the Money,.... Unless it's a rare,+ sought after Hull.....
If you Love the Hull,+ intend to Keep it forEver,,......... Then you might be a canidate.......

And,......
The Best Tip I can give you is,....... Go Buy a Donor Boat,+ Junk it for the driveline......
Then you'll have All the little bitty Expensive pieces that don't come with Kits,+ Crate deals.........................

 

[79Glastron]

Re: Repowering my boat

Ayuh,............ You're starting to talk some Sense........

But,........ Now it's time for you to ask Yourself some Questions.........
This really Can't be done for the Money,.... Unless it's a rare,+ sought after Hull.....
If you Love the Hull,+ intend to Keep it forEver,,......... Then you might be a canidate.......

And,......
The Best Tip I can give you is,....... Go Buy a Donor Boat,+ Junk it for the driveline......
Then you'll have All the little bitty Expensive pieces that don't come with Kits,+ Crate deals.........................

Thanks for the tips and words of wisdom. I don't know how rare or valuable the boat is. I've been going to Raystown lake in PA for years and years and have only seen maybe a hand full of Glastrons my vintage. We really like and enjoy the boat, I don't think selling it is in the cards. Even if I tried to sell it once I say those 3 letters I know people are going to be turned off. Like this year, some guy walked up to me and said nice boat blah blah blah....what engine & drive, I say GM 3.0 OMC, guy says, oh, ok, and then walks away. I think with a Merc it would add value to it even if it couldn't come with that engine option. But I think if they had the 4.3 in 79, they would have offered it.

Yes, I agree about the donor boat, that would be FANTASTIC to find! Even if the engine was shot, it wouldn't matter. If everything was good, I even think getting one for 2 grand would put me farther ahead then if I just started from scratch.......Thanks again for all the help!