`79 Glastron SSV-177 OMC to Mercruiser

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

I've read yourwhole thread twice to see what I'm missing here. I don't understand your using seacast. You have all the old transom out, why are you not replacing with plywood. How are you going to pour seacast with the inner skin removed.

All you need to do right now is mount the plywood and glass it in (cover the outdrive hole in the skin), and glass it all back in. The hole for the OMC drive is much larger than the Merc will be so you'll be recutting the hole anyway.

Actually I don't even see any rot in the old transom.....what made you need to replace it anyway? Guess I'm just not thinking the same way you are here??

The whole point of removing the old transom was to go from an OMC stern drive to a Mercruiser stern drive. Yes, the existing transom was in good shape, with just a bit of rot near the bottom, and around the screw holes that held the boot on the transom exterior. I was just not sure what material I was going to use, the transom was coming out either way. I have decided to use seacast because it is stronger than plywood and it won't rot, ever. I am building a form to pour the seacast into. Yes, plywood is a boat building standard, but like anything else in manufacturing, its the cheapest way to do it, seacast is better, along with a higher price tag. Stay tuned, you will see what I mean.
Thanks!
 

Cadwelder

Lieutenant Commander
Joined
Aug 30, 2010
Messages
1,780
Re: `79 Glastron SSV-177 OMC to Mercruiser

The whole point of removing the old transom was to go from an OMC stern drive to a Mercruiser stern drive. Yes, the existing transom was in good shape, with just a bit of rot near the bottom, and around the screw holes that held the boot on the transom exterior. I was just not sure what material I was going to use, the transom was coming out either way. I have decided to use seacast because it is stronger than plywood and it won't rot, ever. I am building a form to pour the seacast into. Yes, plywood is a boat building standard, but like anything else in manufacturing, its the cheapest way to do it, seacast is better, along with a higher price tag. Stay tuned, you will see what I mean.
Thanks!

Well, thanks for clearing that up (the building a form part). I've never seen that done and lookin forward to the pictures. I've never heard of the cutting of seacast. How are you going to form the opening for the new outdrive? It is going to be formed too or cut out afterwards?

I'm not a fan of seacast and strongly disagree about the stronger part; however you are right about the rotting part, but hey we're all here to help each and learn.....

I'lll follow this one closely. Good luck.

CW
 

Cadwelder

Lieutenant Commander
Joined
Aug 30, 2010
Messages
1,780
Re: `79 Glastron SSV-177 OMC to Mercruiser

No problem.....like I said going to follow along and see how this goes....uncharted waters for me.
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

Great news!!! The pour went.....well......yeah, it didn't happen :( I'm still waiting for my orders to come in. Hopefully the stuff should get it this week, pouring maybe this weekend, but it will probably have to wait til the evening because its forecasted to be 100 Friday, and still plenty warm Sat and Sun.
On another note, I got to work on my `72 Honda CL 450 this weekend and got to ride it a bit. I had the gas tank redone, it was a bit rusty, rebuilt the carbs, new fuel lines, did a tune up and oil change. Installed a new battery and it started right up. I have a lot of work to do with the chrome, hopefully it will polish out ok. I'm gonna get new tires and start riding it everyday I can. Here are a few pics.

IMG_0464.jpgIMG_0463.jpgIMG_0465.jpg
 

vi

Seaman
Joined
May 17, 2010
Messages
56
Re: `79 Glastron SSV-177 OMC to Mercruiser

Why did you give up on the Merc one drive, are there a lot of problems ? I'm planning on going over to one.
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

To answer your question, no, I don't think there is anything wrong with the one drive, I just think the Alpha is a bit better. The biggest problem I was having was the cutout hole, my `74 was different, and it was hard to make something work. I believe `75 and newer the hole is the same. The trim/tilt system is a lot better and more simple. Pour is pending this weekend......
 

vi

Seaman
Joined
May 17, 2010
Messages
56
Re: `79 Glastron SSV-177 OMC to Mercruiser

Any pictures of the setup prior to the pour. Good luck with the pour!
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

Any pictures of the setup prior to the pour. Good luck with the pour!

What would you like pictues of? No pour this weekend.....too hot, it was 106 here today, it needs to be below 90 for seacast, I'm gonna shoot for around 80, the low tonight is gonna be around 85......Next week looks better.
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

I thought I would have got to do my pour this weekend but I was having problems laying down fiberglass. I did take one pic, will post later. I ended up laying down one layer of CSM on the open area of the OMC hole, backed by a piece of laminate and plywood, extending to the old outer skin. I left that cure, did a bit of grinding, and put some peanut butter on the transistion area of the old and new skin. I then attempted to put a layer down of 1708, but I could not seem to get all the air out, even with a steel roller. I ripped off the 1708 and let the resin cure. I guess I couldn't get the air out because the surface was not smooth. So I did a bunch of grinding and sanding, and layed a layer of peanut butter down to fill in some voids, will do some more sanding to get it smooth, and try again. I'm starting to wish I was using plywood, but I would still have this problem......grrrrr....
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

As promised

IMG_0466.jpgIMG_0467.jpg

This is after the first layer of CSM was down, I grounded down a bit to remove some small air bubbles. After this I put some PB down on the transistion area, I then tried to put down 1708, couldn't get the air out, gave up. I grounded down, applied some more BP, and let that cure. I'll try to get the whole area smooth and try again with the 1708.
 

wakeandbake

Cadet
Joined
Aug 2, 2011
Messages
6
Re: `79 Glastron SSV-177 OMC to Mercruiser

Looks Good! I'm conteplating doing the same swap in a boat I may be purchasing. Looking forward to this taking shape!
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

I didn't get a lot done with the boat this weekend. The weather was wet, and hot, rain forest like. It would figure, I wanted to do fiberglass work and it decides it wants to rain, it really hasn't since May. I did get to so some engine work done, I wasn't happy with the compression numbers I got. 140, 140, 120, 110. Oil didn't seem to help 3 and 4 so I wanted to pull the head to see what was going on. It ended up 3 was cracked across the exhaust valve seat, and 4 had a burnt valve seat. However, there was very little ridge on the cylinder walls and the tops of the pistons looked good.
I then pulled the head off the `86 engine to check on it, everything looks good so far execpt for a cracked exhaust valve, no problem, I have some spares now. I'm probably going to have the head checked for cracks, and probably have it cleaned down to bare metal, valve job, and plane it. I'll check the valve springs and push rods, and throw a new set of lifters in. Throw the new manifold on, exchange bellhousing and it should be ready to put in the boat!
Stay tuned!
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

Holy cow where has the time gone??? Hopefully none of you thought I gave up on the project, it?s still going strong! I finally manage to lay down the last layer of fiberglass, a total of 3 layers, the old OMC hole is now a tad thicker than the existing outer skin. It?s a combination of fiberglass and thick BB, very solid NO AIR BUBBLES!!!!! I got tied up yesterday helping out Dad a bit and didn't get a good chance to come back on the boat. I did some final grinding and finish work today. I made my outer piece for my form out of 0.5" plywood, sanded smooth and will be coated in mold release before attaching it to the boat. I glued the sides of the mold to the boat transom skin. I wanted to pour today, but the weather was hot and it was forecasted to have severe storms in the afternoon, and they were right! I also wanted to let the glue set up so the form would be nice and strong. I'm going to try to pour some evening after work. I'm starting to see the light at the end of tunnel, its faint, but I can just see it!
Thanks!

IMG_0480.jpg
 

SouthTexan

Petty Officer 3rd Class
Joined
Jun 10, 2011
Messages
80
Re: `79 Glastron SSV-177 OMC to Mercruiser

This is a very interesting project, I will be following along closely. Good Luck and keep us posted!
 

79Glastron

Petty Officer 1st Class
Joined
Jul 18, 2007
Messages
256
Re: `79 Glastron SSV-177 OMC to Mercruiser

Good news! I busted my butt this week and got the new transom poured this week. Pour one 5 gallon bucket Tuesday evening, added another 2 gallons Wednesday evening. Sorry, no pics at this time. I removed the mold and cutout plug Thursday, the mold release worked and it came apart great. I was a bit disappointed with flatness of the outer skin, it?s a bit low in one spot. I also noticed the entire outer skin is not flat, I assume this was like it from before because I noticed my outer form board did not want to lay flat against the transom. Its not that big of a problem, I just need to do some "body work" to get the area where the transom plate is flat. I wanted to get it poured before the hurricane, and it worked out this time! Anyway, I'm planning on doing the body work, add fiberglass to the inside of transom, drill the holes and test fit the transom plate, yeah!
Thanks!
 

boatnut74

Lieutenant Commander
Joined
Aug 29, 2010
Messages
1,835
Re: `79 Glastron SSV-177 OMC to Mercruiser

Way to go! Looking forward to the pics. Hope the hurricane is gonna steer clear of you.
 
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